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A phospho-BAD BH3 helix activates glucokinase by a mechanism distinct from that of allosteric activators

Abstract

Glucokinase (GK) is a glucose-phosphorylating enzyme that regulates insulin release and hepatic metabolism, and its loss of function is implicated in diabetes pathogenesis. GK activators (GKAs) are attractive therapeutics in diabetes; however, clinical data indicate that their benefits can be offset by hypoglycemia, owing to marked allosteric enhancement of the enzyme's glucose affinity. We show that a phosphomimetic of the BCL-2 homology 3 (BH3) α-helix derived from human BAD, a GK-binding partner, increases the enzyme catalytic rate without dramatically changing glucose affinity, thus providing a new mechanism for pharmacologic activation of GK. Remarkably, BAD BH3 phosphomimetic mediates these effects by engaging a new region near the enzyme's active site. This interaction increases insulin secretion in human islets and restores the function of naturally occurring human GK mutants at the active site. Thus, BAD phosphomimetics may serve as a new class of GKAs.

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Figure 1: Effects of BAD BH3 stapled peptides on glucokinase (GK) activity.
Figure 2: Phospho-BAD BH3 peptides cross-link near the active site of GK.
Figure 3: Mapping the phospho-BAD BH3 helix at the GK interaction site.
Figure 4: Effects of BAD BH3 stapled peptides on human islet function and human GK mutations.

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  1. Ashcroft, F.M. & Rorsman, P. Diabetes mellitus and the β cell: the last ten years. Cell 148, 1160–1171 (2012).

    Article  CAS  Google Scholar 

  2. Samuel, V.T. & Shulman, G.I. Mechanisms for insulin resistance: common threads and missing links. Cell 148, 852–871 (2012).

    Article  CAS  Google Scholar 

  3. Majumdar, S.K. & Inzucchi, S.E. Investigational anti-hyperglycemic agents: the future of type 2 diabetes therapy? Endocrine 44, 47–58 (2013).

    Article  CAS  Google Scholar 

  4. Grimsby, J., Berthel, S.J. & Sarabu, R. Glucokinase activators for the potential treatment of type 2 diabetes. Curr. Top. Med. Chem. 8, 1524–1532 (2008).

    Article  CAS  Google Scholar 

  5. Matschinsky, F.M. Assessing the potential of glucokinase activators in diabetes therapy. Nat. Rev. Drug Discov. 8, 399–416 (2009).

    Article  CAS  Google Scholar 

  6. Dadon, D. et al. Glucose metabolism: key endogenous regulator of β-cell replication and survival. Diabetes Obes. Metab. 14 (suppl. 3), 101–108 (2012).

    Article  CAS  Google Scholar 

  7. Antoine, M., Boutin, J.A. & Ferry, G. Binding kinetics of glucose and allosteric activators to human glucokinase reveal multiple conformational states. Biochemistry 48, 5466–5482 (2009).

    Article  CAS  Google Scholar 

  8. Davis, E.A. et al. Mutants of glucokinase cause hypoglycaemia- and hyperglycaemia syndromes and their analysis illuminates fundamental quantitative concepts of glucose homeostasis. Diabetologia 42, 1175–1186 (1999).

    Article  CAS  Google Scholar 

  9. Grimsby, J. et al. Allosteric activators of glucokinase: potential role in diabetes therapy. Science 301, 370–373 (2003).

    Article  CAS  Google Scholar 

  10. Kamata, K., Mitsuya, M., Nishimura, T., Eiki, J. & Nagata, Y. Structural basis for allosteric regulation of the monomeric allosteric enzyme human glucokinase. Structure 12, 429–438 (2004).

    Article  CAS  Google Scholar 

  11. Larion, M., Salinas, R.K., Bruschweiler-Li, L., Bruschweiler, R. & Miller, B.G. Direct evidence of conformational heterogeneity in human pancreatic glucokinase from high-resolution nuclear magnetic resonance. Biochemistry 49, 7969–7971 (2010).

    Article  CAS  Google Scholar 

  12. Liu, S. et al. Insights into mechanism of glucokinase activation: observation of multiple distinct protein conformations. J. Biol. Chem. 287, 13598–13610 (2012).

    Article  CAS  Google Scholar 

  13. Petit, P. et al. The active conformation of human glucokinase is not altered by allosteric activators. Acta Crystallogr. D Biol. Crystallogr. 67, 929–935 (2011).

