Phosphorylation of tyrosine 474 of the enteropathogenic Escherichia coli (EPEC) Tir receptor molecule is essential for actin nucleating activity and is preceded by additional host modifications.

摘要: The enteropathogenic Escherichia coli (EPEC) Tir protein becomes tyrosine phosphorylated in host cells and displays an increase apparent molecular mass. interaction of with the EPEC outer membrane protein, intimin, triggers actin nucleation beneath adherent bacteria. enterohaemorrhagic E. O157:H7 (EHEC) molecule is not phosphorylated. In this paper, phosphorylation shown to be essential for activity, but mass observed target cells. Tyrosine had no role shift, indicating additional modifications. Analysis intermediates indicates that tyrosine-independent modification functions direct Tir's correct insertion from cytoplasm into membrane. Deletion analysis identified domains participating translocation, association membrane, antibody recognition. Intimin was found bind a 55-amino-acid region (TIBA) within topological sequence suggests located extracellular loop. Homologous TIBA sequences exist integrins, which also intimin. Collectively, study provides definitive evidence importance function reveals differences pathogenicity EHEC. data suggest mechanism as well providing clues mode intimin-integrin interaction.