1. RcsB regulation of the YfdX-mediated acid stress response in Klebsiella pneumoniae CG43S3
- Author
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Chia Jui Liu, Jo Di Chiang, Hwei-Ling Peng, Chih Huan Lin, Kuan Nan Peng, Ching-Ting Lin, Yen Xi Tay, Li Cheng Fan, and Chen Yi Lin
- Subjects
Molecular biology ,Proteomes ,Mutant ,Protein Data Bank (RCSB PDB) ,Gene Expression ,Pathology and Laboratory Medicine ,Biochemistry ,Klebsiella Pneumoniae ,Plasmid ,Mathematical and Statistical Techniques ,Klebsiella ,Nucleic Acids ,Mobile Genetic Elements ,Genes, Regulator ,Medicine and Health Sciences ,Post-Translational Modification ,Phosphorylation ,Promoter Regions, Genetic ,Regulation of gene expression ,0303 health sciences ,Multidisciplinary ,biology ,Chemistry ,Statistics ,Genomics ,Hydrogen-Ion Concentration ,Recombinant Proteins ,Cell biology ,Bacterial Pathogens ,Medical Microbiology ,Research Design ,Physical Sciences ,Medicine ,Pathogens ,Research Article ,Plasmids ,Clinical Research Design ,Forms of DNA ,Science ,DNA construction ,Microbiology ,Promoter Regions ,03 medical and health sciences ,Genetic Elements ,Bacterial Proteins ,Stress, Physiological ,Genetics ,Humans ,Gene Regulation ,Statistical Methods ,Microbial Pathogens ,030304 developmental biology ,Bacteria ,030306 microbiology ,Organisms ,Biology and Life Sciences ,Proteins ,Periplasmic space ,DNA ,Gene Expression Regulation, Bacterial ,Survival Analysis ,Research and analysis methods ,Response regulator ,Molecular biology techniques ,Genes, Bacterial ,Chaperone (protein) ,Plasmid Construction ,biology.protein ,Mutagenesis, Site-Directed ,Acids ,Mathematics ,Gene Deletion - Abstract
In Klebsiella pneumoniae CG43S3, deletion of the response regulator gene rcsB reduced the capsular polysaccharide amount and survival on exposure to acid stress. A comparison of the pH 4.4-induced proteomes between CG43S3 and CG43S3ΔrcsB revealed numerous differentially expressed proteins and one of them, YfdX, which has recently been reported as a periplasmic protein, was absent in CG43S3ΔrcsB. Acid survival analysis was then conducted to determine its role in the acid stress response. Deletion of yfdX increased the sensitivity of K. pneumoniae CG43S3 to a pH of 2.5, and transforming the mutant with a plasmid carrying yfdX restored the acid resistance (AR) levels. In addition, the effect of yfdX deletion was cross-complemented by the expression of the periplasmic chaperone HdeA. Furthermore, the purified recombinant protein YfdX reduced the acid-induced protein aggregation, suggesting that YfdX as well as HdeA functions as a chaperone. The following promoter activity measurement revealed that rcsB deletion reduced the expression of yfdX after the bacteria were subjected to pH 4.4 adaptation. Western blot analysis also revealed that YfdX production was inhibited by rcsB deletion and only the plasmid expressing RcsB or the nonphosphorylated form of RcsB, RcsBD56A, could restore the YfdX production, and the RcsB-mediated complementation was no longer observed when the sensor kinase RcsD gene was deleted. In conclusion, this is the first study demonstrating that YfdX may be involved in the acid stress response as a periplasmic chaperone and that RcsB positively regulates the acid stress response partly through activation of yfdX expression. Moreover, the phosphorylation status of RcsB may affect the YfdX expression under acidic conditions.
- Published
- 2019