MGP Database

New search | Record Overview | Ontology/Pathway Information | Domain Information | UniProt Annotations | Related Proteins
MGP000349

UniProt Annotations

Entry Information
Gene Namecomplement component 1, q subcomponent, B chain
Protein EntryC1QB_HUMAN
UniProt IDP02746
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. {ECO:0000269|PubMed:9476130}. 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.
InteractionP02745:C1QA; NbExp=4; IntAct=EBI-2813376, EBI-1220209;
PtmHydroxylated on lysine and proline residues. Hydroxylated lysine residues can be glycosylated. Human C1Q contains up to 68.3 hydroxylysine-galactosylglucose residues and up to 2.5 hydroxylysine-galactose per molecule. Total percentage hydroxylysine residues glycosylated is 86.4%. {ECO:0000269|PubMed:486087, ECO:0000269|PubMed:6286235, ECO:0000269|PubMed:708376}.
SimilarityContains 1 C1q domain. {ECO:0000255|PROSITE- ProRule:PRU00368}.
SimilarityContains 2 collagen-like domains. {ECO:0000305}.
Subcellular LocationSecreted.
SubunitC1 is a calcium-dependent trimolecular complex of C1q, c1r and C1s 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. {ECO:0000269|PubMed:708376}.
Web ResourceName=C1QBbase; Note=C1QB mutation db; URL="http://structure.bmc.lu.se/idbase/C1QBbase/";
  logo