tailieunhanh - Báo cáo khoa học: Molecular basis of actin reorganization promoted by binding of enterohaemorrhagic Escherichia coli EspB to a-catenin

EspB is a multifunctional protein associated with the type III secretion system of enterohaemorrhagic Escherichia coli, and interacts with various biomolecules includinga-catenin in the host cell. The binding of EspB to a-catenin is thought be involved in actin reorganization during bacterial infection, although the precise mechanism of this phenomenon is still unclear. | Molecular basis of actin reorganization promoted by binding of enterohaemorrhagic Escherichia coli EspB to a-catenin Mitsuhide Hamaguchi1 2 3 Daizo Hamada1 3 Kayo N. Suzuki1 Ikuhiro Sakata2 and Itaru Yanagihara1 1 Department of DevelopmentalInfectious Diseases Research Institute Osaka MedicalCenter for Maternaland Child Health Japan 2 Department of Emergency CriticalCare Medicine Schoolof Medicine Kinki University Osaka Japan 3 Division of StructuralBiology Department of Biochemistry and Molecular Biology Graduate Schoolof Medicine Kobe University Japan Keywords actin branching actin bundling cosedimentation pyrene-actin polymerization type III secretion system Correspondence D. Hamada Division of StructuralBiology GCOE Department of Biochemistry and Molecular Biology Graduate School of Medicine Kobe University 7-5-1 Kusunoki-cho Chuo-ku Kobe 650-0017 Japan Fax 81 78 382 5816 Tel 81 78 382 5817 E-mail daizo@ Present address Laboratory of CellMigration RIKEN Center for DevelopmentalBiology Kobe Japan Received 27 August 2008 revised 17 October 2008 accepted 17 October 2008 doi EspB is a multifunctional protein associated with the type III secretion system of enterohaemorrhagic Escherichia coli and interacts with various biomolecules including a-catenin in the host cell. The binding of EspB to a-catenin is thought be involved in actin reorganization during bacterial infection although the precise mechanism of this phenomenon is still unclear. Recent research shows that dimerization of a-catenin dissociates it from E-cadherin p-catenin a-catenin complexes and that the dimer suppresses Arp2 3-mediated actin branching or polymerization. These results inspired us to evaluate the effect of EspB on the functions of a-catenin. Based on a series of in vitro biochemical approaches including pull-down co-sedimentation and pyrene-actin polymerization assays combined with transmission electron microscopy we conclude that EspB .