Modulation of type M ₂ pyruvate kinase activity by the human papillomavirus type 16 E7 oncoprotein

Abstract

We report here that the E7 oncoprotein encoded by the oncogenic human papillomavirus (HPV) type 16 binds to the glycolytic enzyme type M 2 pyruvate kinase (M2-PK). M2-PK occurs in a tetrameric form with a high affinity to its substrate phosphoenolpyruvate and a dimeric form with a low affinity to phosphoenolpyruvate, and the transition between both conformations regulates the glycolytic f lux in tumor cells. The glycolytic intermediate fructose 1,6-bisphosphate induces the reassociation of the dimeric to the tetrameric form of M2-PK. The expression of E7 in an experimental cell line shifts the equilibrium to the dimeric state despite a significant increase in the fructose 1,6-bisphosphate levels. Investigations of HPV-16 E7 mutants and the nononcogenic HPV-11 subtype suggest that the interaction of HPV-16 E7 with M2-PK may be linked to the transforming potential of the viral oncoprotein.Unicellular organisms have a variety of sensing mechanisms to adapt the cell proliferation rate to variations in their environmental nutrient supply. Several gene products, like the ras or cdc kinase proteins, which are involved in nutrient sensing in yeast (1, 2), are conserved during the evolution of multicellular organisms, and in mammals, these gene products often are altered in tumors. Despite our knowledge about the protein machinery regulating cell proliferation increasing tremendously over the recent years, we are still at the beginning to understand how nutrients contribute to proliferation control in multicellular organisms. There is, however, quite good evidence that phosphometabolites derived from both glycolysis (for recent review, see ref.3) and the pentose phosphate pathway (ref. 4 and references therein) provide some of the signals linking metabolic conditions to cell proliferation. The glycolytic phosphometabolites, which are necessary for the biosynthesis of nucleic acids, phospholipids, and complex carbohydrates, are up-regulated in the G 1 phase of the cell cycle (for recent review, see

Pyruvate kinase type M2 is upregulated in colorectal cancer and promotes proliferation and migration of colon cancer cells

“…So, inhibition of expression of PKM2 may also affect the proliferation of other cells. The superiority of PKM2 compared with PKM1 might be that it can balance energy supply and glycolytic phospho-metabolite pools by switching between two quaternary conformations (12)(13)(14)(15)(16)(17)(18). As is mentioned above, PKM2 can exist as an active tetrameric and an inactive dimeric form.…”

“…Studies have shown that most PKM2 exists mainly as a dimeric form in tumor cells. Some viral oncoproteins like HPV-16E7 and pp60v-Src kinase (12,13) as well as cellular phosphotyrosine signaling (14,15) can induce the dimerization of PKM2, but the Ras oncogene induces the tetramerization of PKM2 (16,17). Recently, Kosugi et al (18) found that PKM2 activity is also regulated by direct binding of oncoprotein MUC1-C. Another important metabolic regulator of PKM2 is fructose 1,6-bisphosphate.…”

Modulation of M2‐type pyruvate kinase activity by the cytoplasmic PML tumor suppressor protein

“…Glycerol gradient fractionation studies indicated that PML-2KA inhibited the activity of the tetrameric form, but not the dimeric form of PKM2. HPV E7 has been previously reported to directly bind to PKM2, and to shift its tetramer-dimer equilibrium towards the dimeric state (Zwerschke et al 1999). The tetramer : dimer ratio of PKM2 is also regulated by ATP, FBP and serine (Eigenbrodt et al 1992).…”

“…1981;Eigenbrodt et al 1992;Boros et al 1997Boros et al , 2000Zwerschke et al 1999;Cascante et al 2000;Mazurek et al 2001). To address whether cPML affects the tetramer : dimer ratio of PKM2, cell lysates were prepared from control and PML-2KA-expressing MCF-7 cells and subjected to glycerolgradient centrifugation.…”

Faecal tumour M2 pyruvate kinase: a new, sensitive screening tool for colorectal cancer

“…The upregulation of the M2-PK protein is under the control of HIF-1 and ras, which are both consistently altered in gastrointestinal tumours (Kress et al, 1998;Mazurek et al, 2001;Nishikawa et al, 2002;Mazurek and Eigenbrodt, 2003). The tetramer : dimer ratio of M2-PK is under the control of several oncoproteins, such as pp60 vÀsrc kinase, HPV-16 E7 and A-Raf ( Figure 1B) (Eigenbrodt et al, 1998b;Zwerschke et al, 1999;Le Mellay et al, 2002). Interestingly, pp60 cÀsrc kinase and A-Raf are consistently altered in gastrointestinal tumours (Bolen et al, 1987;Iravani et al, 1998;Irby et al, 1999;Luckett et al, 2000;Dehm et al, 2001;Dhillon et al, 2003).…”