Plastoquinone redox status influences carboxysome integrity via a RpaA- and reactive oxygen species-dependent regulatory network.

ABSTRACT: Carboxysomes are bacterial microcompartments that encapsulate Rubisco and are a core component of the cyanobacterial carbon concentration mechanism (CCM). While carboxysome number, size, and spatial organization vary in different environmental conditions (CO₂, light availability, redox state, temperature, and light quality), the molecular mechanisms underlying this potentially adaptive process remain elusive. Herein, we observe that mutants of the circadian rhythm/metabolism factor, Regulator of Phycobilisome Association A (RpaA), exhibit a striking breakdown of carboxysomes under certain environmental conditions. We find that conditions leading to overreduction of the plastoquinone (PQ) pool (mixotrophic growth, high irradiance, or chemical inhibition of electron transfer from

SUBMITTER: Santos-Merino M 

PROVIDER: S-EPMC12448279 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature