4fmb
From Proteopedia
VirA-Rab1 complex structure
Structural highlights
FunctionVIRA_SHIFL Alpha-tubulin-specific protease that is required for entry into epithelial cells and for subsequent intra- and intercellular spreading. Contributes to bacterial entry into epithelial cells by inducing microtubule (MT) destabilization and the formation of membrane ruffles. The membrane ruffling evoked by VirA results from the activation of host rac1, which is associated with the destruction of MT networks. Creates a tunnel inside the host cell cytoplasm by breaking down the microtubule infrastructure. This facilitates the bacterium's movement through the cytoplasm and also helps other bacteria move faster during the invasion of the eukaryotic cell. Is absolutely required for virulence.[1] [2] [3] Publication Abstract from PubMedRab 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. Structurally Distinct Bacterial TBC-like GAPs Link Arf GTPase to Rab1 Inactivation to Counteract Host Defenses.,Dong N, Zhu Y, Lu Q, Hu L, Zheng Y, Shao F Cell. 2012 Aug 31;150(5):1029-41. PMID:22939626[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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