Dihydro-orotate dehydrogenase is physically associated with the respiratory complex and its loss leads to mitochondrial dysfunction

Jing Xian Fang, Takeshi Uchiumi, Mikako Yagi, Shinya Matsumoto, Rie Amamoto, Shinya Takazaki, Haruyoshi Yamaza, Kazuaki Nonaka, Dongchon Kang

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Some mutations of the DHODH (dihydro-orotate dehydrogenase) gene lead to postaxial acrofacial dysostosis or Miller syndrome. Only DHODH is localized at mitochondria among enzymes of the de novo pyrimidine biosynthesis pathway. Since the pyrimidine biosynthesis pathway is coupled to the mitochondrial RC (respiratory chain) via DHODH, impairment of DHODH should affect the RC function. To investigate this, we used siRNA (small interfering RNA)-mediated knockdown and observed that DHODH knockdown induced cell growth retardation because of G2/M cell-cycle arrest, whereas pyrimidine deficiency usually causes G1/S arrest. Inconsistent with this, the cell retardation was not rescued by exogenous uridine, which should bypass the DHODH reaction for pyrimidine synthesis. DHODH depletion partially inhibited the RC complex III, decreased the mitochondrial membrane potential, and increased the generation of ROS (reactive oxygen species). We observed that DHODH physically interacts with respiratory complexes II and III by IP (immunoprecipitation) and BN (blue native)/SDS/PAGE analysis. Considering that pyrimidine deficiency alone does not induce craniofacial dysmorphism, the DHODH mutations may contribute to the Miller syndrome in part through somehow altered mitochondrial function.

Original languageEnglish
Article numbere00021
Pages (from-to)217-227
Number of pages11
JournalBioscience reports
Volume33
Issue number2
DOIs
Publication statusPublished - 2013

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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