Complement C5, C5b (C5) Antibody – Mouse Monoclonal

The protein encoded by this gene is the fifth component of complement, which plays an important role in inflammatory and cell killing processes. This protein is comprised of alpha and beta polypeptide chains that are linked by a disulfide bridge. An activation peptide, C5a, which is an anaphylatoxin that possesses potent spasmogenic and chemotactic activity, is derived from the alpha polypeptide via cleavage with a convertase. The C5b macromolecular cleavage product can form a complex with the C6 complement component, and this complex is the basis for formation of the membrane attack complex, which includes additional complement components. Mutations in this gene cause complement component 5 deficiency, a disease where patients show a propensity for severe recurrent infections. Defects in this gene have also been linked to a susceptibility to liver fibrosis and to rheumatoid arthritis. [provided by RefSeq]

C5: Activation of C5 by a C5 convertase initiates the spontaneous assembly of the late complement components, C5-C9, into the membrane attack complex. C5b has a transient binding site for C6. The C5b-C6 complex is the foundation upon which the lytic complex is assembled. Defects in C5 are the cause of complement component 5 deficiency (C5D). A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis. An association study of C5 haplotypes and genotypes in individuals with chronic hepatitis C virus infection shows that individuals homozygous for the C5_1 haplotype have a significantly higher stage of liver fibrosis than individuals carrying at least 1 other allele (PubMed:15995705).

Protein type: Secreted, signal peptide; Secreted

Chromosomal Location of Human Ortholog: 9q33-q34

Cellular Component: membrane attack complex; extracellular space; extracellular region

Molecular Function: protein binding; chemokine activity; endopeptidase inhibitor activity; C5a anaphylatoxin chemotactic receptor binding; receptor binding

Biological Process: activation of MAPK activity; in utero embryonic development; positive regulation of chemotaxis; cytolysis; complement activation, alternative pathway; chemotaxis; glucose homeostasis; leukocyte migration during inflammatory response; complement activation; cellular calcium ion homeostasis; G-protein coupled receptor protein signaling pathway; positive regulation of angiogenesis; cell surface receptor linked signal transduction; regulation of complement activation; response to stress; innate immune response; inflammatory response; negative regulation of dopamine secretion; complement activation, classical pathway

Disease: Complement Component 5 Deficiency; Eculizumab, Poor Response To