query: what are four functions of the cell or plasma membrane

pos: Cell membrane Cell membrane The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment consisting of a lipid bilayer with embedded proteins. The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules. In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and

pos: Cell membrane Cell membrane The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment consisting of a lipid bilayer with embedded proteins. The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules. In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion, ion conductivity and

pos: Cell membrane fluid compartments of the body. Cell membrane The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space) which protects the cell from its environment consisting of a lipid bilayer with embedded proteins. The cell membrane controls the movement of substances in and out of cells and organelles. In this way, it is selectively permeable to ions and organic molecules. In addition, cell membranes are involved in a variety of cellular processes such as

neg: Endomembrane system that perform the functions of the plasma membrane. The plasma membrane is not a fixed or rigid structure, the molecules that compose the membrane are capable of lateral movement. This movement and the multiple components of the membrane are why it is referred to as a fluid mosaic. Smaller molecules such as carbon dioxide, water, and oxygen can pass through the plasma membrane freely by diffusion or osmosis. Larger molecules needed by the cell are assisted by proteins through active transport. The plasma membrane of a cell has multiple functions. These include transporting nutrients into the cell, allowing waste to

neg: Bleb (cell biology) Bleb (cell biology) In cell biology, a bleb is a bulge or protrusion of the plasma membrane of a cell, human bioparticulate or abscess with an internal environment similar to that of a simple cell, characterized by a spherical, bulky morphology. It is characterized by the decoupling of the cytoskeleton from the plasma membrane, degrading the internal structure of the cell, allowing the flexibility required to allow the cell to separate into individual bulges or pockets of the intercellular matrix. Most commonly, blebs are seen in apoptosis (programmed cell death) but are also seen in other non-apoptotic functions. "Blebbing", or

neg: Cell membrane the surfaces of the lipids, a 2:1 ratio was estimated; thus, providing the first basis of the bilayer structure known today. This discovery initiated many new studies that arose globally within various fields of scientific studies, confirming that the structure and functions of the cell membrane are widely accepted. The structure has been variously referred to by different writers as the ectoplast (de Vries, 1885), "Plasmahaut" (plasma skin, Pfeffer, 1877, 1891), "Hautschicht" (skin layer, Pfeffer, 1886; used with a different meaning by Hofmeister, 1867), plasmatic membrane (Pfeffer, 1900), plasma membrane, cytoplasmic membrane, cell envelope and cell membrane. Some authors who

neg: Membrane potential (in this case sodium) is zero. Every animal cell is enclosed in a plasma membrane, which has the structure of a lipid bilayer with many types of large molecules embedded in it. Because it is made of lipid molecules, the plasma membrane intrinsically has a high electrical resistivity, in other words a low intrinsic permeability to ions. However, some of the molecules embedded in the membrane are capable either of actively transporting ions from one side of the membrane to the other or of providing channels through which they can move. In electrical terminology, the plasma membrane functions as a

neg: Cell cortex or hexagonal symmetry, tethered to the plasma membrane and formed primarily by spectrin, actin and ankyrin. In neuronal axons the actin/spectric cytoskeleton forms an array of periodic rings and in the sperm flagellum it forms a helical structure. In plant cells, the cell cortex is reinforced by cortical microtubules underlying the plasma membrane. The direction of these cortical microtubules determines which way the cell elongates when it grows. Cell cortex The cell cortex, also known as the actin cortex or actomyosin cortex, is a specialized layer of cytoplasmic proteins on the inner face of the cell membrane. It functions as

neg: Endomembrane system leave, preventing materials from entering the cell, averting needed materials from leaving the cell, maintaining the pH of the cytosol, and preserving the osmotic pressure of the cytosol. Transport proteins which allow some materials to pass through but not others are used for these functions. These proteins use ATP hydrolysis to pump materials against their concentration gradients. In addition to these universal functions, the plasma membrane has a more specific role in multicellular organisms. Glycoproteins on the membrane assist the cell in recognizing other cells, in order to exchange metabolites and form tissues. Other proteins on the plasma membrane allow

neg: ExoCarta ExoCarta ExoCarta is a manually curated database of exosomal proteins, RNA and lipids. Exosomes are cell-derived vesicles that are present in many and perhaps all biological fluids, including blood, urine, and cultured medium of cell cultures. The reported diameter of exosomes is between 30 and 100 nm, which is larger than LDL, but much smaller than for example, red blood cells. Exosomes are either released from the cell when multivesicular bodies fuse with the plasma membrane or they are released directly from the plasma membrane. It is becoming increasingly clear that exosomes have specialized functions and play a key role

neg: Gene product class of proteins are found in plasma membranes. Membrane proteins can be associated with the plasma membrane in different ways, depending on their structure. These proteins allow the cell to import or export cell products, nutrients or signals to and from the extracellular space. Other proteins help the cell to perform regulatory functions. For example, transcription factors bind to DNA to help transcription of RNA. Gene product A gene product is the biochemical material, either RNA or protein, resulting from expression of a gene. A measurement of the amount of gene product is sometimes used to infer how active a

neg: NG2 proteoglycan NG2 proteoglycan Neural/glial antigen 2, or NG2, is a rat integral membrane proteoglycan found in the plasma membrane of many diverse cell types. Homologous proteins in other species include human CSPG4, also known as melanoma-associated chondroitin sulfate proteoglycan (MCSP), Mouse AN2, and Sea urchin ECM3. This single-pass transmembrane molecule may be plasma membrane-bound or secreted and associated with the extracellular matrix. It is believed to play a role in functions such as cell adhesion, cell-cell and cell-ECM communication, migration and metastasis, proliferation, and axonal growth, guidance and regeneration. NG2-positive cells include oligodendrocyte progenitor cells (OPCs) and other progenitor cell populations,

neg: Plasma membrane Ca2+ ATPase Plasma membrane Ca2+ ATPase The plasma membrane Ca ATPase (PMCA) is a transport protein in the plasma membrane of cells and functions to remove calcium (Ca) from the cell. PMCA function is vital for regulating the amount of Ca within all eukaryotic cells. There is a very large transmembrane electrochemical gradient of Ca driving the entry of the ion into cells, yet it is very important that they maintain low concentrations of Ca for proper cell signalling. Thus, it is necessary for cells to employ ion pumps to remove the Ca. The PMCA and the sodium calcium exchanger (NCX) are

neg: Bacterial cell structure antigenic function. The lipid element is to be found in the membrane where its adhesive properties assist in its anchoring to the membrane. Gram-negative cell walls are thin and unlike the gram-positive cell walls, they contain a thin peptidoglycan layer adjacent to the cytoplasmic membrane. Gram-negative bacteria are stained as pink colour. The chemical structure of the outer membrane's lipopolysaccharide is often unique to specific bacterial sub-species and is responsible for many of the antigenic properties of these strains. The plasma membrane or bacterial cytoplasmic membrane is composed of a phospholipid bilayer and thus has all of the general functions

neg: Plasma membrane Ca2+ ATPase to involve the lymph nodes, and are more common among young women, which could help explain their worse prognosis compared with postmenopausal women. PMCAs were first discovered in the 1960s in the membranes of red blood cells. The presence of an ATPase was discovered in the membranes in 1961, and then in 1966 it was discovered that these ATPases pump Ca out of the cytosol. PMCA was first purified from red blood cell membranes in 1979. Plasma membrane Ca2+ ATPase The plasma membrane Ca ATPase (PMCA) is a transport protein in the plasma membrane of cells and functions to remove

