title: AtFKBP16-1, a chloroplast lumenal immunophilin, mediates response to photosynthetic stress by regulating PsaL stability.
abstract: Arabidopsis contains 16 putative chloroplast lumen-targeted immunophilins (IMMs). Proteomic analysis has enabled the subcellular localization of IMMs experimentally, but the exact biological and physiological roles of most luminal IMMs remain to be discovered. FK506-binding protein (FKBP) 16-1, one of the lumenal IMMs containing poorly conserved amino acid residues for peptidyl-prolyl isomerase (PPIase) activity, was shown to play a possible role in chloroplast biogenesis in Arabidopsis, and was also found to interact with PsaL in wheat. In this study, further evidence is provided for the notion that Arabidopsis FKBP16-1 (AtFKBP16-1) is transcriptionally and post-transcriptionally regulated by environmental stresses including high light (HL) intensity, and that overexpression of AtFKBP16-1 plants exhibited increased photosynthetic stress tolerance. A blue native-polyacrylamide gel electrophoresis/two-dimensional (BN-PAGE/2-D) analysis revealed that the increase of AtFKBP16-1 affected the levels of photosystem I (PSI)-light harvesting complex I (LHCI) and PSI-LHCI-light harvesting complex II (LHCII) supercomplex, and consequently enhanced tolerance under conditions of HL stress. In addition, plants overexpressing AtFKBP16-1 showed increased accumulation of PsaL protein and enhanced drought tolerance. Using a protease protection assay, AtFKBP16-1 protein was found to have a role in PsaL stability. The AtPsaL levels also responded to abiotic stresses derived from drought, and from methyl viologen stresses in wild-type plants. Taken together, these results suggest that AtFKBP16-1 plays a role in the acclimation of plants under photosynthetic stress conditions, probably by regulating PsaL stability.
authors.affiliation: Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, 305-806, Korea.
authors.forename: Min Sook
authors.initials: MS
authors.lastname: Seok
authors.forename: Young Nim
authors.initials: YN
authors.lastname: You
authors.forename: Hyun Ji
authors.initials: HJ
authors.lastname: Park
authors.forename: Sang Sook
authors.initials: SS
authors.lastname: Lee
authors.forename: Fu
authors.initials: F
authors.lastname: Aigen
authors.forename: Sheng
authors.initials: S
authors.lastname: Luan
authors.forename: Jun Cheul
authors.initials: JC
authors.lastname: Ahn
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Cho
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D060365:Chloroplast Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D015151:Immunoblotting; D020104:Immunophilins / Q000235:genetics* / Q000378:metabolism; D008027:Light; D016877:Oxidants / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D010788:Photosynthesis / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D045331:Photosystem I Protein Complex / Q000235:genetics* / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological; D022021:Tacrolimus Binding Proteins / Q000235:genetics* / Q000378:metabolism; D020524:Thylakoids / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D016877:Oxidants; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C082500:photosystem I, psaL subunit; D006861:Hydrogen Peroxide; C000593202:AtFKBP16-1 protein, Arabidopsis; D022021:Tacrolimus Binding Proteins; D020104:Immunophilins; D010269:Paraquat