Impaired photosystem I oxidation induces STN7-dependent phosphorylation of the light-harvesting complex I protein Lhca4 in Arabidopsis thaliana.
Reduction of the plastoquinone (PQ) pool is known to activate phosphorylation of thylakoid proteins. In the Arabidopsis thaliana mutants psad1-1 and psae1-3, oxidation of photosystem I (PSI) is impaired, and the PQ pool is correspondingly over-reduced. We show here that, under these conditions, the antenna protein Lhca4 of PSI becomes a target for phosphorylation. Phosphorylation of the mature Lhca4 protein at Thr16 is suppressed in stn7 psad1 and stn7 psae1 double mutants. Thus, under extreme redox conditions, hyperactivation of thylakoid protein kinases and/or reorganization of thylakoid protein complex distribution increase the susceptibility of PSI to phosphorylation.
Ihnatowicz
Anna
A
Abteilung für Pflanzenzüchtung und Genetik, Max-Planck-Institut für Züchtungsforschung, Carl-von-Linné-Weg 10, 50829 cologne, Germany.
Pesaresi
Paolo
P
Lohrig
Katharina
K
Wolters
Dirk
D
Müller
Bernd
B
Leister
Dario
D
D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D061146:Chlorophyll Binding Proteins; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D009154:Mutation; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D045331:Photosystem I Protein Complex / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D020524:Thylakoids / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; D045342:Light-Harvesting Protein Complexes; D010750:Phosphoproteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; C412446:psaE1 protein, Arabidopsis; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C497212:STN7 protein, Arabidopsis