Description
Complement C1s-1 subcomponent is a serine protease that associates with C1q and C1r to form C1, the initial component of the classical pathway in the complement system. C1r activates C1s, enabling it to subsequently activate C2 and C4. In mice, the C1s gene is duplicated into two alleles: c1sA and c1sB. The c1sA allele is predominantly expressed in the liver, whereas c1sB is found in the reproductive system, including the prostate and seminal vesicles. This variation in expression patterns may be linked to differing requirements for C1s catalytic activity and substrate specificity across various tissues