C1S
Function
C1s B chain is a serine protease that combines with C1q and C1r to form C1, the first component of the classical pathway of the complement system. C1r activates C1s so that it can, in turn, activate C2 and C4. Cleaves also IGFBP5 and thereby inhibits the trophic effects of IGF1.
Involvement in disease
Complement component C1s deficiency
C1SD
A rare defect resulting in C1 deficiency and impaired activation of the complement classical pathway. C1 deficiency generally leads to severe immune complex disease with features of systemic lupus erythematosus and glomerulonephritis.
None
The disease is caused by variants affecting the gene represented in this entry.
Ehlers-Danlos syndrome, periodontal type, 2
EDSPD2
A form of Ehlers-Danlos syndrome, a connective tissue disorder characterized by hyperextensible skin, atrophic cutaneous scars due to tissue fragility and joint hyperlaxity. EDSPD2 is characterized by the association of typical features of Ehlers-Danlos syndrome with gingival recession and severe early-onset periodontal disease, leading to premature loss of permanent teeth. EDSPD2 transmission pattern is consistent with autosomal dominant inheritance.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
The iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains.
Sequence Similarities
Belongs to the peptidase S1 family.
Alternative names
Complement C1s subcomponent, C1 esterase, Complement component 1 subcomponent s, C1S