Myeloid triggered receptor 2 (TREM2) is a single Ig structural domain receptor that is expressed in macrophages and dendritic cells, but not in granulocytes or monocytes. It is most abundantly expressed in the basal ganglia, corpus callosum, medulla oblongata, and spinal cord, whereas microglia in the CNS are the predominant cell type producing TREM2.TREM2 plays a role in chronic inflammation by stimulating constitutive, but not inflammatory, chemokine and cytokine production.TREM2 forms a receptor-signaling complex with TYROBP to activate the macrophage and dendritic cell immune response in macrophages and dendritic cells. It also associates with the splice protein DAP12 to transmit activation signals that play a role in innate and adaptive immune responses.TREM2 signaling is also an important pathway that promotes colonic wound healing.Mutations in TREM2 increase the risk of neurodegenerative diseases such as Alzheimer’s disease, amyotrophic lateral sclerosis, and Parkinson’s disease.