Title
EspFU is a translocated EHEC effector that interacts with Tir and N-WASP and promotes Nck-independent actin assembly
GSBS Program
Biochemistry & Molecular Pharmacology
UMMS Affiliation
Graduate School of Biomedical Sciences; Department of Molecular Genetics and Microbiology
Date
8-7-2004
Document Type
Article
Medical Subject Headings
Actins; Blotting, Western; Carrier Proteins; Cell Nucleus; Escherichia coli; Escherichia coli O157; Escherichia coli Proteins; Gene Deletion; Genetic Complementation Test; Genomic Islands; Hela Cells; Humans; Immunoblotting; Microscopy, Fluorescence; Mutation; Nerve Tissue Proteins; Oncogene Proteins; Phosphotyrosine; Plasmids; Precipitin Tests; Proline; Protein Binding; Protein Structure, Tertiary; Protein Transport; Receptors, Cell Surface; Subcellular Fractions; Two-Hybrid System Techniques; Wiskott-Aldrich Syndrome Protein, Neuronal
Disciplines
Life Sciences | Medicine and Health Sciences
Abstract
Several microbial pathogens including enteropathogenic E. coli (EPEC) exploit mammalian tyrosine-kinase signaling cascades to recruit Nck adaptor proteins and activate N-WASP-Arp2/3-mediated actin assembly. To promote localized actin "pedestal formation," EPEC translocates the bacterial effector protein Tir into the plasma membrane, where it is tyrosine-phosphorylated and binds Nck. Enterohemorrhagic E. coli (EHEC) also generates Tir-dependent pedestals, but in the absence of phosphotyrosines and Nck recruitment. To identify additional EHEC effectors that stimulate phosphotyrosine-independent actin assembly, we systematically generated EHEC mutants containing specific deletions in putative pathogenicity-islands. Among 0.33 Mb of deleted sequences, only one ORF was critical for pedestal formation. It lies within prophage-U, and encodes a protein similar to the known effector EspF. This proline-rich protein, EspFU, is the only EHEC effector of actin assembly absent from EPEC. Whereas EHEC Tir cannot efficiently recruit N-WASP or trigger actin polymerization, EspFU associates with Tir, binds N-WASP, and potently stimulates Nck-independent actin assembly.
Rights and Permissions
Citation: Dev Cell. 2004 Aug;7(2):217-28. Link to article on publisher's site