Functional characterization of the twin-arginine translocation system in Campylobacter jejuni.
Human campylobacterosis is one of the most commonly occurring types of bacterial food poisoning in the United States and other developed countries. Most human cases are due to Campylobacter jejuni that is commonly found in the gastrointestinal tract of chickens. The twin-arginine translocase (TAT) secretion system uses N-terminal peptide tags with a distinct twin-arginine-containing motif to identify partially or fully folded proteins and directs them across the cytoplasmic membrane. In other bacteria, the TAT system contributes to diverse phenotypes, including virulence, but the role of this secretion system in Campylobacter pathophysiology is still not well defined. Genome sequence of C. jejuni revealed TAT pathway genes as well as several proteins that contain TAT pathway targeting motifs. The predicted Tat substrates are highly conserved among all sequenced C. jejuni strains. Phenotypic analyses revealed that the tatC knockout has defects in biofilm formation, motility, and flagellation, as well as an increased susceptibility to antimicrobials. Additionally, the tatC mutant was defective in survival under osmotic shock, oxidative, and nutrient stresses. Our results also indicated that tatC is essential for C. jejuni to sustain colonization in chickens. These findings suggest that the TAT pathway affects Campylobacter physiology and contributes to stress responses, allowing this fastidious pathogen to adapt to various environmental conditions.
Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio 44691, USA. rajashekara.2@osu.edu
Gireesh
G
Rajashekara
Mary
M
Drozd
Dharanesh
D
Gangaiah
Byeonghwa
B
Jeon
Zhe
Z
Liu
Qijing
Q
Zhang
D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002169:Campylobacter Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary; D016123:Campylobacter jejuni / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000472:pathogenicity; D002462:Cell Membrane / Q000378:metabolism; D002645:Chickens / Q000382:microbiology*; D015169:Colony Count, Microbial; D030561:Databases, Nucleic Acid; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D009997:Osmotic Pressure; D018384:Oxidative Stress; D011201:Poultry Diseases / Q000382:microbiology / Q000635:transmission; D021382:Protein Sorting Signals; D021381:Protein Transport / Q000235:genetics; D017384:Sequence Deletion; D013312:Stress, Physiological
D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D021382:Protein Sorting Signals