title: SAICAR induces protein kinase activity of PKM2 that is necessary for sustained proliferative signaling of cancer cells.
abstract: Abnormal metabolism and sustained proliferation are hallmarks of cancer. Pyruvate kinase M2 (PKM2) is a metabolic enzyme that plays important roles in both processes. Recently, PKM2 was shown to have protein kinase activity phosphorylating histone H3 and promoting cancer cell proliferation. However, the mechanism and extent of this protein kinase in cancer cells remain unclear. Here, we report that binding of succinyl-5-aminoimidazole-4-carboxamide-1-ribose-5'-phosphate (SAICAR), a metabolite abundant in proliferating cells, induces PKM2's protein kinase activity in vitro and in cells. Protein microarray experiments revealed that more than 100 human proteins, mostly protein kinases, are phosphorylated by PKM2-SAICAR. In particular, PKM2-SAICAR phosphorylates and activates Erk1/2, which in turn sensitizes PKM2 for SAICAR binding through phosphorylation. Additionally, PKM2-SAICAR was necessary to induce sustained Erk1/2 activation and mitogen-induced cell proliferation. Thus, the ligand-induced protein kinase activity from PKM2 is a mechanism that directly couples cell proliferation with intracellular metabolic status.
authors.affiliation: Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
authors.forename: Kirstie E
authors.initials: KE
authors.lastname: Keller
authors.affiliation: Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
authors.forename: Zainab M
authors.initials: ZM
authors.lastname: Doctor
authors.affiliation: Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
authors.forename: Zachary W
authors.initials: ZW
authors.lastname: Dwyer
authors.affiliation: Department of Biology, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA. Electronic address: ylee99@jhu.edu.
authors.forename: Young-Sam
authors.initials: YS
authors.lastname: Lee
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000737:chemistry; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D008024:Ligands; D008565:Membrane Proteins / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010766:Phosphorylation; D040081:Protein Array Analysis; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000737:chemistry*; D011994:Recombinant Proteins / Q000378:metabolism; D012265:Ribonucleotides / Q000737:chemistry*; D015398:Signal Transduction; D013963:Thyroid Hormones / Q000378:metabolism*; D014982:Xenopus laevis; D000097810:Thyroid Hormone-Binding Proteins
chemical_list: D000244:Adenosine Diphosphate; D000620:Aminoimidazole Carboxamide; D002352:Carrier Proteins; D007527:Isoenzymes; D008024:Ligands; D008565:Membrane Proteins; D048052:Mitogen-Activated Protein Kinase 3; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D012265:Ribonucleotides; D013963:Thyroid Hormones; D000097810:Thyroid Hormone-Binding Proteins; C020635:SAICAR