MGP Database

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MGP000348

UniProt Annotations

Entry Information
Gene Namecomplement component 1, q subcomponent, A chain
Protein EntryC1QA_HUMAN
UniProt IDP02745
SpeciesHuman
Comments
Comment typeDescription
DiseaseComplement component C1q deficiency (C1QD) [MIM:613652]: 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. Note=The disease is caused by mutations affecting the gene represented in this entry.
FunctionC1q 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.
InteractionP02746:C1QB; NbExp=4; IntAct=EBI-1220209, EBI-2813376;
PtmO-linked glycans consist of Glc-Gal disaccharides bound to the oxygen atom of post-translationally added hydroxyl groups. {ECO:0000269|PubMed:16335952, ECO:0000269|PubMed:19159218}.
SimilarityContains 1 C1q domain. {ECO:0000255|PROSITE- ProRule:PRU00368}.
SimilarityContains 1 collagen-like domain. {ECO:0000305}.
Subcellular LocationSecreted.
SubunitC1 is a calcium-dependent trimolecular complex of C1q, R and S in the molar ration of 1:2:2. C1q subcomponent is composed of nine subunits, six of which are disulfide-linked dimers of the A and B chains, and three of which are disulfide-linked dimers of the C chain.
Web ResourceName=C1QAbase; Note=C1QA mutation db; URL="http://structure.bmc.lu.se/idbase/C1QAbase/";
Web ResourceName=SeattleSNPs; URL="http://pga.gs.washington.edu/data/c1qa/";
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