IREM-1/CD300f

IREM-1, formally CD300f, is an inhibitory receptor of the CD300 family expressed mainly on monocytes, macrophages and dendritic cells. Its cytoplasmic tail contains ITIM motifs that recruit SHP-1 and SHP-2, and receptor engagement dampens responses to Fc receptor and Toll-like receptor stimulation, restraining inflammatory cytokine output. The extracellular domain adopts an IgV-like fold similar to other CD300 members, some of which recognize phospholipid ligands such as phosphatidylserine. By counterbalancing activating members of the cluster, IREM-1 contributes to the paired-receptor architecture that governs myeloid cell activation thresholds, and it is a subject of interest in inflammatory disease models.