start-ver=1.4
cd-journal=joma
no-vol=57
cd-vols=
no-issue=6
article-no=
start-page=1115
end-page=1122
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2016
dt-pub=20160601
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Close Relationships Between the PSII Repair Cycle and Thylakoid Membrane Dynamics
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract= In chloroplasts, a three-dimensional network of thylakoid membranes is formed by stacked grana and interconnecting stroma thylakoids. The grana are crowded with photosynthetic proteins, where PSII-light harvesting complex II (LHCII) supercomplexes often show semi-crystalline arrays for efficient energy trapping, transfer and use. Although light is essential for photosynthesis, PSII is damaged by reactive oxygen species that are generated from primary photochemical reactions when plants are exposed to excess light. Because PSII complexes are embedded in the lipid bilayers of thylakoid membranes, their functions are affected by the conditions of the lipids. Electron paramagnetic resonance (EPR) spin trapping measurements showed that singlet oxygen was formed through peroxidation of thylakoid lipids, suggesting that lipid peroxidation can damage proteins, including the D1 protein. After photodamage, PSII is restored by a specific repair system in thylakoid membranes. In the PSII repair cycle, phosphorylation and dephosphorylation of the PSII proteins control the timing of PSII disassembly and subsequent degradation of the D1 protein. Under light stress, stacked grana turn into unstacked thylakoids with bent grana margins. These structural changes may be closely linked to the mechanisms of the PSII repair cycle because PSII can move more easily from the grana core to the stroma thylakoids through an expanded stromal gap between each thylakoid. Thus, plants modulate the structure of thylakoid membranes under high light to carry out efficient PSII repair. This review focuses on the behavior of the PSII complex and the active role of structural changes to thylakoid membranes under light stress.
en-copyright=
kn-copyright=

en-aut-name=Yoshioka-NishimuraMiho
en-aut-sei=Yoshioka-Nishimura
en-aut-mei=Miho
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

affil-num=1
en-affil= Graduate School of Natural Science and Technology, Okayama University
kn-affil=
en-keyword=FtsH protease
kn-keyword=FtsH protease
en-keyword=Light stress
kn-keyword=Light stress
en-keyword=PSII
kn-keyword=PSII
en-keyword=PSII repair cycle
kn-keyword=PSII repair cycle
en-keyword=Photoinhibition
kn-keyword=Photoinhibition
en-keyword=Thylakoid membrane
kn-keyword=Thylakoid membrane
END

start-ver=1.4
cd-journal=joma
no-vol=55
cd-vols=
no-issue=7
article-no=
start-page=1255
end-page=1265
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2014
dt-pub=20140701
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Quality control of photosystem II: direct imaging of the changes in the thylakoid structure and distribution of FtsH proteases in spinach chloroplasts under light stress
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=　Under light stress, the reaction center-binding protein D1 of PSII is photo-oxidatively damaged and removed from PSII complexes by proteases located in the chloroplast. A protease considered to be responsible for degradation of the damaged D1 protein is the metalloprotease FtsH. We showed previously that the active hexameric FtsH protease is abundant at the grana margin and the grana end membranes, and this homo-complex removes the photodamaged D1 protein in the grana. Here, we showed a change in the distribution of FtsH in spinach thylakoids during excessive illumination by transmission electron microscopy (TEM) and immunogold labeling of FtsH. The change in distribution of the protease was accompanied by structural changes to the thylakoids, which we detected using spinach leaves by TEM after chemical fixation of the samples. Quantitative analyses showed several characteristic changes in the structure of the thylakoids, including shrinkage of the grana, outward bending of the marginal portions of the thylakoids and an increase in the height of the grana stacks under excessive illumination. The increase in the height of the grana stacks may include swelling of the thylakoids and an increase in the partition gaps between the thylakoids. These data strongly suggest that excessive illumination induces partial unstacking of the thylakoids, which enables FtsH to access easily the photodamaged D1 protein. Finally three-dimensional tomography of the grana was recorded to observe the effect of light stress on the overall structure of the thylakoids.
en-copyright=
kn-copyright=

en-aut-name=Yoshioka-NishimuraMiho
en-aut-sei=Yoshioka-Nishimura
en-aut-mei=Miho
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=NanbaDaisuke
en-aut-sei=Nanba
en-aut-mei=Daisuke
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

