Reference "A peroxisomal carrier delivers NAD(+) and contributes to optimal fatty acid degradation during storage oil mobilization"

Reference ID

54987

Title

A peroxisomal carrier delivers NAD(+) and contributes to optimal fatty acid degradation during storage oil mobilization

Source

Plant J, 2012, vol. 69, pp. 1-13

Authors (4)

Bernhardt-K	Wilkinson-S
Weber-A-P	Linka-N

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 beta-
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.