title: Effect of different γ-subunit isoforms on the regulation of AMPK.
abstract: AMP-activated protein kinase (AMPK) plays a key role in integrating metabolic pathways in response to energy demand. AMPK activation results in a wide range of downstream responses, many of which are associated with improved metabolic outcome, making AMPK an attractive target for the treatment of metabolic diseases. AMPK is a heterotrimeric complex consisting of a catalytic subunit (α) and two regulatory subunits (β and γ). The γ-subunit harbours the nucleotide-binding sites and plays an important role in AMPK regulation in response to cellular energy levels. In mammals, there are three isoforms of the γ-subunit and these respond differently to regulation by nucleotides, but there is limited information regarding their role in activation by small molecules. Here, we determined the effect of different γ-isoforms on AMPK by a direct activator, 991. In cells, 991 led to a greater activation of γ2-containing AMPK complexes compared with either γ1 or γ3. This effect was dependent on the long N-terminal region of the γ2-isoform. We were able to rule out an effect of Ser108phosphorylation, since mutation of Ser108to alanine in the β2-isoform had no effect on activation of AMPK by 991 in either γ1- or γ2-complexes. The rate of dephosphorylation of Thr172was slower for γ2- compared with γ1-complexes, both in the absence and presence of 991. Our studies show that activation of AMPK by 991 depends on the nature of the γ-isoform. This finding may have implications for the design of isoform-selective AMPK activators.
authors.affiliation: Cellular Stress Group, Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London W12 0NN, U.K.
authors.forename: Robin
authors.initials: R
authors.lastname: Willows
authors.affiliation: Cellular Stress Group, Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London W12 0NN, U.K.
authors.forename: Naveenan
authors.initials: N
authors.lastname: Navaratnam
authors.affiliation: Cellular Stress Group, Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London W12 0NN, U.K.
authors.forename: Ana
authors.initials: A
authors.lastname: Lima
authors.affiliation: AstraZeneca R&D, Discovery Sciences, Darwin Building, 310 Cambridge Science Park, Milton Road, Cambridge CB4 0WG, U.K.
authors.forename: Jon
authors.initials: J
authors.lastname: Read
authors.affiliation: Cellular Stress Group, Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, Imperial College, London W12 0NN, U.K.|Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London W12 0NN, U.K.
authors.forename: David
authors.initials: D
authors.lastname: Carling
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000494:Allosteric Regulation / Q000187:drug effects; D019943:Amino Acid Substitution; D000631:Aminopyridines / Q000494:pharmacology; D001562:Benzimidazoles / Q000494:pharmacology; D001565:Benzoates / Q000494:pharmacology; D001665:Binding Sites; D064113:CRISPR-Cas Systems; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008024:Ligands; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013912:Threonine / Q000378:metabolism
chemical_list: C000620824:5-((6-chloro-5-(1-methylindol-5-yl)-1H-benzimidazol-2-yl)oxy)-2-methylbenzoic acid; D000631:Aminopyridines; D001562:Benzimidazoles; D001565:Benzoates; D020536:Enzyme Activators; D007211:Indoles; D007527:Isoenzymes; D008024:Ligands; C000617641:PF-249; D011994:Recombinant Proteins; D013912:Threonine; C526222:PRKAG1 protein, human; C526223:PRKAG2 protein, human; C526225:PRKAG3 protein, human; D055372:AMP-Activated Protein Kinases
keywords: AMPK; metabolic regulation; protein–serine–threonine kinases