Identification and functional analysis of mutations in FAD-binding domain of mitochondrial glycerophosphate dehydrogenase in caucasian patients with type 2 diabetes mellitus

Endocrine. 2001 Oct;16(1):39-42. doi: 10.1385/ENDO:16:1:39.

Abstract

Ca2+-responsive mitochondrial FAD-linked glycerophosphate dehydrogenase (mGPDH) is a key component of the pancreatic beta-cell glucose-sensing device. The purpose of this study was to examine the association of mutations in the cDNA coding for the FAD-binding domain of mGPDH and to explore the functional consequences of these mutations in vitro. To investigate this association in type 2 diabetes mellitus, we studied a cohort of 168 patients with type 2 diabetes and 179 glucose-tolerant control subjects of Spanish Caucasian origin by single-stranded conformational polymorphism analysis. In vitro site-directed mutagenesis was performed in the mGPDH cDNA sequence to reproduce those mutations that produce amino acid changes in a patient with type 2 diabetes. We detected mutations in the mGPDH FAD-binding domain in a single patient, resulting in a Gly to Arg amino acid change at positions 77, 78, and 81 and a Thr to Pro at position 90. In vitro expression of the mutated constructs in Xenopus oocytes resulted in a significantly lower enzymatic activity than in cells expressing the wild-type form of the enzyme. Our results indicate that although mutations in the mGPDH gene do not appear to have a major role in type 2 diabetes mellitus, the reduction in mGPDH enzymatic activity associated with the newly described mGPDH mutations suggests that they may contribute to the disease in some patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Animals
  • Cells, Cultured
  • Cohort Studies
  • DNA, Complementary / genetics
  • Diabetes Mellitus, Type 2 / genetics*
  • Female
  • Flavin-Adenine Dinucleotide / metabolism*
  • Glycerolphosphate Dehydrogenase / genetics*
  • Glycerolphosphate Dehydrogenase / metabolism*
  • Humans
  • Male
  • Middle Aged
  • Mitochondria / enzymology*
  • Mutation*
  • Oocytes
  • Protein Structure, Tertiary / genetics
  • Xenopus

Substances

  • DNA, Complementary
  • Flavin-Adenine Dinucleotide
  • Glycerolphosphate Dehydrogenase