Unbiased Proteomic Profiling Strategy for Discovery of Bacterial Effector Proteins Reveals that Salmonella Protein PheA Is a Host Cell Cycle Regulator

• Published in: Chemistry & biology Vol. 22; no. 4; pp. 453 - 459
• Main Authors: Na, Ha-Na, Yoo, Young-Hwa, Yoon, Chang No, Lee, Jun-Seok
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 23.04.2015
• Subjects: Animals; Bacterial Proteins - metabolism; Cell Line; E2F7 Transcription Factor - genetics; E2F7 Transcription Factor - metabolism; Electrophoresis, Polyacrylamide Gel; Electrophoretic Mobility Shift Assay; Fluorescent Dyes - chemistry; Fluorescent Dyes - metabolism; G1 Phase Cell Cycle Checkpoints; Genome, Bacterial; Host-Pathogen Interactions; Mice; Microscopy, Fluorescence; Prephenate Dehydratase - metabolism; Proteome - analysis; Proteomics; S Phase Cell Cycle Checkpoints; Salmonella Infections - microbiology; Salmonella Infections - physiopathology; Salmonella typhimurium - cytology; Salmonella typhimurium - enzymology; Salmonella typhimurium - genetics; Salmonella typhimurium - physiology
• ISSN: 1074-5521; 1879-1301
• DOI: 10.1016/j.chembiol.2015.03.008

Salmonella utilizes a type III secretion system to inject bacterial effector proteins into the host cell cytosol. Once in the cytosol, these effectors hijack various biochemical pathways to regulate virulence. Despite the importance of effector proteins, especially for understanding host-pathogen interactions, a potentially large number of effectors are yet to be identified. Here, we demonstrate that unbiased chemical proteomic profiling using off-the-shelf fluorescent probes leads to the discovery of a host cell cycle regulator encoded in the Salmonella genome. Our profiling combined with bioinformatic analysis implicates 29 Salmonella as potential effectors. We follow up on the top candidate, chorismate mutase-P/prehenate dehydratase, PheA, and present evidence that PheA is an effector that mimics E2F7 transcription factor of the host cell and promotes G1/S cell cycle arrest. This validates our strategy and opens opportunities for effector identification in the future. [Display omitted] •Distinctly charged fluorophore targeted a unique subset of Salmonella proteins•Fluorophore labeling conditions significantly affected labeling of target proteins•Competitive chemical proteomic profiling identified fluorophore-tagged proteins•Unbiased chemical profiling and sequence analysis revealed host cell regulator Salmonella regulates host cells by injecting their effector proteins. Na et al. used reactive fluorophores for unbiased Salmonella protein tagging and discovered a host cell cycle regulator by chemical proteomic profiling and genome-wide sequence analysis.