Enteropathogenic Escherichia coli type III effectors alter cytoskeletal function and signalling in Saccharomyces cerevisiae.
Enteropathogenic Escherichia coli (EPEC) strains cause attaching/effacing lesions in enterocytes through the development of actin-supported pedestals at the site of bacterial adhesion. Pathogenesis requires a type III secretion system (TTSS), which injects into the host cell the intimin receptor, Tir, as well as other effectors called Esps (Escherichia secreted proteins). The genes encoding TTSS structural components and Esps are found within a pathogenicity island called the locus of enterocyte effacement (LEE). This paper describes the application of Saccharomyces cerevisiae as a model to probe the functions of LEE-encoded genes. In a systematic approach, the LEE-encoded translocator and effector proteins were endogenously expressed in yeast and their effects on cell growth, cytoskeletal function and signalling pathways were studied. EspD, EspG and Map inhibited growth by depolarizing the actin cortical cytoskeleton, whereas EspF expression altered the septin cytoskeleton. Specific yeast MAP kinase pathways were activated by EspF, EspG, EspH and Map. The yeast system was used to define functional domains in Map by expressing truncated versions; it was concluded that the C-terminal region of the protein is necessary for actin disruption and toxicity, but not for mitochondrial localization. The utility of the yeast model for functional analyses of EPEC pathogenesis is discussed.
Rodríguez-Escudero
Isabel
I
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza Ramón y Cajal s/n, 28040 Madrid, Spain.
Hardwidge
Philip R
PR
Michael Smith Laboratories, #301 - 2185 East Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
Nombela
César
C
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza Ramón y Cajal s/n, 28040 Madrid, Spain.
Cid
Víctor J
VJ
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza Ramón y Cajal s/n, 28040 Madrid, Spain.
Finlay
B Brett
BB
Michael Smith Laboratories, #301 - 2185 East Mall, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
Molina
María
M
Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza Ramón y Cajal s/n, 28040 Madrid, Spain.
D000199:Actins / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009024:Morphogenesis; D012441:Saccharomyces cerevisiae / Q000254:growth & development*; D015398:Signal Transduction / Q000502:physiology*
D000199:Actins; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; C087863:EaeB protein, E coli; D029968:Escherichia coli Proteins; C474481:EspD protein, E coli; C472832:EspH protein, E coli; D008565:Membrane Proteins