neg: MUL1 functions. An apoptotic cell undergoes structural changes including cell shrinkage, plasma membrane blebbing, nuclear condensation, and fragmentation of the DNA and nucleus. This is followed by fragmentation into apoptotic bodies that are quickly removed by phagocytes, thereby preventing an inflammatory response. It is a mode of cell death defined by characteristic morphological, biochemical and molecular changes. It was first described as a "shrinkage necrosis", and then this term was replaced by apoptosis to emphasize its role opposite mitosis in tissue kinetics. In later stages of apoptosis the entire cell becomes fragmented, forming a number of plasma membrane-bounded apoptotic bodies which

neg: HSPA8 chaperone functions under normal conditions, unlike canonical heat shock proteins, Hsc70 is constitutively expressed and performs functions related to normal cellular processes, such as protein ubiquitylation and degradation. The Hsp70 member proteins are important apoptotic constituents. During a normal embryologic processes, or during cell injury (such as ischemia-reperfusion injury during heart attacks and strokes) or during developments and processes in cancer, an apoptotic cell undergoes structural changes including cell shrinkage, plasma membrane blebbing, nuclear condensation, and fragmentation of the DNA and nucleus. This is followed by fragmentation into apoptotic bodies that are quickly removed by phagocytes, thereby preventing an inflammatory

neg: Cell (biology) cell's primary machinery. There are also other kinds of biomolecules in cells. This article lists these primary cellular components, then briefly describes their function. The cell membrane, or plasma membrane, is a biological membrane that surrounds the cytoplasm of a cell. In animals, the plasma membrane is the outer boundary of the cell, while in plants and prokaryotes it is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of phospholipids, which are amphiphilic (partly hydrophobic and partly hydrophilic). Hence, the layer

neg: RAB11FIP5 to the plasma membrane. This is in contrast to the fast constitutive recycling route which allows for the direct transport of cargo from the endosome to the plasma membrane. Rab11FIP5 aids in this sorting process by binding to kinesin II and forming a protein complex to regulate vesicular trafficking. Some of the proteins that are regulated through Rab11FIP5 mediated vesicle trafficking are microtubule proteins and the TfR receptor. This links Rab11FIP5 functionality to the cell cytoskeleton and the iron uptake of a cell, respectively. Rab11FIP5 has been shown to play a role in the nervous system because it functions in

neg: Membrane potential also known as ion transporter or ion pump proteins, actively push ions across the membrane and establish concentration gradients across the membrane, and ion channels allow ions to move across the membrane down those concentration gradients. Ion pumps and ion channels are electrically equivalent to a set of batteries and resistors inserted in the membrane, and therefore create a voltage between the two sides of the membrane. Almost all plasma membranes have an electrical potential across them, with the inside usually negative with respect to the outside. The membrane potential has two basic functions. First, it allows a cell to

neg: Cell-penetrating peptide the guanidinium groups, contribute to the uptake. The proposed mechanism also illustrates the importance of membrane fluctuations. Indeed, mechanisms that involve large fluctuations of the membrane structure, such as transient pores and the insertion of charged amino acid side-chains, may be common and perhaps central to the functions of many membrane protein functions. Endocytosis is the second mechanism liable for cellular internalization. Endocytosis is the process of cellular ingestion by which the plasma membrane folds inward to bring substances into the cell. During this process cells absorb material from the outside of the cell by imbibing it with their cell

neg: Ecto-nox disulfide-thiol exchanger 1 to 26 minutes (Scarlett et al., 2005 [PubMed 15882838]). Ecto-nox disulfide-thiol exchanger 1 Ecto-NOX disulfide-thiol exchanger 1 is a protein that in humans is encoded by the ENOX1 gene. Electron transport pathways are generally associated with mitochondrial membranes, but non-mitochondrial pathways are also biologically significant. Plasma membrane electron transport pathways are involved in functions as diverse as cellular defense, intracellular redox homeostasis, and control of cell growth and survival. Members of the ecto-NOX family, such as CNOX, or ENOX1, are involved in plasma membrane transport pathways. These enzymes exhibit both a hydroquinone (NADH) oxidase activity and a protein disulfide-thiol interchange

neg: Ecto-nox disulfide-thiol exchanger 1 Ecto-nox disulfide-thiol exchanger 1 Ecto-NOX disulfide-thiol exchanger 1 is a protein that in humans is encoded by the ENOX1 gene. Electron transport pathways are generally associated with mitochondrial membranes, but non-mitochondrial pathways are also biologically significant. Plasma membrane electron transport pathways are involved in functions as diverse as cellular defense, intracellular redox homeostasis, and control of cell growth and survival. Members of the ecto-NOX family, such as CNOX, or ENOX1, are involved in plasma membrane transport pathways. These enzymes exhibit both a hydroquinone (NADH) oxidase activity and a protein disulfide-thiol interchange activity in series, with each activity cycling every 22

neg: Endomembrane system A vesicle is a relatively small, membrane-enclosed sac that stores or transports substances. The cell membrane is a protective barrier that regulates what enters and leaves the cell. There is also an organelle known as the Spitzenkörper that is only found in fungi, and is connected with hyphal tip growth. In prokaryotes endomembranes are rare, although in many photosynthetic bacteria the plasma membrane is highly folded and most of the cell cytoplasm is filled with layers of light-gathering membrane. These light-gathering membranes may even form enclosed structures called chlorosomes in green sulfur bacteria. The organelles of the endomembrane system are

neg: Unilamellar liposome cells. For general or overall delivery, SUVs may be used. For topical applications on skin, specialized lipids like phospholipids and sphingolipids may be used to make drug-free liposomes as moisturizers, and with drugs such as for anti-ultraviolet radiation applications. In biomedical research, unilamellar liposomes are extremely useful to study biological systems and mimicking cell functions. As a living cell is very complicated to study, unilamellar liposomes provide a simple tool to study membrane interaction events such as membrane fusion, protein localization in the plasma membrane, study ion channels, etc. Unilamellar liposome An unilamellar liposome is a spherical chamber/vesicle, bounded by

neg: BinCARD NF-kappaB. This protein is reported to interact with other CARD domain containing proteins including CARD9, 10, 11 and 14, which are thought to function as upstream regulators in NF-kappaB signaling. Accordingly, BinCARD protein has a pivotal role in regulating apoptotic functions. Because of its important biological and physiological functions, apoptosis is pivotal in many clinical constituents.During a normal embryologic processes, or during cell injury (such as ischemia-reperfusion injury during heart attacks and strokes) or during developments and processes in cancer, an apoptotic cell undergoes structural changes including cell shrinkage, plasma membrane blebbing, nuclear condensation, and fragmentation of the DNA and

neg: CASY cell counting technology This technology can be applied for cell counting, cell culture analysis at a certain time interval, or even a period of time. Cell viability can be assessed based on the integrity of plasma membrane: the living cells have intact plasma membranes whereas membranes of dead cells are broken. When a cell is exposed to a low voltage field, the electric current cannot go through the intact membrane, which is an electric insulator, if it is viable. Otherwise, as the cellular membrane is broken, electric field can go through the injured cell as there are pores on their membrane. For a

