Peptidoglycan recognition proteins: A novel family of four human innate immunity pattern recognition molecules

Chao Liu, Zhaojun Xu, Dipika Gupta, Roman Dziarski

Research output: Contribution to journalArticle

269 Scopus citations


The innate immune system recognizes microorganisms through a series of pattern recognition receptors that are highly conserved in evolution. Insects have a family of 12 peptidoglycan recognition proteins (PGRPs) that recognize peptidoglycan, a ubiquitous component of bacterial cell walls. We report cloning of three novel human PGRPs (PGRP-L, PGRP-Iα, and PGRP-Iβ) that together with the previously cloned PGRP-S, define a new family of human pattern recognition molecules. PGRP-L, PGRP-Iα, and PGRP-Iβ have 576,341, and 373 amino acids coded by five, seven, and eight exons on chromosomes 19 and 1, and they all have two predicted transmembrane domains. All mammalian and insect PGRPs have at least three highly conserved C-terminal PGRP domains located either in the extracellular or in the cytoplasmic (or in both) portions of the molecules. PGRP-L is expressed in liver, PGRP-Iα and PGRP-Iβ in esophagus (and to a lesser extent in tonsils and thymus), and PGRP-S in bone marrow (and to a lesser extent in neutrophils and fetal liver). All four human PGRPs bind peptidoglyean and Gram-positive bacteria. Thus, these PGRPs may play a role in recognition of bacteria in these organs.

Original languageEnglish (US)
Pages (from-to)34686-34694
Number of pages9
JournalJournal of Biological Chemistry
Issue number37
StatePublished - Sep 14 2001

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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