Complement Component 1, S Subcomponent (C1s)

Complement component 1S is a protein involved in the complement system.C1s cleaves C4, which eventually leads to the production of the C4b-C2a form of C3-convertase.MacKinnon et al. (1987) derived the complete amino acid sequence of C1s from molecular cloning of cDNA. Tosi et al. (1987) presented the complete cDNA sequence of C1s.Kusumoto et al. (1988) found that the amino acid sequence of C1s was 40.5% identical to that of C1r, with excellent matches of tentative disulfide bond locations conserving the overall domain structure of C1r. In a 27-month-old girl with multiple autoimmune diseases, Dragon-Durey et al. (2001) detected selective C1S deficiency resulting from a nonsense mutation in exon 12 of the C1S gene .