neg: Exosome (vesicle) specialized functions and play a key role in processes such as coagulation, intercellular signaling, and waste management. Consequently, there is a growing interest in the clinical applications of exosomes. Exosomes can potentially be used for prognosis, for therapy, and as biomarkers for health and disease . First discovered in the maturing mammalian reticulocyte (immature red blood cell) , exosomes were shown to participate in selective removal of many plasma membrane proteins as the reticulocyte becomes a mature red blood cell (erythrocyte). In the reticulocyte, as in most mammalian cells, portions of the plasma membrane are regularly internalized as endosomes, with

neg: LAMP1 glycoproteins primarily reside across lysosomal membranes, in certain cases they can be expressed across the plasma membrane of the cell. Expression of LAMP1 at the cell surface can occur due to lysosomal fusion with the cell membrane. Cell surface expression of LAMP1 can serve as a ligand for selectins and help mediate cell-cell adhesion. Accordingly, cell surface expression of LAMP1 is seen in cells with migratory or invasive functions, such as cytotoxic T cells, platelets and macrophages. Cell surface expression of LAMP1 and LAMP2 is also often seen in cancer cells, particularly cancers with high metastatic potential, such as colon

neg: Cholesterol sodium ions. Within the cell membrane, cholesterol also functions in intracellular transport, cell signaling and nerve conduction. Cholesterol is essential for the structure and function of invaginated caveolae and clathrin-coated pits, including caveola-dependent and clathrin-dependent endocytosis. The role of cholesterol in endocytosis of these types can be investigated by using methyl beta cyclodextrin (MβCD) to remove cholesterol from the plasma membrane. Recent studies show that cholesterol is also implicated in cell signaling processes, assisting in the formation of lipid rafts in the plasma membrane, which brings receptor proteins in close proximity with high concentrations of second messenger molecules. In multiple

neg: Wiskott–Aldrich syndrome protein and PIP2 localize the N-WASp-Arp2/3 complex to the plasma membrane. This localization ensures the actin polymers will be able to push through the plasma membrane and form filopodium required for cell motility. WASp is required for various functions in myeloid and lymphoid immune cells. Many of these, such as phagocytosis and podosome formation, related to its role in regulating the polymerization of actin filaments. Other functions of WASP depend on its activity as a scaffold protein for assembly of effective signalling complexes downstream of antigen receptor or integrin engagement. Particularly in NK cells it participates in the synapse formation and

neg: Epithelium determines which substances will be able to enter the epithelium. Cell junctions are especially abundant in epithelial tissues. They consist of protein complexes and provide contact between neighbouring cells, between a cell and the extracellular matrix, or they build up the paracellular barrier of epithelia and control the paracellular transport. Cell junctions are the contact points between plasma membrane and tissue cells. There are mainly 5 different types of cell junctions: tight junctions, adherens junctions, desmosomes, hemidesmosomes, and gap junctions. Tight junctions are a pair of trans-membrane protein fused on outer plasma membrane. Adherens junctions are a plaque (protein layer

neg: Cell membrane vesicle to the ambient solution, allows researcher to better understand membrane permeability. Vesicles can be formed with molecules and ions inside the vesicle by forming the vesicle with the desired molecule or ion present in the solution. Proteins can also be embedded into the membrane through solubilizing the desired proteins in the presence of detergents and attaching them to the phospholipids in which the liposome is formed. These provide researchers with a tool to examine various membrane protein functions. Plasma membranes also contain carbohydrates, predominantly glycoproteins, but with some glycolipids (cerebrosides and gangliosides). Carbohydrates are important in the role of

neg: Dermatopontin around myocardial infarct zone) and decreased expression in leiomyoma and fibrosis. In invertebrate, dermatopontin homologue plays a role in hemagglutination, cell-cell aggregation, and expression during parasite infection. Dermatopontin is expressed in the extracellular matrix (ECM), which is a gel-like fluid space outside of a cell that consists of collagen fibers, elastin fibers, glycoproteins, and proteoglycans (1). The components of the ECM are connected to proteins embedded in the plasma membrane of cells. These membrane proteins perform many functions, including transporting materials, serving as enzymes for chemical reactions, transmitting cell signals, and intercellular junction (1). Dermatopontins are expressed primarily in fibroblasts,

neg: Endomembrane system vesicle travels to contains a marker on its cytosolic surface. This marker corresponds with the proteins on the vesicle traveling to the membrane. Once the vesicle finds the membrane, they fuse. There are three well known types of vesicles. They are clathrin-coated, COPI-coated, and COPII-coated vesicles. Each performs different functions in the cell. For example, clathrin-coated vesicles transport substances between the Golgi apparatus and the plasma membrane. COPI- and COPII-coated vesicles are frequently used for transportation between the ER and the Golgi apparatus. Lysosomes are organelles that contain hydrolytic enzymes that are used for intracellular digestion. The main functions of

neg: Vesicle (biology and chemistry) cell membrane. The vesicle "coat" is a collection of proteins that serve to shape the curvature of a donor membrane, forming the rounded vesicle shape. Coat proteins can also function to bind to various transmembrane receptor proteins, called cargo receptors. These receptors help select what material is endocytosed in receptor-mediated endocytosis or intracellular transport. There are three types of vesicle coats: clathrin, COPI and COPII. The various types of coat proteins help with sorting of vesicles to their final destination. Clathrin coats are found on vesicles trafficking between the Golgi and plasma membrane, the Golgi and endosomes and the plasma

neg: Endocytic cycle forward as it moves. • Evidence indicates that those molecules in the cell’s surface that act as the feet of the cell — the integrins, which attach the cell to the substratum — can also be endocytosed and transported through the cell. In this way, fresh adhesion sites (see cell adhesion) are provided at the cell’s front. • The flow of membrane from the front rearward is not a flow of average plasma membrane proteins: The membrane internalised is a subset of plasma membrane proteins, such as LDL or transferrin receptors and the lipid bilayer in which they sit. These

neg: Secretion Secretion Secretion is the movement of material from one point to another, e.g. secreted chemical substance from a cell or gland. In contrast, excretion, is the removal of certain substances or waste products from a cell or organism. The classical mechanism of cell secretion is via secretory portals at the cell plasma membrane called porosomes. Porosomes are permanent cup-shaped lipoprotein structure at the cell plasma membrane, where secretory vesicles transiently dock and fuse to release intra-vesicular contents from the cell. Secretion in bacterial species means the transport or translocation of effector molecules for example: proteins, enzymes or toxins (such as

neg: Cell surface receptor Cell surface receptor Cell surface receptors (membrane receptors, transmembrane receptors) are receptors that are embedded in the plasma membrane of cells. They act in cell signaling by receiving (binding to) extracellular molecules. They are specialized integral membrane proteins that allow communication between the cell and the extracellular space. The extracellular molecules may be hormones, neurotransmitters, cytokines, growth factors, cell adhesion molecules, or nutrients; they react with the receptor to induce changes in the metabolism and activity of a cell. In the process of signal transduction, ligand binding affects a cascading chemical change through the cell membrane. Many membrane receptors are

