Journal Article

Genetically Modified <i>Arabidopsis thaliana</i> Cells Reveal the Involvement of the Mitochondrial Fatty Acid Composition in Membrane Basal and Uncoupling Protein-Mediated Proton Leaks

Cécile Hourton-Cabassa, Ana Rita Matos, Joao Arrabaça, Chantal Demandre, Alain Zachowski and François Moreau

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 50, issue 12, pages 2084-2091
Published in print December 2009 | ISSN: 0032-0781
Published online September 2009 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcp144
Genetically Modified Arabidopsis thaliana Cells Reveal the Involvement of the Mitochondrial Fatty Acid Composition in Membrane Basal and Uncoupling Protein-Mediated Proton Leaks

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

We investigated the role of membrane fatty acids in basal proton leaks and uncoupling protein (UCP)-dependent proton conductance in Arabidopsis mitochondria. Using wild-type cells, cold-sensitive fad2 mutant cells, deficient in ω-6-oleate desaturase, and cold-tolerant FAD3+ transformant cells, overexpressing ω-3-linoleate desaturase, we showed that basal proton leak in the non-phosphorylating state was dependent on lipid composition. The extent of membrane proton leak was drastically reduced in the fad2 mutant, containing low amounts of polyunsaturated fatty acids. Conversely, this proton leak was higher in FAD3+ mitochondria that exhibit a higher polyunsaturated fatty acid content and high protein to lipid ratio. The dependency of membrane leaks upon membrane potential was higher in FAD3+ and lower in fad2. UCP content was higher in both the fad2 mutant and FAD3+ transgenic lines compared with wild-type cells and so was the UCP activity, assayed by the reduction of phosphorylation yield (ADP/O) triggered by palmitate as UCP activator. This UCP assay was validated by measurements of UCP–proton leak in the non-phosphorylating state (flux–force relationships between proton flux and membrane potential). The potential uncoupling capacity of the UCP was high enough to allow the loss of respiratory control in the three genotypes. Taken together, the data reported here suggest that the cold tolerance of FAD3+ cells and the cold sensitivity of fad2 cells are associated with changes in their mitochondrial membrane basal proton leaks, whereas differences in functional expression of UCP are not simply related to cold adaptation in Arabidopsis cells.

Keywords: Arabidopsis thaliana • Cold sensitivity • Lipid desaturase mutants • Membrane and fatty acid composition • Membrane conductance • Uncoupling protein

Journal Article.  4349 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.