The first complement component to act in the activation of CLASSICAL COMPLEMENT PATHWAY. It is a calcium-dependent trimolecular complex made up of three subcomponents: COMPLEMENT C1Q; COMPLEMENT C1R; and COMPLEMENT C1S at 1:2:2 ratios. When the intact C1 binds to at least two antibodies (involving C1q), C1r and C1s are sequentially activated, leading to subsequent steps in the cascade of COMPLEMENT ACTIVATION. (mesh:D003172)



Synonym Reference Specificity
C1 Exact
C1-complex Exact
c1 complex Exact

Incoming Relations

Identifier Name Relation
HGNC:1246 C1R partof
HGNC:1242 C1QB partof
HGNC:1245 C1QC partof
HGNC:1241 C1QA partof
HGNC:1247 C1S partof

Outgoing Relations

None available.