title: AMPK Phosphorylates Desnutrin/ATGL and Hormone-Sensitive Lipase To Regulate Lipolysis and Fatty Acid Oxidation within Adipose Tissue.
abstract: The role of AMP-activated protein kinase (AMPK) in promoting fatty acid (FA) oxidation in various tissues, such as liver and muscle, has been well understood. However, the role of AMPK in lipolysis and FA metabolism in adipose tissue has been controversial. To investigate the role of AMPK in the regulation of adipose lipolysis in vivo, we generated mice with adipose-tissue-specific knockout of both the α1 and α2 catalytic subunits of AMPK (AMPK-ASKO mice) by using aP2-Cre and adiponectin-Cre. Both models of AMPK-ASKO ablation show no changes in desnutrin/ATGL levels but have defective phosphorylation of desnutrin/ATGL at S406 to decrease its triacylglycerol (TAG) hydrolase activity, lowering basal lipolysis in adipose tissue. These mice also show defective phosphorylation of hormone-sensitive lipase (HSL) at S565, with higher phosphorylation at protein kinase A sites S563 and S660, increasing its hydrolase activity and isoproterenol-stimulated lipolysis. With higher overall adipose lipolysis, both models of AMPK-ASKO mice are lean, having smaller adipocytes with lower TAG and higher intracellular free-FA levels. Moreover, FAs from higher lipolysis activate peroxisome proliferator-activated receptor delta to induce FA oxidative genes and increase FA oxidation and energy expenditure. Overall, for the first time, we provide in vivo evidence of the role of AMPK in the phosphorylation and regulation of desnutrin/ATGL and HSL and thus adipose lipolysis.
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA.
authors.forename: Sun-Joong
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Endocrinology Program, University of California, Berkeley, California, USA.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Tang
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA.
authors.forename: Marcia
authors.initials: M
authors.lastname: Abbott
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA.
authors.forename: Jose A
authors.initials: JA
authors.lastname: Viscarra
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California, USA Endocrinology Program, University of California, Berkeley, California, USA hsul@berkeley.edu.
authors.forename: Hei Sook
authors.initials: HS
authors.lastname: Sul
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000235:genetics* / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D005227:Fatty Acids / Q000378:metabolism*; D055786:Gene Knockout Techniques; D008049:Lipase / Q000378:metabolism*; D050356:Lipid Metabolism; D008066:Lipolysis; D051379:Mice; D010084:Oxidation-Reduction; D010766:Phosphorylation; D002787:Sterol Esterase / Q000378:metabolism*; D000217:Acyltransferases
chemical_list: D055372:AMP-Activated Protein Kinases; D005227:Fatty Acids; D008049:Lipase; D002787:Sterol Esterase; C548179:Prkaa1 protein, mouse; C534978:Prkaa2 protein, mouse; C494445:PNPLA2 protein, mouse; D000217:Acyltransferases