Thioredoxin (TRX) is a disulfide reductase present ubi-quitously in all taxa and plays an important role as a regu-lator of cellular redox state. Recently, a redox-independent, chaperone function has also been reported for some thi-oredoxins. We previously identified nodulin-35, the sub-unit of soybean uricase, as an interacting target of a cyto-solic soybean thioredoxin, GmTRX. Here we report the further characterization of the interaction, which turns out to be independent of the disulfide reductase function and results in the co-localization of GmTRX and nodulin-35 in peroxisomes, suggesting a possible function of GmTRX in peroxisomes. In addition, the chaperone function of GmTRX was demonstrated in in vitro molecular chaperone activity assays including the thermal denaturation assay and ma-late dehydrogenase aggregation assay. Our results dem-onstrate that the target of GmTRX is not only confined to the nodulin-35, but many other peroxisomal proteins, including catalase (AtCAT), transthyretin-like protein 1 (AtTTL1), and acyl-coenzyme A oxidase 4 (AtACX4), also interact with the GmTRX. Together with an increased uricase activity of nodulin-35 and reduced ROS accumulation observed in the presence of GmTRX in our results, especially under heat shock and oxidative stress conditions, it appears that GmTRX represents a novel thioredoxin that is co-localized to the peroxisomes, possibly providing functional integrity to peroxisomal proteins.
CITATION STYLE
Du, H., Kim, S., Hur, Y. S., Lee, M. S., Lee, S. H., & Cheon, C. I. (2015). A Cytosolic Thioredoxin Acts as a Molecular Chaperone for Peroxisome Matrix Proteins as Well as Antioxidant in Peroxisome. Molecules and Cells, 38(2), 187–194. https://doi.org/10.14348/MOLCELLS.2015.2255
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