neg: Cell migration for how the cell advances its front edge: the cytoskeletal model and membrane flow model. It is possible that both underlying processes contribute to cell extension. Experimentation has shown that there is rapid actin polymerisation at the cell's front edge. This observation has led to the hypothesis that formation of actin filaments "push" the leading edge forward and is the main motile force for advancing the cell’s front edge. In addition, cytoskeletal elements are able to interact extensively and intimately with a cell's plasma membrane. Other cytoskeletal components (like microtubules) have important functions in cell migration. It has been found

neg: Sarcoglycanopathy Sarcoglycanopathy The sarcoglycanopathies are a collection of diseases resulting from mutations in any of the five sarcoglycan genes: α, β, γ, δ or ε. The five sarcoglycanopathies are: α-sarcoglycanopathy, LGMD2D; β-sarcoglycanopathy, LGMD2E; γ-sarcoglycanopathy, LGMD2C; δ-sarcoglycanopathy, LGMD2F and ε-sarcoglycanopathy, myoclonic dystonia. The four different sarcoglycan genes encode proteins that form a tetrameric complex at the muscle cell plasma membrane. This complex stabilizes the association of dystrophin with the dystroglycans and contributes to the stability of the plasma membrane cytoskeleton. The four sarcoglycan genes are related to each other structurally and functionally, but each has a distinct chromosome location. In outbred populations,

neg: Fences and pickets model of plasma membrane structure Therefore, transmembrane proteins are corralled by both fences and pickets. In both models, membrane proteins and lipids can hop from a compartment to an adjacent one, probably when thermal fluctuations of the membrane and the membrane skeleton create a space between them large enough to allow the passage of integral membrane proteins, when an actin filament temporarily breaks, and/or when membrane molecules have sufficient kinetic energy to cross the barrier when they are in the boundary region. Fences and pickets model of plasma membrane structure The Fences and pickets model of plasma membrane is a concept of cell membrane structure

neg: Fences and pickets model of plasma membrane structure Fences and pickets model of plasma membrane structure The Fences and pickets model of plasma membrane is a concept of cell membrane structure suggesting that the fluid plasma membrane is compartmentalized by actin-based membrane-skeleton “fences” and anchored transmembrane protein “pickets”. This model differs from older cell membrane structure concepts such as the Singer-Nicolson fluid mosaic model and the Saffman-Delbrück two-dimensional continuum fluid model that view the membrane as more or less homogeneous. The fences and pickets model was proposed to explain observations of molecular traffic made due to recent advances in single molecule tracking techniques. The actin-based membrane skeleton (MSK)

neg: Cytosis molecules that cannot pass through the cell membrane. The two major types of endocytosis are pinocytosis and phagocytosis. Exocytosis is when a cell directs the contents of secretory vesicles out of the cell membrane. The vesicles fuse with the cell membrane and their content, usually protein, is released out of the cell. There are two types of exocytosis: Constitutive secretion and Regulated secretion. In both of these types, a vesicle buds from the Golgi Apparatus and are shuttled to the plasma membrane to be exocytosed from the cell. Exocytosis of lysosomes commonly serves to repair damaged areas of the plasma

neg: LAMP2 are disputed. They are believed to be significantly involved in operations of the lysosomes, including maintaining integrity, pH and catabolism. Further, some of the functions of LAMP2 are believed to be protecting the lysosomal membrane from proteolytic enzymes that are within the lysosome itself (as in autodigestion), acting as a receptor into the lysosome for proteins, adhesion (when expressed on the outside surface of the plasma membrane) and signal transduction, both inter- and intra-. It also provides protection for the cell from methylating mutagens. LAMP2 has been specifically implicated in tumor cell metastasis. Both LAMP1 and LAMP2 have been found

neg: Ciliogenesis Ciliogenesis occurs through an ordered set of steps. First, the basal bodies from centrioles must migrate to the surface of the cell and attach to the cortex. Along the way, the basal bodies attach to membrane vesicles and the basal body/membrane vesicle complex fuses with the plasma membrane of the cell. Fusion with the plasma membrane is likely what forms the membrane of the cilia. The alignment of the forming cilia is determined by the original positioning and orientation of the basal bodies. Once the alignment is determined, axonemal microtubules extend from the basal body and go beneath the developing

neg: Dendrite voltage and the activation duration. Action potentials in animal cells are generated by either sodium-gated or calcium-gated ion channels in the plasma membrane. These channels are closed when the membrane potential is near to, or at, the resting potential of the cell. The channels will start to open if the membrane potential increases, allowing sodium or calcium ions to flow into the cell. As more ions enter the cell, the membrane potential continues to rise. The process continues until all of the ion channels are open, causing a rapid increase in the membrane potential that then triggers the decrease in

neg: Transfer cell Transfer cell Transfer cells are specialized parenchyma cells that have an increased surface area, due to infoldings of the plasma membrane. They facilitate the transport of sugars from a sugar source, mainly mature leaves, to a sugar sink, often developing leaves or fruits. They are found in nectaries of flowers and some carnivorous plants. Transfer cells are specially found in plants in the region of absorption or secretion of nutrients. The term transfer cell was coined by B. E. S. Gunning and J. S. Pate.Their presence is generally correlated with the existence of extensive solute infuxes across the plasma membrane.

neg: Transfer cell Transfer cell Transfer cells are specialized parenchyma cells that have an increased surface area, due to infoldings of the plasma membrane. They facilitate the transport of sugars from a sugar source, mainly mature leaves, to a sugar sink, often developing leaves or fruits. They are found in nectaries of flowers and some carnivorous plants. Transfer cells are specially found in plants in the region of absorption or secretion of nutrients. The term transfer cell was coined by B. E. S. Gunning and J. S. Pate.Their presence is generally correlated with the existence of extensive solute infuxes across the plasma membrane.

neg: Negative-sense single-stranded RNA virus virus, Marburg virus are included within the NSV. The life cycle of NSV has a number of steps. The virus first infects the host cell by binding to the host cell receptor through a viral surface glycoprotein. The fusion of the glycoprotein viral membrane with the plasma membrane of the host cell in an acidic environment allows for the release of viral ribonucleoprotein (RNP) complexes into the cytoplasm. Most NSV replicate in the cytoplasm of infected cells. Newly synthesized RNP complexes are assembled with viral structural proteins at the plasma membrane or at membranes of the Golgi apparatus. This is

neg: Protein complex homomultimeric complexes in a cell, majority of proteins in the Protein Data Bank are homomultimeric. Homooligomers are responsible for the diversity and specificity of many pathways, may mediate and regulate gene expression, activity of enzymes, ion channels, receptors, and cell adhesion processes. The voltage-gated potassium channels in the plasma membrane of a neuron are heteromultimeric proteins composed of four of forty known alpha subunits. Subunits must be of the same subfamily to form the multimeric protein channel. The tertiary structure of the channel allows ions to flow through the hydrophobic plasma membrane. Connexons are an example of a homomultimeric protein

neg: Vesicle (biology and chemistry) vesicles can fuse with the plasma membrane to release their contents outside the cell. Vesicles can also fuse with other organelles within the cell. Vesicles perform a variety of functions. Because it is separated from the cytosol, the inside of the vesicle can be made to be different from the cytosolic environment. For this reason, vesicles are a basic tool used by the cell for organizing cellular substances. Vesicles are involved in metabolism, transport, buoyancy control, and temporary storage of food and enzymes. They can also act as chemical reaction chambers. The 2013 Nobel Prize in Physiology or Medicine was

