Diabetic changes in the redox status of the microsomal protein folding machinery.

Gábor Nardai, Krisztián Stadler, Eszter Papp, Tamás Korcsmáros, Judit Jakus, Péter Csermely

Department of Medical Chemistry, Semmelweis University, P.O. Box 260, H-1444 Budapest 8, Hungary.

Biochemical and biophysical research communications 2005 Sep 2

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Changes in assisted protein folding are largely unexplored in diabetes. In the present studies, we have identified a reductive shift in the redox status of rat liver microsomes after 4 weeks of streptozotocin-induced diabetes. This change was reflected by a significant increase in the total- and protein-sulfhydryl content, as well as in the free sulfhydryl groups of the major protein disulfide isomerases (PDIs), the 58 kDa PDI and the 57 kDa ERp57 but not other chaperones. A parallel decrease of the protein-disulfide oxidoreductase activity was detected in the microsomal fraction of diabetic livers. The oxidant of PDI, Ero1-Lalpha showed a more oxidized status in diabetic rats. Our results reveal major changes in the redox status of the endoplasmic reticulum and its redox chaperones in diabetic rats, which may contribute to the defective protein secretion of the diabetic liver.

Citation

Gábor Nardai, Krisztián Stadler, Eszter Papp, Tamás Korcsmáros, Judit Jakus, Péter Csermely. Diabetic changes in the redox status of the microsomal protein folding machinery. Biochemical and biophysical research communications. 2005 Sep 2;334(3):787-95