Uses
This gene encodes a serine protease, which is a major constituent of the human complement subcomponent C1. C1s associates with two other complement components C1r and C1q in order to yield the first component of the serum complement system. Defects in this gene are the cause of selective C1s deficiency. (provided by RefSeq)
Biological Activity
Complement component 1 subcomponent s (C1S) is a subcomponent of C1, the first component of the complement system. The complement system is a first line of innate immune defense in cells. C1S is a serine protease. Activated C1S participates in immune response by binding and cleaving the effector molecule complement component-4 (C4). The CUB1 (C1r/C1s, Uegf, Bmp1)-EGF (Epidermal growth factor-like) region of C1S is responsible for mediating interaction between C1S and other components of C1 (C1R and C1Q). Absence of C1S is associated with autoimmune diseases, for instance lupus-like syndrome, Hashimotoμs thyroiditis, and autoimmune hepatitis.
