Nutrient sensing in Arabidopsis and Maize
Nutrient sensing is important to both plants and animals. One important nutrient sensing pathway is through O-linked N-acetylglucosamine transferases (OGTs), which modify and modulate target proteins using donor substrate UDP-GlcNAc derived from nutrients through the hexosamine biosynthetic pathway. Genetic studies have shown essential functions of O-GlcNAc modification in plants. However, the proteins and sites subject to this post-translational modification were largely unknown. Using lectin weak affinity chromatography to enrich modified peptides, followed by mass spectrometry, we reported the first large scale proteomic identification of O-GlcNAc-modified proteins and sites in the model plant Arabidopsis thaliana. Our study generates a snapshot of the O-GlcNAc modification landscape in plants, indicating functions in many cellular regulation pathways and providing a powerful resource for further dissecting these functions at the molecular level. We are currently developing an improved O-GlcNAc TRAP to enrich O-GlcNAc modified proteins, and we will also focus on understanding substrates, function and regulation of O-GlcNAcylation in both Arabidopsis and Maize.