Redox-dependent regulation of the stress-induced zinc-finger protein SAP12 in Arabidopsis thaliana.
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.
Ströher
Elke
E
Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany.
Wang
Xin-Jia
XJ
Roloff
Nils
N
Klein
Peter
P
Husemann
Arne
A
Dietz
Karl-Josef
KJ
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*
D029681:Arabidopsis Proteins; C532616:SAP12 protein, Arabidopsis; D014157:Transcription Factors