Publication Date:
2010-12-21
Description:
The fidelity and specificity of information flow within a cell is controlled by scaffolding proteins that assemble and link enzymes into signalling circuits. These circuits can be inhibited by bacterial effector proteins that post-translationally modify individual pathway components. However, there is emerging evidence that pathogens directly organize higher-order signalling networks through enzyme scaffolding, and the identity of the effectors and their mechanisms of action are poorly understood. Here we identify the enterohaemorrhagic Escherichia coli O157:H7 type III effector EspG as a regulator of endomembrane trafficking using a functional screen, and report ADP-ribosylation factor (ARF) GTPases and p21-activated kinases (PAKs) as its relevant host substrates. The 2.5 A crystal structure of EspG in complex with ARF6 shows how EspG blocks GTPase-activating-protein-assisted GTP hydrolysis, revealing a potent mechanism of GTPase signalling inhibition at organelle membranes. In addition, the 2.8 A crystal structure of EspG in complex with the autoinhibitory Ialpha3-helix of PAK2 defines a previously unknown catalytic site in EspG and provides an allosteric mechanism of kinase activation by a bacterial effector. Unexpectedly, ARF and PAKs are organized on adjacent surfaces of EspG, indicating its role as a 'catalytic scaffold' that effectively reprograms cellular events through the functional assembly of GTPase-kinase signalling complex.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675890/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675890/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Selyunin, Andrey S -- Sutton, Sarah E -- Weigele, Bethany A -- Reddick, L Evan -- Orchard, Robert C -- Bresson, Stefan M -- Tomchick, Diana R -- Alto, Neal M -- 1R01AI083359-01/AI/NIAID NIH HHS/ -- 5T32AI007520-12/AI/NIAID NIH HHS/ -- R01 AI083359/AI/NIAID NIH HHS/ -- R01 AI083359-01/AI/NIAID NIH HHS/ -- T32 AI007520/AI/NIAID NIH HHS/ -- T32 AI007520-12/AI/NIAID NIH HHS/ -- England -- Nature. 2011 Jan 6;469(7328):107-11. doi: 10.1038/nature09593. Epub 2010 Dec 19.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-8816, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21170023" target="_blank"〉PubMed〈/a〉
Keywords:
ADP-Ribosylation Factors/chemistry/*metabolism
;
Allosteric Regulation
;
Animals
;
*Biocatalysis
;
Biological Transport
;
Catalytic Domain
;
Cell Line
;
Crystallography, X-Ray
;
Endoplasmic Reticulum/metabolism
;
Enzyme Activation
;
Escherichia coli O157/*chemistry/metabolism
;
Escherichia coli Proteins/chemistry/*metabolism
;
Golgi Apparatus/metabolism
;
Guanosine Triphosphate/chemistry/metabolism
;
Humans
;
Hydrolysis
;
Intracellular Membranes/metabolism
;
Mice
;
Models, Molecular
;
Protein Binding
;
Protein Conformation
;
Protein Interaction Mapping
;
Protein Unfolding
;
Rats
;
*Signal Transduction
;
Two-Hybrid System Techniques
;
p21-Activated Kinases/chemistry/*metabolism
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
