51
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Allosteric regulation of AMP-activated protein kinase by adenylate nucleotides and small-molecule drugs. Biochem Soc Trans 2019; 47:733-741. [PMID: 31000529 DOI: 10.1042/bst20180625] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/31/2019] [Accepted: 04/02/2019] [Indexed: 02/08/2023]
Abstract
The AMP (adenosine 5'-monophosphate)-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis that co-ordinates metabolic processes to ensure energy supply meets demand. At the cellular level, AMPK is activated by metabolic stresses that increase AMP or adenosine 5'-diphosphate (ADP) coupled with falling adenosine 5'-triphosphate (ATP) and acts to restore energy balance by choreographing a shift in metabolism in favour of energy-producing catabolic pathways while inhibiting non-essential anabolic processes. AMPK also regulates systemic energy balance and is activated by hormones and nutritional signals in the hypothalamus to control appetite and body weight. Failure to maintain energy balance plays an important role in chronic diseases such as obesity, type 2 diabetes and inflammatory disorders, which has prompted a major drive to develop pharmacological activators of AMPK. An array of small-molecule allosteric activators has now been developed, several of which can activate AMPK by direct allosteric activation, independently of Thr172 phosphorylation, which was previously regarded as indispensable for AMPK activity. In this review, we summarise the state-of-the-art regarding our understanding of the molecular mechanisms that govern direct allosteric activation of AMPK by adenylate nucleotides and small-molecule drugs.
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Aledavood E, Moraes G, Lameira J, Castro A, Luque FJ, Estarellas C. Understanding the Mechanism of Direct Activation of AMP-Kinase: Toward a Fine Allosteric Tuning of the Kinase Activity. J Chem Inf Model 2019; 59:2859-2870. [PMID: 30924649 DOI: 10.1021/acs.jcim.8b00890] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mammalian AMP-activated protein kinase (AMPK) is a Ser/Thr protein kinase with a key role as a sensor in cellular energy homeostasis. It has a major role in numerous metabolic disorders, such as type 2 diabetes, obesity, and cancer, and hence it has gained progressive interest as a potential therapeutic target. AMPK is a heterotrimeric enzyme composed by an α-catalytic subunit and two regulatory subunits, β and γ. It is regulated by several mechanisms, including indirect activators such as metformin and direct activators such as compound A-769662. The crystal structure of AMPK bound to A-769662 has been recently reported, suggesting a hypothetical allosteric mechanism of AMPK activation assisted by phosphorylated Ser108 at the β-subunit. Here, we have studied the direct activation mechanism of A-769662 by means of molecular dynamics simulations, suggesting that the activator may act as a glue, coupling the dynamical motion of the β-subunit and the N-terminal domain of the α-subunit, and assisting the preorganization of the ATP-binding site. This is achieved through the formation of an allosteric network that connects the activator and ATP-binding sites, particularly through key interactions formed between αAsp88 and βArg83 and between βpSer108 and αLys29. Overall, these studies shed light into key mechanistic determinants of the allosteric regulation of this cellular energy sensor, and pave the way for the fine-tuning of the rational design of direct activators of this cellular energy sensor.
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Affiliation(s)
- Elnaz Aledavood
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicina (IBUB) and Institute of Theoretical and Computational Chemistry (IQTCUB) , University of Barcelona , Santa Coloma de Gramenet 08921 , Spain
| | - Gleiciane Moraes
- Faculdade de Ciências Naturais , Campus Universitário do Marajó-Breves, Universidade Federal do Pará (CUMB-UFPA) , Breves , Brasil
| | - Jeronimo Lameira
- Faculdade de Ciências Naturais , Campus Universitário do Marajó-Breves, Universidade Federal do Pará (CUMB-UFPA) , Breves , Brasil
| | - Ana Castro
- Instituto de Química Médica, Consejo Superior de Investigaciones Científicas (IQM-CSIC) , 28006 Madrid , Spain
| | - F Javier Luque
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicina (IBUB) and Institute of Theoretical and Computational Chemistry (IQTCUB) , University of Barcelona , Santa Coloma de Gramenet 08921 , Spain
| | - Carolina Estarellas
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicina (IBUB) and Institute of Theoretical and Computational Chemistry (IQTCUB) , University of Barcelona , Santa Coloma de Gramenet 08921 , Spain
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53
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Synthetic energy sensor AMPfret deciphers adenylate-dependent AMPK activation mechanism. Nat Commun 2019; 10:1038. [PMID: 30833561 PMCID: PMC6399333 DOI: 10.1038/s41467-019-08938-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 02/04/2019] [Indexed: 02/07/2023] Open
Abstract
AMP-activated protein kinase AMPK senses and regulates cellular energy state. AMPK activation by increasing AMP and ADP concentrations involves a conformational switch within the heterotrimeric complex. This is exploited here for the construction of a synthetic sensor of cellular energetics and allosteric AMPK activation, AMPfret. Based on engineered AMPK fused to fluorescent proteins, the sensor allows direct, real-time readout of the AMPK conformational state by fluorescence resonance energy transfer (FRET). AMPfret faithfully and dynamically reports the binding of AMP and ADP to AMPK γ-CBS sites, competed by Mg2+-free ATP. FRET signals correlate with activation of AMPK by allosteric mechanisms and protection from dephosphorylation, attributed here to specific CBS sites, but does not require activation loop phosphorylation. Moreover, AMPfret detects binding of pharmacological compounds to the AMPK α/β-ADaM site enabling activator screening. Cellular assays demonstrate that AMPfret is applicable in vivo for spatiotemporal analysis of energy state and allosteric AMPK activation. AMP-activated protein kinase AMPK senses and regulates cellular energy state. Here the authors engineer a synthetic sensor, AMPfret, that allows direct, real-time readout of the AMPK conformational state by fluorescence resonance energy transfer (FRET).
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54
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Abstract
Regulation of AMP-activated protein kinase (AMPK) signalling is complex and involves contributions from adenine nucleotides, co-/posttranslational modifications, and isoform composition of the AMPK heterotrimer. It is becoming apparent that AMPK activation/inhibition by synthetic drugs involves similar levels of complexity. Major advances in our understanding of these mechanisms have been gained from recombinant expression systems that provide sufficient quantities of highly purified material for structure/function studies. Here, we provide a detailed protocol for transient expression of affinity-tagged AMPK complexes in mammalian cells. We have found this system to be optimal as a source of enzyme possessing regulatory modifications found in vivo.
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55
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Role of AMPK in mammals reproduction: Specific controls and whole-body energy sensing. C R Biol 2018; 342:1-6. [PMID: 30580936 DOI: 10.1016/j.crvi.2018.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 10/10/2018] [Accepted: 10/31/2018] [Indexed: 01/02/2023]
Abstract
AMP-activated protein kinase (AMPK) is a key enzyme involved in linking the energy sensing to metabolic pathways. As such, it plays a central role at the whole-body level to translate endocrine communications into adapted responses aimed either at saving energy when food is scarce or at allocating it to various functions, particularly reproduction, when food is available. AMPK also plays major roles in the energy individual cells use in order to realize their specific functions. This is of course especially true for all cells involved in the reproductive function (gonads, gametes) or in its control (hypothalamus, pituitary). In the present review, I report a survey of the various roles of AMPK functions in reproduction, either directly in reproductive organs, or indirectly in organs controlling reproduction, particularly at hypothalamus level.
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56
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Arias-Del-Val J, Santo-Domingo J, García-Casas P, Alvarez-Illera P, Núñez Galindo A, Wiederkehr A, Fonteriz RI, Montero M, Alvarez J. Regulation of inositol 1,4,5-trisphosphate-induced Ca 2+ release from the endoplasmic reticulum by AMP-activated kinase modulators. Cell Calcium 2018; 77:68-76. [PMID: 30557841 DOI: 10.1016/j.ceca.2018.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 12/10/2018] [Accepted: 12/10/2018] [Indexed: 01/28/2023]
Abstract
The 5' AMP-activated protein kinase (AMPK) is a nutrient-sensitive kinase that plays a key role in the control of cellular energy metabolism. We have explored here the relationship between AMPK and Ca2+ signaling by looking at the effect of an AMPK activator (A769662) and an AMPK inhibitor (dorsomorphin) on histamine-induced Ca2+-release from the endoplasmic reticulum (ER) in HeLa cells. Our data show that incubation with A769662 (EC50 = 29 μM) inhibited histamine-induced Ca2+-release from the ER in intact cells, as well as inositol-1,4,5-trisphosphate (IP3)-induced Ca2+ release in permeabilized cells. On the contrary, dorsomorphin (EC50 = 0.4 μM) activated both histamine and IP3-induced Ca2+-release and reversed the effect of A769662. These results suggest a direct effect of AMPK regulation on IP3 receptor (IP3R) function. A phosphoproteomic study did not reveal changes in IP3R phosphorylation, but showed significant changes in phosphorylation of proteins placed upstream in the IP3R interactome and in several proteins related with Ca2+ metabolism, which could be candidates to mediate the effects observed. In conclusion, our data suggest that AMPK negatively regulates IP3R. This effect constitutes a novel and very important link between Ca2+ signaling and the AMPK pathway.
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Affiliation(s)
- Jessica Arias-Del-Val
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain
| | - Jaime Santo-Domingo
- Mitochondrial Function and Proteomics, Nestle Institute of Health Science S.A. EPFL Innovation Park, 1015, Lausanne, Switzerland
| | - Paloma García-Casas
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain
| | - Pilar Alvarez-Illera
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain
| | - Antonio Núñez Galindo
- Mitochondrial Function and Proteomics, Nestle Institute of Health Science S.A. EPFL Innovation Park, 1015, Lausanne, Switzerland
| | - Andreas Wiederkehr
- Mitochondrial Function and Proteomics, Nestle Institute of Health Science S.A. EPFL Innovation Park, 1015, Lausanne, Switzerland
| | - Rosalba I Fonteriz
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain
| | - Mayte Montero
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain
| | - Javier Alvarez
- Institute of Biology and Molecular Genetics (IBGM), Department of Biochemistry and Molecular Biology and Physiology, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, 7, E-47005 Valladolid, Spain.
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57
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Yan Y, Zhou XE, Novick SJ, Shaw SJ, Li Y, Brunzelle JS, Hitoshi Y, Griffin PR, Xu HE, Melcher K. Structures of AMP-activated protein kinase bound to novel pharmacological activators in phosphorylated, non-phosphorylated, and nucleotide-free states. J Biol Chem 2018; 294:953-967. [PMID: 30478170 DOI: 10.1074/jbc.ra118.004883] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is an attractive therapeutic target for managing metabolic diseases. A class of pharmacological activators, including Merck 991, binds the AMPK ADaM site, which forms the interaction surface between the kinase domain (KD) of the α-subunit and the carbohydrate-binding module (CBM) of the β-subunit. Here, we report the development of two new 991-derivative compounds, R734 and R739, which potently activate AMPK in a variety of cell types, including β2-specific skeletal muscle cells. Surprisingly, we found that they have only minor effects on direct kinase activity of the recombinant α1β2γ1 isoform yet robustly enhance protection against activation loop dephosphorylation. This mode of activation is reminiscent of that of ADP, which activates AMPK by binding to the nucleotide-binding sites in the γ-subunit, more than 60 Å away from the ADaM site. To understand the mechanisms of full and partial AMPK activation, we determined the crystal structures of fully active phosphorylated AMPK α1β1γ1 bound to AMP and R734/R739 as well as partially active nonphosphorylated AMPK bound to R734 and AMP and phosphorylated AMPK bound to R734 in the absence of added nucleotides at <3-Å resolution. These structures and associated analyses identified a novel conformational state of the AMPK autoinhibitory domain associated with partial kinase activity and provide new insights into phosphorylation-dependent activation loop stabilization in AMPK.
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Affiliation(s)
- Yan Yan
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,Van Andel Research Institute-Shanghai Institute of Materia Medica (VARI-SIMM) Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China.,University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
| | - X Edward Zhou
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Scott J Novick
- Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - Simon J Shaw
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Yingwu Li
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Joseph S Brunzelle
- Northwestern University Synchrotron Research Center, Life Sciences Collaborative Access Team, Northwestern University, Argonne, Illinois 60439
| | - Yasumichi Hitoshi
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, and
| | - Patrick R Griffin
- Department of Molecular Medicine, The Scripps Research Institute, Scripps Florida, Jupiter, Florida 33458
| | - H Eric Xu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,Van Andel Research Institute-Shanghai Institute of Materia Medica (VARI-SIMM) Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Karsten Melcher
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503,
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58
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Interactive Roles for AMPK and Glycogen from Cellular Energy Sensing to Exercise Metabolism. Int J Mol Sci 2018; 19:ijms19113344. [PMID: 30373152 PMCID: PMC6274970 DOI: 10.3390/ijms19113344] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/15/2018] [Accepted: 10/23/2018] [Indexed: 12/12/2022] Open
Abstract
The AMP-activated protein kinase (AMPK) is a heterotrimeric complex with central roles in cellular energy sensing and the regulation of metabolism and exercise adaptations. AMPK regulatory β subunits contain a conserved carbohydrate-binding module (CBM) that binds glycogen, the major tissue storage form of glucose. Research over the past two decades has revealed that the regulation of AMPK is impacted by glycogen availability, and glycogen storage dynamics are concurrently regulated by AMPK activity. This growing body of research has uncovered new evidence of physical and functional interactive roles for AMPK and glycogen ranging from cellular energy sensing to the regulation of whole-body metabolism and exercise-induced adaptations. In this review, we discuss recent advancements in the understanding of molecular, cellular, and physiological processes impacted by AMPK-glycogen interactions. In addition, we appraise how novel research technologies and experimental models will continue to expand the repertoire of biological processes known to be regulated by AMPK and glycogen. These multidisciplinary research advances will aid the discovery of novel pathways and regulatory mechanisms that are central to the AMPK signaling network, beneficial effects of exercise and maintenance of metabolic homeostasis in health and disease.
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59
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Gu X, Bridges MD, Yan Y, de Waal PW, Zhou XE, Suino-Powell KM, Xu HE, Hubbell WL, Melcher K. Conformational heterogeneity of the allosteric drug and metabolite (ADaM) site in AMP-activated protein kinase (AMPK). J Biol Chem 2018; 293:16994-17007. [PMID: 30206123 DOI: 10.1074/jbc.ra118.004101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 09/05/2018] [Indexed: 12/12/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a master regulator of energy homeostasis and a promising drug target for managing metabolic diseases such as type 2 diabetes. Many pharmacological AMPK activators, and possibly unidentified physiological metabolites, bind to the allosteric drug and metabolite (ADaM) site at the interface between the kinase domain (KD) in the α-subunit and the carbohydrate-binding module (CBM) in the β-subunit. Here, using double electron-electron resonance (DEER) spectroscopy, we demonstrate that the CBM-KD interaction is partially dissociated and the interface highly disordered in the absence of pharmacological ADaM site activators as inferred from a low depth of modulation and broad DEER distance distributions. ADaM site ligands such as 991, and to a lesser degree phosphorylation, stabilize the KD-CBM association and strikingly reduce conformational heterogeneity in the ADaM site. Our findings that the ADaM site, formed by the KD-CBM interaction, can be modulated by diverse ligands and by phosphorylation suggest that it may function as a hub for integrating regulatory signals.
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Affiliation(s)
- Xin Gu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Michael D Bridges
- the Jules Stein Eye Institute and Department of Chemistry and Biochemistry, UCLA School of Medicine, University of California, Los Angeles, California 90095-7008, and
| | - Yan Yan
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,the VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Parker W de Waal
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - X Edward Zhou
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Kelly M Suino-Powell
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - H Eric Xu
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503.,the VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Wayne L Hubbell
- the Jules Stein Eye Institute and Department of Chemistry and Biochemistry, UCLA School of Medicine, University of California, Los Angeles, California 90095-7008, and
| | - Karsten Melcher
- From the Center of Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan 49503,
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60
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Jiang S, Li T, Ji T, Yi W, Yang Z, Wang S, Yang Y, Gu C. AMPK: Potential Therapeutic Target for Ischemic Stroke. Am J Cancer Res 2018; 8:4535-4551. [PMID: 30214637 PMCID: PMC6134933 DOI: 10.7150/thno.25674] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 07/16/2018] [Indexed: 02/07/2023] Open
Abstract
5'-AMP-activated protein kinase (AMPK), a member of the serine/threonine (Ser/Thr) kinase group, is universally distributed in various cells and organs. It is a significant endogenous defensive molecule that responds to harmful stimuli, such as cerebral ischemia, cerebral hemorrhage, and, neurodegenerative diseases (NDD). Cerebral ischemia, which results from insufficient blood flow or the blockage of blood vessels, is a major cause of ischemic stroke. Ischemic stroke has received increased attention due to its '3H' effects, namely high mortality, high morbidity, and high disability. Numerous studies have revealed that activation of AMPK plays a protective role in the brain, whereas its action in ischemic stroke remains elusive and poorly understood. Based on existing evidence, we introduce the basic structure, upstream regulators, and biological roles of AMPK. Second, we analyze the relationship between AMPK and the neurovascular unit (NVU). Third, the actions of AMPK in different phases of ischemia and current therapeutic methods are discussed. Finally, we evaluate existing controversy and provide a detailed analysis, followed by ethical issues, potential directions, and further prospects of AMPK. The information complied here may aid in clinical and basic research of AMPK, which may be a potent drug candidate for ischemic stroke treatment in the future.
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61
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Dite TA, Langendorf CG, Hoque A, Galic S, Rebello RJ, Ovens AJ, Lindqvist LM, Ngoei KRW, Ling NXY, Furic L, Kemp BE, Scott JW, Oakhill JS. AMP-activated protein kinase selectively inhibited by the type II inhibitor SBI-0206965. J Biol Chem 2018; 293:8874-8885. [PMID: 29695504 DOI: 10.1074/jbc.ra118.003547] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Indexed: 12/30/2022] Open
Abstract
Inhibition of the metabolic regulator AMP-activated protein kinase (AMPK) is increasingly being investigated for its therapeutic potential in diseases where AMPK hyperactivity results in poor prognoses, as in established cancers and neurodegeneration. However, AMPK-inhibitory tool compounds are largely limited to compound C, which has a poor selectivity profile. Here we identify the pyrimidine derivative SBI-0206965 as a direct AMPK inhibitor. SBI-0206965 inhibits AMPK with 40-fold greater potency and markedly lower kinase promiscuity than compound C and inhibits cellular AMPK signaling. Biochemical characterization reveals that SBI-0206965 is a mixed-type inhibitor. A co-crystal structure of the AMPK kinase domain/SBI-0206965 complex shows that the drug occupies a pocket that partially overlaps the ATP active site in a type IIb inhibitor manner. SBI-0206965 has utility as a tool compound for investigating physiological roles for AMPK and provides fresh impetus to small-molecule AMPK inhibitor therapeutic development.
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Affiliation(s)
- Toby A Dite
- From the Metabolic Signalling Laboratory and
| | - Christopher G Langendorf
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | | | - Sandra Galic
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | - Richard J Rebello
- the Prostate Cancer Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.,the Cancer Program, Biomedicine Discovery Institute, and Department of Anatomy and Developmental Biology, Monash University, Clayton 3800, Victoria, Australia
| | | | - Lisa M Lindqvist
- the Cell Signalling and Cell Death Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Kevin R W Ngoei
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia
| | | | - Luc Furic
- the Prostate Cancer Translational Research Laboratory, Peter MacCallum Cancer Centre, Melbourne, Victoria 3000, Australia.,the Cancer Program, Biomedicine Discovery Institute, and Department of Anatomy and Developmental Biology, Monash University, Clayton 3800, Victoria, Australia.,the Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria 3010, Australia, and
| | - Bruce E Kemp
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia.,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
| | - John W Scott
- Protein Chemistry and Metabolism Unit, St. Vincent's Institute of Medical Research, University of Melbourne, Fitzroy 3065, Victoria, Australia.,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
| | - Jonathan S Oakhill
- From the Metabolic Signalling Laboratory and .,the Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria 3000, Australia
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62
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Structural Determinants for Small-Molecule Activation of Skeletal Muscle AMPK α2β2γ1 by the Glucose Importagog SC4. Cell Chem Biol 2018; 25:728-737.e9. [PMID: 29657085 DOI: 10.1016/j.chembiol.2018.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/31/2018] [Accepted: 03/19/2018] [Indexed: 12/20/2022]
Abstract
The AMP-activated protein kinase (AMPK) αβγ heterotrimer regulates cellular energy homeostasis with tissue-specific isoform distribution. Small-molecule activation of skeletal muscle α2β2 AMPK complexes may prove a valuable treatment strategy for type 2 diabetes and insulin resistance. Herein, we report the small-molecule SC4 is a potent, direct AMPK activator that preferentially activates α2 complexes and stimulates skeletal muscle glucose uptake. In parallel with the term secretagog, we propose "importagog" to define a substance that induces or augments cellular uptake of another substance. Three-dimensional structures of the glucose importagog SC4 bound to activated α2β2γ1 and α2β1γ1 complexes reveal binding determinants, in particular a key interaction between the SC4 imidazopyridine 4'-nitrogen and β2-Asp111, which provide a design paradigm for β2-AMPK therapeutics. The α2β2γ1/SC4 structure reveals an interaction between a β2 N-terminal α helix and the α2 autoinhibitory domain. Our results provide a structure-function guide to accelerate development of potent, but importantly tissue-specific, β2-AMPK therapeutics.
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63
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Abstract
Mammalian AMPK is known to be activated by falling cellular energy status, signaled by rising AMP/ATP and ADP/ATP ratios. We review recent information about how this occurs but also discuss new studies suggesting that AMPK is able to sense glucose availability independently of changes in adenine nucleotides. The glycolytic intermediate fructose-1,6-bisphosphate (FBP) is sensed by aldolase, which binds to the v-ATPase on the lysosomal surface. In the absence of FBP, interactions between aldolase and the v-ATPase are altered, allowing formation of an AXIN-based AMPK-activation complex containing the v-ATPase, Ragulator, AXIN, LKB1, and AMPK, causing increased Thr172 phosphorylation and AMPK activation. This nutrient-sensing mechanism activates AMPK but also primes it for further activation if cellular energy status subsequently falls. Glucose sensing at the lysosome, in which AMPK and other components of the activation complex act antagonistically with another key nutrient sensor, mTORC1, may have been one of the ancestral roles of AMPK.
