CD84 Gene (SLAMF5): Function, Expression, and Disease Associations | Biomedical SEO

CD84 (also known as SLAMF5) is a type I transmembrane glycoprotein belonging to the signaling lymphocytic activation molecule (SLAM) family of immunoreceptors. It is expressed on various hematopoietic cells, including T cells, B cells, NK cells, platelets, and monocytes. CD84 functions as a homophilic adhesion molecule, mediating cell-cell interactions and modulating immune responses. It contains an extracellular domain with immunoglobulin-like domains and an intracellular domain with immunoreceptor tyrosine-based switch motifs (ITSMs) that recruit SH2 domain-containing proteins (e.g., SAP, EAT-2) to transduce signals. CD84 is involved in immune regulation, platelet activation, and has been implicated in autoimmune diseases and cancer.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• SLAM family signaling pathway (SAP/ERS)

• T cell receptor signaling pathway

• B cell receptor signaling pathway

• NK cell mediated cytotoxicity

• Platelet activation

The CD84 protein is a 339-amino acid type I transmembrane glycoprotein with a molecular weight of ~37 kDa (unglycosylated). It consists of an extracellular region containing two immunoglobulin-like domains (V-type and C2-type), a transmembrane domain, and a cytoplasmic tail with two immunoreceptor tyrosine-based switch motifs (ITSMs). CD84 undergoes homophilic interactions (CD84-CD84) between adjacent cells, mediating cell adhesion. Upon ligand binding, its ITSMs are phosphorylated by Src family kinases, recruiting SH2 domain-containing proteins such as SAP (SH2D1A) and EAT-2 (SH2D1B), which propagate downstream signaling. CD84 is expressed on most hematopoietic cells and plays roles in immune synapse formation, cytokine production, and platelet aggregation. Alternative splicing generates multiple isoforms, some of which may be soluble.