| Tissue Specificity | Expressed by CD19-positive B cells and CD4-positive and CD8-positive T cell populations in primary and secondary lymphoid tissues (at protein level). Among B cell subsets, detected in a subset of bone marrow pro- and pre-B cells, in most follicular and memory B cells and in a small subset of germinal center B cells (at protein level). Expressed at lower levels in CD56-positive NK cells (at protein level). Expressed in lymph nodes, lung, thymus and kidneys. Very weak expression detected in spleen, liver, heart, and salivary gland. |
| Post Translational Modifications | Phosphorylated on both Tyr and Ser residues. O-glycosylated. Sialylated. O-linked glycans regulate trafficking to the plasma membrane. |
| Function | High-affinity Fc receptor for immunoglobulin M (IgM), both secreted and membrane-bound IgM. Primarily regulates IgM transport and homeostasis. In lymphoid cells, enables exocytosis of membrane-bound IgM on the plasma membrane as well as endocytosis of IgM-antigen complexes toward lysosomes for degradation. In mucosal epithelium, mediates retrotranscytosis of antigen-IgM complexes across mucosal M cells toward antigen-presenting cells in mucosal lymphoid tissues. Triggers costimulatory signaling and mediates most of IgM effector functions involved in B cell development and primary immune response to infection. Likely limits tonic IgM BCR signaling to self-antigens for proper negative selection of autoreactive B cells in the bone marrow and for the maintenance of regulatory B cell pool in peripheral lymphoid organs. Mediates antibody responses to T cell-dependent and T cell-independent antigens and promotes induction of an efficient neutralizing IgG response. Engages in cross-talk with antigen-receptor signaling via the non-canonical NF-kappa-B, MAP kinases and calcium signaling pathways. |
| Protein Name | Immunoglobulin Mu Fc ReceptorIgm FcrFas Apoptotic Inhibitory Molecule 3Faim3Regulator Of Fas-Induced Apoptosis Toso |
| Cellular Localisation | Cell MembraneSingle-Pass Membrane ProteinEarly Endosome MembraneGolgi ApparatusTrans-Golgi Network MembraneLysosome MembraneContinuously Recycles Between Cytoplasmic Pool And The Plasma Membrane To Bind As Much Igm As PossibleIsoform 3: SecretedDetected In The Serum |
| Alternative Antibody Names | Anti-Immunoglobulin Mu Fc Receptor antibodyAnti-Igm Fcr antibodyAnti-Fas Apoptotic Inhibitory Molecule 3 antibodyAnti-Faim3 antibodyAnti-Regulator Of Fas-Induced Apoptosis Toso antibodyAnti-FCMR antibodyAnti-FAIM3 antibodyAnti-TOSO antibody |
Information sourced from Uniprot.org
