title: Redox-dependent regulation of the stress-induced zinc-finger protein SAP12 in Arabidopsis thaliana.
abstract: The stress-associated protein SAP12 belongs to the stress-associated protein (SAP) family with 14 members in Arabidopsis thaliana. SAP12 contains two AN1 zinc fingers and was identified in diagonal 2D redox SDS-PAGE as a protein undergoing major redox-dependent conformational changes. Its transcript was strongly induced under cold and salt stress in a time-dependent manner similar to SAP10, with high levels after 6 h and decreasing levels after 24 and 48 h. The transcript regulation resembled those of the stress marker peroxiredoxin PrxIID at 24 and 48 h. Recombinant SAP12 protein showed redox-dependent changes in quaternary structure as visualized by altered electrophoretic mobility in non-reducing SDS polyacrylamide gel electrophoresis. The oxidized oligomer was reduced by high dithiothreitol concentrations, and also by E. coli thioredoxin TrxA with low dithiothreitol (DTT) concentrations or NADPH plus NADPH-dependent thioredoxin reductase. From Western blots, the SAP12 protein amount was estimated to be in the range of 0.5 ng mug(-1) leaf protein. SAP12 protein decreased under salt and cold stress. These data suggest a redox state-linked function of SAP12 in plant cells particularly under cold and salt stress.
authors.affiliation: Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany.
authors.forename: Elke
authors.initials: E
authors.lastname: Ströher
authors.forename: Xin-Jia
authors.initials: XJ
authors.lastname: Wang
authors.forename: Nils
authors.initials: N
authors.lastname: Roloff
authors.forename: Peter
authors.initials: P
authors.lastname: Klein
authors.forename: Arne
authors.initials: A
authors.lastname: Husemann
authors.forename: Karl-Josef
authors.initials: KJ
authors.lastname: Dietz
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological; D014157:Transcription Factors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C532616:SAP12 protein, Arabidopsis; D014157:Transcription Factors