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C1QA

Function

C1q associates with the proenzymes C1r and C1s to yield C1, the first component of the serum complement system. The collagen-like regions of C1q interact with the Ca(2+)-dependent C1r(2)C1s(2) proenzyme complex, and efficient activation of C1 takes place on interaction of the globular heads of C1q with the Fc regions of IgG or IgM antibody present in immune complexes.

Involvement in disease

Complement component C1q deficiency

C1QD

A disorder caused by impaired activation of the complement classical pathway. It generally leads to severe immune complex disease with features of systemic lupus erythematosus and glomerulonephritis.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

O-linked glycans are assumed to be the Glc-Gal disaccharides typically found as secondary modifications of hydroxylated lysines in collagen-like domains.

Cellular localization

  • Secreted

Alternative names

  • Complement C1q subcomponent subunit A
  • C1QA

Target type

Proteins

Primary research area

Neuroscience

Molecular weight

26017Da