title: AMP-activated protein kinase beta subunit tethers alpha and gamma subunits via its C-terminal sequence (186-270).
abstract: AMP-activated protein kinase (AMPK) is an important metabolic stress-sensing protein kinase responsible for regulating metabolism in response to changing energy demand and nutrient supply. Mammalian AMPK is a stable alphabetagamma heterotrimer comprising a catalytic alpha and two non-catalytic subunits, beta and gamma. The beta subunit targets AMPK to membranes via an N-terminal myristoyl group and to glycogen via a mid-molecule glycogen-binding domain. Here we find that the conserved C-terminal 85-residue sequence of the beta subunit, beta1-(186-270), is sufficient to form an active AMP-dependent heterotrimer alpha1beta1-(186-270)-gamma1, whereas the 25-residue beta1 C-terminal (246-270) sequence is sufficient to bind gamma1, gamma2, or gamma3 but not the alpha subunit. Deletion of the beta C-terminal Ile-270 precludes betagamma association in the absence of the alpha subunit, but the presence of the alpha subunit or substitution of Ile-270 with Ala or Glu restores betagamma binding. Truncation of the alpha subunit reveals that beta1 binding requires the alpha1-(313-473) sequence. The conserved C-terminal 85-residue sequence of the beta subunit (90% between beta1 and beta2) is the primary alphagamma binding sequence responsible for the formation of the AMPK alphabetagamma heterotrimer.
authors.affiliation: St. Vincent's Institute, University of Melbourne, Victoria, Australia.
authors.forename: Tristan J
authors.initials: TJ
authors.lastname: Iseli
authors.forename: Mark
authors.initials: M
authors.lastname: Walter
authors.forename: Bryce J W
authors.initials: BJ
authors.lastname: van Denderen
authors.forename: Frosa
authors.initials: F
authors.lastname: Katsis
authors.forename: Lee A
authors.initials: LA
authors.lastname: Witters
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Kemp
authors.forename: Belinda J
authors.initials: BJ
authors.lastname: Michell
authors.forename: David
authors.initials: D
authors.lastname: Stapleton
mesh_terms: D055372:AMP-Activated Protein Kinases; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D005656:Fungal Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; C071570:SNF1-related protein kinases; C526182:PRKAB1 protein, human; C526183:PRKAB2 protein, human; C526222:PRKAG1 protein, human; C526225:PRKAG3 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C526180:PRKAA1 protein, human