title: Voltage-dependent-anion-channels (VDACs) in Arabidopsis have  a dual localization in the cell but show a distinct role  in mitochondria.
abstract: In mammals, the Voltage-dependent anion channels (VDACs) are predominant proteins of the outer mitochondrial membrane (OMM) where they contribute to the exchange of small metabolites essential for respiration. They were shown to be as well associated with the plasma membrane (PM) and act as redox enzyme or are involved in ATP release for example. In Arabidopsis, we show that four out of six genomic sequences encode AtVDAC proteins. All four AtVDACs are ubiquitously expressed in the plant but each of them displays a specific expression pattern in root cell types. Using two complementary approaches, we demonstrate conclusively that the four expressed AtVDACs are targeted to both mitochondria and plasma membrane but in differential abundance, AtVDAC3 being the most abundant in PM, and conversely, AtVDAC4 almost exclusively associated with mitochondria. These are the first plant proteins to be shown to reside in both these two membranes. To investigate a putative function of AtVDACs, we analyzed T-DNA insertion lines in each of the corresponding genes. Knock-out mutants for AtVDAC1, AtVDAC2 and AtVDAC4 present slow growth, reduced fertility and yellow spots in leaves when atvdac3 does not show any visible difference compared to wildtype plants. Analyses of atvdac1 and atvdac4 reveal that yellow areas correspond to necrosis and the mitochondria are swollen in these two mutants. All these results suggest that, in spite of a localization in plasma membrane for three of them, AtVDAC1, AtVDAC2 and AtVDAC4 have a main function in mitochondria.
authors.affiliation: Institut des Sciences du Végétal, CNRS-UPR 2355, Bât. 22, 91198 Gif sur Yvette Cedex, France.
authors.forename: Nadia
authors.initials: N
authors.lastname: Robert
authors.forename: Isabelle
authors.initials: I
authors.lastname: d'Erfurth
authors.forename: Anne
authors.initials: A
authors.lastname: Marmagne
authors.forename: Mathieu
authors.initials: M
authors.lastname: Erhardt
authors.forename: Michèle
authors.initials: M
authors.lastname: Allot
authors.forename: Karine
authors.initials: K
authors.lastname: Boivin
authors.forename: Lionel
authors.initials: L
authors.lastname: Gissot
authors.forename: Dario
authors.initials: D
authors.lastname: Monachello
authors.forename: Morgane
authors.initials: M
authors.lastname: Michaud
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Duchêne
authors.forename: Hélène
authors.initials: H
authors.lastname: Barbier-Brygoo
authors.forename: Laurence
authors.initials: L
authors.lastname: Maréchal-Drouard
authors.forename: Geneviève
authors.initials: G
authors.lastname: Ephritikhine
authors.forename: Sophie
authors.initials: S
authors.lastname: Filleur
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004269:DNA, Bacterial; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D009336:Necrosis; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D050994:Voltage-Dependent Anion Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; C036483:T-DNA; D050994:Voltage-Dependent Anion Channels