PGRP-LC and PGRP-LE have essential yet distinct functions in the drosophila immune response to monomeric DAP-type peptidoglycan
Graduate School of Biomedical Sciences; Department of Medicine, Division of Infectious Disease and Immunology
Medical Subject Headings
Amino Acid Motifs; Amino Acid Sequence; Animals; Bordetella pertussis; Carrier Proteins; Cell Membrane; Cells, Cultured; Diaminopimelic Acid; Drosophila Proteins; Drosophila melanogaster; Escherichia coli; Gene Expression Regulation; Hemolymph; Intracellular Fluid; Malpighian Tubules; Molecular Sequence Data; Peptide Fragments; Peptidoglycan; RNA Interference; Recombinant Fusion Proteins; Signal Transduction; Transfection; Virulence Factors, Bordetella
Life Sciences | Medicine and Health Sciences
Drosophila rely entirely on an innate immune response to combat microbial infection. Diaminopimelic acid-containing peptidoglycan, produced by Gram-negative bacteria, is recognized by two receptors, PGRP-LC and PGRP-LE, and activates a homolog of transcription factor NF-kappaB through the Imd signaling pathway. Here we show that full-length PGRP-LE acted as an intracellular receptor for monomeric peptidoglycan, whereas a version of PGRP-LE containing only the PGRP domain functioned extracellularly, like the mammalian CD14 molecule, to enhance PGRP-LC-mediated peptidoglycan recognition on the cell surface. Interaction with the imd signaling protein was not required for PGRP-LC signaling. Instead, PGRP-LC and PGRP-LE signaled through a receptor-interacting protein homotypic interaction motif-like motif. These data demonstrate that like mammals, drosophila use both extracellular and intracellular receptors, which have conserved signaling mechanisms, for innate immune recognition.
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Citation: Nat Immunol. 2006 Jul;7(7):715-23. Epub 2006 Jun 11. Link to article on publisher's site