    Article  CAS  Google Scholar 

  14. Pfefferkorn, J.A. et al. Discovery of (S)-6-(3-cyclopentyl-2-(4-(trifluoromethyl)-1H-imidazol-1-yl)propanamido)nicotinic acid as a hepatoselective glucokinase activator clinical candidate for treating type 2 diabetes mellitus. J. Med. Chem. 55, 1318–1333 (2012).

    Article  CAS  Google Scholar 

  15. Futamura, M. et al. An allosteric activator of glucokinase impairs the interaction of glucokinase and glucokinase regulatory protein and regulates glucose metabolism. J. Biol. Chem. 281, 37668–37674 (2006).

    Article  CAS  Google Scholar 

  16. Pfefferkorn, J.A. et al. Pyridones as glucokinase activators: identification of a unique metabolic liability of the 4-sulfonyl-2-pyridone heterocycle. Bioorg. Med. Chem. Lett. 19, 3247–3252 (2009).

    Article  CAS  Google Scholar 

  17. Bonadonna, R.C. et al. Piragliatin (RO4389620), a novel glucokinase activator, lowers plasma glucose both in the postabsorptive state and after a glucose challenge in patients with type 2 diabetes mellitus: a mechanistic study. J. Clin. Endocrinol. Metab. 95, 5028–5036 (2010).

    Article  CAS  Google Scholar 

  18. Ericsson, H. et al. Tolerability, pharmacokinetics, and pharmacodynamics of the glucokinase activator AZD1656, after single ascending doses in healthy subjects during euglycemic clamp. Int. J. Clin. Pharmacol. Ther. 50, 765–777 (2012).

    Article  CAS  Google Scholar 

  19. Meininger, G.E. et al. Effects of MK-0941, a novel glucokinase activator, on glycemic control in insulin-treated patients with type 2 diabetes. Diabetes Care 34, 2560–2566 (2011).

    Article  CAS  Google Scholar 

  20. Danial, N.N. BAD: undertaker by night, candyman by day. Oncogene 27 (suppl. 1), S53–S70 (2008).

    Article  CAS  Google Scholar 

  21. Danial, N.N. et al. BAD and glucokinase reside in a mitochondrial complex that integrates glycolysis and apoptosis. Nature 424, 952–956 (2003).

    Article  CAS  Google Scholar 

  22. Danial, N.N. et al. Dual role of proapoptotic BAD in insulin secretion and beta cell survival. Nat. Med. 14, 144–153 (2008).

    Article  CAS  Google Scholar 

  23. Liu, S. et al. Insulin signaling regulates mitochondrial function in pancreatic β-cells. PLoS ONE 4, e7983 (2009).

    Article  Google Scholar 

  24. Gavathiotis, E. et al. BAX activation is initiated at a novel interaction site. Nature 455, 1076–1081 (2008).

    Article  CAS  Google Scholar 

  25. LaBelle, J.L. et al. A stapled BIM peptide overcomes apoptotic resistance in hematologic cancers. J. Clin. Invest. 122, 2018–2031 (2012).

    Article  CAS  Google Scholar 

  26. Leshchiner, E.S., Braun, C.R., Bird, G.H. & Walensky, L.D. Direct activation of full-length proapoptotic BAK. Proc. Natl. Acad. Sci. USA 110, E986–E995 (2013).

    Article  CAS  Google Scholar 

  27. Bebernitz, G.R. et al. Investigation of functionally liver selective glucokinase activators for the treatment of type 2 diabetes. J. Med. Chem. 52, 6142–6152 (2009).

    Article  CAS  Google Scholar 

  28. Brocklehurst, K.J. et al. Stimulation of hepatocyte glucose metabolism by novel small molecule glucokinase activators. Diabetes 53, 535–541 (2004).

    Article  CAS  Google Scholar 

  29. Castelhano, A.L. et al. Glucokinase-activating ureas. Bioorg. Med. Chem. Lett. 15, 1501–1504 (2005).

    Article  CAS  Google Scholar 

  30. Efanov, A.M. et al. A novel glucokinase activator modulates pancreatic islet and hepatocyte function. Endocrinology 146, 3696–3701 (2005).

    Article  CAS  Google Scholar 

  31. Fyfe, M.C. et al. Glucokinase activator PSN-GK1 displays enhanced antihyperglycaemic and insulinotropic actions. Diabetologia 50, 1277–1287 (2007).

    Article  CAS  Google Scholar 

  32. Ralph, E.C., Thomson, J., Almaden, J. & Sun, S. Glucose modulation of glucokinase activation by small molecules. Biochemistry 47, 5028–5036 (2008).

    Article  CAS  Google Scholar 

  33. Braun, C.R. et al. Photoreactive stapled BH3 peptides to dissect the BCL-2 family interactome. Chem. Biol. 17, 1325–1333 (2010).

