Background:
Peptidoglycan recognition protein 1 (PGLYRP1, also known as PGRP-S) belongs to a family of evolutionary conserved innate immunity proteins, which in mammals also include PGLYRP2, PGLYRP3, and PGLYRP4 (PMID: 17275309; 20418257). PGLYRP1 is highly expressed in polymorphonuclear leukocytes and to a lower extent in many non-immune cells (PMID: 20418257). It recognizes bacterial peptidoglycan and functions in antibacterial immunity and inflammation (PMID: 20418257). PGLYRP1 has been identified as a ligand for TREM-1 (PMID: 25595774).