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SKAP2
Src kinase-associated phosphoprotein 2 is an enzyme that in humans is encoded by the ''SKAP2'' gene. Function The protein encoded by this gene belongs to the src family kinases. This protein is similar to the src kinase associated phosphoprotein 1. It is an adaptor protein that is thought to play an essential role in the src signaling pathway in various cells, but particularly specific in macrophages. It inhibits PTK2B/RAFTK activity and regulates alpha-synuclein phosphorylation. It interacts with Signal-regulatory protein alpha Signal regulatory protein α (SIRPα) is a regulatory membrane glycoprotein from SIRP family expressed mainly by myeloid cells and also by stem cells or neurons. SIRPα acts as inhibitory receptor and interacts with a broadly expressed transmembra ... and directs integrin-activated cytoskeletal reorganization in macrophages. References Further reading * * * * * * * * * * * * {{gene-7-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Src Family Kinase
Src kinase family is a family of non-receptor tyrosine kinases that includes nine members: Src, Yes, Fyn, and Fgr, forming the SrcA subfamily, Lck, Hck, Blk, and Lyn in the SrcB subfamily, and Frk in its own subfamily. Frk has homologs in invertebrates such as flies and worms, and Src homologs exist in organisms as diverse as unicellular choanoflagellates, but the SrcA and SrcB subfamilies are specific to vertebrates. Src family kinases contain six conserved domains: a N-terminal myristoylated segment, a SH2 domain, a SH3 domain, a linker region, a tyrosine kinase domain, and C-terminal tail. Src family kinases interact with many cellular cytosolic, nuclear and membrane proteins, modifying these proteins by phosphorylation of tyrosine residues. A number of substrates have been discovered for these enzymes. Deregulation, including constitutive activation or over expression, may contribute to the progression of cellular transformation and oncogenic activity. Structure S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoprotein
A phosphoprotein is a protein that is posttranslationally modified by the attachment of either a single phosphate group, or a complex molecule such as 5'-phospho-DNA, through a phosphate group. The target amino acid is most often serine, threonine, or tyrosine residues (mostly in eukaryotes), or aspartic acid or histidine residues (mostly in prokaryotes). Biological function The phosphorylation of proteins is a major regulatory mechanism in cells. Clinical significance Phosphoproteins have been proposed as biomarkers for breast cancer. See also *Protein phosphorylation Protein phosphorylation is a reversible post-translational modification of proteins in which an amino acid residue is phosphorylated by a protein kinase by the addition of a covalently bound phosphate group. Phosphorylation alters the structural ... References Phosphoproteins {{protein-stub ... [...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] |
Macrophages
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cells, microbes, cellular debris, and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. The process is called phagocytosis, which acts to defend the host against infection and injury. These large phagocytes are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microglia, and others), but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense (innate immunity) and also help initiate specific defense mechanisms (adaptive immunity) by recruiting other immun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PTK2B
Protein tyrosine kinase 2 beta is an enzyme that in humans is encoded by the ''PTK2B'' gene. Function This gene encodes a cytoplasmic protein tyrosine kinase that is involved in calcium-induced regulation of ion channels and activation of the map kinase signaling pathway. The encoded protein may represent an important signaling intermediate between neuropeptide-activated receptors or neurotransmitters that increase calcium flux and the downstream signals that regulate neuronal activity. The encoded protein undergoes rapid tyrosine phosphorylation and activation in response to increases in the intracellular calcium concentration , nicotinic acetylcholine receptor activation, membrane depolarization, or protein kinase C activation. In addition, SOCE-induced Pyk2 activation mediates disassembly of endothelial adherens junctions, via tyrosine (Y1981-residue) phosphorylation of VE-PTP. This protein has been shown to bind a CRK-associated substrate, a nephrocystin, a GTPase reg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha-synuclein
Alpha-synuclein is a protein that, in humans, is encoded by the ''SNCA'' gene. Alpha-synuclein is a neuronal protein that regulates synaptic vesicle trafficking and subsequent neurotransmitter release. It is abundant in the brain, while smaller amounts are found in the heart, muscle and other tissues. In the brain, alpha-synuclein is found mainly in the axon terminals of presynaptic neurons. Within these terminals, alpha-synuclein interacts with phospholipids and proteins. Presynaptic terminals release chemical messengers, called neurotransmitters, from compartments known as synaptic vesicles. The release of neurotransmitters relays signals between neurons and is critical for normal brain function. The human alpha-synuclein protein is made of 140 amino acids. An alpha-synuclein fragment, known as the non- Abeta component (NAC) of Alzheimer's disease amyloid, originally found in an amyloid-enriched fraction, was shown to be a fragment of its precursor protein, NACP. It was later de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal-regulatory Protein Alpha
Signal regulatory protein α (SIRPα) is a regulatory membrane glycoprotein from SIRP family expressed mainly by myeloid cells and also by stem cells or neurons. SIRPα acts as inhibitory receptor and interacts with a broadly expressed transmembrane protein CD47 also called the "don't eat me" signal. This interaction negatively controls effector function of innate immune cells such as host cell phagocytosis. SIRPα diffuses laterally on the macrophage membrane and accumulates at a phagocytic synapse to bind CD47 and signal 'self', which inhibits the cytoskeleton-intensive process of phagocytosis by the macrophage. This is analogous to the self signals provided by MHC class I molecules to NK cells via Ig-like or Ly49 receptors. NB. Protein shown to the right is CD47 not SIRP α. Structure The cytoplasmic region of SIRPα is highly conserved between rats, mice and humans. Cytoplasmic region contains a number of tyrosine residues, which likely act as ITIMs. Upon CD47 ligation, SIRP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integrin
Integrins are transmembrane receptors that facilitate cell-cell and cell-extracellular matrix (ECM) adhesion. Upon ligand binding, integrins activate signal transduction pathways that mediate cellular signals such as regulation of the cell cycle, organization of the intracellular cytoskeleton, and movement of new receptors to the cell membrane. The presence of integrins allows rapid and flexible responses to events at the cell surface (''e.g''. signal platelets to initiate an interaction with coagulation factors). Several types of integrins exist, and one cell generally has multiple different types on its surface. Integrins are found in all animals while integrin-like receptors are found in plant cells. Integrins work alongside other proteins such as cadherins, the immunoglobulin superfamily cell adhesion molecules, selectins and syndecans, to mediate cell–cell and cell–matrix interaction. Ligands for integrins include fibronectin, vitronectin, collagen and laminin. Stru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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