title: Possible compensatory role among chloroplast proteases under excess-light stress condition.
abstract: The reaction center protein D1 of photosystem II (PSII), known as a primary target of photodamage, is repaired efficiently by the PSII repair cycle, to cope with constant photooxidative damage. Recent studies of Arabidopsis show that the endo-type Deg protease and the exo-type FtsH proteases cooperatively degrade D1 in the PSII repair in vivo. It is particularly interesting that we observed upregulation of Clp and SppA proteases when FtsH was limited in the mutant lacking FtsH2. To examine how the complementary functions of chloroplastic proteases are commonly regulated, we undertook a high-light stress on wild-type Arabidopsis leaves. The result that wild type leaves also showed increased levels of these proteases upon exposure to excessively strong illumination not only revealed the importance of FtsH and Deg in the PSII repair, but also implied cooperation among chloroplastic proteases under chronic stress conditions.
authors.affiliation: Institute of Plant Science and Resources (IPSR); Okayama University; Kurashiki, Okayama, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kato
authors.forename: Wataru
authors.initials: W
authors.lastname: Sakamoto
mesh_terms: D000222:Adaptation, Physiological; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology*; D008027:Light; D009154:Mutation; D018384:Oxidative Stress; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D029681:Arabidopsis Proteins; D045332:Photosystem II Protein Complex; D010447:Peptide Hydrolases
keywords: D1 protein degradation; Deg; FtsH; chloroplast; photoinhibition; photosynthesis; photosystem II repair cycle; protease