neg: PTPRK proliferation. Because the presence of PTPkappa at the cell membrane was shown to sequester β-catenin to the plasma membrane, these data suggest that one mechanism whereby PTPkappa functions as a tumor suppressor is by regulating the intracellular localization of free-β-catenin. The intracellular fragments of PTPkappa, PΔE and PIC, are catalytically active, and can also dephosphorylate β-catenin. Tyrosine phosphorylated β-catenin translocates to the cell nucleus and activates TCF-mediated transcription to promote cell proliferation and migration. While full-length PTPkappa antagonizes TCF-mediated transcription, the PIC fragment augments it, perhaps by regulating other proteins in TCF-mediated transcription. This suggests that phosphatase activity of the

neg: Depolarization cell's plasma membrane. The transport of the ions across the plasma membrane is accomplished through several different types of transmembrane proteins embedded in the cell's plasma membrane that function as pathways for ions both into and out of the cell, such as ion channels, sodium potassium pumps, and voltage-gated ion channels. The resting potential must be established within a cell before the cell can be depolarized. There are many mechanisms by which a cell can establish a resting potential, however there is a typical pattern of generating this resting potential that many cells follow. The cell uses ion channels, ion

neg: Proton ATPase gastric mucosa and functions to acidify the stomach. This enzyme is a P2C ATPase, characterized by having an supporting beta-subunit, and is closely related to the Na/K ATPase. V-type proton ATPase (or V-ATPase) translocate protons into intracellular organelles other than mitochondria and chloroplasts, but in certain cell types they are also found in the plasma membrane. V-type ATPases acidify the lumen of the vacuole (hence the symbol 'V') of fungi and plants, and that of the lysosome in animal cells. Furthermore, they are found in endosomes, clathrin coated vesicles, hormone storage granules, secretory granules, Golgi vesicles and in the plasma

neg: Plasma membrane H+-ATPase demonstrated to take part in the regulation of protein activity. Plasma membrane -ATPases are found throughout the plant in all cell types investigated, but some cell types have much higher concentrations of -ATPase than others. In general, these cell types are specialised for intensive active transport and accumulate solutes from their surroundings. Most studies of these roles come from genetic studies on "Arabidopsis thaliana". -ATPases in plants are expressed from a multigene subfamily, and "Arabidopsis thaliana" for instance, have 12 different -ATPase genes. Some important physiological processes the plant -ATPase is involved in are: Plasma membrane H+-ATPase This enzyme belongs

neg: Unconventional protein secretion pathway. Two types of unconventional protein secretion are these: signal-peptid-containing proteins and cytoplasmatic and nuclear proteins that are missing an ER-signal peptide (1). These proteins contain a specific signal-peptide sequence, which is to be translated into the endoplasmic reticulum, but are, however, able to reach the cell surface unconventionally. They can be packed into a COPII-coated vesicle and directly fuse with plasma membrane or can fuse with endosomal or lysosomal compartment. Alternatively, they can be packed into non-COPII-coated vesicle as well and fuse with Golgi (before reaching plasma membrane) or directly delivered to the plasma membrane. Soluble proteins can reach

neg: SNARE (protein) by their C-terminal domains, whereas SNAP-25 is tethered to the plasma membrane via several cysteine-linked palmitoyl chains. The core "trans"-SNARE complex is a four-formula_1-helix bundle, where one formula_1-helix is contributed by syntaxin 1, one formula_1-helix by synaptobrevin and two formula_1-helices are contributed by SNAP-25. The plasma membrane-resident SNAREs have been shown to be present in distinct microdomains or clusters, the integrity of which is essential for the exocytotic competence of the cell. During membrane fusion, v-SNARE and t-SNARE proteins on separate membranes combine to form a "trans"-SNARE complex, also known as a "SNAREpin". Depending on the stage of fusion of

neg: TRPV2 harmful, carcinogenic cell survival. TRPV2 is expressed in the spleen, lymphocytes, and myeloid cells including granulocytes, macrophages and mast cells. Among these cell types, TRPV2 mediates cytokine release, phagocytosis, endocytosis, podosome assembly, and inflammation. The influx of calcium seems to play an important role in these functions. Mast cells are leukocytes (white blood cells) rich in histamine which are able to respond to a variety of stimuli, often initiating inflammatory and/or allergic responses. The responses generated by mast cells rely on the calcium influx in the plasma membrane with the help of channels. Surface localization of the TRPV2 protein along

neg: Dermatopontin The components of the ECM are connected to proteins embedded in the plasma membrane, which in turn are connected to the internal cytoskeleton of the cell. These connections also facilitate cell-to-cell communication (1). Dermatopontin mediates adhesion by cell surface integrin binding and accelerates collagen fibril formation that determines the size and arrangement of collagen fibrils within the extracellular matrix (2). Other functions of dermatopontin include stabilizing collagen fibrils against low temperature dissociation, inhibiting cell proliferation, enhancing TGFB1 activity, and possibly serving as a communication link between the dermal fibroblast cell surface and its extracellular environment (3). Dermatopontin itself is a

neg: TRPV2 that it is expressed in arterial muscle cells, which can then be influenced by blood pressure; though it was evident that TRPV2 expression was localized in the intracellular area, some growth factors localized it to the plasma cell membrane. In circulatory organs, studies and data suggest that TRPV2 may be a mechanosensor, meaning that it can sense changes in external stimuli; the mechanisms involved in opening TRPV2 by membrane stretching or hypoosmotic cell swelling have not yet been determined. In mus musculus (house mouse), TRPV2 functions as a protein coding gene. There is broad expression of TRPV2 in the thymus,

neg: Endosome delivered by mannose-6-phosphate receptors. These soluble molecules remain in endosomes and are therefore delivered to lysosomes. Also, the transmembrane EGFRs, bound to EGF, are tagged with ubiquitin and are therefore sorted into lumenal vesicles by the ESCRTs. Endosome In cell biology, an endosome is a membrane-bound compartment inside eukaryotic cells. It is a compartment of the endocytic membrane transport pathway originating from the "trans" Golgi membrane. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation, or they can be recycled back to the plasma membrane. Molecules are also transported to

neg: Ganglioside of the cell plasma membrane that modulates cell signal transduction events, and appears to concentrate in lipid rafts. Recently, gangliosides have been found to be highly important molecules in immunology. Natural and semisynthetic gangliosides are considered possible therapeutics for neurodegenerative disorders. Gangliosides are present and concentrated on cell surfaces, with the two hydrocarbon chains of the ceramide moiety embedded in the plasma membrane and the oligosaccharides located on the extracellular surface, where they present points of recognition for extracellular molecules or surfaces of neighboring cells. They are found predominantly in the nervous system where they constitute 6% of all phospholipids.

