title: Downregulation of TAP38/PPH1 enables LHCII hyperphosphorylation in Arabidopsis mutant lacking LHCII docking site in PSI.
abstract: Redox-regulated reversible phosphorylation of the light-harvesting complex II (LHCII) controls the excitation energy distribution between photosystem (PS) II and PSI. The PsaL and PsaH subunits of PSI enable the association of pLHCII to PSI. Here, we show that the failure of the psal mutant to dock pLHCII to PSI induces excessive phosphorylation of LHCII, primarily due to a marked downregulation of the TAP38/PPH1 phosphatase occurring at post-transcriptional level. TAP38/PPH1 is shown to be associated with megacomplex that contains both photosystems in a light- and LHCII-PSII core-phosphorylation-dependent manner. It is suggested that proper megacomplex-related association of TAP38/PPH1 protects it against degradation.
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, FI-20014 University of Turku, Turku, Finland.
authors.forename: Marjaana
authors.initials: M
authors.lastname: Rantala
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, FI-20014 University of Turku, Turku, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Lehtimäki
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, FI-20014 University of Turku, Turku, Finland.
authors.forename: Eva-Mari
authors.initials: EM
authors.lastname: Aro
authors.affiliation: Molecular Plant Biology, Department of Biochemistry, FI-20014 University of Turku, Turku, Finland.
authors.forename: Marjaana
authors.initials: M
authors.lastname: Suorsa
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D015536:Down-Regulation; D017343:Genes, Plant; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D011499:Protein Processing, Post-Translational; D055550:Protein Stability
chemical_list: D029681:Arabidopsis Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C082500:photosystem I, psaL subunit; D010749:Phosphoprotein Phosphatases; C550563:TAP38 protein, Arabidopsis
keywords: TAP38/PPH1; light-harvesting complex II; phosphorylation; photosystem I