The medium is the messenger.
Enteropathogenic Escherichia coli (EPEC), like many bacterial pathogens, employ a type III secretion system to deliver effector proteins across the bacterial cell. In EPEC, four proteins are known to be exported by a type III secretion system--EspA, EspB and EspD required for subversion of host cell signal transduction pathways and a translocated intimin receptor (Tir) protein (formerly Hp90) which is tyrosine-phosphorylated following transfer to the host cell to become a receptor for intimin-mediated intimate attachment and "attaching and effacing" (A/E) lesion formation. The structural basis for protein translocation has yet to be fully elucidated for any type III secretion system. Here, we describe a novel EspA-containing filamentous organelle that is present on the bacterial surface during the early stage of A/E lesion formation, forms a physical bridge between the bacterium and the infected eukaryotic cell surface and is required for the translocation of EspB into infected epithelial cells.
Phillips
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AD
University Department of Paediatric Gastroenterology, Royal Free Hospital, Pond Street, London NW3 2QG, UK.
D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000502:physiology*; D003967:Diarrhea / Q000382:microbiology*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D004927:Escherichia coli Infections / Q000378:metabolism*; D006801:Humans
D001426:Bacterial Proteins