Polyphosphate affects cytoplasmic and chromosomal dynamics in nitrogen-starved Pseudomonas aeruginosa

• 成果类型: Article
• 署名作者: Magkiriadou, Sofia; Stepp, Willi L.; Newman, Dianne K.; Manley, Suliana; Racki, Lisa R.
• 署名单位: Swiss Federal Institutes of Technology Domain; Ecole Polytechnique Federale de Lausanne; California Institute of Technology; California Institute of Technology; Scripps Research Institute
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14443
• DOI: 10.1073/pnas.2313004121
• 发表日期: 2024-04-09
• 关键词: inorganic polyphosphate; starvation; virulence; GROWTH; atp

摘要

Polyphosphate (polyP) synthesis is a ubiquitous stress and starvation response in bacteria. In diverse species, mutants unable to make polyP have a wide variety of physiological defects, but the mechanisms by which this simple polyanion exerts its effects remain unclear. One possibility is that polyP's many functions stem from global effects on the biophysical properties of the cell. We characterize the effect of polyphosphate on cytoplasmic mobility under nitrogen-starvation conditions in the opportunistic pathogen Pseudomonas aeruginosa. Using fluorescence microscopy and particle tracking, we quantify the motion of chromosomal loci and cytoplasmic tracer particles. In the absence of polyP and upon starvation, we observe a 2- to 10-fold increase in mean cytoplasmic diffusivity. Tracer particles reveal that polyP also modulates the partitioning between a more mobile and a less mobile population: Small particles in cells unable to make polyP are more likely to be mobile and explore more of the cytoplasm, particularly during starvation. Concomitant with this larger freedom of motion in polyP-deficient cells, we observe decompaction of the nucleoid and an increase in the steady-state concentration of ATP. The dramatic polyP-dependent effects we observe on cytoplasmic transport properties occur under nitrogen starvation, but not carbon starvation, suggesting that polyP may have distinct functions under different types of starvation.