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Guanine Nucleotide Exchange Factors
Guanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity. Some GEFs can activate multiple GTPases while others are specific to a single GTPase. Function Guanine nucleotide exchange factors (GEFs) are proteins or protein domains involved in the activation of small GTPases. Small GTPases act as molecular switches in intracellular signaling pathways and have many downstream targets. The most well-known GTPases comprise the Ras superfamily and are involved in essential cell processes such as cell differentiation and proliferation, cytoskeletal organization, vesicle trafficking, and nuclear transport. GTPases are active when bound to GTP and inactive when bound to GDP, allowing their activity to be regulated by GEFs and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleckstrin Homology Domain
Pleckstrin homology domain (PH domain) or (PHIP) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton. This domain can bind phosphatidylinositol lipids within biological membranes (such as phosphatidylinositol (3,4,5)-trisphosphate and phosphatidylinositol (4,5)-bisphosphate), and proteins such as the βγ-subunits of heterotrimeric G proteins, and protein kinase C. Through these interactions, PH domains play a role in recruiting proteins to different membranes, thus targeting them to appropriate cellular compartments or enabling them to interact with other components of the signal transduction pathways. Lipid binding specificity Individual PH domains possess specificities for phosphoinositides phosphorylated at different sites within the inositol ring, e.g., some bind phosphatidylinositol (4,5)-bisphosphate but not phosphatidylinositol (3,4,5)-trisphosphate or p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ras (protein)
Ras, from "Rat sarcoma virus", is a family of related proteins that are expressed in all animal cell lineages and organs. All Ras protein family members belong to a class of protein called small GTPase, and are involved in transmitting signals within cells (cellular signal transduction). Ras is the prototypical member of the Ras superfamily of proteins, which are all related in three-dimensional structure and regulate diverse cell behaviours. When Ras is 'switched on' by incoming signals, it subsequently switches on other proteins, which ultimately turn on genes involved in cell growth, differentiation, and survival. Mutations in Ras genes can lead to the production of permanently activated Ras proteins, which can cause unintended and overactive signaling inside the cell, even in the absence of incoming signals. Because these signals result in cell growth and division, overactive Ras signaling can ultimately lead to cancer. The three Ras genes in humans (''HRAS'', ''KRAS'', an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EGF Receptor , China Railway telegraph code EGF
{{disambiguation ...
EGF may refer to: * E.G.F., a Gabonese company * East Grand Forks, Minnesota, a city * East Garforth railway station in England * Epidermal growth factor * Equity Group Foundation, a Kenyan charity * European Gendarmerie Force, a military unit of the European Union * European Genetics Foundation, a training organization * European Globalisation Adjustment Fund * European Go Federation * Exponential generating function * Xinxiang East railway station Xinxiang East railway station () is a railway station on the Beijing–Guangzhou–Shenzhen–Hong Kong high-speed railway located in Xinxiang, Henan, People's Republic of China China, officially the People's Republic of China (PRC), is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MAPK/ERK Pathway
The MAPK/ERK pathway (also known as the Ras-Raf-MEK-ERK pathway) is a chain of proteins in the cell that communicates a signal from a receptor on the surface of the cell to the DNA in the nucleus of the cell. The signal starts when a signaling molecule binds to the receptor on the cell surface and ends when the DNA in the nucleus expresses a protein and produces some change in the cell, such as cell division. The pathway includes many proteins, such as mitogen-activated protein kinases (MAPKs), originally called extracellular signal-regulated kinases (ERKs), which communicate by adding phosphate groups to a neighboring protein ( phosphorylating it), thereby acting as an "on" or "off" switch. When one of the proteins in the pathway is mutated, it can become stuck in the "on" or "off" position, a necessary step in the development of many cancers. In fact, components of the MAPK/ERK pathway were first discovered in cancer cells, and drugs that reverse the "on" or "off" switch are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Son Of Sevenless
