Human Lens Thioredoxin: Molecular Cloning and Functional Characterization

Yegorova, Svitlana; Liu, Aimin; Lou, Marjorie F.

doi:10.1167/iovs.02-1322

Cited by 29 publications

(25 citation statements)

References 39 publications

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“…In each case, oxidative stress transiently up-regulated TRx as we have previously observed (Yegorova et al, 2003,Moon et al, 2004. It is reasonable to expect that cells under oxidative stress would require more TRx as an antioxidant to combat oxidative stress, or as an oxidation damage repair system to maintain redox homeostasis.…”

Section: Discussionsupporting

confidence: 79%

“…Such treatment showed no effect on the mitochondrial isoform of TRx (TRx-2) (Bhuyan et al, 2002). Our laboratory has shown that exposure of human lens epithelial (HLE-B3) cells to H 2 O 2 caused a transient up-regulation of TRx gene, corroborating the transient increase in enzyme activity and protein level (Yegorova et al, 2003). A similar result in transient TRx-1 up-regulation was found in the epithelium of cultured porcine lenses exposed to H 2 O 2 (Moon et al, 2004).…”

Section: Introductionmentioning

confidence: 79%

“…Human cDNA for TRx was cloned into pET23a(+) vector, expressed in E. coli, and the TRx was purified using His-bind column as described earlier (Yegorova et al, 2003). Rabbit antiTRx antibody was prepared by Proteintech Group, Inc. (Chicago, IL, USA) using purified recombinant human TRx.…”

Section: Recombinant Human Lens Trx and Anti-trx Antibodymentioning

confidence: 99%

“…Oxidative stress was able to transiently increase TRx expression both in HLE B3 cells and in the epithelium of organ cultured pig lenses (Yegorova et al, 2003,Moon et al, 2004. Therefore, if TBP-2 can negatively regulate the bioavailability of TRx, oxidative stress may suppress the expression of TBP-2 to allow more available free and functional TRx in the cells.…”

Section: Effect Of H 2 O 2 On Tbp-2 and Trx Mrna And Protein Expressimentioning

confidence: 99%

“…Human lens TRx has been cloned and is known to participate in the oxidative defense of the lens (Yegorova et al, 2003). Bhuyan and associates have shown that the cytosolic isoenzyme TRx-1 was transiently upregulated in the lens of Emory mouse when exposed to UV radiation.…”

Section: Introductionmentioning

confidence: 99%

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Regulation of the bioavailability of thioredoxin in the lens by a specific thioredoxin-binding protein (TBP-2)

Liyanage

Fernando

Lou

2007

Experimental Eye Research

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Thioredoxin (TRx) is known to control redox homeostasis in cells. In recent years, a specific TRx binding protein called thioredoxin binding protein-2 (TBP-2) was found in other cell types and it appeared to negatively regulate TRx bioavailability and thereby control TRx biological function. In view of the sensitivity of lens transparency to redox status, proper regulation of TRx bioavailability is of the utmost importance. This study was conducted to examine the presence and function of TBP-2 in human lens epithelial cells (HLE B3). We cloned human lens TBP-2 from a human cDNA library (GenBank accession number AY 594328) and showed that it is fully homologous to the human brain TBP-2 gene. The recombinant TBP-2 protein was partially purified and mass spectrometric analysis confirmed its sequence homology to that of brain TBP-2. Immunoprecipitates obtained from HLE B3 cells using anti-TRx and anti-TBP-2 antibodies showed the presence of TRx and TBP-2 in immunoprecipitates indicating the formation of a TRx-TBP-2 complex in vivo. Furthermore, under H 2 O 2 -stress conditions, TRx gene expression was transiently up-regulated while TBP-2 gene expression was inversely down-regulated as seen in both HLE B3 cells and in the epithelial cell layers from cultured pig lenses. Cells with overexpressed TBP-2 showed lower TRx activity, grew slower and were more susceptible to oxidative stress-induced apoptosis. This is the first report of the presence of a TRx-specific binding protein in the lens. Our data suggest that TBP-2 is likely a negative regulator for the bioavailability, and therefore, the overall function of TRx in the lens.

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Section: Discussionsupporting

confidence: 79%

Section: Introductionmentioning

confidence: 79%

Section: Recombinant Human Lens Trx and Anti-trx Antibodymentioning

confidence: 99%

Section: Effect Of H 2 O 2 On Tbp-2 and Trx Mrna And Protein Expressimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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