3PCR

Structure of EspG-Arf6 complex

Summary for 3PCR

• Entry DOI: 10.2210/pdb3pcr/pdb
• Related: 3PCS
• Descriptor: EspG, ADP-ribosylation factor 6, GUANOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
• Functional Keywords: bacterial effector, small g protein, small gtp-binding protein, arf, adp-ribosylation factor 6, protein transport
• Biological source: Escherichia coli; More
• Cellular location: Golgi apparatus: P62330
• Total number of polymer chains: 2
• Total formula weight: 59442.96

Authors

Tomchick, D.R.,Alto, N.M.,Selyunin, A.S. (deposition date: 2010-10-21, release date: 2011-01-05, Last modification date: 2024-10-30)

Primary citation

Selyunin, A.S.,Sutton, S.E.,Weigele, B.A.,Reddick, L.E.,Orchard, R.C.,Bresson, S.M.,Tomchick, D.R.,Alto, N.M.
The assembly of a GTPase-kinase signalling complex by a bacterial catalytic scaffold.
Nature, 469:107-111, 2011

PubMed Abstract: 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 Å 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 Å crystal structure of EspG in complex with the autoinhibitory Iα3-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.

PubMed: 21170023
DOI: 10.1038/nature09593

Experimental method

X-RAY DIFFRACTION (2.5 Å)