In cell signalling, ''Son of Sevenless'' (''SOS'') refers to a set of genes encoding guanine nucleotide exchange factors that act on the Ras subfamily of small GTPases. History and name The gene was so named because the Sos protein that it encoded was found to operate downstream of the ''sevenless'' gene in ''Drosophila melanogaster'' in a Ras/MAP kinase pathway. When ''sevenless'' is mutated or otherwise dysfunctional during development of the fly's ultraviolet light-sensitive compound eye, the seventh, central photoreceptor (R7) of each ommatidium fails to form. Similarly, the mammalian orthologues of Sos, SOS1 and SOS2, function downstream of many growth factor and adhesion receptors. Function Ras-GTPases act as molecular switches that bind to downstream effectors, such as the protein kinase c-Raf, and localise them to the membrane, resulting in their activation. Ras-GTPases are considered inactive when bound to guanosine diphosphate (GDP), and active when bound to guanosine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Transducing Adaptor Protein
Signal transducing adaptor proteins (STAPs) are proteins that are accessory to main proteins in a signal transduction pathway. Adaptor proteins contain a variety of protein-binding modules that link protein-binding partners together and facilitate the creation of larger signaling complexes. These proteins tend to lack any intrinsic enzymatic activity themselves, instead mediating specific protein–protein interactions that drive the formation of protein complexes. Examples of adaptor proteins include MYD88, Grb2 and SHC1. Signaling components Much of the specificity of signal transduction depends on the recruitment of several signalling components such as protein kinases and G-protein GTPases into short-lived active complexes in response to an activating signal such as a growth factor binding to its receptor. Domains Adaptor proteins usually contain several domains within their structure (e.g., Src homology 2 (SH2) and SH3 domains) that allow specific interactions with sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vesicle (biology)
In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm 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, the vesicles are called ''unilamellar liposomes''; otherwise they are called ''multilamellar liposomes''. The membrane enclosing the vesicle is also a lamellar phase, similar to that of the plasma membrane, and intracellular vesicles can fuse with the plasma membrane to release their contents outside the cell. Vesicles can also fuse with other organelles within the cell. A vesicle released from the cell is known as an extracellular vesicle. Vesicles perform a variety of functions. Because it is separated from the cytosol, the inside of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ADP Ribosylation Factor
ADP ribosylation factors (ARFs) are members of the ARF family of GTP-binding proteins of the Ras superfamily. ARF family proteins are ubiquitous in eukaryotic cells, and six highly conserved members of the family have been identified in mammalian cells. Although ARFs are soluble, they generally associate with membranes because of N-terminus myristoylation. They function as regulators of vesicular traffic and actin remodelling. The small ADP ribosylation factor (Arf) GTP-binding proteins are major regulators of vesicle biogenesis in intracellular traffic. They are the founding members of a growing family that includes Arl (Arf-like), Arp (Arf-related proteins) and the remotely related Sar (Secretion-associated and Ras-related) proteins. Arf proteins cycle between inactive GDP-bound and active GTP-bound forms that bind selectively to effectors. The classical structural GDP/GTP switch is characterised by conformational changes at the so-called switch 1 and switch 2 regions, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ARF GTPase
ARF may refer to: Organizations * Advertising Research Foundation * Animal Rescue Foundation * Armenian Revolutionary Federation * ASEAN Regional Forum People * Cahit Arf (1910–1997), Turkish mathematician Science, medicine, and mathematics * Acute renal failure * Acute rheumatic fever * ADP ribosylation factor, a small GTP-binding protein * The Arf invariant in mathematics * Argon fluoride laser or ArF laser * Atomic Resonance Filter or atomic line filter * Auxin Response Factors in plants * p14arf or ARF tumor suppressor Other uses * Arf (''Nanoha''), character in ''Magical Girl Lyrical Nanoha'' * Abuse Reporting Format * Almost-Ready-to-Fly model aircraft A model aircraft is a small unmanned aircraft. Many are replicas of real aircraft. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models. Aircraft manufactur ... * The Azkena Rock Festival, Vitoria-Gasteiz, Spain {{Disambigu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
