title: A peroxisomal carrier delivers NAD⁺ and contributes to optimal fatty acid degradation during storage oil mobilization.
abstract: The existence of a transport protein that imports cytosolic NAD(+)  into peroxisomes has been controversially discussed for decades. Nevertheless, the biosynthesis of NAD(+)  in the cytosol necessitates the import of NAD(+)  into peroxisomes for numerous reduction/oxidation (redox) reactions. However, a gene encoding such a transport system has not yet been identified in any eukaryotic organism. Here, we describe the peroxisomal NAD(+)  carrier in Arabidopsis. Our candidate gene At2g39970 encodes for a member of the mitochondrial carrier family. We confirmed its peroxisomal localization using fluorescence microscopy. For a long time At2g39970 was assumed to represent the peroxisomal ATP transporter. In this study, we could show that the recombinant protein mediated the transport of NAD(+) . Hence, At2g39970 was named PXN for peroxisomal NAD(+)  carrier. The loss of PXN in Arabidopsis causes defects in NAD(+) -dependent β-oxidation during seedling establishment. The breakdown of fatty acid released from storage oil was delayed, which led to the retention of oil bodies in pxn mutant seedlings. Based on our results, we propose that PXN delivers NAD(+)  for optimal fatty acid degradation during storage oil mobilization.
authors: Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
authors: Kristin
authors: K
authors: Bernhardt
authors: Sabrina
authors: S
authors: Wilkinson
authors: Andreas P M
authors: AP
authors: Weber
authors: Nicole
authors: N
authors: Linka
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000227:Adenine Nucleotides / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009243:NAD / Q000378:metabolism*; D010084:Oxidation-Reduction; D020675:Peroxisomes / Q000378:metabolism*; D010938:Plant Oils / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
chemical_list: D000227:Adenine Nucleotides; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D005227:Fatty Acids; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D010938:Plant Oils; D011994:Recombinant Proteins; C574424:solute carrier family 25 member 17 protein, Arabidopsis; D009243:NAD; D015084:2,4-Dichlorophenoxyacetic Acid; D013395:Sucrose; C004764:4-(2,4-dichlorophenoxy)butyric acid