Analysis of the Chloroplast Protein Kinase Stt7 during State Transitions

Article Article scientifique Article Analysis of the Chloroplast Protein Kinase Stt7 during State Transitions eng 2009 author Lemeille Sylvain 637517 author Willig Adrian 130236 author Depege Nathalie Janine 520447 author Delessert Christian 135641 author Bassi Roberto 45196 author Rochaix Jean-David 25289 0664-0675 10.1371/journal.pbio.1000045 1544-9173 http://dx.plos.org/10.1371/journal.pbio.1000045 State transitions allow for the balancing of the light excitation energy between photosystem I and photosystem II and for optimal photosynthetic activity when photosynthetic organisms are subjected to changing light conditions. This process is regulated by the redox state of the plastoquinone pool through the Stt7/STN7 protein kinase required for phosphorylation of the light-harvesting complex LHCII and for the reversible displacement of the mobile LHCII between the photosystems. We show that Stt7 is associated with photosynthetic complexes including LHCII, photosystem I, and the cytochrome b6f complex. Our data reveal that Stt7 acts in catalytic amounts. We also provide evidence that Stt7 contains a transmembrane region that separates its catalytic kinase domain on the stromal side from its N-terminal end in the thylakoid lumen with two conserved Cys that are critical for its activity and state transitions. On the basis of these data, we propose that the activity of Stt7 is regulated through its transmembrane domain and that a disulfide bond between the two lumen Cys is essential for its activity. The high-light–induced reduction of this bond may occur through a transthylakoid thiol–reducing pathway driven by the ferredoxin-thioredoxin system which is also required for cytochrome b6f assembly and heme biogenesis. Dewey 570 Dewey 580 Dewey 616 43 Département de biologie moléculaire 161 45 Département des sciences végétales 163 54 Département de microbiologie et médecine moléculaire 21B false PLoS biology 7 3 969ad9c6-1aa4-4334-b124-699553c7b40b Article (Published version) Public journal.pbio.1000045.pdf 662342 application/pdf openAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire Faculté des sciences / Section de biologie / Département des sciences végétales Faculté de médecine / Section de médecine fondamentale / Département de microbiologie et médecine moléculaire

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Analysis of the Chloroplast Protein Kinase Stt7 during State Transitions	PLoS biology			2009	641	381

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Delessert, Christian