摘要
Pyruvate kinase isoform M2 （PKM2） converts phospho- enolpyruvate （PEP） to pyruvate and plays an important role in cancer metabolism. Here, we show that post- translational modifications and a patient-derived muta- tion regulate pyruvate kinase activity of PKM2 through modulating the conformation of the PKM2 tetramer. We determined crystal structures of human PKM2 mutants and proposed a ＂seesaw＂ model to illustrate confor- mational changes between an inactive T-state and an active R-state tetramers of PKM2. Biochemical and structural analyses demonstrate that PKM2^Y105E （phos- phorylation mimic of Y105） decreases pyruvate kinase activity by inhibiting FBP （fructose 1,6-bisphosphate）- induced R-state formation, and PKM2K^3305Q （acetylation mimic of K305） abolishes the activity by hindering tet- ramer formation. K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions. Our study reveals the mechanism for dynamic regulation of PKM2 by post- translational modifications and a patient-derived muta- tion and provides a structural basis for further investi- gation of other modifications and mutations of PKM2 yet to be discovered.
Pyruvate kinase isoform M2 （PKM2） converts phospho- enolpyruvate （PEP） to pyruvate and plays an important role in cancer metabolism. Here, we show that post- translational modifications and a patient-derived muta- tion regulate pyruvate kinase activity of PKM2 through modulating the conformation of the PKM2 tetramer. We determined crystal structures of human PKM2 mutants and proposed a ＂seesaw＂ model to illustrate confor- mational changes between an inactive T-state and an active R-state tetramers of PKM2. Biochemical and structural analyses demonstrate that PKM2^Y105E （phos- phorylation mimic of Y105） decreases pyruvate kinase activity by inhibiting FBP （fructose 1,6-bisphosphate）- induced R-state formation, and PKM2K^3305Q （acetylation mimic of K305） abolishes the activity by hindering tet- ramer formation. K422R, a patient-derived mutation of PKM2, favors a stable, inactive T-state tetramer because of strong intermolecular interactions. Our study reveals the mechanism for dynamic regulation of PKM2 by post- translational modifications and a patient-derived muta- tion and provides a structural basis for further investi- gation of other modifications and mutations of PKM2 yet to be discovered.
