The Escherichia coli Phosphotyrosine Proteome Relates to Core Pathways and Virulence

PLoS Pathogens

Santosh Renuse¹  Harrys K. C. Jacob²  Anne-Marie Hansen³  Akhilesh Pandey⁴  Bernard Delanghe⁴  Nandini A. Sahasrabuddhe⁴  Andrew Emili⁴  J. Javier Díaz-Mejía⁴  Raghothama Chaerkady⁴  Nidhi Tyagi⁵  James B. Kaper⁵  Min-Sik Kim⁶  Narayanaswamy Srinivasan⁶  Jyoti Sharma⁶  Sneha M. Pinto⁷ 

[1] Banting and Best Department of Medical Research, Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada;Department of Biology, Wilfrid Laurier University, Waterloo, Canada;Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America;Institute of Bioinformatics, International Tech Park, Bangalore, India;Manipal University, Manipal, India;McKusick-Nathans Institute of Genetic Medicine and Department of Biological Chemistry, Johns Hopkins University, Baltimore, Maryland, United States of America;Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India

关键词: Phosphorylation;    Tyrosine kinases;    Tyrosine;    Sequence motif analysis;    Protein metabolism;    Proteomes;    Secretion systems;    Gene expression;   

DOI  :  10.1371/journal.ppat.1003403

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

While phosphotyrosine modification is an established regulatory mechanism in eukaryotes, it is less well characterized in bacteria due to low prevalence. To gain insight into the extent and biological importance of tyrosine phosphorylation in Escherichia coli, we used immunoaffinity-based phosphotyrosine peptide enrichment combined with high resolution mass spectrometry analysis to comprehensively identify tyrosine phosphorylated proteins and accurately map phosphotyrosine sites. We identified a total of 512 unique phosphotyrosine sites on 342 proteins in E. coli K12 and the human pathogen enterohemorrhagic E. coli (EHEC) O157:H7, representing the largest phosphotyrosine proteome reported to date in bacteria. This large number of tyrosine phosphorylation sites allowed us to define five phosphotyrosine site motifs. Tyrosine phosphorylated proteins belong to various functional classes such as metabolism, gene expression and virulence. We demonstrate for the first time that proteins of a type III secretion system (T3SS), required for the attaching and effacing (A/E) lesion phenotype characteristic for intestinal colonization by certain EHEC strains, are tyrosine phosphorylated by bacterial kinases. Yet, A/E lesion and metabolic phenotypes were unaffected by the mutation of the two currently known tyrosine kinases, Etk and Wzc. Substantial residual tyrosine phosphorylation present in an etk wzc double mutant strongly indicated the presence of hitherto unknown tyrosine kinases in E. coli. We assess the functional importance of tyrosine phosphorylation and demonstrate that the phosphorylated tyrosine residue of the regulator SspA positively affects expression and secretion of T3SS proteins and formation of A/E lesions. Altogether, our study reveals that tyrosine phosphorylation in bacteria is more prevalent than previously recognized, and suggests the involvement of phosphotyrosine-mediated signaling in a broad range of cellular functions and virulence.

【 授权许可】

CC BY