Identification of a renal-specific oxido-reductase in newborn diabetic mice

Qiwei Yang, Bharat Dixit, Jun Wada, Yufeng Tian, Elisabeth I. Wallner, Satish K. Srivastva, Yashpal S. Kanwar*

*Corresponding author for this work

Research output: Contribution to journalArticle

45 Scopus citations

Abstract

Aldose reductase (ALR2), a NADPH-dependent aldo-keto reductase (AKR), is widely distributed in mammalian tissues and has been implicated in complications of diabetes, including diabetic nephropathy. To identify a renal-specific reductase belonging to the AKR family, representational difference analyses of cDNA from diabetic mouse kidney were performed. A full-length cDNA with an ORF of 855 nt and yielding a ≃ 1.5-kb mRNA transcript was isolated from a mouse kidney library. Human and rat homologues also were isolated, and they had ≃ 91% and ≃ 97% amino acid identity with mouse protein. In vitro translation of the cDNA yielded a protein product of ≃ 33 kDa. Northern and Western blot analyses, using the cDNA and antirecombinant protein antibody, revealed its expression exclusively confined to the kidney. Like ALR2, the expression was up-regulated in diabetic kidneys. Its mRNA and protein expression was restricted to renal proximal tubules. The gene neither codistributed with Tamm-Horsfall protein nor aquaporin-2. The deduced protein sequence revealed an AKR-3 motif located near the N terminus, unlike the other AKR family members where it is confined to the C terminus. Fluorescence quenching and reactive blue agarose chromatography studies revealed that it binds to NADPH with high affinity (K(dNADPH) = 66.9 ± 2.3 nM). This binding domain is a tetrapeptide (Met-Ala-Lys-Ser) located within the AKR-3 motif that is similar to the other AKR members. The identified protein is designated as RSOR because it is renal-specific with properties of an oxido-reductase, and like ALR2 it may be relevant in the renal complications of diabetes mellitus.

Original languageEnglish (US)
Pages (from-to)9896-9901
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume97
Issue number18
DOIs
StatePublished - Aug 29 2000

Keywords

  • Diabetes mellitus
  • Diabetic nephropathy

ASJC Scopus subject areas

  • General

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