– Triggering Receptor Expressed on Myeloid Cells-Like Protein 1 (TREML1) is a single-pass type I membrane protein. TREML1 precursor contains a 15 amino acid signal peptide, a 147 amino acid extracellular domain with an Ig-like V-type (immunoglobulin-like) domain, and 128 amino acid cytoplasmic domain. It can be expressed exclusively in platelets and megakaryocytes (MKs). It is a cell surface receptor that may play a role in the innate and adaptive immune response. TREML1 Sequestered in cytoplasmic vesicles in resting platelets. TREML1 be transported to the cell surface after stimulation by thrombin. Soluble fragments can be released into the serum by proteolysis. The phosphorylated TREML1 can interact with PTPN6 and PTPN11. TREML1 may participate in maintaining vascular hemostasis and regulating coagulation and inflammation at sites of injury.