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Affiliation(s)
- Sheng-Cai Lin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an Campus, Xiamen, Fujian 361102, China.
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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64
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Olivier S, Foretz M, Viollet B. Promise and challenges for direct small molecule AMPK activators. Biochem Pharmacol 2018; 153:147-158. [PMID: 29408352 DOI: 10.1016/j.bcp.2018.01.049] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/31/2018] [Indexed: 12/11/2022]
Abstract
AMP-activated protein kinase (AMPK) is an evolutionary conserved and ubiquitously expressed serine/threonine kinase playing a central role in the coordination of energy homeostasis. Based on the beneficial outcomes of its activation on metabolism, AMPK has emerged as an attractive target for the treatment of metabolic diseases. Identification of novel downstream targets of AMPK beyond the regulation of energy metabolism has renewed considerable attention in exploiting AMPK signaling for novel therapeutic targeting strategies including treatment of cancer and inflammatory diseases. The complexity of AMPK system with tissue- and species-specific expression of multiple isoform combination regulated by various inputs, post-traductional modifications and subcellular locations presents unique challenges for drug discovery. Here, we review the most recent advances in the understanding of the mechanism(s) of action of direct small molecule AMPK activators and the potential therapeutic opportunities.
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Affiliation(s)
- Séverine Olivier
- INSERM, U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, France
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France; CNRS, UMR8104, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, France.
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Boudaba N, Marion A, Huet C, Pierre R, Viollet B, Foretz M. AMPK Re-Activation Suppresses Hepatic Steatosis but its Downregulation Does Not Promote Fatty Liver Development. EBioMedicine 2018; 28:194-209. [PMID: 29343420 PMCID: PMC5835560 DOI: 10.1016/j.ebiom.2018.01.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/05/2018] [Accepted: 01/05/2018] [Indexed: 12/12/2022] Open
Abstract
Nonalcoholic fatty liver disease is a highly prevalent component of disorders associated with disrupted energy homeostasis. Although dysregulation of the energy sensor AMP-activated protein kinase (AMPK) is viewed as a pathogenic factor in the development of fatty liver its role has not been directly demonstrated. Unexpectedly, we show here that liver-specific AMPK KO mice display normal hepatic lipid homeostasis and are not prone to fatty liver development, indicating that the decreases in AMPK activity associated with hepatic steatosis may be a consequence, rather than a cause, of changes in hepatic metabolism. In contrast, we found that pharmacological re-activation of downregulated AMPK in fatty liver is sufficient to normalize hepatic lipid content. Mechanistically, AMPK activation reduces hepatic triglyceride content both by inhibiting lipid synthesis and by stimulating fatty acid oxidation in an LKB1-dependent manner, through a transcription-independent mechanism. Furthermore, the effect of the antidiabetic drug metformin on lipogenesis inhibition and fatty acid oxidation stimulation was enhanced by combination treatment with small-molecule AMPK activators in primary hepatocytes from mice and humans. Overall, these results demonstrate that AMPK downregulation is not a triggering factor in fatty liver development but in contrast, establish the therapeutic impact of pharmacological AMPK re-activation in the treatment of fatty liver disease. Hepatic AMPK deficiency is not sufficient to trigger fatty liver development Re-activation of downregulated AMPK in fatty liver normalizes hepatic lipid content Hepatic AMPK activation both inhibits lipogenesis and stimulates fatty acid oxidation AMPK activation modulates lipid metabolism via a transcription-independent mechanism Small-molecule AMPK activators enhance metformin effects on hepatic lipid metabolism
Nonalcoholic fatty liver disease is a highly prevalent component of metabolic syndrome, for which treatment options are limited. Downregulation of the energy sensor AMPK is viewed as a pathogenic factor in the development of fatty liver. However, we show here hepatic AMPK suppression is not sufficient to promote hepatic lipid accumulation, indicating that the decreases in AMPK activity associated with hepatic steatosis may be a consequence, rather than a cause, of changes in hepatic metabolism. In contrast, we found that pharmacological re-activation of downregulated AMPK in fatty liver is sufficient to normalize hepatic lipid content. Thus, these results establish the therapeutic impact of pharmacological AMPK re-activation in the treatment of fatty liver disease.
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Affiliation(s)
- Nadia Boudaba
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Allison Marion
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Camille Huet
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Rémi Pierre
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75014, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75014, France.
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66
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The Stress-Induced Transcription Factor NR4A1 Adjusts Mitochondrial Function and Synapse Number in Prefrontal Cortex. J Neurosci 2018; 38:1335-1350. [PMID: 29295823 PMCID: PMC5815341 DOI: 10.1523/jneurosci.2793-17.2017] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/10/2017] [Accepted: 12/08/2017] [Indexed: 12/28/2022] Open
Abstract
The energetic costs of behavioral chronic stress are unlikely to be sustainable without neuronal plasticity. Mitochondria have the capacity to handle synaptic activity up to a limit before energetic depletion occurs. Protective mechanisms driven by the induction of neuronal genes likely evolved to buffer the consequences of chronic stress on excitatory neurons in prefrontal cortex (PFC), as this circuitry is vulnerable to excitotoxic insults. Little is known about the genes involved in mitochondrial adaptation to the buildup of chronic stress. Using combinations of genetic manipulations and stress for analyzing structural, transcriptional, mitochondrial, and behavioral outcomes, we characterized NR4A1 as a stress-inducible modifier of mitochondrial energetic competence and dendritic spine number in PFC. NR4A1 acted as a transcription factor for changing the expression of target genes previously involved in mitochondrial uncoupling, AMP-activated protein kinase activation, and synaptic growth. Maintenance of NR4A1 activity by chronic stress played a critical role in the regressive synaptic organization in PFC of mouse models of stress (male only). Knockdown, dominant-negative approach, and knockout of Nr4a1 in mice and rats (male only) protected pyramidal neurons against the adverse effects of chronic stress. In human PFC tissues of men and women, high levels of the transcriptionally active NR4A1 correlated with measures of synaptic loss and cognitive impairment. In the context of chronic stress, prolonged expression and activity of NR4A1 may lead to responses of mitochondria and synaptic connectivity that do not match environmental demand, resulting in circuit malfunction between PFC and other brain regions, constituting a pathological feature across disorders. SIGNIFICANCE STATEMENT The bioenergetic cost of chronic stress is too high to be sustainable by pyramidal prefrontal neurons. Cellular checkpoints have evolved to adjust the responses of mitochondria and synapses to the buildup of chronic stress. NR4A1 plays such a role by controlling the energetic competence of mitochondria with respect to synapse number. As an immediate-early gene, Nr4a1 promotes neuronal plasticity, but sustained expression or activity can be detrimental. NR4A1 expression and activity is sustained by chronic stress in animal models and in human studies of neuropathologies sensitive to the buildup of chronic stress. Therefore, antagonism of NR4A1 is a promising avenue for preventing the regressive synaptic reorganization in cortical systems in the context of chronic stress.
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Curry DW, Stutz B, Andrews ZB, Elsworth JD. Targeting AMPK Signaling as a Neuroprotective Strategy in Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2018; 8:161-181. [PMID: 29614701 PMCID: PMC6004921 DOI: 10.3233/jpd-171296] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder. It is characterized by the accumulation of intracellular α-synuclein aggregates and the degeneration of nigrostriatal dopaminergic neurons. While no treatment strategy has been proven to slow or halt the progression of the disease, there is mounting evidence from preclinical PD models that activation of 5'-AMP-activated protein kinase (AMPK) may have broad neuroprotective effects. Numerous dietary supplements and pharmaceuticals (e.g., metformin) that increase AMPK activity are available for use in humans, but clinical studies of their effects in PD patients are limited. AMPK is an evolutionarily conserved serine/threonine kinase that is activated by falling energy levels and functions to restore cellular energy balance. However, in response to certain cellular stressors, AMPK activation may exacerbate neuronal atrophy and cell death. This review describes the regulation and functions of AMPK, evaluates the controversies in the field, and assesses the potential of targeting AMPK signaling as a neuroprotective treatment for PD.
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Affiliation(s)
- Daniel W Curry
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Bernardo Stutz
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Zane B Andrews
- Department of Physiology, Monash University, Melbourne, VIC, Australia
- Monash Biomedicine Discovery Institute, Monash University, VIC, Australia
| | - John D Elsworth
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
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68
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Fyffe FA, Hawley SA, Gray A, Hardie DG. Cell-Free Assays to Measure Effects of Regulatory Ligands on AMPK. Methods Mol Biol 2018; 1732:69-86. [PMID: 29480469 DOI: 10.1007/978-1-4939-7598-3_5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
AMP-activated protein kinase (AMPK) is an energy sensor that is activated by increases in the cellular AMP/ATP and ADP/ATP ratios by three mechanisms: (1) allosteric activation, (2) promotion of phosphorylation at Thr172 on the α subunit by upstream kinases, and (3) inhibition of dephosphorylation of Thr172 by protein phosphatases. All of these effects are triggered by the binding of AMP or ADP at one or more of three sites on the γ subunit, where they displace ATP. AMPK is also activated by ligands that bind in the ADaM site, which is located between the α and β subunits. In this chapter we describe cell-free assays that can be used to study these varied activation mechanisms.
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Affiliation(s)
- Fiona A Fyffe
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Simon A Hawley
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Alexander Gray
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - D Grahame Hardie
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, Scotland, UK.
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69
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Yan Y, Gu X, Xu HE, Melcher K. A Highly Sensitive Non-Radioactive Activity Assay for AMP-Activated Protein Kinase (AMPK). Methods Protoc 2017; 1. [PMID: 29451563 PMCID: PMC5809138 DOI: 10.3390/mps1010003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
While many methods exist to quantitatively determine protein kinase activities, 32P-based radioactive assays remain the workhorse of many laboratories due to their high sensitivity, high signal to noise ratio, lack of interference by fluorescent and light-absorbing small molecules, and easy quantitation. Here, we demonstrate that the interaction between the yeast Rad53 Forkhead-associated (FHA) domain and a peptide optimized for phosphorylation by AMP-Activated Protein Kinase (AMPK), which has previously been exploited for the generation of intracellular phosphorylation sensors, can serve as a readout for a highly sensitive two-step AMPK AlphaScreen kinase assay with exceptional signal-to-noise ratio.
