O- GlcNAcylation destabilizes the active tetrameric PKM2 to promote the Warburg effect

Significance Cancer cells are characterized by a high rate of glycolysis even under normal oxygen availability to meet the demand of biomass production during rapid proliferation. An isoform of pyruvate kinase (PK), PKM2, preferentially expressed in cancers, was recently shown to be critical for this metabolic reprogramming with adjustable activity and dynamic cellular relocalization. However, specific molecular mechanisms mediating PKM2’s role in cancer-specific metabolism remain largely elusive. We demonstrate that O- GlcNAcylation of PKM2 on threonine/serine encoded by an alternatively spliced exon disrupts the intersubunit interactions in the active PKM2 tetramer. This causes the tetramer disassembly, reduced PK activity, and its nuclear translocation to facilitate cell proliferation. Thus, our findings furnish a key piece in the puzzle of aerobic glycolysis in cancer.