Complement C1q subcomponent subunit A is a protein that in humans is encoded by the C1QAgene.[1]
This gene encodes a major constituent of the human complement system subcomponent C1q.
C1q associates with C1r and C1s in order to yield the first component of the serum complement system. Deficiency of C1q has been associated with lupus erythematosus and glomerulonephritis. C1q is composed of 18 polypeptide chains: six A-chains, six B-chains, and six C-chains. Each chain contains a collagen-like region located near the N terminus and a C-terminal globular region. The A-, B-, and C-chains are arranged in the order A-C-B on chromosome 1. This gene encodes the A-chain polypeptide of human complement subcomponent C1q.[2]
References
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Busby TF, Ingham KC (1990). "NH2-terminal calcium-binding domain of human complement C1s- mediates the interaction of C1r- with C1q". Biochemistry. 29 (19): 4613–8. doi:10.1021/bi00471a016. PMID2372546.
Stoiber H, Thielens NM, Ebenbichler C, et al. (1994). "The envelope glycoprotein of HIV-1 gp120 and human complement protein C1q bind to the same peptides derived from three different regions of gp41, the transmembrane glycoprotein of HIV-1, and share antigenic homology". Eur. J. Immunol. 24 (2): 294–300. doi:10.1002/eji.1830240203. PMID7507842.
Stoiber H, Ebenbichler CF, Thielens NM, et al. (1995). "HIV-1 rsgp41 depends on calcium for binding of human c1q but not for binding of gp120". Mol. Immunol. 32 (5): 371–4. doi:10.1016/0161-5890(94)00156-U. PMID7739575.
Gulati P, Guc D, Lemercier C, et al. (1994). "Expression of the components and regulatory proteins of the classical pathway of complement in normal and diseased synovium". Rheumatol. Int. 14 (1): 13–9. doi:10.1007/BF00302666. PMID7939135.
Gulati P, Lemercier C, Guc D, et al. (1994). "Regulation of the synthesis of C1 subcomponents and C1-inhibitor". Behring Inst. Mitt. (93): 196–203. PMID8172568.
Thielens NM, Bally IM, Ebenbichler CF, et al. (1994). "Further characterization of the interaction between the C1q subcomponent of human C1 and the transmembrane envelope glycoprotein gp41 of HIV-1". J. Immunol. 151 (11): 6583–92. PMID8245486.