Mechanism of Action of Compound-13: An α1-Selective Small Molecule Activator of AMPK

Roger W Hunter,Marc Foretz,Laurent Bultot,Morgan D Fullerton,Maria Deak,Fiona A Ross,Simon A Hawley,Natalia Shpiro,Benoit Viollet,Denis Barron,Bruce E Kemp,Gregory R Steinberg,D Grahame Hardie,Kei Sakamoto

doi:10.1016/j.chembiol.2014.05.014

Abstract

SummaryAMPK is a sensor of cellular energy status and a promising target for drugs aimed at metabolic disorders. We have studied the selectivity and mechanism of a recently described activator, C2, and its cell-permeable prodrug, C13. C2 was a potent allosteric activator of α1-complexes that, like AMP, also protected against Thr172 dephosphorylation. Compared with AMP, C2 caused only partial allosteric activation of α2-complexes and failed to protect them against dephosphorylation. We show that both effects could be fully restored by exchanging part of the linker between the autoinhibitory and C-terminal domains in α2, containing the equivalent region from α1 thought to interact with AMP bound in site 3 of the γ subunit. Consistent with our results in cell-free assays, C13 potently inhibited lipid synthesis in hepatocytes from wild-type and was largely ineffective in AMPK-knockout hepatocytes; its effects were more severely affected by knockout of α1 than of α2, β1, or β2.

Highlights

AMP-activated protein kinase (AMPK) is a central energy sensor and regulator of energy homeostasis (Hardie et al, 2012; Steinberg and Kemp, 2009)
AMPK is a sensor of cellular energy status and a promising target for drugs aimed at metabolic disorders
Compared with AMP, Compound 2 (C2) caused only partial allosteric activation of a2-complexes and failed to protect them against dephosphorylation. We show that both effects could be fully restored by exchanging part of the linker between the autoinhibitory and C-terminal domains in a2, containing the equivalent region from a1 thought to interact with AMP bound in site 3 of the g subunit

Summary

Introduction

AMP-activated protein kinase (AMPK) is a central energy sensor and regulator of energy homeostasis (Hardie et al, 2012; Steinberg and Kemp, 2009). AMPK is activated by metabolic stresses that lower cellular energy status by decreasing the catabolic generation of ATP or by accelerating ATP consumption. Upon activation, it functions to restore cellular energy homeostasis by switching off anabolic pathways and other ATP-consuming processes while switching on ATP-producing catabolic pathways. Thr172 can be phosphorylated in a Ca2+mediated process catalyzed by Ca2+/calmodulin-dependent protein kinase kinases (Hardie et al, 2012; Steinberg and Kemp, 2009)

Results

Discussion

Conclusion