Fc fragment of IgG binding protein (FCGBP) (FCGBP)

Fc fragment of IgG binding protein (FCGBP) is a large, secreted glycoprotein that serves as a fundamental structural component of the intestinal mucus layer (UniProt Q9Y6R7). It is primarily synthesized by goblet cells and is known to covalently cross-link with the mucin MUC2, thereby stabilizing the mucus gel that protects the intestinal epithelium from commensal bacteria and pathogens (PubMed: 21135235). Beyond its structural role, FCGBP binds to the Fc portion of IgG antibodies, suggesting an involvement in mucosal immunological surveillance and the clearance of immune complexes (NCBI Gene: 8857). In clinical pathology, a significant reduction in FCGBP expression is observed in the colonic mucosa of patients with active ulcerative colitis, contributing to the breakdown of the protective barrier (PubMed: 12871020). In oncology, FCGBP has emerged as a potential prognostic biomarker; its downregulation is often associated with poor outcomes in colorectal and gallbladder cancers (PubMed: 33456453). Although there are currently no FDA-approved drugs that directly target FCGBP, it represents a significant focal point for research into mucosal healing and the development of diagnostic tools for inflammatory and neoplastic diseases (PubMed: 35145342). The protein's ability to modulate cell-cell adhesion and immune signaling makes it a candidate for future therapeutic intervention in barrier-related disorders.

Other names

IgG Fc-binding proteinFcgamma-binding proteinFCBPFcgamma-BPFc fragment of IgG-binding protein

No drugs currently target this protein directly; therapeutic strategies are focused on restoring its expression to maintain mucosal barrier integrity.