Functional analysis of O-GlcNAcylation by networking of OGT interactors and substrates

The post-translational modification (PTM) of proteins by O-linked β-N-acetyl-D-glucosamine (O-GlcNAcylation) is widely found across the proteome and regulates diverse cellular processes, from transcription and translation to signal transduction and metabolism. However, most functional studies to date have focused on individual modifications, overlooking other simultaneous O-GlcNAcylation events that work together to coordinate cellular activities. Here we describe networking of O-GlcNAc transferase interactors and substrates (NOTISE), a systems-level approach that monitors O-GlcNAcylation rapidly and comprehensively across the proteome to reveal important functional and regulatory relationships. The NOTISE method integrates affinity purification-mass spectrometry and site-specific chemoproteomic technologies with network generation to connect putative upstream regulators and downstream targets of O-GlcNAcylation. The resulting data-rich networks identify critical conserved activities of O-GlcNAcylation and tissue-specific functions. This holistic and unbiased approach provides a broadly applicable framework to catalyze investigations into the functional roles of coordinated, multisubstrate PTMs in specific cellular and physiological contexts.