    Article  CAS  Google Scholar 

  34. Zelent, B. et al. Mutational analysis of allosteric activation and inhibition of glucokinase. Biochem. J. 440, 203–215 (2011).

    Article  CAS  Google Scholar 

  35. Gidh-Jain, M. et al. Glucokinase mutations associated with non-insulin-dependent (type 2) diabetes mellitus have decreased enzymatic activity: implications for structure/function relationships. Proc. Natl. Acad. Sci. USA 90, 1932–1936 (1993).

    Article  CAS  Google Scholar 

  36. Gloyn, A. et al. in Glucokinase and Glycemic Diseases: From the Basics to Novel Therapeutics (eds. Matschinsky, F.M. & Magnuson, M.A.) 92–109 (Karger, Basel, 2004).

  37. Kesavan, P. et al. Structural instability of mutant β-cell glucokinase: implications for the molecular pathogenesis of maturity-onset diabetes of the young (type-2). Biochem. J. 322, 57–63 (1997).

    Article  CAS  Google Scholar 

  38. Liang, Y. et al. Variable effects of maturity-onset-diabetes-of-youth (MODY)-associated glucokinase mutations on substrate interactions and stability of the enzyme. Biochem. J. 309, 167–173 (1995).

    Article  CAS  Google Scholar 

  39. Osbak, K.K. et al. Update on mutations in glucokinase (GCK), which cause maturity-onset diabetes of the young, permanent neonatal diabetes, and hyperinsulinemic hypoglycemia. Hum. Mutat. 30, 1512–1526 (2009).

    Article  CAS  Google Scholar 

  40. Cullen, K.S., Matschinsky, F.M., Agius, L. & Arden, C. Susceptibility of glucokinase-MODY mutants to inactivation by oxidative stress in pancreatic β-cells. Diabetes 60, 3175–3185 (2011).

    Article  CAS  Google Scholar 

  41. Barrio, R. et al. Nine novel mutations in maturity-onset diabetes of the young (MODY) candidate genes in 22 Spanish families. J. Clin. Endocrinol. Metab. 87, 2532–2539 (2002).

    Article  CAS  Google Scholar 

  42. Larion, M. & Miller, B.G. Global fit analysis of glucose binding curves reveals a minimal model for kinetic cooperativity in human glucokinase. Biochemistry 49, 8902–8911 (2010).

    Article  CAS  Google Scholar 

  43. Lin, S.X. & Neet, K.E. Demonstration of a slow conformational change in liver glucokinase by fluorescence spectroscopy. J. Biol. Chem. 265, 9670–9675 (1990).

    CAS  PubMed  Google Scholar 

  44. Molnes, J., Bjorkhaug, L., Sovik, O., Njolstad, P.R. & Flatmark, T. Catalytic activation of human glucokinase by substrate binding: residue contacts involved in the binding of D-glucose to the super-open form and conformational transitions. FEBS J. 275, 2467–2481 (2008).

    Article  CAS  Google Scholar 

  45. Larion, M. & Miller, B.G. Homotropic allosteric regulation in monomeric mammalian glucokinase. Arch. Biochem. Biophys. 519, 103–111 (2012).

    Article  CAS  Google Scholar 

  46. Barbetti, F. et al. Opposite clinical phenotypes of glucokinase disease: description of a novel activating mutation and contiguous inactivating mutations in human glucokinase (GCK) gene. Mol. Endocrinol. 23, 1983–1989 (2009).

    Article  CAS  Google Scholar 

  47. Kassem, S. et al. Large islets, beta-cell proliferation, and a glucokinase mutation. N. Engl. J. Med. 362, 1348–1350 (2010).

    Article  CAS  Google Scholar 

  48. Ferre, T., Riu, E., Franckhauser, S., Agudo, J. & Bosch, F. Long-term overexpression of glucokinase in the liver of transgenic mice leads to insulin resistance. Diabetologia 46, 1662–1668 (2003).

    Article  CAS  Google Scholar 

  49. O'Doherty, R.M., Lehman, D.L., Telemaque-Potts, S. & Newgard, C.B. Metabolic impact of glucokinase overexpression in liver: lowering of blood glucose in fed rats is accompanied by hyperlipidemia. Diabetes 48, 2022–2027 (1999).

    Article  CAS  Google Scholar 

  50. Peter, A. et al. Hepatic glucokinase expression is associated with lipogenesis and fatty liver in humans. J. Clin. Endocrinol. Metab. 96, E1126–E1130 (2011).

