Dephosphorylation of photosystem II proteins and phosphorylation of CP29 in barley photosynthetic membranes as a response to water stress.
Kinetic studies of protein dephosphorylation in barley thylakoid membranes revealed accelerated dephosphorylation of photosystem II (PSII) proteins, and meanwhile rapidly induced phosphorylation of a light-harvesting complex (LHCII) b4, CP29 under water stress. Inhibition of dephosphorylation aggravates stress damages and hampers photosystem recovery after rewatering. This increased dephosphorylation is catalyzed by both intrinsic and extrinsic membrane protein phosphatase. Water stress did not cause any thylakoid destacking, and the lateral migration from granum membranes to stroma-exposed lamellae was only found to CP29, but not other PSII proteins. Activation of plastid proteases and release of TLP40, an inhibitor of the membrane phosphatases, were also enhanced during water stress. Phosphorylation of CP29 may facilitate disassociation of LHCII from PSII complex, disassembly of the LHCII trimer and its subsequent degradation, while general dephosphorylation of PSII proteins may be involved in repair cycle of PSII proteins and stress-response-signaling.
Liu
Wen-Juan
WJ
Ministry of Education Key Laboratory for Bio-Resource and Eco-Environment, College of Life Science, Sichuan University, Chengdu, China.
Chen
Yang-Er
YE
Tian
Wen-Juan
WJ
Du
Jun-Bo
JB
Zhang
Zhong-Wei
ZW
Xu
Fei
F
Zhang
Fan
F
Yuan
Shu
S
Lin
Hong-Hui
HH
D002734:Chlorophyll / Q000378:metabolism; D003681:Dehydration; D004789:Enzyme Activation; D001467:Hordeum / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D020104:Immunophilins / Q000378:metabolism; D007425:Intracellular Membranes / Q000201:enzymology / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D036226:Seedlings / Q000648:ultrastructure; D020524:Thylakoids / Q000201:enzymology / Q000648:ultrastructure
C069660:CP29 light harvesting complex; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll; D010744:Phosphoric Monoester Hydrolases; D010447:Peptide Hydrolases; C111548:TLP40 protein, plant; D020104:Immunophilins