title: Dynamics of reversible protein phosphorylation in thylakoids of flowering plants: the roles of STN7, STN8 and TAP38.
abstract: Phosphorylation is the most common post-translational modification found in thylakoid membrane proteins of flowering plants, targeting more than two dozen subunits of all multiprotein complexes, including some light-harvesting proteins. Recent progress in mass spectrometry-based technologies has led to the detection of novel low-abundance thylakoid phosphoproteins and localised their phosphorylation sites. Three of the enzymes involved in phosphorylation/dephosphorylation cycles in thylakoids, the protein kinases STN7 and STN8 and the phosphatase TAP38/PPH1, have been characterised in the model species Arabidopsis thaliana. Differential protein phosphorylation is associated with changes in illumination and various other environmental parameters, and has been implicated in several acclimation responses, the molecular mechanisms of which are only partly understood. The phenomenon of State Transitions, which enables rapid adaptation to short-term changes in illumination, has recently been shown to depend on reversible phosphorylation of LHCII by STN7-TAP38/PPH1. STN7 is also necessary for long-term acclimation responses that counteract imbalances in energy distribution between PSII and PSI by changing the rates of accumulation of their reaction-centre and light-harvesting proteins. Another aspect of photosynthetic acclimation, the modulation of thylakoid ultrastructure, depends on phosphorylation of PSII core proteins, mainly executed by STN8. Here we review recent advances in the characterisation of STN7, STN8 and TAP38/PPH1, and discuss their physiological significance within the overall network of thylakoid protein phosphorylation. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
authors: Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli studi di Milano, I-20133 Milano, Italy.
authors: Paolo
authors: P
authors: Pesaresi
authors: Mathias
authors: M
authors: Pribil
authors: Tobias
authors: T
authors: Wunder
authors: Dario
authors: D
authors: Leister
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology / Q000528:radiation effects; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D020524:Thylakoids / Q000201:enzymology* / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; 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