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Structurally Distinct Bacterial TBC-like GAPs Link Arf GTPase to Rab1 Inactivation to Counteract Host Defenses

Journal Article · · Cell
Rab GTPases are frequent targets of vacuole-living bacterial pathogens for appropriate trafficking of the vacuole. Here we discover that bacterial effectors including VirA from nonvacuole Shigella flexneri and EspG from extracellular Enteropathogenic Escherichia coli (EPEC) harbor TBC-like dual-finger motifs and exhibits potent RabGAP activities. Specific inactivation of Rab1 by VirA/EspG disrupts ER-to-Golgi trafficking. S. flexneri intracellular persistence requires VirA TBC-like GAP activity that mediates bacterial escape from autophagy-mediated host defense. Rab1 inactivation by EspG severely blocks host secretory pathway, resulting in inhibited interleukin-8 secretion from infected cells. Crystal structures of VirA/EspG-Rab1-GDP-aluminum fluoride complexes highlight TBC-like catalytic role for the arginine and glutamine finger residues and reveal a 3D architecture distinct from that of the TBC domain. Structure of Arf6-EspG-Rab1 ternary complex illustrates a pathogenic signaling complex that rewires host Arf signaling to Rab1 inactivation. Structural distinctions of VirA/EspG further predict a possible extensive presence of TBC-like RabGAP effectors in counteracting various host defenses.
Research Organization:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Organization:
FOREIGNUNIVERSITYHHMI
OSTI ID:
1050745
Journal Information:
Cell, Journal Name: Cell Journal Issue: (5) ; 08, 2012 Vol. 150; ISSN 0092-8674; ISSN CELLB5
Country of Publication:
United States
Language:
ENGLISH