en-aut-name=TakakiTakashi
en-aut-sei=Takaki
en-aut-mei=Takashi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=3
ORCID=

en-aut-name=OhbaChikako
en-aut-sei=Ohba
en-aut-mei=Chikako
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=4
ORCID=

en-aut-name=TsumuraNodoka
en-aut-sei=Tsumura
en-aut-mei=Nodoka
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=5
ORCID=

en-aut-name=MoritaNoriko
en-aut-sei=Morita
en-aut-mei=Noriko
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=6
ORCID=

en-aut-name=SakamotoHirotaka
en-aut-sei=Sakamoto
en-aut-mei=Hirotaka
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=7
ORCID=

en-aut-name=MurataKazuyoshi
en-aut-sei=Murata
en-aut-mei=Kazuyoshi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=8
ORCID=

en-aut-name=YamamotoYasusi
en-aut-sei=Yamamoto
en-aut-mei=Yasusi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=9
ORCID=

affil-num=1
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=2
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=3
en-affil= Techinical support center, JEOL
kn-affil=

affil-num=4
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=5
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=6
en-affil=Graduate School of Natural Science and Technology, Okayama University
kn-affil=

affil-num=7
en-affil=Ushimado Marine Institute, Okayama University
kn-affil=

affil-num=8
en-affil=National Institute for Physiological Sciences
kn-affil=

affil-num=9
en-affil= Graduate School of Natural Science and Technology, Okayama University
kn-affil=
en-keyword=FtsH protease
kn-keyword=FtsH protease
en-keyword=Light stress
kn-keyword=Light stress
en-keyword=Photosystem II
kn-keyword=Photosystem II
en-keyword=Spinach chloroplast
kn-keyword=Spinach chloroplast
en-keyword=TEM
kn-keyword=TEM
en-keyword=Thylakoid
kn-keyword=Thylakoid
END

start-ver=1.4
cd-journal=joma
no-vol=137
cd-vols=
no-issue=
article-no=
start-page=100
end-page=106
dt-received=
dt-revised=
dt-accepted=
dt-pub-year=2014
dt-pub=2014
dt-online=
en-article=
kn-article=
en-subject=
kn-subject=
en-title=
kn-title=Quality control of Photosystem II: The molecular basis for the action of FtsH protease and the dynamics of the thylakoid membranes
en-subtitle=
kn-subtitle=
en-abstract=
kn-abstract=The reaction center-binding D1 protein of Photosystem II is damaged by excessive light, which leads to photoinhibition of Photosystem II. The damaged D1 protein is removed immediately by specific proteases, and a metalloprotease FtsH located in the thylakoid membranes is involved in the proteolytic process. According to recent studies on the distribution and organization of the protein complexes/supercomplexes in the thylakoid membranes, the grana of higher plant chloroplasts are crowded with Photosystem II complexes and light-harvesting complexes. For the repair of the photodamaged D1 protein, the majority of the active hexameric FtsH proteases should be localized in close proximity to the Photosystem II complexes. The unstacking of the grana may increase the area of the grana margin and facilitate easier access of the FtsH proteases to the damaged D1 protein. These results suggest that the structural changes of the thylakoid membranes by light stress increase the mobility of the membrane proteins and support the quality control of Photosystem II.
en-copyright=
kn-copyright=

en-aut-name=Yoshioka-NishimuraMiho
en-aut-sei=Yoshioka-Nishimura
en-aut-mei=Miho
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=1
ORCID=

en-aut-name=YamamotoYasusi
en-aut-sei=Yamamoto
en-aut-mei=Yasusi
kn-aut-name=
kn-aut-sei=
kn-aut-mei=
aut-affil-num=2
ORCID=

affil-num=1
en-affil=
kn-affil=Graduate School of Natural Science and Technology, Okayama University

affil-num=2
en-affil=
kn-affil=Graduate School of Natural Science and Technology, Okayama University
en-keyword=Photosystem II
kn-keyword=Photosystem II
en-keyword=Light stress
kn-keyword=Light stress
en-keyword=FtsH protease
kn-keyword=FtsH protease
en-keyword=Grana
kn-keyword=Grana
en-keyword=Thylakoid
kn-keyword=Thylakoid
END