[Intra- and extracellular recognition of pathogens and activation of innate immunity].
One of the fundamental questions in innate immunity is how a large battery of invading pathogens is recognized by a limited number of germ line-encoding receptors. In Drosophila, peptidoglycan recognition protein (PGRP) family members have a crucial role in recognizing invading bacterial pathogens and in inducing immune reactions. PGRP-SA, -SD, and -SC1a are involved in recognizing gram-positive bacteria and in activating the Toll pathway to produce antimicrobial peptides. PGRP-LC and -LE recognize diaminopimelic acid (DAP)-containing peptidoglycans, which are cell wall components of many gram-negative bacteria and some gram-positive bacteria, and activate the imd pathway to produce antibacterial peptides. In addition to the extracellular function of PGRP-LE to activate immune reactions in the hemolymph, PGRP-LE acts as an intracellular receptor for monomeric DAP-type peptidoglycans. Moreover, a version of PGRP-LE containing only the PGRP domain functions extracellularly as a CD14-like accessory factor, capable of enhancing PGRP-LC-mediated peptidoglycan recognition. Subsequent intracellular signaling is transduced through the RHIM-like motif found in PGRP-LC and -LE.
Kurata
Shoichiro
S
Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai City, Japan. kurata@mail.pharm.tohoku.ac.jp
D000818:Animals; D001419:Bacteria / Q000166:cytology / Q000276:immunology*; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology*; D002473:Cell Wall / Q000276:immunology; D004331:Drosophila melanogaster / Q000276:immunology; D007111:Immunity, Cellular / Q000276:immunology*; D007113:Immunity, Innate / Q000276:immunology*; D010457:Peptidoglycan / Q000276:immunology; D051193:Toll-Like Receptors / Q000276:immunology
D002352:Carrier Proteins; D010457:Peptidoglycan; D051193:Toll-Like Receptors; C118897:peptidoglycan recognition protein