Quinone sensing by the circadian input kinase of the cyanobacterial circadian clock.

ABSTRACT: Circadian rhythms are endogenous cellular programs that time metabolic and behavioral events to occur at optimal times in the daily cycle. Light and dark cycles synchronize the endogenous clock with the external environment through a process called entrainment. Previously, we identified the bacteriophytochrome-like circadian input kinase CikA as a key factor for entraining the clock in the cyanobacterium Synechococcus elongatus PCC 7942. Here, we present evidence that CikA senses not light but rather the redox state of the plastoquinone pool, which, in photosynthetic organisms, varies as a function of the light environment. Furthermore, CikA associates with the Kai proteins of the circadian oscillator, and it influences the phosphorylation state of KaiC during resetting of circadian phase

SUBMITTER: Ivleva NB 

PROVIDER: S-EPMC1859952 | biostudies-literature | 2006 Nov

REPOSITORIES: biostudies-literature