C4b-Binding Protein

• C4b-binding protein (C4BP) is the main fluid-phase inhibitor of the classical complement pathway. It serves as cofactor in factor I-mediated cleavage of C4b and C3b and it accelerates the decay of complement convertases. The main role of C4BP is to prevent overt complement-mediated inflammation both in solution and on self-molecules recognised by C1q, such as amyloid. Furthermore, C4BP is frequently recruited onto the surface of various pathogens, which allows these to evade immune response. The main isoform of C4BP has a oligomeric structure and consists of seven chains, which confer complement inhibitory activity, and a single chain, which binds anticoagulant protein S and docks the molecule to negatively charged phospholipids exposed, e.g., on the surface of dying cells. Both α- and β- chains are built from complement control protein (CCP) domains typical of complement inhibitors. C4BP is one of the acute-phase proteins and its expression is upregulated by proinflammatory cytokines.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Läkemedelskemi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Medicinal Chemistry (hsv//eng)

Keyword

CCP domain

Complement convertase autoimmunity

Complement inhibitor

Complement system

Publication and Content Type

kap (subject category)

ref (subject category)