The dimer form Pyruvate kinase M2 (PKM2) possesses lower glycolytic ability compared to its terameter form. This is of great importance for cancer cells since dimer PKM2 increases the levels of glycolytic intermediates for cell proliferation and growth. Accumulating evidence has also revealed that dimer PKM2 has many non-glycolytic functions including acting as a transcription factor and protein kinase. Our recent work has uncovered a novel non-glycolytic function of dimer PKM2. PKM2 coordinates the switch between glycolysis and glutaminolysis in cancer cells. We further discovered that dimer PKM2 upregulates glutaminolysis through internal ribosome entry site (IRES)-dependent translation of c-Myc. Here in this commentary, we discuss several most important unanswered questions relevant to this new finding, in hope to inspire future studies. We discussed several possibilities that dimer PKM2 regulates IRES-dependent translation of other genes as well as the role(s) of dimer PKM2 in regulation of glutaminolysis in non-cancer cells. Furthermore, we also discuss the potential mechanism of PKM2 in regulating IRES-dependent translation of c-Myc.

Pyruvate kinase M2, IRES (Internal ribosome entry site), Glutaminolysis, c-Myc