title: AMP-activated protein kinase does not associate with glycogen alpha-particles from rat liver.
abstract: The AMP-activated protein kinase (AMPK) is heterotrimer consisting of alpha catalytic subunit and beta/gamma regulatory subunits. It acts as a critical focal point for whole body and cellular mechanisms maintaining energy homeostasis by regulating carbohydrate and lipid metabolism, food intake, gene transcription, and protein synthesis. The AMPK beta subunit contains a glycogen-binding domain that has been shown to associate with glycogen particles in vitro and glycogen phosphorylase and glycogen synthase in cultured cells. To determine whether AMPK associates with glycogen particles in vivo, we developed a procedure to purify glycogen alpha-particles to apparent homogeneity from rat liver. Using immunoreactivity and mass spectrometry we determined that AMPK does not associate with the glycogen particle in livers from random-fed rats. This surprising finding indicates that the glycogen-binding properties of the AMPK beta subunit are likely regulated and responsive to the metabolic status of the hepatocyte.
authors.affiliation: Department of Medicine, Rm 4C464B SOM, 30 N 1900 E, 84132, School of Medicine, University of Utah, Salt Lake City, UT, USA.
authors.forename: Glendon J
authors.initials: GJ
authors.lastname: Parker
authors.forename: Ann
authors.initials: A
authors.lastname: Koay
authors.forename: Ryan
authors.initials: R
authors.lastname: Gilbert-Wilson
authors.forename: Lynne J
authors.initials: LJ
authors.lastname: Waddington
authors.forename: David
authors.initials: D
authors.lastname: Stapleton
mesh_terms: D000091162:AMP-Activated Protein Kinase Kinases; D000818:Animals; D004789:Enzyme Activation; D006003:Glycogen / Q000737:chemistry*; D066298:In Vitro Techniques; D008099:Liver / Q000737:chemistry*; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry*; D021122:Protein Subunits / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D021122:Protein Subunits; D006003:Glycogen; D011494:Protein Kinases; D000091162:AMP-Activated Protein Kinase Kinases