MGP Database

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MGP000352

UniProt Annotations

Entry Information
Gene Namecomplement component 1, s subcomponent
Protein EntryC1S_HUMAN
UniProt IDP09871
SpeciesHuman
Comments
Comment typeDescription
Biophysicochemical PropertiesKinetic parameters: KM=12.3 uM for complement component C2 (at 37 degrees Celsius) {ECO:0000269|PubMed:11527969}; KM=1.9 uM for complement component C4 (at 37 degrees Celsius) {ECO:0000269|PubMed:11527969}; Note=Less efficient than MASP2 in C4 cleavage.;
Catalytic ActivityCleavage 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. {ECO:0000269|PubMed:11527969}.
DiseaseComplement 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. {ECO:0000269|PubMed:11390518}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Enzyme RegulationInhibited by SERPING1. {ECO:0000269|PubMed:11527969}.
FunctionC1s 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.
InteractionSelf; NbExp=2; IntAct=EBI-2810045, EBI-2810045; P00736:C1R; NbExp=3; IntAct=EBI-2810045, EBI-3926504;
PtmThe iron and 2-oxoglutarate dependent 3-hydroxylation of aspartate and asparagine is (R) stereospecific within EGF domains. {ECO:0000269|PubMed:2141278}.
SimilarityBelongs to the peptidase S1 family. {ECO:0000255|PROSITE-ProRule:PRU00274}.
SimilarityContains 1 EGF-like domain. {ECO:0000305}.
SimilarityContains 1 peptidase S1 domain. {ECO:0000255|PROSITE- ProRule:PRU00274}.
SimilarityContains 2 CUB domains. {ECO:0000255|PROSITE- ProRule:PRU00059}.
SimilarityContains 2 Sushi (CCP/SCR) domains. {ECO:0000255|PROSITE-ProRule:PRU00302}.
SubunitC1 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. {ECO:0000269|PubMed:2007122}.
Web ResourceName=C1Sbase; Note=C1S mutation db; URL="http://structure.bmc.lu.se/idbase/C1Sbase/";
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