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Protein Page:
C1QB (human)

C1QB C1q associates with the proenzymes C1r and C1s to yield C1, the first component of the serum complement system. The collagen-like regions of C1q interact with the Ca(2+)-dependent C1r(2)C1s(2) proenzyme complex, and efficient activation of C1 takes place on interaction of the globular heads of C1q with the Fc regions of IgG or IgM antibody present in immune complexes. Defects in C1QB are a cause of complement component C1q deficiency (C1QD). 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. Note: This description may include information from UniProtKB.
Protein type: Secreted; Secreted, signal peptide
Chromosomal Location of Human Ortholog: 1p36.12
Cellular Component: complement component C1 complex; extracellular region
Molecular Function: serine-type endopeptidase activity
Biological Process: complement activation; complement activation, classical pathway
Disease: C1q Deficiency
Reference #:  P02746 (UniProtKB)
Alt. Names/Synonyms: C1QB; Complement C1q subcomponent subunit B; complement component 1, q subcomponent, B chain; complement component 1, q subcomponent, beta polypeptide; complement component C1q, B chain; complement subcomponent C1q chain B
Gene Symbols: C1QB
Molecular weight: 26,722 Da
Basal Isoelectric point: 8.83  Predict pI for various phosphorylation states
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