background:
C1 Inactivator is a highly glycosylated plasma protein involved in the regulation of the complement cascade. Its protein inhibits activated C1r and C1s of the first complement component and thus regulates complement activation. Deficiency of this protein is associated with hereditary angioneurotic oedema (HANE). Alternative splicing results in multiple transcript variants encoding the same isoform.
Function:
Activation of the C1 complex is under control of the C1-inhibitor. It forms a proteolytically inactive stoichiometric complex with the C1r or C1s proteases. May play a potentially crucial role in regulating important physiological pathways including complement activation, blood coagulation, fibrinolysis and the generation of kinins. Very efficient inhibitor of FXIIa. Inhibits chymotrypsin and kallikrein.
Subunit:
Binds to E.coli stcE which allows localization of SERPING1 to cell membranes thus protecting the bacteria against complement-mediated lysis. Interacts with MASP1.
Subcellular Location:
Secreted.
Post-translational modifications:
Highly glycosylated (49%) with N- and O-glycosylation. O-glycosylated with core 1 or possibly core 8 glycans. N-glycan heterogeneity at Asn-25: Hex5HexNAc4 (minor), dHex1Hex5HexNAc4 (minor), Hex6HexNAc5 (major) and dHex1Hex6HexNAc5 (minor).
Can be proteolytically cleaved by E.coli stcE.
DISEASE:
Defects in SERPING1 are the cause of hereditary angioedema (HAE) [MIM:106100]; also called hereditary angioneurotic edema (HANE). HAE is an autosomal dominant disorder characterized by episodic local subcutaneous edema and submucosal edema involving the upper respiratory and gastrointestinal tracts. HAE due to C1 esterase inhibitor deficiency is comprised of two clinically indistinguishable forms. In HAE type 1, representing 85% of patients, serum levels of C1 esterase inhibitor are less than 35% of normal. In HAE type 2, the levels are normal or elevated, but the protein is non-functional.
Similarity:
Belongs to the serpin family.
Database links:
UniProtKB/Swiss-Prot: P05155.2
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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