Lipid-mediated nuclear moonlighting of cytosolic glyceraldehyde-3-phosphate dehydrogenase in plant heat response

Abstract

AbstractCytosolic glyceraldehyde-3-phosphate dehydrogenase (GAPC) is a glycolytic enzyme, but it undergoes stress-induced nuclear translocation for moonlighting and regulating gene expression. To elucidate how the cytosolic enzyme moves into the nuclei under stress, we show that the plasma membrane-associated phospholipase Dδ(PLDδ) and its product phosphatidic acid (PA) promote heat-induced nuclear translocation of GAPC. The GAPC nuclear accumulation and Arabidopsis seedling tolerance to heat stress were reduced in pldδ, which was restored by genetic complementation with intact PLDδ, but not with catalytically inactive enzyme. GAPC overexpression enhanced the seedling thermotolerance and the expression of heat-inducible genes, but this was not observed when GAPC was overexpressed in the pldδ background. The GAPC nuclear accumulation and seedling thermotolerance were also decreased by application with a vesicle trafficking inhibitor brefeldin A (BFA) or zinc that inhibited the PA-GAPC interaction. Heat stress elevated PA levels in nuclei from wild-type, but not from pldδ and BFA-treated plants. Lipid labeling and fluorescence resonance energy transfer analyses demonstrated heat-induced nuclear co-localization of PA and GAPC, which was impaired by BFA or zinc treatment. Taken together, our data suggest that PLDδ-produced PA mediates nuclear translocation of GAPC via lipid-protein interaction and vesicle trafficking for plants to cope with heat.One sentence summaryThe lipid mediator phosphatidic acid produced by a plasma membrane-associated phospholipase D mediates the nuclear moonlighting of cytosolic glyceraldehyde-3-phosphate dehydrogenase under heat.