During the stationary growth phase, Yarrowia lipolytica prevents the overproduction of reactive oxygen species by activating an uncoupled mitochondrial respiratory pathway

Biochim Biophys Acta. 2012 Feb;1817(2):353-62. doi: 10.1016/j.bbabio.2011.11.007. Epub 2011 Nov 22.

Abstract

In the branched mitochondrial respiratory chain from Yarrowia lipolytica there are two alternative oxido-reductases that do not pump protons, namely an external type II NADH dehydrogenase (NDH2e) and the alternative oxidase (AOX). Direct electron transfer between these proteins is not coupled to ATP synthesis and should be avoided in most physiological conditions. However, under low energy-requiring conditions an uncoupled high rate of oxygen consumption would be beneficial, as it would prevent overproduction of reactive oxygen species (ROS). In mitochondria from high energy-requiring, logarithmic-growth phase cells, most NDH2e was associated to cytochrome c oxidase and electrons from NADH were channeled to the cytochromic pathway. In contrast, in the low energy requiring, late stationary-growth phase, complex IV concentration decreased, the cells overexpressed NDH2e and thus a large fraction of this enzyme was found in a non-associated form. Also, the NDH2e-AOX uncoupled pathway was activated and the state IV external NADH-dependent production of ROS decreased. Association/dissociation of NDH2e to/from complex IV is proposed to be the switch that channels electrons from external NADH to the coupled cytochrome pathway or allows them to reach an uncoupled, alternative, ΔΨ-independent pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle / physiology
  • Cell Respiration / physiology
  • Down-Regulation
  • Enzyme Activation
  • Fungal Proteins / analysis
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Mitochondria / enzymology
  • Mitochondria / metabolism
  • Mitochondrial Proteins / analysis
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • NAD / metabolism
  • NADH Dehydrogenase / metabolism
  • Organisms, Genetically Modified
  • Oxidoreductases / genetics
  • Oxidoreductases / metabolism
  • Oxygen Consumption / physiology
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Reactive Oxygen Species / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Spectrum Analysis
  • Yarrowia / enzymology
  • Yarrowia / genetics
  • Yarrowia / growth & development*
  • Yarrowia / metabolism*

Substances

  • Fungal Proteins
  • Mitochondrial Proteins
  • Plant Proteins
  • Reactive Oxygen Species
  • NAD
  • Oxidoreductases
  • alternative oxidase
  • NADH dehydrogenase II
  • NADH Dehydrogenase