Fc Receptor-like 3
Fc Receptor-like 3 (FCRL3) is an immunoregulatory member of the Fc receptor-like family expressed predominantly on B cells, including germinal-center and memory populations. The receptor carries extracellular immunoglobulin-like domains and a cytoplasmic tail containing both ITIM and ITAM-like motifs, allowing it to deliver context-dependent inhibitory or activating signals that fine-tune B-cell receptor responsiveness. FCRL3 is notable for a promoter polymorphism, commonly designated FCRL3_3, that creates an NF-κB binding site, raises receptor expression, and has been reproducibly associated with susceptibility to rheumatoid arthritis, systemic lupus erythematosus, Graves disease, and other autoimmune conditions. This disease linkage makes FCRL3 a recurring focus of autoimmunity genetics.