neg: Vesicle (biology and chemistry) Vesicle (biology and chemistry) In cell biology, a vesicle is a large structure within a cell, or extracellular, consisting of liquid enclosed by a lipid bilayer. Vesicles form naturally during the processes of secretion (exocytosis), uptake (endocytosis) and transport of materials within the plasma membrane. Alternatively, they may be prepared artificially, in which case they are called liposomes (not to be confused with lysosomes). If there is only one phospholipid bilayer, they are called "unilamellar liposome" vesicles; otherwise they are called "multilamellar". The membrane enclosing the vesicle is also a lamellar phase, similar to that of the plasma membrane and

neg: Endosome Endosome In cell biology, an endosome is a membrane-bound compartment inside eukaryotic cells. It is a compartment of the endocytic membrane transport pathway originating from the "trans" Golgi membrane. Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation, or they can be recycled back to the plasma membrane. Molecules are also transported to endosomes from the "trans"-Golgi network and either continue to lysosomes or recycle back to the Golgi. Endosomes can be classified as early, sorting, or late depending on their stage post internalization. Endosomes represent a major sorting compartment

neg: G protein-gated ion channel (Na), and chloride (Cl) across the plasma membrane. Four G protein gated inwardly-rectifying potassium (GIRK) channel subunits have been identified in mammals: GIRK1, GIRK2, GIRK3, and GIRK4. The GIRK subunits come together to form GIRK ion channels. These ion channels, once activated, allow for the flow of potassium ions (K) from the extracellular space surrounding the cell across the plasma membrane and into the cytoplasm. Each channel consists of domains which span the plasma membrane, forming the K-selective pore region through which the K ions will flow. Both the N-and C-terminal ends of the GIRK channels are located within the

neg: Bleb (cell biology) was shown to inhibit the formation of blebs. This agent was discovered in a screen for small molecule inhibitors of nonmuscle myosin IIA and was shown to lower the affinity of myosin with actin, thus altering the contractile forces that impinge on the cytoskeleton-membrane interface. Bleb (cell biology) In cell biology, a bleb is a bulge or protrusion of the plasma membrane of a cell, human bioparticulate or abscess with an internal environment similar to that of a simple cell, characterized by a spherical, bulky morphology. It is characterized by the decoupling of the cytoskeleton from the plasma membrane, degrading

neg: Exosome (vesicle) Exosome (vesicle) Exosomes are cell-derived vesicles that are present in many and perhaps all eukaryotic fluids, including blood, urine, and cultured medium of cell cultures. A sub-type of exosomes, defined as matrix-bound nanovesicles (MBVs), was reported to be present in extracellular matrix (ECM) bioscaffolds (non-fluid). The reported diameter of exosomes is between 30 and 100 nm, which is larger than low-density lipoproteins (LDL) but much smaller than, for example, red blood cells. Exosomes are either released from the cell when multivesicular bodies fuse with the plasma membrane or released directly from the plasma membrane. Evidence is accumulating that exosomes have

neg: Symbiogenesis loses its flagella and cytoskeleton, while "Hatena", now a host, switches to photosynthetic nutrition, gains the ability to move towards light and loses its feeding apparatus. The process of secondary endosymbiosis left its evolutionary signature within the unique topography of plastid membranes. Secondary plastids are surrounded by three (in euglenophytes and some dinoflagellates) or four membranes (in haptophytes, heterokonts, cryptophytes, and chlorarachniophytes). The two additional membranes are thought to correspond to the plasma membrane of the engulfed alga and the phagosomal membrane of the host cell. The endosymbiotic acquisition of a eukaryote cell is represented in the cryptophytes; where the

neg: Secretion nonclassical pathways. At least four nonclassical (unconventional) protein secretion pathways have been described. They include 1) direct translocation of proteins across the plasma membrane likely through membrane transporters, 2) blebbing, 3) lysosomal secretion, and 4) release via exosomes derived from multivesicular bodies. In addition, proteins can be released from cells by mechanical or physiological wounding and through nonlethal, transient oncotic pores in the plasma membrane induced by washing cells with serum-free media or buffers. Many human cell types have the ability to be secretory cells. They have a well-developed endoplasmic reticulum and Golgi apparatus to fulfill their function. Tissues in

neg: Cell membrane a variety of mechanisms: The cell membrane consists of three classes of amphipathic lipids: phospholipids, glycolipids, and sterols. The amount of each depends upon the type of cell, but in the majority of cases phospholipids are the most abundant, often contributing for over 50% of all lipids in plasma membranes. Glycolipids only account for a minute amount of about 2% and sterols make up the rest. In RBC studies, 30% of the plasma membrane is lipid. However, for the majority of eukaryotic cells, the composition of plasma membranes is about half lipids and half proteins by weight. The fatty chains

neg: Cell cycle analysis precursor whose detection offers certain advantages over BrdU, has now become the preferred methodology do detect DNA replicating (S-phase) cells. Unless staining is performed using Hoechst 33342, the first step in preparing cells for cell cycle analysis is permeabilisation of the cells' plasma membranes. This is usually done by incubating them in a buffer solution containing a mild detergent such as Triton X-100 or NP-40, or by fixating them in ethanol. Most fluorescent DNA dyes (one of exceptions is Hoechst 33342) are not plasma membrane permeant, that is, unable to pass through an intact cell membrane. Permeabilisation is therefore crucial

neg: Cilium play an important role in the function of many human organs. The current scientific understanding of primary cilia views them as "sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation.". The primary non-motile cilia has a “9+0” axonemal structure and is divided into subdomains. The entire structure is enclosed by a plasma membrane continuous with the plasma membrane of the cell. The basal body, where the cilia originates, is located within the ciliary pocket. The cilium membrane and the basal body microtubules are

neg: Cell surface receptor combinatorially mapping ligands, which is referred to as receptor-based drug design. In this case, ligand molecules are engineered within the constraints of a binding pocket by assembling small pieces in a stepwise manner. These pieces can be either atoms or molecules. The key advantage of such a method is that novel structures can be discovered. Cell surface receptor Cell surface receptors (membrane receptors, transmembrane receptors) are receptors that are embedded in the plasma membrane of cells. They act in cell signaling by receiving (binding to) extracellular molecules. They are specialized integral membrane proteins that allow communication between the cell and

neg: Basal body feet, which are anchored to cytoplasmic microtubules and are necessary for polarized alignment of the cilium. Second, basal bodies have pinwheel-shaped transition fibers that originate from the appendages of mother centriole. In multiciliated cells, however, in many cases basal bodies are not made from centrioles but are generated "de novo" from a special protein structure called the deuterosome. During cell cycle quiescence, basal bodies organize primary cilia and reside at the cell cortex in proximity to plasma membrane. On cell cycle entry, cilia resorb and the basal body migrates to the nucleus where it functions to organize centrosomes. Centrioles, basal

neg: Sodium-chloride symporter have two control mechanisms affecting protein trafficking to the plasma membrane and transporter kinetics by phosphorylation and de-phosphorylation of conserved serine/threonine residues. As NCC has to be at the plasma membrane to function, its activity can be regulated by increasing or decreasing the amount of protein at the plasma membrane. Some NCC modulators, such as the WNK3 and WNK4 kinases may regulate the amount of NCC at the cell surface by inducing the insertion or removal, respectively, of the protein from the plasma membrane. Furthermore, many residues of NCC can be phosphorylated or dephosphorylated to activate or inhibit NCC uptake

neg: FASTKD1 cell shrinkage, plasma membrane blebbing, nuclear condensation, and fragmentation of the DNA and nucleus. This is followed by fragmentation into apoptotic bodies that are quickly removed by phagocytes, thereby preventing an inflammatory response. It is a mode of cell death defined by characteristic morphological, biochemical and molecular changes. It was first described as a "shrinkage necrosis", and then this term was replaced by apoptosis to emphasize its role opposite mitosis in tissue kinetics. In later stages of apoptosis the entire cell becomes fragmented, forming a number of plasma membrane-bounded apoptotic bodies which contain nuclear and or cytoplasmic elements. The ultrastructural

