complement component 5a anaphylatoxin chemotactic receptors, member of the class A family of seven-transmembrane G protein-coupled receptors
The anaphylatoxin receptors are a group of G-protein coupled receptors which bind anaphylatoxins; members of this group include C3a receptors and C5a receptors. Anaphylatoxins are also known as complement peptides (C3a, C4a and C5a) that are produced from the activation of the complement system cascade. These complement anaphylatoxins can trigger degranulation of endothelial cells, mast cells, or phagocytes, which induce a local inflammatory response and stimulate smooth muscle cell contraction, histamine release, and increased vascular permeability. They are potent mediators involved in chemotaxis, inflammation, and generation of cytotoxic oxygen-derived free radicals. In humans, a single receptor for C3a (C3AR1) and two receptors for C5a (C5AR1 and C5AR2, also known as C5L2 or GPR77) have been identified, but there is no known receptor for C4a.
Comment:based on the structures of some class A family members with bound ligands (peptides or chemicals), agonists, or antagonists
Comment:Small-molecule chemical ligands tend to bind deeper within the receptor core, compared to a peptide ligand neurotensin, which binds towards the extracellular surface of its receptor.
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