Human Gene C1S (ENST00000406697.5) Description and Page Index
Description: 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. (from UniProt P09871) Gencode Transcript: ENST00000406697.5 Gencode Gene: ENSG00000182326.15 Transcript (Including UTRs) Position: hg38 chr12:6,988,259-7,071,032 Size: 82,774 Total Exon Count: 15 Strand: + Coding Region Position: hg38 chr12:7,061,913-7,070,651 Size: 8,739 Coding Exon Count: 11
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Comments and Description Text from UniProtKB
ID:C1S_HUMAN DESCRIPTION: RecName: Full=Complement C1s subcomponent; EC=3.4.21.42; AltName: Full=C1 esterase; AltName: Full=Complement component 1 subcomponent s; Contains: RecName: Full=Complement C1s subcomponent heavy chain; Contains: RecName: Full=Complement C1s subcomponent light chain; Flags: Precursor; 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. CATALYTIC ACTIVITY: Cleavage of Arg-|-Ala bond in complement component C4 to form C4a and C4b, and Lys(or Arg)-|-Lys bond in complement component C2 to form C2a and C2b: the 'classical' pathway C3 convertase. ENZYME REGULATION: Inhibited by SERPING1. BIOPHYSICOCHEMICAL PROPERTIES: Kinetic parameters: KM=12.3 uM for complement component C2 (at 37 degrees Celsius); KM=1.9 uM for complement component C4 (at 37 degrees Celsius); Note=Less efficient than MASP2 in C4 cleavage; SUBUNIT: C1 is a calcium-dependent trimolecular complex of C1q, C1r and C1s in the molar ration of 1:2:2. Activated C1s is an disulfide-linked heterodimer of a heavy chain and a light chain. PTM: The iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains. DISEASE: Defects in C1S are the cause of complement component C1s deficiency (C1SD) [MIM:613783]. 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. SIMILARITY: Belongs to the peptidase S1 family. SIMILARITY: Contains 2 CUB domains. SIMILARITY: Contains 1 EGF-like domain. SIMILARITY: Contains 1 peptidase S1 domain. SIMILARITY: Contains 2 Sushi (CCP/SCR) domains. WEB RESOURCE: Name=C1Sbase; Note=C1S mutation db; URL="http://bioinf.uta.fi/C1Sbase/";
ModBase Predicted Comparative 3D Structure on P09871
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