title: EspH, a new cytoskeleton-modulating effector of enterohaemorrhagic and enteropathogenic Escherichia coli.
abstract: Enteropathogenic Escherichia coli (EPEC) and enterohaemorrhagic E. coli (EHEC) are closely related pathogens. During infection, EPEC and EHEC use a type III secretion system (TTSS) to translocate effector proteins into the infected cells and thereby modify specific host functions. These include transient filopodium formation which is Cdc42-dependent. Filopodia formation is followed by assembly of actin pedestals, the process enhanced by inhibition of Cdc42. We discovered that orf 18 of the enterocyte effacement locus encodes a new effector, which we termed EspH. We show that EspH is translocated efficiently into the infected cells by the TTSS and localizes beneath the EPEC microcolonies. Inactivation of espH resulted in enhanced formation of filopodia and attenuated the pedestals formation. Furthermore, overexpression of EspH resulted in strong repression of filopodium formation and heightened pedestal formation. We also demonstrate that overexpression of EspH by EHEC induces marked elongation of the typically flat pedestals. Similar pedestal elongation was seen upon infection of COS cells overexpressing EspH. EspH transiently expressed by the COS cells was localized to the membrane and disrupted the actin cytoskeletal structure. Our findings indicate that EspH is a modulator of the host actin cytoskeleton structure.
authors.affiliation: Department of Molecular Genetics and Biotechnology, The Hebrew University, Faculty of Medicine, POB 12272, Jerusalem 91120, Israel.
authors.forename: Xuanlin
authors.initials: X
authors.lastname: Tu
authors.forename: Israel
authors.initials: I
authors.lastname: Nisan
authors.forename: Chen
authors.initials: C
authors.lastname: Yona
authors.forename: Emanuel
authors.initials: E
authors.lastname: Hanski
authors.forename: Ilan
authors.initials: I
authors.lastname: Rosenshine
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D019556:COS Cells; D003599:Cytoskeleton / Q000235:genetics / Q000473:pathology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D015964:Gene Expression Regulation, Bacterial; D006367:HeLa Cells; D006801:Humans; D018613:Microscopy, Confocal; D016366:Open Reading Frames; D011554:Pseudopodia / Q000648:ultrastructure; D014162:Transfection
chemical_list: D000199:Actins; D029968:Escherichia coli Proteins; C472832:EspH protein, E coli