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Affiliation(s)
- Yan Yan
- Laboratory of Structural Sciences and Laboratory of Structural Biology and Biochemistry, Center of Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue Northeast, Grand Rapids, MI 49503, USA;
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
| | - Xin Gu
- Laboratory of Structural Sciences and Laboratory of Structural Biology and Biochemistry, Center of Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue Northeast, Grand Rapids, MI 49503, USA;
| | - H Eric Xu
- Laboratory of Structural Sciences and Laboratory of Structural Biology and Biochemistry, Center of Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue Northeast, Grand Rapids, MI 49503, USA;
- VARI-SIMM Center, Center for Structure and Function of Drug Targets, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CAS), Shanghai 201203, China
| | - Karsten Melcher
- Laboratory of Structural Sciences and Laboratory of Structural Biology and Biochemistry, Center of Cancer and Cell Biology, Van Andel Research Institute, 333 Bostwick Avenue Northeast, Grand Rapids, MI 49503, USA;
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70
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Abstract
Orthologues of AMP-activated protein kinase (AMPK) occur in essentially all eukaryotes as heterotrimeric complexes comprising catalytic α subunits and regulatory β and γ subunits. The canonical role of AMPK is as an energy sensor, monitoring levels of the nucleotides AMP, ADP, and ATP that bind competitively to the γ subunit. Once activated, AMPK acts to restore energy homeostasis by switching on alternate ATP-generating catabolic pathways while switching off ATP-consuming anabolic pathways. However, its ancestral role in unicellular eukaryotes may have been in sensing of glucose rather than energy. In this article, we discuss a few interesting recent developments in the AMPK field. Firstly, we review recent findings on the canonical pathway by which AMPK is regulated by adenine nucleotides. Secondly, AMPK is now known to be activated in mammalian cells by glucose starvation by a mechanism that occurs in the absence of changes in adenine nucleotides, involving the formation of complexes with Axin and LKB1 on the surface of the lysosome. Thirdly, in addition to containing the nucleotide-binding sites on the γ subunits, AMPK heterotrimers contain a site for binding of allosteric activators termed the allosteric drug and metabolite (ADaM) site. A large number of synthetic activators, some of which show promise as hypoglycaemic agents in pre-clinical studies, have now been shown to bind there. Fourthly, some kinase inhibitors paradoxically activate AMPK, including one (SU6656) that binds in the catalytic site. Finally, although downstream targets originally identified for AMPK were mainly concerned with metabolism, recently identified targets have roles in such diverse areas as mitochondrial fission, integrity of epithelial cell layers, and angiogenesis.
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Affiliation(s)
- David Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Sheng-Cai Lin
- State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiang’an Campus, Xiamen, China
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71
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The autophagy initiator ULK1 sensitizes AMPK to allosteric drugs. Nat Commun 2017; 8:571. [PMID: 28924239 PMCID: PMC5603566 DOI: 10.1038/s41467-017-00628-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 07/14/2017] [Indexed: 01/10/2023] Open
Abstract
AMP-activated protein kinase (AMPK) is a metabolic stress-sensing enzyme responsible for maintaining cellular energy homeostasis. Activation of AMPK by salicylate and the thienopyridone A-769662 is critically dependent on phosphorylation of Ser108 in the β1 regulatory subunit. Here, we show a possible role for Ser108 phosphorylation in cell cycle regulation and promotion of pro-survival pathways in response to energy stress. We identify the autophagy initiator Unc-51-like kinase 1 (ULK1) as a β1-Ser108 kinase in cells. Cellular β1-Ser108 phosphorylation by ULK1 was dependent on AMPK β-subunit myristoylation, metabolic stress associated with elevated AMP/ATP ratio, and the intrinsic energy sensing capacity of AMPK; features consistent with an AMP-induced myristoyl switch mechanism. We further demonstrate cellular AMPK signaling independent of activation loop Thr172 phosphorylation, providing potential insight into physiological roles for Ser108 phosphorylation. These findings uncover new mechanisms by which AMPK could potentially maintain cellular energy homeostasis independently of Thr172 phosphorylation. AMPK is involved in sensing of metabolic stress. The authors show that the autophagy initiator ULK1 phosphorylates β1-Ser108 on the regulatory β1-subunit, sensitizing AMPK to allosteric drugs, and activates signaling pathways that appear independent of Thr172 phosphorylation in the kinase activation loop.
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72
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Abstract
AMPK is a highly conserved master regulator of metabolism, which restores energy balance during metabolic stress both at the cellular and physiological levels. The identification of numerous AMPK targets has helped explain how AMPK restores energy homeostasis. Recent advancements illustrate novel mechanisms of AMPK regulation, including changes in subcellular localization and phosphorylation by non-canonical upstream kinases. Notably, the therapeutic potential of AMPK is widely recognized and heavily pursued for treatment of metabolic diseases such as diabetes, but also obesity, inflammation, and cancer. Moreover, the recently solved crystal structure of AMPK has shed light both into how nucleotides activate AMPK and, importantly, also into the sites bound by small molecule activators, thus providing a path for improved drugs.
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Affiliation(s)
- Daniel Garcia
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Reuben J Shaw
- The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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73
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Phosphorylation of AMPK by upstream kinases is required for activity in mammalian cells. Biochem J 2017; 474:3059-3073. [PMID: 28694351 PMCID: PMC5565919 DOI: 10.1042/bcj20170458] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 06/29/2017] [Accepted: 07/10/2017] [Indexed: 01/01/2023]
Abstract
AMP-activated protein kinase (AMPK) plays a major role in regulating metabolism and has attracted significant attention as a therapeutic target for treating metabolic disorders. AMPK activity is stimulated more than 100-fold by phosphorylation of threonine 172 (Thr172). Binding of AMP to the γ subunit allosterically activates the kinase. Additionally, many small molecules, e.g. 991, have been identified that bind between the kinase domain and the carbohydrate-binding module of the β subunit, stabilising their interaction and leading to activation. It was reported recently that non-phosphorylated Thr172 AMPK is activated by AMP and A769662. We present here the crystal structure of non-phosphorylated Thr172 AMPK in complex with AMP and 991. This structure reveals that the activation loop, as well as the complex overall, is similar to the Thr172 phosphorylated complex. We find that in the presence of AMP and 991 non-phosphorylated Thr172, AMPK is much less active than the Thr172 phosphorylated enzyme. In human cells, the basal level of Thr172 phosphorylation is very low (∼1%), but is increased 10-fold by treatment with 2-deoxyglucose. In cells lacking the major Thr172 kinases, LKB1 and CaMKKβ, Thr172 phosphorylation is almost completely abolished, and AMPK activity is virtually undetectable. Our data show that AMP and 991 binding to non-phosphorylated Thr172 AMPK can induce an ordered, active-like, conformation of the activation loop explaining how AMPK activity can be measured in vitro without Thr172 phosphorylation. However, in a cellular context, phosphorylation of Thr172 is critical for significant activation of AMPK.
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74
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Ross FA, Hawley SA, Auciello FR, Gowans GJ, Atrih A, Lamont DJ, Hardie DG. Mechanisms of Paradoxical Activation of AMPK by the Kinase Inhibitors SU6656 and Sorafenib. Cell Chem Biol 2017; 24:813-824.e4. [PMID: 28625738 PMCID: PMC5522529 DOI: 10.1016/j.chembiol.2017.05.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 02/28/2017] [Accepted: 05/17/2017] [Indexed: 02/07/2023]
Abstract
SU6656, a Src kinase inhibitor, was reported to increase fat oxidation and reduce body weight in mice, with proposed mechanisms involving AMP-activated protein kinase (AMPK) activation via inhibition of phosphorylation of either LKB1 or AMPK by the Src kinase, Fyn. However, we report that AMPK activation by SU6656 is independent of Src kinases or tyrosine phosphorylation of LKB1 or AMPK and is not due to decreased cellular energy status or binding at the ADaM site on AMPK. SU6656 is a potent AMPK inhibitor, yet binding at the catalytic site paradoxically promotes phosphorylation of Thr172 by LKB1. This would enhance phosphorylation of downstream targets provided the lifetime of Thr172 phosphorylation was sufficient to allow dissociation of the inhibitor and subsequent catalysis prior to its dephosphorylation. By contrast, sorafenib, a kinase inhibitor in clinical use, activates AMPK indirectly by inhibiting mitochondrial metabolism and increasing cellular AMP:ADP and/or ADP:ATP ratios.
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Affiliation(s)
- Fiona A Ross
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Simon A Hawley
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - F Romana Auciello
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Graeme J Gowans
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Abdelmadjid Atrih
- Fingerprints Proteomics Facility, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Douglas J Lamont
- Fingerprints Proteomics Facility, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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75
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Liang Z, Li T, Jiang S, Xu J, Di W, Yang Z, Hu W, Yang Y. AMPK: a novel target for treating hepatic fibrosis. Oncotarget 2017; 8:62780-62792. [PMID: 28977988 PMCID: PMC5617548 DOI: 10.18632/oncotarget.19376] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 07/08/2017] [Indexed: 12/19/2022] Open
Abstract
Fibrosis is a common process of excessive extracellular matrix (ECM) accumulation following inflammatory injury. Fibrosis is involved in the pathogenesis of almost all liver diseases for which there is no effective treatment. 5'-AMP-activated protein kinase (AMPK) is a cellular energy sensor that can ameliorate the process of hepatic fibrogenesis. Given the existing evidence, we first introduce the basic background of AMPK and hepatic fibrosis and the actions of AMPK in hepatic fibrosis. Second, we discuss the three phases of hepatic fibrosis and potential drugs that target AMPK. Third, we analyze possible anti-fibrosis mechanisms and other benefits of AMPK on the liver. Finally, we summarize and briefly explain the current objections to targeting AMPK. This review may aid clinical and basic research on AMPK, which may be a novel drug candidate for hepatic fibrosis.
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Affiliation(s)
- Zhenxing Liang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Tian Li
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an 710069, China.,Department of Biomedical Engineering, The Fourth Military Medical University, Xi'an 710032, China
| | - Shuai Jiang
- Department of Aerospace Medicine, The Fourth Military Medical University, Xi'an 710032, China
| | - Jing Xu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, China
| | - Wencheng Di
- Department of Cardiology, Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Zhi Yang
- Department of Biomedical Engineering, The Fourth Military Medical University, Xi'an 710032, China
| | - Wei Hu
- Department of Biomedical Engineering, The Fourth Military Medical University, Xi'an 710032, China
| | - Yang Yang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences, Northwest University, Xi'an 710069, China.,Department of Biomedical Engineering, The Fourth Military Medical University, Xi'an 710032, China
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76
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Molecular mechanisms of appetite and obesity: a role for brain AMPK. Clin Sci (Lond) 2017; 130:1697-709. [PMID: 27555613 DOI: 10.1042/cs20160048] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 07/07/2016] [Indexed: 01/15/2023]
Abstract
Feeding behaviour and energy storage are both crucial aspects of survival. Thus, it is of fundamental importance to understand the molecular mechanisms regulating these basic processes. The AMP-activated protein kinase (AMPK) has been revealed as one of the key molecules modulating energy homoeostasis. Indeed, AMPK appears to be essential for translating nutritional and energy requirements into generation of an adequate neuronal response, particularly in two areas of the brain, the hypothalamus and the hindbrain. Failure of this physiological response can lead to energy imbalance, ultimately with extreme consequences, such as leanness or obesity. Here, we will review the data that put brain AMPK in the spotlight as a regulator of appetite.
