Protein kinases and phosphatases involved in the acclimation of the photosynthetic apparatus to a changing light environment

• Published in: Philosophical transactions of the Royal Society of London. Series B. Biological sciences 2012-12, Vol.367 (1608), p.3466-3474
• Main Authors: Rochaix, Jean-David, Lemeille, Sylvain, Shapiguzov, Alexey, Samol, Iga, Fucile, Geoffrey, Willig, Adrian, Goldschmidt-Clermont, Michel
• Format: Article
• Language: English
• Subjects: Acclimation; Acclimatization; Amino Acid Sequence; Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Chlamydomonas reinhardtii - enzymology; Chlamydomonas reinhardtii - genetics; Chloroplast; Chloroplasts; Chloroplasts - enzymology; Chloroplasts - genetics; Electrons; Environment; Grana; Light; Light-Harvesting Protein Complexes - genetics; Light-Harvesting Protein Complexes - metabolism; Molecular Sequence Data; Oxidation-Reduction; Phosphatases; Phosphoprotein Phosphatases - genetics; Phosphoprotein Phosphatases - metabolism; Phosphorylation; Photosynthesis; Photosystem II; Photosystem II Protein Complex - genetics; Photosystem II Protein Complex - metabolism; Plants; Plastoquinone - metabolism; Protein Kinase; Protein Kinases - genetics; Protein Kinases - metabolism; Protein Phosphatase; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Proteins; Review; State Transitions; Thylakoids
• ISSN: 0962-8436; 1471-2970
• DOI: 10.1098/rstb.2012.0064

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 b6f 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.