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The ancestral symbiont sensor kinase CSK links photosynthesis with gene expression in chloroplasts

2008; National Academy of Sciences; Volume: 105; Issue: 29 Linguagem: Inglês

10.1073/pnas.0803928105

1091-6490

Sujith Puthiyaveetil, Tony A. Kavanagh, Peter Cain, James A. Sullivan, C. A. Newell, John C. Gray, Colin Robinson, Mark van der Giezen, Matthew B. Rogers, John F. Allen,

Light effects on plants

We describe a novel, typically prokaryotic, sensor kinase in chloroplasts of green plants. The gene for this chloroplast sensor kinase (CSK) is found in cyanobacteria, prokaryotes from which chloroplasts evolved. The CSK gene has moved, during evolution, from the ancestral chloroplast to the nuclear genomes of eukaryotic algae and green plants. The CSK protein is now synthesised in the cytosol of photosynthetic eukaryotes and imported into their chloroplasts as a protein precursor. In the model higher plant Arabidopsis thaliana, CSK is autophosphorylated and required for control of transcription of chloroplast genes by the redox state of an electron carrier connecting photosystems I and II. CSK therefore provides a redox regulatory mechanism that couples photosynthesis to gene expression. This mechanism is inherited directly from the cyanobacterial ancestor of chloroplasts, is intrinsic to chloroplasts, and is targeted to chloroplast genes.