title: Protein Kinase A Opposes the Phosphorylation-dependent Recruitment of Glycogen Synthase Kinase 3β to A-kinase Anchoring Protein 220.
abstract: The proximity of an enzyme to its substrate can influence rate and magnitude of catalysis. A-kinase anchoring protein 220 (AKAP220) is a multivalent anchoring protein that can sequester a variety of signal transduction enzymes. These include protein kinase A (PKA) and glycogen synthase kinase 3β (GSK3β). Using a combination of molecular and cellular approaches we show that GSK3β phosphorylation of Thr-1132 on AKAP220 initiates recruitment of this kinase into the enzyme scaffold. We also find that AKAP220 anchors GSK3β and its substrate β-catenin in membrane ruffles. Interestingly, GSK3β can be released from the multienzyme complex in response to PKA phosphorylation on serine 9, which suppresses GSK3β activity. The signaling scaffold may enhance this regulatory mechanism, as AKAP220 has the capacity to anchor two PKA holoenzymes. Site 1 on AKAP220 (residues 610-623) preferentially interacts with RII, whereas site 2 (residues 1633-1646) exhibits a dual specificity for RI and RII. In vitro affinity measurements revealed that site 2 on AKAP220 binds RII with ∼10-fold higher affinity than site 1. Occupancy of both R subunit binding sites on AKAP220 could provide a mechanism to amplify local cAMP responses and enable cross-talk between PKA and GSK3β.
authors.affiliation: From the Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Whiting
authors.affiliation: From the Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Nygren
authors.affiliation: Translational Oncology, Array BioPharma, Inc., Boulder, Colorado 80301, and.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Tunquist
authors.affiliation: From the Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195.
authors.forename: Lorene K
authors.initials: LK
authors.lastname: Langeberg
authors.affiliation: From the Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, Department of Pharmacy, University of Tromsø, The Arctic University of Norway, 9037 Tromsø, Norway.
authors.forename: Ole-Morten
authors.initials: OM
authors.lastname: Seternes
authors.affiliation: From the Howard Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, scottjdw@uw.edu.
authors.forename: John D
authors.initials: JD
authors.lastname: Scott
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology*; D005786:Gene Expression Regulation / Q000187:drug effects; D005818:Genetic Engineering; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D000071679:Glycogen Synthase Kinase 3 beta; D057809:HEK293 Cells; D020035:Holoenzymes / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D017433:Protein Structure, Secondary; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D054758:A Kinase Anchor Proteins; D020035:Holoenzymes; D021122:Protein Subunits; D011994:Recombinant Proteins; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D017868:Cyclic AMP-Dependent Protein Kinases; D038362:Glycogen Synthase Kinase 3
keywords: A-kinase anchoring protein (AKAP); cyclic AMP (cAMP); glycogen synthase kinase 3 (GSK-3); protein complex; protein kinase; protein kinase A (PKA); protein phosphorylation; β-catenin (B-catenin)