neg: Extracellular digestion tip. The contents are released at the tip. Some enzymes are actively excreted through the plasma membrane, where they diffuse through or act in the cell wall. Note that the enzymes released from the hyphal tip require an aqueous environment for release and subsequent degradative activity. The molecules absorbed through the plasma membrane tend to be smaller than 5,000 Da, so only simple sugars, amino acids, fatty acids and other small molecules can be taken up following digestion. The molecules are taken up in solution. In some cases, the molecules are processed by enzymes located within the cell wall. For

neg: Polar auxin transport its own by crossing the lipid bilayer. Hence the export of auxin from the cell requires an active component in plasma membrane - i.e. some membrane transport protein. Two protein families: The PIN proteins and ABCB (PGP proteins) transporters are functioning as "auxin efflux carriers" and transport the anionic form of auxin out of the cell. While the PGP auxin efflux carriers are evenly distributed, the PIN proteins are most often maintaining polar (i.e. asymmetric) localisation on the plasma membrane. That is to say that they locate mostly on one side of the cell. Furthermore, the asymmetrical localisation of the

neg: Plasma cell on light microscopy. They have amphophilic cytoplasm and an eccentric nucleus with heterochromatin in a characteristic cartwheel or clock face arrangement. Their cytoplasm also contains a pale zone that on electron microscopy contains an extensive Golgi apparatus and centrioles (EM picture). Abundant rough endoplasmic reticulum combined with a well-developed Golgi apparatus makes plasma cells well-suited for secreting immunoglobulins. Other organelles in a plasma cell include ribosomes, lysosomes, mitochondria, and the plasma membrane. Terminally differentiated plasma cells express relatively few surface antigens, and do not express common pan-B cell markers, such as CD19 and CD20. Instead, plasma cells are identified through

neg: Cell membrane endocytosis, to secrete substances such as hormones and enzymes, and to transport a substance completely across a cellular barrier. In the process of exocytosis, the undigested waste-containing food vacuole or the secretory vesicle budded from Golgi apparatus, is first moved by cytoskeleton from the interior of the cell to the surface. The vesicle membrane comes in contact with the plasma membrane. The lipid molecules of the two bilayers rearrange themselves and the two membranes are, thus, fused. A passage is formed in the fused membrane and the vesicles discharges its contents outside the cell Prokaryotes are divided into two different

neg: Membrane vesicle trafficking Membrane vesicle trafficking Membrane vesicle trafficking in "eukaryotic" animal cells involves movement of important biochemical signal molecules from synthesis-and-packaging locations in the Golgi body to specific 'release' locations on the inside of the plasma membrane of the secretory cell, in the form of Golgi membrane-bound micro-sized vesicles, termed "membrane vesicles" (MVs). In this process, the 'packed' cellular products are released/secreted outside the cell across its plasma membrane. However, this vesicular membrane is retained and recycled by the secretory cells. This phenomenon has key role in synaptic neurotransmission, endocrine secretion, mucous secretion, granular-product secretion by neutrophils, etc. The scientists behind this

neg: Syndecan-4 Syndecan-4 Syndecan-4 is a protein that in humans is encoded by the "SDC4" gene. Syndecan-4 is one of the four vertebrate syndecans and has a molecular weight of ~20 kDa. Syndecans are the best-characterized plasma membrane proteoglycans. Their intracellular domain of membrane-spanning core protein interacts with actin cytoskeleton and signaling molecules in the cell cortex. Syndecans are normally found on the cell surface of fibroblasts and epithelial cells. Syndecans interact with fibronectin on the cell surface, cytoskeletal and signaling proteins inside the cell to modulate the function of integrin in cell-matrix adhesion. Also, syndecans bind to FGFs and bring them

neg: Immunogenic cell death players of intracellular signaling pathways that govern ICD. ICD is characterized by secretion of damage-associated molecular patterns (DAMPs).There are three most important DAMPs which are exposed to the cell surface during ICD. Calreticulin (CRT), one of the DAMP molecules, which is normally in the lumen of endoplasmic reticulum (ER), is translocated after the induction of immunogenic apoptosis to the surface of dying cell where it functions as an "eat me" signal for professional phagocytes. Other important surface exposed DAMPs are heat-shock proteins (HSPs), namely HSP70 and HSP90, which are under stress condition also translocated to the plasma membrane. On the

neg: Sodium-calcium exchanger after an excitotoxic insult. Another, more ubiquitous transmembrane pump that exports calcium from the cell is the plasma membrane Ca ATPase (PMCA), which has a much higher affinity but a much lower capacity. Since the PMCA is capable of effectively binding to Ca even when its concentrations are quite low, it is better suited to the task of maintaining the very low concentrations of calcium that are normally within a cell. Therefore, the activities of the NCX and the PMCA complement each other. The exchanger is involved in a variety of cell functions including the following: The exchanger is also

neg: ROCK1 of actin-myosin contraction, stability, and cell polarity. These contribute to many progresses such as regulation of morphology, gene transcription, proliferation, differentiation, apoptosis and oncogenic transformation. Other functions involve smooth muscle contraction, actin cytoskeleton organization, stress fiber and focal adhesion formation, neurite retraction, cell adhesion and motility. These functions are activated by phosphorylation of DAPK3, GFAP, LIMK1, LIMK2, MYL9/MLC2, PFN1 and PPP1R12A. Additionally, ROCK1 phosphorylates FHOD1 and acts synergistically with it to promote SRC-dependent non-apoptotic plasma membrane blebbing. It is also required for centrosome positioning and centrosome-dependent exit from mitosis. ROCK1 has been shown to interact with: In humans, the main

neg: Cell membrane lipid bilayer seven times responding to signal molecules (i.e. hormones and neurotransmitters). G-protein coupled receptors are used in processes such as cell to cell signaling, the regulation of the production of cAMP, and the regulation of ion channels. The cell membrane, being exposed to the outside environment, is an important site of cell–cell communication. As such, a large variety of protein receptors and identification proteins, such as antigens, are present on the surface of the membrane. Functions of membrane proteins can also include cell–cell contact, surface recognition, cytoskeleton contact, signaling, enzymatic activity, or transporting substances across the membrane. Most membrane

neg: Hyaluronic acid providing the dynamic force to the cell, HA synthesis has also been shown to associate with cell migration. Basically, HA is synthesized at the plasma membrane and released directly into the extracellular environment. This may contribute to the hydrated microenvironment at sites of synthesis, and is essential for cell migration by facilitating cell detachment. HA plays an important role in the normal epidermis. HA also has crucial functions in the reepithelization process due to several of its properties. It serves as an integral part of the extracellular matrix of basal keratinocytes, which are major constituents of the epidermis; its free-radical

neg: Cytokeratin association between the plasma membrane and the nuclear surface provides important implications for the organization of the cytoplasm and cellular communication mechanisms. Apart from the relatively static functions provided in terms of supporting the nucleus and providing tensile strength to the cell, the cytokeratin networks undergo rapid phosphate exchanges mediated depolymerization, with important implications in the more dynamic cellular processes such as mitosis and post-mitotic period, cell movement and differentiation. Cytokeratins interact with desmosomes and hemidesmosomes, thus collaborating to cell-cell adhesion and basal cell-underlying connective tissue connection. The intermediate filaments of the eukaryotic cytoskeleton, which the cytokeratins are one of

