During the stationary growth phase, Yarrowia lipolytica prevents the overproduction of reactive oxygen species by activating an uncoupled mitochondrial respiratory pathway
| Autor: | Salvador Uribe-Carvajal, Sergio Guerrero-Castillo, Alfredo Cabrera-Orefice, Diego González-Halphen, Miriam Vázquez-Acevedo |
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| Rok vydání: | 2011 |
| Předmět: |
Yarrowia lipolytica
Alternative oxidase Cellular respiration Cell Respiration Biophysics Down-Regulation Yarrowia Mitochondrion Biochemistry Fungal Proteins Mitochondrial Proteins Reactive oxygen species ROS Oxygen Consumption Cytochrome c oxidase Plant Proteins Physiological uncoupling biology ATP synthase Organisms Genetically Modified Spectrum Analysis Cell Cycle NADH dehydrogenase NADH Dehydrogenase Cell Biology biology.organism_classification NAD Mitochondria Enzyme Activation Mitochondrial respiratory chain biology.protein Oxidoreductases Reactive Oxygen Species Branched respiratory chain Alternative NADH dehydrogenase Signal Transduction |
| Zdroj: | Biochimica et biophysica acta. 1817(2) |
| ISSN: | 0006-3002 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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