title: Protein kinases and phosphatases involved in the acclimation of the photosynthetic apparatus to a changing light environment.
abstract: Photosynthetic organisms are subjected to frequent changes in light quality and quantity and need to respond accordingly. These acclimatory processes are mediated to a large extent through thylakoid protein phosphorylation. Recently, two major thylakoid protein kinases have been identified and characterized. The Stt7/STN7 kinase is mainly involved in the phosphorylation of the LHCII antenna proteins and is required for state transitions. It is firmly associated with the cytochrome b(6)f complex, and its activity is regulated by the redox state of the plastoquinone pool. The other kinase, Stl1/STN8, is responsible for the phosphorylation of the PSII core proteins. Using a reverse genetics approach, we have recently identified the chloroplast PPH1/TAP38 and PBPC protein phosphatases, which counteract the activity of STN7 and STN8 kinases, respectively. They belong to the PP2C-type phosphatase family and are conserved in land plants and algae. The picture that emerges from these studies is that of a complex regulatory network of chloroplast protein kinases and phosphatases that is involved in light acclimation, in maintenance of the plastoquinone redox poise under fluctuating light and in the adjustment to metabolic needs.
authors.affiliation: Departments of Molecular Biology and Plant Biology, University of Geneva, 30 Quai Ernest Ansermet, Geneva 4, Switzerland. jean-david.rochaix@unige.ch
authors.forename: Jean-David
authors.initials: JD
authors.lastname: Rochaix
authors.forename: Sylvain
authors.initials: S
authors.lastname: Lemeille
authors.forename: Alexey
authors.initials: A
authors.lastname: Shapiguzov
authors.forename: Iga
authors.initials: I
authors.lastname: Samol
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Fucile
authors.forename: Adrian
authors.initials: A
authors.lastname: Willig
authors.forename: Michel
authors.initials: M
authors.lastname: Goldschmidt-Clermont
mesh_terms: D000064:Acclimatization; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016825:Chlamydomonas reinhardtii / Q000201:enzymology / Q000235:genetics; D002736:Chloroplasts / Q000201:enzymology / Q000235:genetics; D004777:Environment; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D010971:Plastoquinone / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C497212:STN7 protein, Arabidopsis; C504925:STN8 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases; C550563:TAP38 protein, Arabidopsis; D010971:Plastoquinone