CD84
Developmental stage
Expression is slightly increased in naive B-cells after the first dividion. By contrast, expression on memory B-cells decreased with each successive division.
Domain
The ITSMs (immunoreceptor tyrosine-based switch motifs) with the consensus sequence T-X-Y-X-X-[VI] present in SLAM family receptors have overlapping specificity for activating and inhibitory SH2 domain-containingbinding partners. Especially they mediate the interaction with the SH2 domain of SH2D1A and SH2D1B. A 'three-pronged' mechanism is proposed involving threonine (position -2), phosphorylated tyrosine (position 0) and valine/isoleucine (position +3).
Function
Self-ligand receptor of the signaling lymphocytic activation molecule (SLAM) family. SLAM receptors triggered by homo- or heterotypic cell-cell interactions are modulating the activation and differentiation of a wide variety of immune cells and thus are involved in the regulation and interconnection of both innate and adaptive immune response. Activities are controlled by presence or absence of small cytoplasmic adapter proteins, SH2D1A/SAP and/or SH2D1B/EAT-2. Can mediate natural killer (NK) cell cytotoxicity dependent on SH2D1A and SH2D1B (By similarity). Increases proliferative responses of activated T-cells and SH2D1A/SAP does not seem be required for this process. Homophilic interactions enhance interferon gamma/IFNG secretion in lymphocytes and induce platelet stimulation via a SH2D1A-dependent pathway. May serve as a marker for hematopoietic progenitor cells (PubMed:11564780, PubMed:12115647, PubMed:12928397, PubMed:12962726, PubMed:16037392) Required for a prolonged T-cell:B-cell contact, optimal T follicular helper function, and germinal center formation. In germinal centers involved in maintaining B-cell tolerance and in preventing autoimmunity (By similarity). In mast cells negatively regulates high affinity immunoglobulin epsilon receptor signaling; independent of SH2D1A and SH2D1B but implicating FES and PTPN6/SHP-1 (PubMed:22068234). In macrophages enhances LPS-induced MAPK phosphorylation and NF-kappaB activation and modulates LPS-induced cytokine secretion; involving ITSM 2 (By similarity). Positively regulates macroautophagy in primary dendritic cells via stabilization of IRF8; inhibits TRIM21-mediated proteasomal degradation of IRF8 (PubMed:29434592).
Post-translational modifications
Phosphorylated by tyrosine-protein kinase LCK on tyrosine residues following ligation induced by agonist monoclonal antibody. The association with SH2D1A is dependent of tyrosine phosphorylation of its cytoplasmic domain. Phosphorylated on Tyr-296 and Tyr-316 following platelet aggregation. Phosphorylated on tyrosine residues upon high affinity immunoglobulin epsilon receptor aggregation in mast cells.
N-glycosylated.
Tissue Specificity
Predominantly expressed in hematopoietic tissues, such as lymph node, spleen and peripheral leukocytes. Expressed in macrophages, B-cells, monocytes, platelets, thymocytes, T-cells and dendritic cells. Highly expressed in memory T-cells. Expressed in mast cells.
Cellular localization
- Cell membrane
- Single-pass type I membrane protein
Alternative names
CD84, SLAMF5, SLAM family member 5, Cell surface antigen MAX.3, Hly9-beta, Leukocyte differentiation antigen CD84, Signaling lymphocytic activation molecule 5