Ser/Thr protein kinase Stk1 phosphorylates the key transcriptional regulator AlgR to modulate virulence and resistance in Pseudomonas aeruginosa

ABSTRACT

Pseudomonas aeruginosa is one of the leading causes of nosocomial infections worldwide and has emerged as a serious public health threat, due in large part to its multiple virulence factors and remarkable resistance capabilities. Stk1, a eukaryotic-type Ser/Thr protein kinase, has been shown in our previous work to be involved in the regulation of several signalling pathways and biological processes. Here, we demonstrate that deletion of stk1 leads to alterations in several virulence- and resistance-related physiological functions, including reduced pyocyanin and pyoverdine production, attenuated twitching motility, and enhanced biofilm production, extracellular polysaccharide secretion, and antibiotic resistance. Moreover, we identified AlgR, an important transcriptional regulator, as a substrate for Stk1, with its phosphorylation at the Ser143 site catalysed by Stk1. Intriguingly, both the deletion of stk1 and the mutation of Ser143 of AlgR to Ala result in similar changes in the above-mentioned physiological functions. Furthermore, assays of algR expression in these strains suggest that changes in the phosphorylation state of AlgR, rather than its expression level, underlie changes in these physiological functions. These findings uncover Stk1-mediated phosphorylation of AlgR as an important mechanism for regulating virulence and resistance in P. aeruginosa.

KEYWORDS:

• Pseudomonas aeruginosa
• Ser/Thr protein kinase Stk1
• transcriptional regulator AlgR
• phosphorylation
• Virulence
• Resistance

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

Rui Li: Writing – original draft, Methodology, Validation, Data curation. Xuan Zhu: Writing – original draft, Methodology, Investigation, Data curation, Formal analysis. Pengfei Zhang: Methodology, Investigation, Data curation, Formal analysis. Xuan Wu: Formal analysis, Methodology. Qian Jin: Formal analysis, Methodology. Jianyi Pan: Funding acquisition, Project administration, Supervision, Investigation, Writing – review & editing.

Data availability statement

The data that support the findings of this study are openly available in figshare at https://doi.org/10.6084/m9.figshare.25551474.v3, reference number 25,551,474.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/21505594.2024.2367649

Additional information

Funding

This work was supported by grants from the Basic Public Welfare Research Program of Zhejiang Province (LY22C010003), National Natural Science Foundation of China (32270198) and the 521 Talent Program of Zhejiang Sci-Tech University, China, to J. Pan.