Fc receptor-like protein 6 (FCRL6)

Fc receptor-like protein 6 (FCRL6) is a type I transmembrane glycoprotein and member of the immunoglobulin superfamily, encoded by the FCRL6 gene. Unlike other Fc receptor-like (FCRL) family members, which are mainly expressed on B cells, FCRL6 is primarily found on cytotoxic T lymphocytes (CD8+ T cells), natural killer (NK) cells, γδ T cells, and rare cytotoxic CD4+ T cells[1][2][3]. It contains immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and mediates inhibitory signaling after binding to MHC class II/HLA-DR molecules on target cells, consequently suppressing effector functions of cytotoxic lymphocytes. Upregulation of FCRL6 in the tumor microenvironment, particularly in immune checkpoint inhibitor (ICI)-resistant tumors, implicates it in adaptive resistance and immune evasion. As such, FCRL6 is a promising but as-yet untargeted receptor in immuno-oncology, with potential roles as a therapeutic target and biomarker for immune modulation and cancer prognosis[2][3][1].

Other names

FCRH6FcR-like protein 6FcRL6IFGP6FLJ16056Fc receptor homolog 6Fc receptor-like protein 7

Inhibition of cytotoxic lymphocyte effector function via engagement with MHC class II/HLA-DR molecules Recruitment of tyrosine phosphatases (e.g., SHP-2) via ITIM, leading to downstream inhibitory signaling