title: Architectural switch in plant photosynthetic membranes induced by light stress.
abstract: Unavoidable side reactions of photosynthetic energy conversion can damage the water-splitting photosystem II (PSII) holocomplex embedded in the thylakoid membrane system inside chloroplasts. Plant survival is crucially dependent on an efficient molecular repair of damaged PSII realized by a multistep repair cycle. The PSII repair cycle requires a brisk lateral protein traffic between stacked grana thylakoids and unstacked stroma lamellae that is challenged by the tight stacking and low protein mobility in grana. We demonstrated that high light stress induced two main structural changes that work synergistically to improve the accessibility between damaged PSII in grana and its repair machinery in stroma lamellae: lateral shrinkage of grana diameter and increased protein mobility in grana thylakoids. It follows that high light stress triggers an architectural switch of the thylakoid network that is advantageous for swift protein repair. Studies of the thylakoid kinase mutant stn8 and the double mutant stn7/8 demonstrate the central role of protein phosphorylation for the structural alterations. These findings are based on the elaboration of mathematical tools for analyzing confocal laser-scanning microscopic images to study changes in the sophisticated thylakoid architecture in intact protoplasts.
authors.affiliation: Institute of Biological Chemistry, College of Agricultural, Human, and Natural Resource Sciences, Washington State University, Pullman, WA 99164, USA.
authors.forename: Miroslava
authors.initials: M
authors.lastname: Herbstová
authors.forename: Stefanie
authors.initials: S
authors.lastname: Tietz
authors.forename: Christopher
authors.initials: C
authors.lastname: Kinzel
authors.forename: Maria V
authors.initials: MV
authors.lastname: Turkina
authors.forename: Helmut
authors.initials: H
authors.lastname: Kirchhoff
mesh_terms: D017360:Arabidopsis; D005453:Fluorescence; D036681:Fluorescence Recovery After Photobleaching; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D008027:Light / Q000009:adverse effects*; D018613:Microscopy, Confocal; D010766:Phosphorylation; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology; D013050:Spectrometry, Fluorescence; D020524:Thylakoids / Q000378:metabolism / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D045332:Photosystem II Protein Complex; D011494:Protein Kinases; C504925:STN8 protein, Arabidopsis