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77
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Huang T, Sun J, Zhou S, Gao J, Liu Y. Identification of Direct Activator of Adenosine Monophosphate-Activated Protein Kinase (AMPK) by Structure-Based Virtual Screening and Molecular Docking Approach. Int J Mol Sci 2017; 18:ijms18071408. [PMID: 28665353 PMCID: PMC5535900 DOI: 10.3390/ijms18071408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/24/2017] [Accepted: 06/27/2017] [Indexed: 12/25/2022] Open
Abstract
Adenosine monophosphate-activated protein kinase (AMPK) plays a critical role in the regulation of energy metabolism and has been targeted for drug development of therapeutic intervention in Type II diabetes and related diseases. Recently, there has been renewed interest in the development of direct β1-selective AMPK activators to treat patients with diabetic nephropathy. To investigate the details of AMPK domain structure, sequence alignment and structural comparison were used to identify the key amino acids involved in the interaction with activators and the structure difference between β1 and β2 subunits. Additionally, a series of potential β1-selective AMPK activators were identified by virtual screening using molecular docking. The retrieved hits were filtered on the basis of Lipinski’s rule of five and drug-likeness. Finally, 12 novel compounds with diverse scaffolds were obtained as potential starting points for the design of direct β1-selective AMPK activators.
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Affiliation(s)
- Tonghui Huang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
| | - Jie Sun
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
| | - Shanshan Zhou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
| | - Jian Gao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
| | - Yi Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou 221004, China.
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78
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Houde VP, Donzelli S, Sacconi A, Galic S, Hammill JA, Bramson JL, Foster RA, Tsakiridis T, Kemp BE, Grasso G, Blandino G, Muti P, Steinberg GR. AMPK β1 reduces tumor progression and improves survival in p53 null mice. Mol Oncol 2017; 11:1143-1155. [PMID: 28544264 PMCID: PMC5579332 DOI: 10.1002/1878-0261.12079] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/15/2017] [Accepted: 05/16/2017] [Indexed: 12/21/2022] Open
Abstract
The AMP-activated protein kinase (AMPK) is a heterotrimeric protein complex that is an important sensor of cellular energy status. Reduced expression of the AMPK β1 isoform has been linked to reduced survival in different cancers, but whether this accelerates tumor progression and the potential mechanism mediating these effects are not known. Furthermore, it is unknown whether AMPK β1 is implicated in tumorigenesis, and if so, what tissues may be most sensitive. In the current study, we find that in the absence of the tumor suppressor p53, germline genetic deletion of AMPK β1 accelerates the appearance of a T-cell lymphoma that reduces lifespan compared to p53 deficiency alone. This increased tumorigenesis is linked to increases in interleukin-1β (IL1β), reductions in acetyl-CoA carboxylase (ACC) phosphorylation, and elevated lipogenesis. Collectively, these data indicate that reductions in the AMPK β1 subunit accelerate the development of T-cell lymphoma, suggesting that therapies targeting this AMPK subunit or inhibiting lipogenesis may be effective for limiting the proliferation of p53-mutant tumors.
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Affiliation(s)
- Vanessa P Houde
- Department of Oncology, McMaster University, Hamilton, Canada.,Department of Medicine, McMaster University, Hamilton, Canada
| | - Sara Donzelli
- Oncogenomic and Epigenetic Unit, Italian National Cancer Institute 'Regina Elena', Rome, Italy
| | - Andrea Sacconi
- Oncogenomic and Epigenetic Unit, Italian National Cancer Institute 'Regina Elena', Rome, Italy
| | - Sandra Galic
- St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Australia
| | - Joanne A Hammill
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Jonathan L Bramson
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Robert A Foster
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Canada
| | | | - Bruce E Kemp
- St. Vincent's Institute of Medical Research and Department of Medicine, University of Melbourne, Australia.,Mary MacKillop Institute for Health Research Australian Catholic University, Fitzroy, Australia
| | - Giuseppe Grasso
- Oncogenomic and Epigenetic Unit, Italian National Cancer Institute 'Regina Elena', Rome, Italy
| | - Giovanni Blandino
- Department of Oncology, McMaster University, Hamilton, Canada.,Oncogenomic and Epigenetic Unit, Italian National Cancer Institute 'Regina Elena', Rome, Italy
| | - Paola Muti
- Department of Oncology, McMaster University, Hamilton, Canada
| | - Gregory R Steinberg
- Department of Medicine, McMaster University, Hamilton, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
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79
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Guigas B, Viollet B. Targeting AMPK: From Ancient Drugs to New Small-Molecule Activators. ACTA ACUST UNITED AC 2017; 107:327-350. [PMID: 27812986 DOI: 10.1007/978-3-319-43589-3_13] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The AMP-activated protein kinase (AMPK) is an evolutionary conserved and ubiquitously expressed serine/threonine kinase mainly acting as a key regulator of cellular energy homeostasis. AMPK is a heterotrimeric protein complex, consisting of a catalytic α subunit and two regulatory β and γ subunits, whose activity is tightly regulated by changes in adenine nucleotides and several posttranslational modifications. Once activated in response to energy deficit, AMPK concomitantly inhibits ATP-consuming anabolic processes and promotes ATP-generating catabolic pathways via direct phosphorylation of multiple downstream effectors, leading to restoration of cellular energy balance. A growing number of energy/nutrient-independent functions of AMPK are also regularly reported, progressively expanding its role to regulation of non-metabolic cellular processes. Historically, AMPK as a therapeutic target has attracted much of interest due to its potential impact on metabolic disorders, such as obesity and type 2 diabetes, but has also recently received considerable renewed attention in the framework of cancer studies, highlighting the persistent need for selective, reversible, potent, and tissue-specific activators. In this chapter, we review the most recent advances in the understanding of the mechanism(s) of action of the current portfolio of AMPK activators, including plant-derived natural compounds and newly discovered small-molecule agonists directly targeting various AMPK subunits.
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Affiliation(s)
- Bruno Guigas
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
- Department of Parasitology, Leiden University Medical Center, 9600, Postzone L40-Q, 2300 RC, Leiden, The Netherlands.
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, France
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80
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Abstract
AMP-activated protein kinase is a family of heterotrimeric serine/threonine protein kinases that come in twelve different flavors. They serve an essential function in all eukaryotes of conserving cellular energy levels. AMPK complexes are regulated by changes in cellular AMP:ATP or ADP:ATP ratios and by a number of neutraceuticals and some of the widely-used diabetes medications such as metformin and thiazolinonediones. Moreover, biochemical activities of AMPK are tightly regulated by phosphorylation or dephosphorylation by upstream kinases and phosphatases respectively. Efforts are underway in many pharmaceutical companies to discover direct AMPK activators for the treatment of cardiovascular and metabolic diseases such as diabetes, non-alcoholic steatohepatitis (NASH) and diabetic nephropathy. Many advances have been made in the AMPK structural biology arena over the last few years that are beginning to provide detailed molecular insights into the overall topology of these fascinating enzymes and how binding of small molecules elicit subtle conformational changes leading to their activation and protection from dephosphorylation. In the brief review below on AMPK structure and function, we have focused on the recent crystallographic results especially on specific molecular interactions of direct synthetic AMPK activators which lead to biased activation of a sub-family of AMPK isoforms.
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Affiliation(s)
- Ravi G Kurumbail
- Pfizer Worldwide Research and Development, Pfizer Inc, Eastern Point Road, Groton, CT, 06340, USA.
| | - Matthew F Calabrese
- Pfizer Worldwide Research and Development, Pfizer Inc, Eastern Point Road, Groton, CT, 06340, USA
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81
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Abstract
The AMP-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis, which acts to restore energy homoeostasis whenever cellular energy charge is depleted. Over the last 2 decades, it has become apparent that AMPK regulates several other cellular functions and has specific roles in cardiovascular tissues, acting to regulate cardiac metabolism and contractile function, as well as promoting anticontractile, anti-inflammatory, and antiatherogenic actions in blood vessels. In this review, we discuss the role of AMPK in the cardiovascular system, including the molecular basis of mutations in AMPK that alter cardiac physiology and the proposed mechanisms by which AMPK regulates vascular function under physiological and pathophysiological conditions.
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Affiliation(s)
- Ian P Salt
- From the Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Scotland, United Kingdom (I.P.S.); and Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Scotland, United Kingdom (D.G.H.).
| | - D Grahame Hardie
- From the Institute of Cardiovascular & Medical Sciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Scotland, United Kingdom (I.P.S.); and Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Scotland, United Kingdom (D.G.H.)
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82
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Li T, Jiang S, Yang Z, Ma Z, Yi W, Wang D, Yang Y. Targeting the energy guardian AMPK: another avenue for treating cardiomyopathy? Cell Mol Life Sci 2017; 74:1413-1429. [PMID: 27815596 PMCID: PMC11107559 DOI: 10.1007/s00018-016-2407-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/25/2016] [Accepted: 11/01/2016] [Indexed: 12/11/2022]
Abstract
5'-AMP-activated protein kinase (AMPK) is a pivotal regulator of endogenous defensive molecules in various pathological processes. The AMPK signaling regulates a variety of intracellular intermedial molecules involved in biological reactions, including glycogen metabolism, protein synthesis, and cardiac fibrosis, in response to hypertrophic stimuli. Studies have revealed that the activation of AMPK performs a protective role in cardiovascular diseases, whereas its function in cardiac hypertrophy and cardiomyopathy remains elusive and poorly understood. In view of the current evidence of AMPK, we introduce the biological information of AMPK and cardiac hypertrophy as well as some upstream activators of AMPK. Next, we discuss two important types of cardiomyopathy involving AMPK, RKAG2 cardiomyopathy, and hypertrophic cardiomyopathy. Eventually, therapeutic research, genetic screening, conflicts, obstacles, challenges, and potential directions are also highlighted in this review, aimed at providing a comprehensive understanding of AMPK for readers.
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Affiliation(s)
- Tian Li
- Department of Thoracic and Cardiovascular Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, China
- Department of Biomedical Engineering, The Fourth Military Medical University, 169 Changle West Road, Xi'an, 710032, China
| | - Shuai Jiang
- Department of Aerospace Medicine, The Fourth Military Medical University, 169 Changle West Road, Xi'an, 710032, China
| | - Zhi Yang
- Department of Biomedical Engineering, The Fourth Military Medical University, 169 Changle West Road, Xi'an, 710032, China
| | - Zhiqiang Ma
- Department of Thoracic Surgery, Tangdu Hospital, The Fourth Military Medical University, 1 Xinsi Road, Xi'an, 710038, China
| | - Wei Yi
- Department of Cardiovascular Surgery, Xijing Hospital, The Fourth Military Medical University, 127 Changle West Road, Xi'an, 710038, China
| | - Dongjin Wang
- Department of Thoracic and Cardiovascular Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, China.
| | - Yang Yang
- Department of Thoracic and Cardiovascular Surgery, Affiliated Drum Tower Hospital of Nanjing University Medical School, 321 Zhongshan Road, Nanjing, 210008, Jiangsu, China.
- Department of Biomedical Engineering, The Fourth Military Medical University, 169 Changle West Road, Xi'an, 710032, China.
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83
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Nguyen TMD. Impact of 5'-amp-activated Protein Kinase on Male Gonad and Spermatozoa Functions. Front Cell Dev Biol 2017; 5:25. [PMID: 28386541 PMCID: PMC5362614 DOI: 10.3389/fcell.2017.00025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/07/2017] [Indexed: 12/12/2022] Open
Abstract
As we already know, the male reproductive system requires less energetic investment than the female one. Nevertheless, energy balance is an important feature for spermatozoa production in the testis and for spermatozoa properties after ejaculation. The 5'-AMP-activated protein kinase, AMPK, is a sensor of cell energy, that regulates many metabolic pathways and that has been recently shown to control spermatozoa quality and functions. It is indeed involved in the regulation of spermatozoa quality through its action on the proliferation of testicular somatic cells (Sertoli and Leydig), on spermatozoa motility and acrosome reaction. It also favors spermatozoa quality through the management of lipid peroxidation and antioxidant enzymes. I review here the most recent data available on the roles of AMPK in vertebrate spermatozoa functions.
