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Molecular invasion of EPEC (and Citrobacter rodentium)

学友会セミナー

学友会セミナー

2003年開催 学友会セミナー

開催日時: 平成15年8月1日(金)  11:00~12:30
開催場所: 1号館2階会議室
講  師: Dr. Gadi Frankel
所  属: Centre for Molecular Microbiology and Infection, Imperial College London
演  題: Molecular invasion of EPEC (and Citrobacter rodentium)
概  要:

Many pathogens infect the host via the intestine. We use a combination of whole animal imaging approaches together with defined tissue-based assays to investigate how virulence factors integrate during colonisation and infection.

While remaining extracellular the human enteropathogenic Escherichia coli (EPEC) and the mouse Citrobacter rodentium pathogens establish direct links with the cytoskeleton of the target epithelial cell leading to formation of actin rich pedestals underneath attached bacteria. The translocated adaptor protein Tir, which is delivered to the cytosol of the host cell through a filamentous type III secretion system, forms the transmembrane bridge between the cytoskeleton and the bacterium; the extracellular domain of Tir functions as a receptor for the bacterial adhesin intimin, while the intracellular amino and carboxy termini interact with a number of focal adhesion and other cytoskeletal proteins. Using Tir as bait and HeLa cell cDNA library as prey in a yeast two hybrid screen we identified cytokeratin 18 as a novel Tir partner protein. Cytokeratin 18 is recruited to the EPEC-induced pedestal and has a direct role in actin accretion and cytoskeleton reorganisation. Using STM in Citrobacter rodentium we have found novel colonisation factors, attributed new functions to known effector proteins and determine colonisation patterns following oral challenge.

世 話 人: 伊庭 英夫、○笹川 千尋