neg: Lipid-anchored protein then amide linked to the C-terminal of the carboxyl group of the respective protein. The GPI attachment occurs through the action of GPI-transamidase complex. The fatty acid chains of the phosphatidylinositol are inserted into the membrane and thus are what anchor the protein to the membrane. These proteins are only located on the exterior surface of the plasma membrane. The sugar residues in the tetrasaccaride and the fatty acid residues in the phosphatidylinositol group vary depending on the protein. This great diversity is what allows the GPI proteins to have a wide range of functions including acting as hydrolytic enzymes,

neg: Lysosome is responsible for carbohydrates, and lysosomal acid phosphatase is necessary to release phosphate groups of phospholipids. Many components of animal cells are recycled by transferring them inside or embedded in sections of membrane. For instance, in endocytosis (more specifically, macropinocytosis), a portion of the cell's plasma membrane pinches off to form vesicles that will eventually fuse with an organelle within the cell. Without active replenishment, the plasma membrane would continuously decrease in size. It is thought that lysosomes participate in this dynamic membrane exchange system and are formed by a gradual maturation process from endosomes. The production of lysosomal proteins

neg: PCDHB13 clusters, the transcripts from these genes are made up of only one large exon, not sharing common 3' exons as expected. These neural cadherin-like cell adhesion proteins are integral plasma membrane proteins. Their specific functions are unknown but they most likely play a critical role in the establishment and function of specific cell-cell neural connections. PCDHB13 Protocadherin beta-13 is a protein that in humans is encoded by the "PCDHB13" gene. This gene is a member of the protocadherin beta gene cluster, one of three related gene clusters tandemly linked on chromosome five. The gene clusters demonstrate an unusual genomic organization

neg: Plasmolysis is always irreversible while concave plasmolysis is usually reversible. During concave plasmolysis, the plasma membrane and the enclosed protoplast partially shrinks from the cell wall due to half-spherical, inwarding curving pockets forming between the plasma membrane and the cell wall. During convex plasmolysis, the plasma membrane and the enclosed protoplast shrinks completely from the cell wall, with the plasma membrane's ends in a symmetrically, spherically curved pattern. Plasmolysis Plasmolysis is the process in which cells lose water in a hypertonic solution. The reverse process, cytolysis, can occur if the cell is in a hypotonic solution resulting in a lower external

neg: Proton pump are found in nature. In a single cell (for example those of fungi and plants), representatives from all three groups of proton ATPases may be present. The plasma membrane -ATPase is a single subunit P-type ATPase found in the plasma membrane of plants, fungi, protists and many prokaryotes. The plasma membrane -ATPase creates the electrochemical gradients in the plasma membrane of plants, fungi, protists, and many prokaryotes. Here, proton gradients are used to drive secondary transport processes. As such, it is essential for the uptake of most metabolites, and also for responses to the environment (e.g., movement of leaves in

neg: Exocyst involved in exocytosis. Sec3 (EXOC1) and Exo70 (EXOC7) are localized to the plasma membrane, and are physically attached to the membrane by Rho GTPases such as CDC42. Other complementary exocyst components such as Sec15 (EXOC6) and Sec4 are localized to the vesicle membrane. Exocyst proteins on the plasma membrane bind vesicular exocyst proteins, bringing the vesicle very close to the plasma membrane in a fashion similar to the SNARE interactions to facilitate fusion. The exocyst also interacts with Rho GTPases responsible for controlling cell polarity and the activity of the cytoskeleton. Exocyst The exocyst is an octameric protein complex involved

neg: Endoplasm endoplasm and ectoplasm to create a pseudopod. Pseudopod, or “false foot” is the term for the extension of a cell’s plasma membrane into what appears to be an appendage that pulls the cell forward. The process behind this involves the gel of the ectoplasm, and sol, more fluid, portion of the endoplasm. To create the pseudopod, the gel of the ectoplasm begins to convert to sol which, along with the endoplasm, pushes a portion of the plasma membrane into an appendage. Once the pseudopod is extended, the sol within begins to peripherally convert back to gel, converting back to the

neg: Microvesicles phospholipids. aminophospholipids, phosphatidylserine, and phosphatidylethanolamine are specifically sequestered in the inner leaflet of the membrane. The transbilayer lipid distribution is under the control of three phospholipidic pumps: an inward-directed pump, or flippase; an outward-directed pump, or floppase; and a lipid scramblase, responsible for non-specific redistribution of lipids across the membrane. After cell stimulation, including apoptosis, a subsequent cytosolic Ca increase promotes the loss of phospholipid asymmetry of the plasma membrane, subsequent phosphatidylserine exposure, and a transient phospholipidic imbalance between the external leaflet at the expense of the inner leaflet, leading to budding of the plasma membrane and microvesicle release. The

neg: Endoplasm on the needs of the cell and/or organism. Some components of the cytoskeleton run throughout the endoplasm though most are concentrated in the ectoplasm - towards the cells edges, closer to the plasma membrane. The endoplasm’s granules are suspended in cytosol. The term granule refers to a small particle within the endoplasm, typically the secretory vesicles. The granule is the defining characteristic of the endoplasm, as they are typically not present within the ectoplasm. These offshoots of the endomembrane system are enclosed by a phospholipid bilayer and can fuse with other organelles as well as the plasma membrane. Their membrane

neg: Laminin associated with type IV collagen networks via entactin, fibronectin, and perlecan. They also bind to cell membranes through integrin receptors and other plasma membrane molecules, such as the dystroglycan glycoprotein complex and Lutheran blood group glycoprotein. Through these interactions, laminins critically contribute to cell attachment and differentiation, cell shape and movement, maintenance of tissue phenotype, and promotion of tissue survival. Some of these biological functions of laminin have been associated with specific amino-acid sequences or fragments of laminin. For example, the peptide sequence [GTFALRGDNGDNGQ], which is located on the alpha-chain of laminin, promotes adhesion of endothelial cells. Laminin alpha4 is

neg: Archaea apart. Like bacteria, archaea lack interior membranes and organelles. Like bacteria, the cell membranes of archaea are usually bounded by a cell wall and they swim using one or more flagella. Structurally, archaea are most similar to gram-positive bacteria. Most have a single plasma membrane and cell wall, and lack a periplasmic space; the exception to this general rule is "Ignicoccus", which possess a particularly large periplasm that contains membrane-bound vesicles and is enclosed by an outer membrane. Most archaea (but not "Thermoplasma" and "Ferroplasma") possess a cell wall. In most archaea the wall is assembled from surface-layer proteins, which

neg: Eisosome membrane consists of three compartments: The MCC, a furrow in the plasma membrane, is generated by eisosomes, it disappears in a cell lacking Pil1 which is one of the main eisosome components. These are large protein complexes composed primarily of subunits of two Bin-Amphiphysin-RVS (BAR) domain containing proteins Pil1 and Lsp1. These two paralogue proteins self-assemble in higher order structure helices and bind preferentially to phosphoinositide-containing membrane. It is also found that eisosome associated proteins Slm1 and Slm 2 have F-BAR domains that are used for targeting furrow like plasma membrane invagination. Eisosome Eisosomes ('eis' meaning into or portal and