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Affiliation(s)
- Thi Mong Diep Nguyen
- Physiologie de la Reproduction et des Comportements, INRANouzilly, France; Quy Nhon UniversityQuy Nhon, Vietnam
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84
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GFAT1 phosphorylation by AMPK promotes VEGF-induced angiogenesis. Biochem J 2017; 474:983-1001. [PMID: 28008135 DOI: 10.1042/bcj20160980] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 02/07/2023]
Abstract
Activation of AMP-activated protein kinase (AMPK) in endothelial cells regulates energy homeostasis, stress protection and angiogenesis, but the underlying mechanisms are incompletely understood. Using a label-free phosphoproteomic analysis, we identified glutamine:fructose-6-phosphate amidotransferase 1 (GFAT1) as an AMPK substrate. GFAT1 is the rate-limiting enzyme in the hexosamine biosynthesis pathway (HBP) and as such controls the modification of proteins by O-linked β-N-acetylglucosamine (O-GlcNAc). In the present study, we tested the hypothesis that AMPK controls O-GlcNAc levels and function of endothelial cells via GFAT1 phosphorylation using biochemical, pharmacological, genetic and in vitro angiogenesis approaches. Activation of AMPK in primary human endothelial cells by 5-aminoimidazole-4-carboxamide riboside (AICAR) or by vascular endothelial growth factor (VEGF) led to GFAT1 phosphorylation at serine 243. This effect was not seen when AMPK was down-regulated by siRNA. Upon AMPK activation, diminished GFAT activity and reduced O-GlcNAc levels were observed in endothelial cells containing wild-type (WT)-GFAT1 but not in cells expressing non-phosphorylatable S243A-GFAT1. Pharmacological inhibition or siRNA-mediated down-regulation of GFAT1 potentiated VEGF-induced sprouting, indicating that GFAT1 acts as a negative regulator of angiogenesis. In cells expressing S243A-GFAT1, VEGF-induced sprouting was reduced, suggesting that VEGF relieves the inhibitory action of GFAT1/HBP on angiogenesis via AMPK-mediated GFAT1 phosphorylation. Activation of GFAT1/HBP by high glucose led to impairment of vascular sprouting, whereas GFAT1 inhibition improved sprouting even if glucose level was high. Our findings provide novel mechanistic insights into the role of HBP in angiogenesis. They suggest that targeting AMPK in endothelium might help to ameliorate hyperglycaemia-induced vascular dysfunction associated with metabolic disorders.
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85
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Hu K, Gong X, Ai Q, Lin L, Dai J, Cai L, Jiang R, Ge P, Zhang L. Endogenous AMPK acts as a detrimental factor in fulminant hepatitis via potentiating JNK-dependent hepatocyte apoptosis. Cell Death Dis 2017; 8:e2637. [PMID: 28252653 PMCID: PMC5386558 DOI: 10.1038/cddis.2017.62] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 01/19/2017] [Accepted: 01/24/2017] [Indexed: 02/06/2023]
Abstract
The energy sensor AMP-activated protein kinase (AMPK) is crucial for energy homeostasis. Recent studies have revealed that AMPK is involved in various energy-intensive pathological processes such as inflammation and apoptosis. The physiological functions of hepatic AMPK have been well studied, but the pathological significance of AMPK in liver disorders remains largely unknown. In the present study, the phosphorylation status and the roles of AMPK were investigated in mice with lipopolysaccharide (LPS)/d-galactosamine (D-Gal)-induced fulminant hepatitis. The experimental data indicated that the phosphorylation of hepatic AMPK increased in mice with LPS/D-Gal-induced fulminant hepatitis. Pretreatment with the AMPK inhibitor compound C enhanced the early production of pro-inflammatory cytokines but suppressed the late activation of the caspase cascade, reduced the number of TUNEL-positive cells, decreased the elevation of aminotransferases, alleviated the histological abnormalities and improved the survival rate of LPS/D-Gal-insulted mice. Pretreatment with compound C suppressed LPS/D-Gal-induced phosphorylation of JNK. Inhibition of JNK alleviated LPS/D-Gal-induced liver injury, but the level of p53 remained unchanged in mice exposed to LPS/D-Gal. Post-insult treatment with the AMPK activator A-769662 further increased the phosphorylation levels of AMPK and JNK, enhanced hepatocyte apoptosis and deteriorated liver injury, all of these effects could be reversed by co-administration of the AMPK inhibitor or JNK inhibitor. Interestingly, post-insult treatment with the AMPK inhibitor also resulted in beneficial outcomes. These data suggested that AMPK might be a late detrimental factor in LPS/D-Gal-induced hepatitis via potentiating JNK-dependent hepatocyte apoptosis and AMPK might become a pharmacological target for the intervention of fulminant hepatitis.
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Affiliation(s)
- Kai Hu
- Department of Pathophysiology, Chongqing Medical University, Chongqing, China
| | - Xianqiong Gong
- Department of Pathophysiology, Chongqing Medical University, Chongqing, China.,Hepatology Center, Xiamen Hospital of Traditional Chinese Medicine, Xiamen, Fujian Province, China
| | - Qing Ai
- Department of Physiology, Chongqing Medical University, Chongqing, China
| | - Ling Lin
- Department of Pathophysiology, Chongqing Medical University, Chongqing, China
| | - Jie Dai
- Hospital of Chongqing University of Arts and Sciences, Chongqing, China
| | - Lu Cai
- Department of Pathogenic Biology, Chongqing Medical University, Chongqing, China
| | - Rong Jiang
- Laboratory of Stem cell and Tissue Engineering, Chongqing Medical University, Chongqing, China
| | - Pu Ge
- Department of Pathophysiology, Chongqing Medical University, Chongqing, China
| | - Li Zhang
- Department of Pathophysiology, Chongqing Medical University, Chongqing, China.,Laboratory of Stem cell and Tissue Engineering, Chongqing Medical University, Chongqing, China
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86
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Khan AS, Frigo DE. A spatiotemporal hypothesis for the regulation, role, and targeting of AMPK in prostate cancer. Nat Rev Urol 2017; 14:164-180. [PMID: 28169991 PMCID: PMC5672799 DOI: 10.1038/nrurol.2016.272] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The 5'-AMP-activated protein kinase (AMPK) is a master regulator of cellular homeostasis. Despite AMPK's known function in physiology, its role in pathological processes such as prostate cancer is enigmatic. However, emerging evidence is now beginning to decode the paradoxical role of AMPK in cancer and, therefore, inform clinicians if - and how - AMPK could be therapeutically targeted. Spatiotemporal regulation of AMPK complexes could be one of the mechanisms that governs this kinase's role in cancer. We hypothesize that different upstream stimuli will activate select subcellular AMPK complexes. This hypothesis is supported by the distinct subcellular locations of the various AMPK subunits. Each of these unique AMPK complexes regulates discrete downstream processes that can be tumour suppressive or oncogenic. AMPK's final biological output is then determined by the weighted net function of these downstream signalling events, influenced by additional prostate-specific signalling.
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Affiliation(s)
- Ayesha S. Khan
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX USA
| | - Daniel E. Frigo
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX USA
- Genomic Medicine Program, The Houston Methodist Research Institute, Houston, TX USA
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87
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Carling D. AMPK signalling in health and disease. Curr Opin Cell Biol 2017; 45:31-37. [PMID: 28232179 DOI: 10.1016/j.ceb.2017.01.005] [Citation(s) in RCA: 499] [Impact Index Per Article: 71.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/23/2017] [Indexed: 12/22/2022]
Abstract
In eukaryotic cells AMP-activated protein kinase (AMPK) plays a major role in regulating cellular energy balance. AMPK responds to changes in intracellular adenine nucleotide levels, being activated by an increase in AMP/ADP relative to ATP. Activation of AMPK increases the rate of catabolic (ATP-generating) pathways and decreases the rate of anabolic (ATP-utilising) pathways. In addition to its role in maintaining intracellular energy balance, AMPK regulates whole body energy metabolism. Given its key role in controlling energy homeostasis, AMPK has attracted widespread interest as a potential therapeutic target for metabolic diseases, including type 2 diabetes and, more recently, cancer. Here I review the regulation of AMPK and its potential as a target for therapeutic intervention in human disease.
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Affiliation(s)
- David Carling
- MRC London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London W12 0NN UK.
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88
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Yan T, Zhang J, Tang D, Zhang X, Jiang X, Zhao L, Zhang Q, Zhang D, Huang Y. Hypoxia Regulates mTORC1-Mediated Keratinocyte Motility and Migration via the AMPK Pathway. PLoS One 2017; 12:e0169155. [PMID: 28068384 PMCID: PMC5221764 DOI: 10.1371/journal.pone.0169155] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 12/13/2016] [Indexed: 01/06/2023] Open
Abstract
Keratinocyte migration, the initial event and rate-limiting step in wound healing, plays a vital role in restoration of the intact skin barrier, also known as re-epithelialization. After acute tissue injury, hypoxic microenvironment gradually develops and acts as an early stimulus to initiate the healing process. Although we have previously found that hypoxia induces keratinocyte migration, the underlying mechanism remains unknown. Here, we first observed that hypoxia increased mTORC1 activity. Recombinant lentivirus vector and Rapamycin were used for silencing mTORC1 in HaCaT cells and primary mouse keratinocytes (MKs). Using cell migration assay and a Zeiss chamber equipped with imaging system, we also demonstrated that mTORC1 downregulation reversed hypoxia-induced keratinocyte motility and lateral migration. Importantly, hypoxia-activated mTORC1 was accompanied by the AMPK downregulation, and we found that the AMPK pathway activators Metformin (Met) and 5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) decreased the mTORC1 activity, cell motility and lateral migration. Thus, our results suggest that hypoxia regulates mTORC1-mediated keratinocyte motility and migration via the AMPK pathway.
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Affiliation(s)
- Tiantian Yan
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Junhui Zhang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Di Tang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xingyue Zhang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xupin Jiang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Liping Zhao
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Qiong Zhang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Dongxia Zhang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Yuesheng Huang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, Third Military Medical University, Chongqing, China
- * E-mail:
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89
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Ward J, Reyes AR, Kurumbail RG. Allosteric Modulation of AMPK Enzymatic Activity: In Vitro Characterization. Methods Enzymol 2016; 587:481-509. [PMID: 28253974 DOI: 10.1016/bs.mie.2016.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric serine/threonine protein kinase found in nearly all eukaryotes that functions as a master energy sensor in cells. During times of cell stress and changes in the AMP/ATP ratio, AMPK becomes activated and phosphorylates a multitude of protein substrates involved in various cellular processes such as metabolism, cell growth and autophagy. The endogenous ligand AMP is known to bind to the γ-subunit and activates the enzyme via three distinct mechanisms (1) enhancing phosphorylation by upstream kinases of Thr172 in the activation loop (a site critical for AMPK activity), (2) protecting Thr172 from dephosphorylation by phosphatases, and (3) allosteric activation of the kinase activity. Given the important regulatory role for AMPK in various cellular processes and the multiple known modes of activation, there is great interest in identifying small-molecule activators of this kinase and a need for assays to identify and characterize compounds. Here we describe several assay formats that have been used for identifying and characterizing small-molecule AMPK activators.
