Dual Redox Regulation of the DNA-Binding Activity of the Response Regulator RpaB in the Cyanobacterium Synechocystis sp. PCC 6803

Naoki Kato, Kazuki Iwata, Taro Kadowaki, Kintake Sonoike, Yukako Hihara

研究成果: Article査読

抄録

The response regulator RpaB plays a central role in transcriptional regulation of photosynthesis-related genes in cyanobacteria. RpaB is phosphorylated by its cognate histidine kinase Hik33 and functions as both an activator and a repressor under low-light conditions, whereas its phosphorylation level and DNA-binding activity promptly decrease upon the upshift of photon flux density, causing changes in the gene expression profile. In this study, we assessed the possibility of redox regulation of the DNA-binding activity of RpaB in Synechocystis sp. PCC 6803 by the addition of inhibitors of photosynthetic electron transport, 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone, or the reducing agent dithiothreitol under different photon flux densities. Analysis of the phosphorylation level of RpaB revealed that reduction of QA and increase in the availability of reducing equivalents at the acceptor side of photosystem I (PSI) can independently trigger dephosphorylation. The redox-state-dependent regulation by an unidentified thiol other than Cys59 of RpaB is prerequisite for the phosphorylation-dependent regulation of the DNA-binding activity. Environmental signals, recognized by Hik33, and metabolic signals recognized as the availability of reducing equivalents, must be integrated at the master regulator RpaB, in order to attain the flexible regulation of acclimatory responses.

本文言語English
ページ(範囲)1078-1090
ページ数13
ジャーナルPlant & cell physiology
63
8
DOI
出版ステータスPublished - 2022 8月 17

ASJC Scopus subject areas

  • 生理学
  • 植物科学
  • 細胞生物学

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