Fibrinogen beta chain

Fibrinogen beta chain (FGB) is a structural protein component of blood clots and the fibrin matrix (UniProt: P02675). It is proteolytically cleaved by thrombin and polymerizes with fibrinogen alpha and gamma chains to form insoluble fibrin, which plays critical roles in hemostasis, wound repair, and immune responses against infection. The protein also enhances platelet activation and supports successful pregnancy through maternal fibrinogen deposition.

FGB is primarily associated with hemostasis and vascular biology, though fibrin deposition occurs in diverse pathological contexts including infection and tissue injury. Genetic defects in FGB cause rare bleeding disorders such as congenital afibrinogenemia and dysfibrinogenemia (UniProt: P02675).

In Alzheimer's disease, FGB is significantly upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +1.35 (Chaparral AD proteomics). This upregulation was detected across subcellular fractions in quantitative proteomics analysis, suggesting potential involvement of fibrinogen or fibrin-related processes in AD neuropathology, though the mechanistic contribution remains to be clarified.