Quality control of Photosystem II: cleavage and aggregation of heat-damaged D1 protein in spinach thylakoids.
Moderate heat stress (40 degrees C, 30 min) on spinach thylakoids induced cleavage of the D1 protein, producing an N-terminal 23-kDa fragment, a C-terminal 9-kDa fragment, and aggregation of the D1 protein. A homologue of Arabidopsis FtsH2 protease, which is responsible for degradation of the damaged D1 protein, was abundant in the stroma thylakoids. Two processes occurred in the thylakoids in response to heat stress: dephosphorylation of the D1 protein in the stroma thylakoids, and aggregation of the phosphorylated D1 protein in the grana. Heat stress also induced the release of the extrinsic PsbO, P and Q proteins from Photosystem II, which affected D1 degradation and aggregation significantly. The cleavage and aggregation of the D1 protein appear to be two alternative processes influenced by protein phosphorylation/dephosphorylation, distribution of FtsH, and intactness of the thylakoids.
Komayama
Keisuke
K
Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
Khatoon
Mahbuba
M
Takenaka
Daichi
D
Horie
Junko
J
Yamashita
Amu
A
Yoshioka
Miho
M
Nakayama
Yohsuke
Y
Yoshida
Mari
M
Ohira
Satoshi
S
Morita
Noriko
N
Velitchkova
Maya
M
Enami
Isao
I
Yamamoto
Yasusi
Y
D006358:Hot Temperature; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011786:Quality Control; D018724:Spinacia oleracea; D020524:Thylakoids / Q000737:chemistry* / Q000378:metabolism
D045332:Photosystem II Protein Complex; D010940:Plant Proteins