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Affiliation(s)
- J Ward
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, United States.
| | - A R Reyes
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, United States
| | - R G Kurumbail
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research and Development, Groton, CT, United States
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90
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β-subunit myristoylation functions as an energy sensor by modulating the dynamics of AMP-activated Protein Kinase. Sci Rep 2016; 6:39417. [PMID: 28000716 PMCID: PMC5175161 DOI: 10.1038/srep39417] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/22/2016] [Indexed: 12/14/2022] Open
Abstract
The heterotrimeric AMP-activated protein kinase (AMPK), consisting of α, β and γ subunits, is a stress-sensing enzyme that is activated by phosphorylation of its activation loop in response to increases in cellular AMP. N-terminal myristoylation of the β-subunit has been shown to suppress Thr172 phosphorylation, keeping AMPK in an inactive state. Here we use amide hydrogen-deuterium exchange mass spectrometry (HDX-MS) to investigate the structural and dynamic properties of the mammalian myristoylated and non-myristoylated inactivated AMPK (D139A) in the presence and absence of nucleotides. HDX MS data suggests that the myristoyl group binds near the first helix of the C-terminal lobe of the kinase domain similar to other kinases. Our data, however, also shows that ATP.Mg2+ results in a global stabilization of myristoylated, but not non-myristoylated AMPK, and most notably for peptides of the activation loop of the α-kinase domain, the autoinhibitory sequence (AIS) and the βCBM. AMP does not have that effect and HDX measurements for myristoylated and non-myristoylated AMPK in the presence of AMP are similar. These differences in dynamics may account for a reduced basal rate of phosphorylation of Thr172 in myristoylated AMPK in skeletal muscle where endogenous ATP concentrations are very high.
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91
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Li J, Li S, Wang F, Xin F. Structural and biochemical insights into the allosteric activation mechanism of AMP-activated protein kinase. Chem Biol Drug Des 2016; 89:663-669. [PMID: 27809416 DOI: 10.1111/cbdd.12897] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/11/2016] [Accepted: 10/23/2016] [Indexed: 12/12/2022]
Abstract
The AMP-activated protein kinase (AMPK), a complicated αβγ heterotrimer, can sense cellular energy status and maintain energy homeostasis via switching catabolic and anabolic pathways. AMPK also participates in the regulation of many other life activities, including the cell cycle, cell polarity, autophagy, and life span. Therefore, AMPK is widely studied as a potential drug target for treatment of type 2 diabetes and some other metabolic diseases, cancers, and cardiovascular diseases. Similar to other kinases, the phosphorylation of α-Thr172 in the activation loop by upstream kinases is crucial for the activation of AMPK. In addition, the binding of AMP and its analogues to the γ subunit causes further allosteric activation, which makes AMPK distinctive from other kinases. Here, we give a brief introduction to the domain constitutions of mammalian AMPK and then systematically review its allosteric activation mechanism from a structural and biochemical view.
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Affiliation(s)
- Jin Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Shuying Li
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Fengzhong Wang
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Fengjiao Xin
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
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92
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Kim J, Yang G, Ha J. Targeting of AMP-activated protein kinase: prospects for computer-aided drug design. Expert Opin Drug Discov 2016; 12:47-59. [PMID: 27797589 DOI: 10.1080/17460441.2017.1255194] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Dysregulation of energy homeostasis has been implicated in a number of human chronic diseases including diabetes, obesity, cancer, and inflammation. Given the functional attributes as a central regulator of energy homeostasis, AMP-activated protein kinase (AMPK) is emerging as a therapeutic target for these diseases, and lines of evidence have highlighted the need for rational and robust screening systems for identifying specific AMPK modulators with a therapeutic potential for preventing and/or curing these diseases. Areas covered: Here, the authors review the recent advances in the understanding of three-dimensional structures of AMPK in relationship with the regulatory mechanisms, potentials of AMPK as a therapeutic target in human chronic diseases, and prospects of computer-based drug design for AMPK. Expert opinion: Accumulating information of AMPK structure has provided us with deep insight into the molecular basis underlying the regulatory mechanisms, and further discloses several structural domains, which can be served for a target site for computer-based drug design. Molecular docking and simulations provides useful information about the binding sites between potent drugs and AMPK as well as a rational screening format to discover isoform-specific AMPK modulators. For these reasons, the authors suggest that computer-aided virtual screening methods hold promise as a rational approach for discovering more specific AMPK modulators.
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Affiliation(s)
- Joungmok Kim
- a Department of Oral Biochemistry and Molecular Biology, School of Dentistry , Kyung Hee University , Dongdaemun-gu , Republic of Korea
| | - Goowon Yang
- b Department of Biochemistry and Molecular Biology, Graduate School , Kyung Hee University , Seoul , Republic of Korea
| | - Joohun Ha
- b Department of Biochemistry and Molecular Biology, Graduate School , Kyung Hee University , Seoul , Republic of Korea
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93
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Lazo-Fernández Y, Baile G, Meade P, Torcal P, Martínez L, Ibañez C, Bernal ML, Viollet B, Giménez I. Kidney-specific genetic deletion of both AMPK α-subunits causes salt and water wasting. Am J Physiol Renal Physiol 2016; 312:F352-F365. [PMID: 28179232 DOI: 10.1152/ajprenal.00169.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 11/07/2016] [Accepted: 11/07/2016] [Indexed: 11/22/2022] Open
Abstract
AMP-activated kinase (AMPK) controls cell energy homeostasis by modulating ATP synthesis and expenditure. In vitro studies have suggested AMPK may also control key elements of renal epithelial electrolyte transport but in vivo physiological confirmation is still insufficient. We studied sodium renal handling and extracellular volume regulation in mice with genetic deletion of AMPK catalytic subunits. AMPKα1 knockout (KO) mice exhibit normal renal sodium handling and a moderate antidiuretic state. This is accompanied by higher urinary aldosterone excretion rates and reduced blood pressure. Plasma volume, however, was found to be increased compared with wild-type mice. Thus blood volume is preserved despite a significantly lower hematocrit. The lack of a defect in renal function in AMPKα1 KO mice could be explained by a compensatory upregulation in AMPK α2-subunit. Therefore, we used the Cre-loxP system to knock down AMPKα2 expression in renal epithelial cells. Combining this approach with the systemic deletion of AMPKα1 we achieved reduced renal AMPK activity, accompanied by a shift to a moderate water- and salt-wasting phenotype. Thus we confirm the physiologically relevant role of AMPK in the kidney. Furthermore, our results indicate that in vivo AMPK activity stimulates renal sodium and water reabsorption.
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Affiliation(s)
| | - Goretti Baile
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Patricia Meade
- Department of Cellular Biology and Biochemistry University of Zaragoza, Zaragoza, Spain.,IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Pilar Torcal
- IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Laura Martínez
- IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
| | - Carmen Ibañez
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Maria Luisa Bernal
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris, France.,CNRS (UMR 8104), Paris, France; and.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ignacio Giménez
- Department of Pharmacology and Physiology, University of Zaragoza, Zaragoza, Spain; .,IIS Aragón. Instituto Aragonés de Ciencias de la Salud, Zaragoza, Spain
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94
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Bultot L, Jensen TE, Lai YC, Madsen ALB, Collodet C, Kviklyte S, Deak M, Yavari A, Foretz M, Ghaffari S, Bellahcene M, Ashrafian H, Rider MH, Richter EA, Sakamoto K. Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle. Am J Physiol Endocrinol Metab 2016; 311:E706-E719. [PMID: 27577855 PMCID: PMC5241553 DOI: 10.1152/ajpendo.00237.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/19/2016] [Indexed: 11/22/2022]
Abstract
AMP-activated protein kinase (AMPK) plays diverse roles and coordinates complex metabolic pathways for maintenance of energy homeostasis. This could be explained by the fact that AMPK exists as multiple heterotrimer complexes comprising a catalytic α-subunit (α1 and α2) and regulatory β (β1 and β2)- and γ (γ1, γ2, γ3)-subunits, which are uniquely distributed across different cell types. There has been keen interest in developing specific and isoform-selective AMPK-activating drugs for therapeutic use and also as research tools. Moreover, establishing ways of enhancing cellular AMPK activity would be beneficial for both purposes. Here, we investigated if a recently described potent AMPK activator called 991, in combination with the commonly used activator 5-aminoimidazole-4-carboxamide riboside or contraction, further enhances AMPK activity and glucose transport in mouse skeletal muscle ex vivo. Given that the γ3-subunit is exclusively expressed in skeletal muscle and has been implicated in contraction-induced glucose transport, we measured the activity of AMPKγ3 as well as ubiquitously expressed γ1-containing complexes. We initially validated the specificity of the antibodies for the assessment of isoform-specific AMPK activity using AMPK-deficient mouse models. We observed that a low dose of 991 (5 μM) stimulated a modest or negligible activity of both γ1- and γ3-containing AMPK complexes. Strikingly, dual treatment with 991 and 5-aminoimidazole-4-carboxamide riboside or 991 and contraction profoundly enhanced AMPKγ1/γ3 complex activation and glucose transport compared with any of the single treatments. The study demonstrates the utility of a dual activator approach to achieve a greater activation of AMPK and downstream physiological responses in various cell types, including skeletal muscle.
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Affiliation(s)
- Laurent Bultot
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Thomas E Jensen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Yu-Chiang Lai
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Agnete L B Madsen
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Caterina Collodet
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland; School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Samanta Kviklyte
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Maria Deak
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland
| | - Arash Yavari
- Experimental Therapeutics and Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Marc Foretz
- U1016, Institut National de la Santé et de la Recherche Médicale, Institut Cochin, Paris, France; UMR8104, Centre National de la Recherche Scientifique, Paris, France; and Université Paris Descartes, Paris, France
| | - Sahar Ghaffari
- Experimental Therapeutics and Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mohamed Bellahcene
- Experimental Therapeutics and Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Houman Ashrafian
- Experimental Therapeutics and Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Mark H Rider
- Université catholique de Louvain and de Duve Institute, Brussels, Belgium
| | - Erik A Richter
- Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Kei Sakamoto
- Nestlé Institute of Health Sciences SA, EPFL Innovation Park, Lausanne, Switzerland; School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland;
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95
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Smith BK, Marcinko K, Desjardins EM, Lally JS, Ford RJ, Steinberg GR. Treatment of nonalcoholic fatty liver disease: role of AMPK. Am J Physiol Endocrinol Metab 2016; 311:E730-E740. [PMID: 27577854 DOI: 10.1152/ajpendo.00225.2016] [Citation(s) in RCA: 336] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 08/28/2016] [Indexed: 01/15/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a growing worldwide epidemic and an important risk factor for the development of insulin resistance, type 2 diabetes, nonalcoholic steatohepatitis (NASH), and hepatic cellular carcinoma (HCC). Despite the prevalence of NAFLD, lifestyle interventions involving exercise and weight loss are the only accepted treatments for this disease. Over the last decade, numerous experimental compounds have been shown to improve NAFLD in preclinical animal models, and many of these therapeutics have been shown to increase the activity of the cellular energy sensor AMP-activated protein kinase (AMPK). Because AMPK activity is reduced by inflammation, obesity, and diabetes, increasing AMPK activity has been viewed as a viable therapeutic strategy to improve NAFLD. In this review, we propose three primary mechanisms by which AMPK activation may improve NAFLD. In addition, we examine the mechanisms by which AMPK is activated. Finally, we identify 27 studies that have used AMPK activators to reduce NAFLD. Future considerations for studies examining the relationship between AMPK and NAFLD are highlighted.
