This gene encodes the acidic form of complement factor 4, part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion.

2025年3月28日 · This gene encodes the acidic form of complement factor 4, part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion.

2024年8月1日 · This brief overview seeks to clarify the difference between C4A and C4a and to aid in the interpretation of the C4A and C4a changes observed in psychosis. The complement system comprises three pathways activated by distinct mechanisms: classical (CP), lectin (LP) and alternative pathway (AP).

2025年2月8日 · This gene encodes the acidic form of complement factor 4, part of the classical activation pathway. The protein is expressed as a single chain precursor which is proteolytically cleaved into a trimer of alpha, beta, and gamma chains prior to secretion.

C4A isotype is responsible for effective binding to form amide bonds with immune aggregates or protein antigens, while C4B isotype catalyzes the transacylation of the thioester carbonyl group to form ester bonds with carbohydrate antigens.

The human complement C4 gene (C4A and C4B genes) locus is located in the highly polymorphic major histocompatibility complex (MHC) class III gene region on chromosome 6, which could be a short form (C4S, 14.6 kb) or a long form (C4L, 21 kb), depending on the absence or the presence of the 6.36 kb endogenous retroviral sequence HERV-K(C4) in ...

Human C4 is the most polymorphic protein of the complement system. In this review, we summarize the current concepts on the 1-2-3 loci model of C4A and C4B genes in the population, factors affecting the expression levels of C4 transcripts and proteins, and the structural, functional and serological diversities of the C4A and C4B proteins.

C4 is a 205 kDa protein, synthesized as a single polypeptide chain, but processed on secretion into a form with three disulfide-linked polypeptides, named α, β and γ (97, 75 and 33 kDa). C4 is homologous to C3 and C5, and also to the family of protease inhibitors related to α 2 …

The complete exon-intron structure of a human complement component C4A gene: DNA sequences, polymorphism, and linkage to the 21-hydroxylase gene. J. Immun. 146: 1057-1066, 1991. [PubMed: 1988494]

Complement component 4 (C4) is cleaved by activated C1 to form C4b and C4a. C4b forms part of the classical C3 convertase (C4b2a). As yet there are no reports of associations with AMD. Plasma C4 levels in AMD patients are similar to controls, with no association with known AMD genotype variations (Scholl et al. 2008).