WRINKLED1 as a novel 14-3-3 client: function of 14-3-3 proteins in plant lipid metabolism.

The conserved plant 14-3-3 proteins (14-3-3s) function by binding to phosphorylated client proteins to regulate their function. Previous studies indicate that 14-3-3s are involved in the regulation of plant primary metabolism; however, not much is known regarding the functions of 14-3-3s in plant oil biosynthesis. Our recent work shows that 14-3-3 plays a role in mediating plant oil biosynthesis through interacting with the transcription factor, WRINKLED1 (WRI1). WRI1 is critical for the transcriptional control of plant oil biosynthesis. Arabidopsis WRI1 physically interacts with 14-3-3s. Transient co-expression of AtWRI1 with 14-3-3s enhances plant oil biosynthesis in leaves of Nicotiana benthamiana. Transgenic plants overexpressing of a 14-3-3 show enhanced seed oil content. Co-expression of a 14-3-3 with AtWRI1 results in increased transcriptional activity and protein stability of AtWRI1. Our transcriptional regulation model supports a concept that interaction of a 14-3-3 with a transcription factor enhances the transcriptional activity through protein stabilization.