C4 Binding Protein Beta (C4BPb) ELISA Kit for Human

This gene encodes a member of a superfamily of proteins composed predominantly of tandemly arrayed short consensus repeats of approximately 60 amino acids. A single, unique beta-chain encoded by this gene assembles with seven identical alpha-chains into the predominant isoform of C4b-binding protein, a multimeric protein that controls activation of the complement cascade through the classical pathway. C4b-binding protein has a regulatory role in the coagulation system also, mediated through the beta-chain binding of protein S, a vitamin K-dependent protein that serves as a cofactor of activated protein C. The genes encoding both alpha and beta chains are located adjacent to each other on human chromosome 1 in the regulator of complement activation gene cluster. Alternative splicing gives rise to multiple transcript variants. [provided by RefSeq, Jul 2008]

C4BPB: Controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. It also interacts with anticoagulant protein S and with serum amyloid P component. The beta chain binds protein S. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Secreted; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 1q32

Cellular Component: extracellular space; extracellular region; plasma membrane

Molecular Function: protein binding

Biological Process: negative regulation of complement activation, classical pathway; regulation of complement activation; positive regulation of protein catabolic process; innate immune response; blood coagulation; complement activation, classical pathway