CD300e molecule (CD300E)

CD300e molecule (CD300E) is a type I transmembrane glycoprotein and part of the CD300 family within the immunoglobulin superfamily, expressed predominantly on monocytes, myeloid dendritic cells, and certain tissue macrophages[1][2][3]. It associates with the signaling adaptor DAP12 via a charged lysine in its transmembrane region, acting as an activating immune receptor that triggers intracellular calcium flux, production of reactive oxygen species, and secretion of pro-inflammatory cytokines upon receptor engagement[1][2][3]. Besides promoting cell survival and immune activation, CD300e engagement upregulates activation markers and co-stimulatory molecules but paradoxically downregulates HLA class II antigen presentation in monocytes, impairing STAT1-dependent transcription and thus inhibiting T cell activation downstream[1][4]. Its dual properties make CD300e both an immunoregulatory receptor and a phenotypic marker of myeloid lineage cells. Sphingomyelin has been identified as a possible ligand, and binding can modulate cytokine signals and presumably function in inflammatory processes[3]. The molecule serves as a useful biomarker for isolating human monocytes for differentiation studies. There are currently no known therapeutic drugs targeting CD300e, and pharmacological mechanisms of action remain undefined, though safety concerns could include imbalances in immune activation versus antigen presentation leading to altered host defense or autoimmunity[1][4].

Other names

CMRF35-like molecule 2CD300LECLM2CLM-2CMRF35A5IREM2IREM-2PIgR-2PIgR2Poly-Ig receptor 2Polymeric immunoglobulin receptor 2CD300 antigen-like family member ECMRF35-A5Immune receptor expressed on myeloid cells 2CD300e antigen

Pharmacological mechanisms of action remain undefined.