Year: 2026
Type: preprint
Abstract: rapidly accumulates polyP, which drives the formation of RNA-protein granules that sustain long-term survival. What triggers this upregulation has remained unknown. Here we show that polyamines, a group of highly conserved, amino acid-derived polycations, regulate polyP accumulation during N starvation. We found that deleting all nine polyamine biosynthesis genes elevates polyP during exponential growth and by more than 5-fold under N starvation, with shorter chains preferentially accumulating. To dissect which polyamine matters, we further deleted the three catabolic enzymes that consume polyamines as a nitrogen source, which enabled complementation assays. Supplying any one of the three physiological polyamines, putrescine, spermidine, or cadaverine, restored wild-type polyP levels during N starvation. We found that the absence of polyamines did not affect the steady-state levels of either the polyP-synthesizing kinase PPK or the exopolyphosphatase PPX, pointing instead to post-translational control of enzyme activity or to as-yet-unidentified polyamine-dependent regulators. These findings establish a direct metabolic link between two universal, functionally intertwined biomolecules and suggest that the polyamine decline upon N starvation contributes to the observed polyP accumulation.
Authors: Jian Guan, Pavithra Mahadevan, Ursula Jakob
Institutions: University of Michigan, Michigan Medicine
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W7213658286