title: Systematic exploration of thioredoxin target proteins in plant mitochondria.
abstract: The thioredoxin (Trx) system is known to play a pivotal role in cellular redox regulation, but its target proteins in plant mitochondria remain largely uncharacterized. In this study, we systemically screened Trx target candidates in plant mitochondria. Mitochondrial protein extracts were prepared from Arabidopsis shoots, spinach leaves and potato tubers, and then subfractionated into soluble matrix and insoluble membrane fractions. Protein extracts were loaded onto an affinity column immobilizing Arabidopsis mitochondria-localized o-type Trx mutant protein, in which one of two internal cysteines at the active site was substituted by serine. Proteins forming mixed-disulfide intermediates with the mutated Trx were identified by proteomic approaches. This procedure allowed the determination of 101 Trx target candidate proteins involved in a broad spectrum of mitochondrial processes. Furthermore, biochemical assay revealed that one of the potential Trx target proteins, alternative oxidase, is actually redox regulated by Trx. This study provides insights into the regulatory mechanism of diverse functions in mitochondrial biology that are mediated through the Trx system.
authors: Chemical Resources Laboratory, Tokyo Institute of Technology, Nagatsuta 4259-R1-8, Midori-ku, Yokohama 226-8503, Japan.
authors: Keisuke
authors: K
authors: Yoshida
authors: Ko
authors: K
authors: Noguchi
authors: Ken
authors: K
authors: Motohashi
authors: Toru
authors: T
authors: Hisabori
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism; D002457:Cell Extracts; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010449:Peptide Mapping; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D010944:Plants / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020539:Sequence Analysis, Protein; D011198:Solanum tuberosum / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism*; D000099188:Alternative Oxidase
chemical_list: D002457:Cell Extracts; D024101:Mitochondrial Proteins; D050505:Mutant Proteins; D010088:Oxidoreductases; D010940:Plant Proteins; D011994:Recombinant Proteins; D013879:Thioredoxins; D000099188:Alternative Oxidase
keywords: Alternative oxidase (AOX); Arabidopsis; Mitochondria; Redox regulation; Thioredoxin (Trx)