FCMR
FCMR is the high-affinity Fc receptor for immunoglobulin M (IgM), acting on both secreted and membrane-bound IgM. It is also known as TOSO, FcmuR and FAIM3, and it primarily regulates IgM transport and homeostasis. Browse Assay Genie's current range of FCMR research reagents below, or read on for the biology behind the target.
FCMR (Fc mu receptor) binds the Fc region of IgM with high affinity, recognising both secreted and membrane-bound forms. Its main role is to regulate IgM transport and homeostasis. In lymphoid cells it enables exocytosis of membrane-bound IgM at the plasma membrane and endocytosis of IgM-antigen complexes towards lysosomes for degradation. In mucosal epithelium it mediates retrotranscytosis of antigen-IgM complexes across mucosal M cells towards antigen-presenting cells in mucosal lymphoid tissues.
FCMR also contributes to immune signalling. It triggers costimulatory signalling and mediates most IgM effector functions involved in B cell development and the primary immune response to infection. It likely limits tonic IgM BCR signalling to self-antigens, which supports proper negative selection of autoreactive B cells in the bone marrow and maintenance of the regulatory B cell pool in peripheral lymphoid organs. It mediates antibody responses to T cell-dependent and T cell-independent antigens and promotes an efficient neutralising IgG response. It engages in cross-talk with antigen-receptor signalling via the non-canonical NF-kappa-B, MAP kinase and calcium signalling pathways.
The FCMR protein is found at the cell membrane, in early endosome, trans-Golgi network and lysosome membranes, and in a secreted form. The gene is a member of the V-set domain containing, immunoglobulin like domain containing and Fc receptor groups. It was previously named Fas apoptotic inhibitory molecule 3 (FAIM3) and Fc fragment of IgM receptor, and is also known as TOSO. Mouse and rat orthologs are both designated Fcmr.
FCMR supports B cell development and likely limits tonic IgM BCR signalling, helping negative selection of autoreactive B cells in the bone marrow.
FCMR mediates retrotranscytosis of antigen-IgM complexes across mucosal M cells towards antigen-presenting cells in mucosal lymphoid tissues.
FCMR regulates IgM transport, including exocytosis of membrane-bound IgM and endocytosis of IgM-antigen complexes towards lysosomes for degradation.
FCMR mediates responses to T cell-dependent and independent antigens and cross-talks with non-canonical NF-kappa-B, MAP kinase and calcium signalling.
FCMR is the high-affinity Fc receptor for IgM, binding secreted and membrane-bound forms. It primarily regulates IgM transport and homeostasis, mediates retrotranscytosis across mucosal M cells, and triggers costimulatory signalling that contributes to B cell development and the primary immune response to infection.
The gene has carried several names over time. Its previous names include Fas apoptotic inhibitory molecule 3 (FAIM3) and Fc fragment of IgM receptor, and TOSO and FcmuR are used as aliases. The current HGNC name is Fc mu receptor, with the symbol FCMR.
Yes. Mouse and rat orthologs exist and both carry the gene symbol Fcmr, so the receptor can be studied in rodent models. Check the datasheet of any product for its validated reactivity.
Other Fc receptors, immunoglobulin-binding proteins and B cell signalling markers studied alongside FCMR.
Gene and protein annotations from HGNC, NCBI Gene and UniProt O60667; product specifications from Assay Genie datasheets.