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.
C1QA protein sequence
This sequence information is just for reference only.From Uniport
C1QA cDNA / gene is a gene with protein product which located on 1p36.12. The C1QA gene is conserved in chimpanzee, Rhesus monkey, dog, cow, mouse, rat, chicken, and zebrafish. 165 organisms have orthologs with human gene C1QA.