Protein Name complement C4A (Chido/Rodgers blood group)
Organism Homo sapiens
Gene ID 720
Gene Symbol


UniProt P0C0L4 (CO4A_HUMAN)
Relationships Total Number of functionally related compound(s) : 1468
Total Number of Articles : 1225

complement C4A (Chido/Rodgers blood group)

Gene Summary

This gene encodes the acidic form of complement factor 4, part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion. The trimer provides a surface for interaction between the antigen-antibody complex and other complement components. The alpha chain is cleaved to release C4 anaphylatoxin, an antimicrobial peptide and a mediator of local inflammation. Deficiency of this protein is associated with systemic lupus erythematosus and type I diabetes mellitus. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. Varying haplotypes of this gene cluster exist, such that individuals may have 1, 2, or 3 copies of this gene. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Nov 2014]

  • complement C4-A
  • C3 and PZP-like alpha-2-macroglobulin domain-containing protein 2
  • C4A anaphylatoxin
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