Tyrosine phosphorylation of eukaryotic proteins and translocated intimin receptor by enteropathogenic Escherichia coli

Abstract

Publisher Summary Enteropathogenic Escherichia coli (EPEC) is a major cause of neonatal diarrhea worldwide EPEC adheres tightly to the surface of intestinal epithelial cells, which results in a dramatic remodeling of the host actin cytoskeleton, and the formation of actin pedestals beneath the adhering bacteria. EPEC uses a novel mechanism to modulate the host actin cytoskeleton: it inserts its own receptor for adherence, called Tir (translocated intimin receptor) into the host cell membrane, where it becomes tyrosine phosphorylated, binds a bacterial outer membrane ligand called intimin, and becomes the centerpiece for pedestal formation. In addition to Tir tyrosine phosphorylation, EPEC infection stimulates both the tyrosine phosphorylation and dephosphorylation of a number of host cell proteins. EPEC can prevent its own uptake into macrophage cell lines. This antiphagocytic effect requires the tyrosine dephosphorylation of several macrophage proteins. A method for examining the localization of Tir within pedestals formed by EPEC using immunofluorescence microscopy is presented in the chapter.