title: FtsH-mediated repair of the photosystem II complex in response to light stress.
abstract: A common feature of light stress in plants, algae, and cyanobacteria is the light-induced damage to the photosystem II complex (PSII), which catalyses the photosynthetic oxidation of water to molecular oxygen. A repair cycle operates to replace damaged subunits within PSII, in particular, the D1 reaction centre polypeptide, by newly synthesized copies. As yet the molecular details of this physiologically important process remain obscure. A key aspect of the process that has attracted much attention is the identity of the protease or proteases involved in D1 degradation. The results are summarized here of recent mutagenesis experiments that were designed to assess the functional importance of the DegP/HtrA and FtsH protease families in the cyanobacterium Synechocystis sp. PCC 6803. Based on these results and the analysis of Arabidopsis mutants, a general model for PSII repair is suggested in which FtsH complexes alone are able to degrade damaged D1.
authors.affiliation: Wolfson Laboratories, Department of Biological Sciences, Imperial College London, S. Kensington campus, London SW7 2AZ, UK. p.nixon@imperial.ac.uk
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Nixon
authors.forename: Myles
authors.initials: M
authors.lastname: Barker
authors.forename: Marko
authors.initials: M
authors.lastname: Boehm
authors.forename: Remco
authors.initials: R
authors.lastname: de Vries
authors.forename: Josef
authors.initials: J
authors.lastname: Komenda
mesh_terms: D049069:ATP-Dependent Proteases; D017360:Arabidopsis / Q000378:metabolism; D029681:Arabidopsis Proteins; D000458:Cyanobacteria / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000502:physiology; D008027:Light; D008565:Membrane Proteins / Q000502:physiology*; D010447:Peptide Hydrolases / Q000378:metabolism; D033903:Periplasmic Proteins / Q000502:physiology; D045332:Photosystem II Protein Complex / Q000378:metabolism* / Q000528:radiation effects*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D017382:Reactive Oxygen Species; D012697:Serine Endopeptidases / Q000502:physiology; D015398:Signal Transduction; D046939:Synechocystis / Q000378:metabolism
chemical_list: D049069:ATP-Dependent Proteases; D029681:Arabidopsis Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D010447:Peptide Hydrolases; D033903:Periplasmic Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D012697:Serine Endopeptidases; C061682:DegP protease; C402651:AT2G30950 protein, Arabidopsis