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Affiliation(s)
- Brennan K Smith
- Division of Endocrinology and Metabolism, Department of Medicine; and
| | - Katarina Marcinko
- Division of Endocrinology and Metabolism, Department of Medicine; and
| | - Eric M Desjardins
- Division of Endocrinology and Metabolism, Department of Medicine; and
| | - James S Lally
- Division of Endocrinology and Metabolism, Department of Medicine; and
| | - Rebecca J Ford
- Division of Endocrinology and Metabolism, Department of Medicine; and
| | - Gregory R Steinberg
- Division of Endocrinology and Metabolism, Department of Medicine; and Department of Biochemistry, McMaster University, Hamilton, Ontario, Canada
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96
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Evans AM, Mahmoud AD, Moral-Sanz J, Hartmann S. The emerging role of AMPK in the regulation of breathing and oxygen supply. Biochem J 2016; 473:2561-72. [PMID: 27574022 PMCID: PMC5003690 DOI: 10.1042/bcj20160002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/20/2016] [Accepted: 05/03/2016] [Indexed: 01/25/2023]
Abstract
Regulation of breathing is critical to our capacity to accommodate deficits in oxygen availability and demand during, for example, sleep and ascent to altitude. It is generally accepted that a fall in arterial oxygen increases afferent discharge from the carotid bodies to the brainstem and thus delivers increased ventilatory drive, which restores oxygen supply and protects against hypoventilation and apnoea. However, the precise molecular mechanisms involved remain unclear. We recently identified as critical to this process the AMP-activated protein kinase (AMPK), which is key to the cell-autonomous regulation of metabolic homoeostasis. This observation is significant for many reasons, not least because recent studies suggest that the gene for the AMPK-α1 catalytic subunit has been subjected to natural selection in high-altitude populations. It would appear, therefore, that evolutionary pressures have led to AMPK being utilized to regulate oxygen delivery and thus energy supply to the body in the short, medium and longer term. Contrary to current consensus, however, our findings suggest that AMPK regulates ventilation at the level of the caudal brainstem, even when afferent input responses from the carotid body are normal. We therefore hypothesize that AMPK integrates local hypoxic stress at defined loci within the brainstem respiratory network with an index of peripheral hypoxic status, namely afferent chemosensory inputs. Allied to this, AMPK is critical to the control of hypoxic pulmonary vasoconstriction and thus ventilation-perfusion matching at the lungs and may also determine oxygen supply to the foetus by, for example, modulating utero-placental blood flow.
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Affiliation(s)
- A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K.
| | - Amira D Mahmoud
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Javier Moral-Sanz
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
| | - Sandy Hartmann
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, U.K
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97
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Moral-Sanz J, Mahmoud AD, Ross FA, Eldstrom J, Fedida D, Hardie DG, Evans AM. AMP-activated protein kinase inhibits Kv 1.5 channel currents of pulmonary arterial myocytes in response to hypoxia and inhibition of mitochondrial oxidative phosphorylation. J Physiol 2016; 594:4901-15. [PMID: 27062501 PMCID: PMC5009768 DOI: 10.1113/jp272032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/26/2016] [Indexed: 12/29/2022] Open
Abstract
KEY POINTS Progression of hypoxic pulmonary hypertension is thought to be due, in part, to suppression of voltage-gated potassium channels (Kv ) in pulmonary arterial smooth muscle by hypoxia, although the precise molecular mechanisms have been unclear. AMP-activated protein kinase (AMPK) has been proposed to couple inhibition of mitochondrial metabolism by hypoxia to acute hypoxic pulmonary vasoconstriction and progression of pulmonary hypertension. Inhibition of complex I of the mitochondrial electron transport chain activated AMPK and inhibited Kv 1.5 channels in pulmonary arterial myocytes. AMPK activation by 5-aminoimidazole-4-carboxamide riboside, A769662 or C13 attenuated Kv 1.5 currents in pulmonary arterial myocytes, and this effect was non-additive with respect to Kv 1.5 inhibition by hypoxia and mitochondrial poisons. Recombinant AMPK phosphorylated recombinant human Kv 1.5 channels in cell-free assays, and inhibited K(+) currents when introduced into HEK 293 cells stably expressing Kv 1.5. These results suggest that AMPK is the primary mediator of reductions in Kv 1.5 channels following inhibition of mitochondrial oxidative phosphorylation during hypoxia and by mitochondrial poisons. ABSTRACT Progression of hypoxic pulmonary hypertension is thought to be due, in part, to suppression of voltage-gated potassium channels (Kv ) in pulmonary arterial smooth muscle cells that is mediated by the inhibition of mitochondrial oxidative phosphorylation. We sought to determine the role in this process of the AMP-activated protein kinase (AMPK), which is intimately coupled to mitochondrial function due to its activation by LKB1-dependent phosphorylation in response to increases in the cellular AMP:ATP and/or ADP:ATP ratios. Inhibition of complex I of the mitochondrial electron transport chain using phenformin activated AMPK and inhibited Kv currents in pulmonary arterial myocytes, consistent with previously reported effects of mitochondrial inhibitors. Myocyte Kv currents were also markedly inhibited upon AMPK activation by A769662, 5-aminoimidazole-4-carboxamide riboside and C13 and by intracellular dialysis from a patch-pipette of activated (thiophosphorylated) recombinant AMPK heterotrimers (α2β2γ1 or α1β1γ1). Hypoxia and inhibitors of mitochondrial oxidative phosphorylation reduced AMPK-sensitive K(+) currents, which were also blocked by the selective Kv 1.5 channel inhibitor diphenyl phosphine oxide-1 but unaffected by the presence of the BKCa channel blocker paxilline. Moreover, recombinant human Kv 1.5 channels were phosphorylated by AMPK in cell-free assays, and K(+) currents carried by Kv 1.5 stably expressed in HEK 293 cells were inhibited by intracellular dialysis of AMPK heterotrimers and by A769662, the effects of which were blocked by compound C. We conclude that AMPK mediates Kv channel inhibition by hypoxia in pulmonary arterial myocytes, at least in part, through phosphorylation of Kv 1.5 and/or an associated protein.
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Affiliation(s)
- Javier Moral-Sanz
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Amira D Mahmoud
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Fiona A Ross
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - Jodene Eldstrom
- Department of Anaesthesiology. Pharmacology and Therapeutics, University of British Columbia, 2350 Health Science Mall, Vancouver, Canada, V6T 1Z3
| | - David Fedida
- Department of Anaesthesiology. Pharmacology and Therapeutics, University of British Columbia, 2350 Health Science Mall, Vancouver, Canada, V6T 1Z3
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dow Street, Dundee, DD1 5EH, UK
| | - A Mark Evans
- Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh, EH8 9XD, UK
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98
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Emanuelle S, Doblin MS, Stapleton DI, Bacic A, Gooley PR. Molecular Insights into the Enigmatic Metabolic Regulator, SnRK1. TRENDS IN PLANT SCIENCE 2016; 21:341-353. [PMID: 26642889 DOI: 10.1016/j.tplants.2015.11.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/13/2015] [Accepted: 11/03/2015] [Indexed: 05/20/2023]
Abstract
Sucrose non-fermenting-1 (SNF1)-related kinase 1 (SnRK1) lies at the heart of metabolic homeostasis in plants and is crucial for normal development and response to stress. Evolutionarily related to SNF1 in yeast and AMP-activated kinase (AMPK) in mammals, SnRK1 acts protectively to maintain homeostasis in the face of fluctuations in energy status. Despite a conserved function, the structure and regulation of the plant kinase differ considerably from its relatively well-understood opisthokont orthologues. In this review, we highlight the known plant-specific modes of regulation involving SnRK1 together with new insights based on a 3D molecular model of the kinase. We also summarise how these differences from other orthologues may be specific adaptations to plant metabolism, and offer insights into possible avenues of future inquiry into this enigmatic enzyme.
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Affiliation(s)
- Shane Emanuelle
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Monika S Doblin
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia
| | - David I Stapleton
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Antony Bacic
- Australian Research Council Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Parkville, VIC 3010, Australia.
| | - Paul R Gooley
- Department of Biochemistry & Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia
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99
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Kim J, Yang G, Kim Y, Kim J, Ha J. AMPK activators: mechanisms of action and physiological activities. Exp Mol Med 2016; 48:e224. [PMID: 27034026 PMCID: PMC4855276 DOI: 10.1038/emm.2016.16] [Citation(s) in RCA: 490] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 12/28/2015] [Accepted: 12/29/2015] [Indexed: 02/07/2023] Open
Abstract
AMP-activated protein kinase (AMPK) is a central regulator of energy homeostasis, which coordinates metabolic pathways and thus balances nutrient supply with energy demand. Because of the favorable physiological outcomes of AMPK activation on metabolism, AMPK has been considered to be an important therapeutic target for controlling human diseases including metabolic syndrome and cancer. Thus, activators of AMPK may have potential as novel therapeutics for these diseases. In this review, we provide a comprehensive summary of both indirect and direct AMPK activators and their modes of action in relation to the structure of AMPK. We discuss the functional differences among isoform-specific AMPK complexes and their significance regarding the development of novel AMPK activators and the potential for combining different AMPK activators in the treatment of human disease.
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Affiliation(s)
- Joungmok Kim
- Depatment of Oral Biochemistry and Molecular Biology, School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Goowon Yang
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Yeji Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Jin Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul, Korea
| | - Joohun Ha
- Department of Biochemistry and Molecular Biology, Graduate School, Kyung Hee University, Seoul, Korea
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100
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Structural basis of allosteric and synergistic activation of AMPK by furan-2-phosphonic derivative C2 binding. Nat Commun 2016; 7:10912. [PMID: 26952388 PMCID: PMC4786773 DOI: 10.1038/ncomms10912] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 01/29/2016] [Indexed: 12/20/2022] Open
Abstract
The metabolic stress-sensing enzyme AMP-activated protein kinase (AMPK) is responsible for regulating metabolism in response to energy supply and demand. Drugs that activate AMPK may be useful in the treatment of metabolic diseases including type 2 diabetes. We have determined the crystal structure of AMPK in complex with its activator 5-(5-hydroxyl-isoxazol-3-yl)-furan-2-phosphonic acid (C2), revealing two C2-binding sites in the γ-subunit distinct from nucleotide sites. C2 acts synergistically with the drug A769662 to activate AMPK α1-containing complexes independent of upstream kinases. Our results show that dual drug therapies could be effective AMPK-targeting strategies to treat metabolic diseases.
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