A peroxisomal carrier delivers NAD+ and contributes to optimal fatty acid degradation during storage oil mobilization
Article first published online: 25 OCT 2011
© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd
The Plant Journal
Volume 69, Issue 1, pages 1–13, January 2012
How to Cite
Bernhardt, K., Wilkinson, S., Weber, A. P. M. and Linka, N. (2012), A peroxisomal carrier delivers NAD+ and contributes to optimal fatty acid degradation during storage oil mobilization. The Plant Journal, 69: 1–13. doi: 10.1111/j.1365-313X.2011.04775.x
- Issue published online: 21 DEC 2011
- Article first published online: 25 OCT 2011
- Accepted manuscript online: 5 SEP 2011 12:02PM EST
- Received 6 July 2011; revised 26 August 2011; accepted 31 August 2011; published online 25 October 2011.
- transport protein;
- NAD import;
- fatty acid oxidation;
- storage oil mobilisation
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.