Dynamic Interplay between O-Linked N-Acetylglucosaminylation and Glycogen

O-GlcNAcylation on serine and threonine side chains of nuclear and cytoplasmic proteins is dynamically regulated in response to various environmental and biological stim-uli. O-GlcNAcylation is remarkably similar to O-phospho-rylation and appears to have a dynamic interplay with O-phosphate in cellular regulation. A systematic glyco-proteomics analysis of the affects of inhibiting specific kinases on O-GlcNAcylation should help reveal both the global and specific dynamic relationships between these two abundant post-translational modifications. Here we report the O-GlcNAc perturbations in response to inhibition of glycogen synthase kinase-3 (GSK-3), a pivotal kinase involved in many signaling pathways. By combining immu-noaffinity chromatography and SILAC (stable isotope label-ing with amino acids in cell culture)-based quantitativ