Journal of Biological Chemistry
Volume 287, Issue 3, 13 January 2012, Pages 1903-1914
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Signal Transduction
Histidine-containing Phosphotransfer Protein-B (HptB) Regulates Swarming Motility through Partner-switching System in Pseudomonas aeruginosa PAO1 Strain

https://doi.org/10.1074/jbc.M111.256586Get rights and content
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The histidine-containing phosphotransfer protein-B (HptB; PA3345) is an intermediate protein involved in transferring a phosphoryl group from multiple sensor kinases to the response regulator PA3346 in Pseudomonas aeruginosa PAO1. The objective of this study was to elucidate the biological significance of the HptB-PA3346 interaction and the regulatory mechanisms thereafter. The transcription profiling analysis of an hptB knock-out mutant showed that the expression of a number of motility-related genes was altered consistent with the non-swarming phenotype observed for the mutant. Domain analysis indicated that the PA3346 C-terminal region (PA3346C) exhibits ∼30% identity with the anti-σ factor SpoIIAB of Bacillus subtilis. The presence of Ser/Thr protein kinase activity targeting an anti-σ antagonist, PA3347, at Ser-56 was confirmed in PA3346C using an in vitro phosphorelay assay. Furthermore, PA3346C and the anti-σ28 factor FlgM were found to interact with PA3347 individually both in vivo and in vitro. FlgM displaced PA3346C in binding of PA3347 and was then competitively displaced by σ28 from the PA3347-FlgM complex, forming a phosphorylation-dependent partner-switching system. The significance of PA3347 phosphorylation in linking the partner-switching system and swarming motility was established by analyzing the swarming phenotype of the PA3347 knock-out mutant and its complement strains.

Bacterial Genetics
Bacterial Protein Kinases
Bacterial Protein Phosphatases
Bacterial Signal Transduction
Bacterial Transcription
Microarray
Protein-Protein Interactions
Serine/Threonine Protein Kinase
Serine/Threonine Protein Phosphatase
Transcription Regulation

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