Disease relevance of ATTRX2

• Three members of a novel small gene-family from Arabidopsis thaliana able to complement functionally an Escherichia coli mutant defective in PAPS reductase activity encode proteins with a thioredoxin-like domain and "APS reductase" activity [1].

High impact information on ATTRX2

• FKBP20-2 has a unique pair of cysteines at the C terminus and was found to be reduced by thioredoxin (Trx) (itself reduced by NADPH by means of NADP-Trx reductase) [2].
• However, unlike microbial PAPS reductases, each PRH protein has an N-terminal extension, characteristic of a plastid transit peptide, and a C-terminal extension that has amino acid and deduced three-dimensional homology to thioredoxin proteins [1].
• Activation of reduced alpha protein does not require dithiothreitol or thioredoxin anymore, and activation rates are much faster than previously reported [3].
• We have constructed hybrid proteins between these two thioredoxins and show that all information necessary for sulfate assimilation is present in the C-terminal part of AtTRX2, whereas some information needed for H(2)O(2) tolerance is located in the N-terminal part of AtTRX3 [4].
• Expression of one of the multiple Arabidopsis thaliana thioredoxins h in this mutant complements only some aspects of the phenotype, depending on the expressed thioredoxin: AtTRX2 or AtTRX3 induce methionine sulfoxide assimilation and restore a normal cell cycle [4].

Biological context of ATTRX2

• These finding suggest that GPX isoenzymes may function to detoxify H2O2 and organic hydroperoxides using thioredoxin in vivo and may also be involved in regulation of the cellular redox homeostasis by maintaining the thiol/disulfide or NADPH/NADP balance [5].
• Thioredoxin (TRX) is a small multifunctional protein with a disulfide active site involved in redox regulation [6].
• The abundance of the CDSP32 thioredoxin, a critical component of the defence system against oxidative damage and lipid peroxidation, was found to be higher in T. halophila than in A. thaliana under control conditions and salt treatment [7].

Anatomical context of ATTRX2

• Thus, the yield of active ATP N peroxidase can be increased 50-fold by using thioredoxin reductase negative strains, which facilitate the formation of disulfide bonds in inclusion body protein [8].

Associations of ATTRX2 with chemical compounds

• In addition AtTRX2 also confers growth on sulfate but no H(2)O(2) tolerance [4].
• In the two first approaches targets present in a mixture of soluble leaf proteins were reduced by the cytosolic TRX h3, then the new thiols were labeled either with radioactive iodoacetamide allowing specific detection (first method) or with a biotinylated thiol-specific compound allowing selective retention on an avidin column (second method) [6].
• Interestingly, these recombinant proteins were able to reduce H2O2, cumene hydroperoxide, phosphatidylcholine and linoleic acid hydroperoxides using thioredoxin but not glutathione or NADPH as an electron donor [5].

References