@article{paquette_caspase-mediated_2010,
title = {Caspase-mediated cleavage, IAP binding, and ubiquitination: linking three mechanisms crucial for Drosophila NF-kappaB signaling},
author = {Nicholas Paquette and Meike Broemer and Kamna Aggarwal and Li Chen and Marie Husson and Deniz Ertürk-Hasdemir and Jean-Marc Reichhart and Pascal Meier and Neal Silverman},
doi = {10.1016/j.molcel.2009.12.036},
issn = {1097-4164},
year = {2010},
date = {2010-01-01},
journal = {Mol. Cell},
volume = {37},
number = {2},
pages = {172--182},
abstract = {Innate immune responses are critical for the immediate protection against microbial infection. In Drosophila, infection leads to the rapid and robust production of antimicrobial peptides through two NF-kappaB signaling pathways-IMD and Toll. The IMD pathway is triggered by DAP-type peptidoglycan, common to most Gram-negative bacteria. Signaling downstream from the peptidoglycan receptors is thought to involve K63 ubiquitination and caspase-mediated cleavage, but the molecular mechanisms remain obscure. We now show that PGN stimulation causes caspase-mediated cleavage of the imd protein, exposing a highly conserved IAP-binding motif (IBM) at its neo-N terminus. A functional IBM is required for the association of cleaved IMD with the ubiquitin E3-ligase DIAP2. Through its association with DIAP2, IMD is rapidly conjugated with K63-linked polyubiquitin chains. These results mechanistically connect caspase-mediated cleavage and K63 ubiquitination in immune-induced NF-kappaB signaling.},
keywords = {Alleles, Amino Acid Motifs, Animals, Biological, Caspases, Inhibitor of Apoptosis Proteins, M3i, MAP Kinase Kinase Kinases, Models, NF-kappa B, reichhart, Sequence Alignment, Signal Transduction, Ubiquitin-Protein Ligases, Ubiquitination},
pubstate = {published},
tppubtype = {article}
}
Innate immune responses are critical for the immediate protection against microbial infection. In Drosophila, infection leads to the rapid and robust production of antimicrobial peptides through two NF-kappaB signaling pathways-IMD and Toll. The IMD pathway is triggered by DAP-type peptidoglycan, common to most Gram-negative bacteria. Signaling downstream from the peptidoglycan receptors is thought to involve K63 ubiquitination and caspase-mediated cleavage, but the molecular mechanisms remain obscure. We now show that PGN stimulation causes caspase-mediated cleavage of the imd protein, exposing a highly conserved IAP-binding motif (IBM) at its neo-N terminus. A functional IBM is required for the association of cleaved IMD with the ubiquitin E3-ligase DIAP2. Through its association with DIAP2, IMD is rapidly conjugated with K63-linked polyubiquitin chains. These results mechanistically connect caspase-mediated cleavage and K63 ubiquitination in immune-induced NF-kappaB signaling.