    Article  Google Scholar 

  51. Kiyosue, A., Hayashi, N., Komori, H., Leonsson-Zachrisson, M. & Johnsson, E. Dose-ranging study with the glucokinase activator AZD1656 as monotherapy in Japanese patients with type 2 diabetes mellitus. Diabetes Obes. Metab. 15, 923–930 (2013).

    Article  CAS  Google Scholar 

  52. Wilding, J.P., Leonsson-Zachrisson, M., Wessman, C. & Johnsson, E. Dose-ranging study with the glucokinase activator AZD1656 in patients with type 2 diabetes mellitus on metformin. Diabetes Obes. Metab. 15, 750–759 (2013).

    Article  CAS  Google Scholar 

  53. Eng, J.K., McCormack, A.L. & Yates, J.R. An approach to correlate tandem mass spectral data of peptides with amino acid sequences in a protein database. J. Am. Soc. Mass Spectrom. 5, 976–989 (1994).

    Article  CAS  Google Scholar 

  54. Murdoch, T.B., McGhee-Wilson, D., Shapiro, A.M. & Lakey, J.R. Methods of human islet culture for transplantation. Cell Transplant. 13, 605–617 (2004).

    Article  Google Scholar 

  55. Barbaro, B. et al. Increased albumin concentration reduces apoptosis and improves functionality of human islets. Artif. Cells Blood Substit. Immobil. Biotechnol. 36, 74–81 (2008).

    Article  CAS  Google Scholar 

  56. Mahdi, T. et al. Secreted frizzled-related protein 4 reduces insulin secretion and is overexpressed in type 2 diabetes. Cell Metab. 16, 625–633 (2012).

    Article  CAS  Google Scholar 

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Acknowledgements

We thank K. Robertson and P. Chen for technical assistance; F. Bernal, S. Devarakonda and C. Buettger for advice on protein purification; E. Gavathiotis, A. West and R. McNally for advice on structural studies; and M. Eck, N. Gray, S. Blacklow, G. Yellen and members of the Danial and Walensky laboratories for valuable discussions. This work was supported by US National Institutes of Health grants R01DK078081 (N.N.D.) and R01GM090299 (L.D.W.), a Burroughs Wellcome Fund Career Award in Biomedical Sciences (N.N.D.), Juvenile Diabetes Research Foundation grant 17-2011-595 (N.N.D.), a Claudia Adams Barr Award in Innovative Basic Cancer Research (N.N.D.), a Stand Up to Cancer Innovative Research Grant (L.D.W.), a National Sciences and Engineering Research Council of Canada postgraduate scholarship (C.R.B.), a Swiss National Science Foundation postdoctoral fellowship (S.L.) and a Juvenile Diabetes Research Foundation postdoctoral fellowship (M.A.O.).

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Contributions

B.S., E.P., M.A.O. and N.N.D. purified recombinant proteins and performed enzyme kinetic analyses. C.R.B., G.H.B. and L.D.W. designed, synthesized and characterized SAHB compounds. C.R.B. and L.D.W. performed cross-linking, MS and structural analyses. S.L. and N.N.D. performed analyses in human donor islets. B.S., C.R.B., L.D.W. and N.N.D. wrote the manuscript. F.M.M. provided critical advice and reviewed the manuscript.

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Correspondence to Loren D Walensky or Nika N Danial.

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L.D.W. is a consultant and member of the scientific advisory board for Aileron Therapeutics.

Integrated supplementary information

Supplementary Figure 1 Phospho-BAD BH3 peptides cross-link to GK after UV exposure in the presence or absence of glucose.

Uncropped gels related to Fig. 2a document detection of BAD SAHBA–GK crosslinked complex as visualized by western blot analysis using an anti-biotin antibody. The lower band corresponds to monomeric GK crosslinked to the BAD SAHBA compound, which was excised and subjected to MS/MS analysis.

Supplementary Figure 2 Cross-linking profile of BAD BH3 stapled peptide in the presence of glucose and RO0281675.

Spectral count frequency of BAD SAHBA (S118pS D123R F125Bpa) crosslinked along the GK protein sequence. GK residues involved in crosslinking, which were unique to that peptide (with a frequency >25%), are labeled.

Supplementary information

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Supplementary Figures 1 and 2 and Supplementary Tables 1–3 (PDF 8934 kb)

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Szlyk, B., Braun, C., Ljubicic, S. et al. A phospho-BAD BH3 helix activates glucokinase by a mechanism distinct from that of allosteric activators. Nat Struct Mol Biol 21, 36–42 (2014). https://doi.org/10.1038/nsmb.2717

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