TREM-1: intracellular signaling pathways and interaction with pattern recognition receptors

Review of the intracellular pathway of TREM‐1 signaling, its interactions with PRR pathways, focusing on TLRs and NLRs. TREM‐1 is an important signaling receptor expressed on neutrophils and monocytes that plays an important role in systemic infections. Here, we review the intracellular signaling pathways that mediate the immunological effects of TREM‐1. Because of the absence of signaling motifs, TREM‐1 constitutively associates with DAP12 for induction of intracellular signals. After phosphorylation of DAP12, production of chemokines and cytokines is induced. Moreover, TREM‐1 also modulates signaling pathways induced by known classes of PRRs, such as TLRs and NLRs. The exact mechanisms through which TREM‐1 influences TLR and NLR pathways are still largely elusive.