title: Gpr161 anchoring of PKA consolidates GPCR and cAMP signaling.
abstract: Scaffolding proteins organize the information flow from activated G protein-coupled receptors (GPCRs) to intracellular effector cascades both spatially and temporally. By this means, signaling scaffolds, such as A-kinase anchoring proteins (AKAPs), compartmentalize kinase activity and ensure substrate selectivity. Using a phosphoproteomics approach we identified a physical and functional connection between protein kinase A (PKA) and Gpr161 (an orphan GPCR) signaling. We show that Gpr161 functions as a selective high-affinity AKAP for type I PKA regulatory subunits (RI). Using cell-based reporters to map protein-protein interactions, we discovered that RI binds directly and selectively to a hydrophobic protein-protein interaction interface in the cytoplasmic carboxyl-terminal tail of Gpr161. Furthermore, our data demonstrate that a binary complex between Gpr161 and RI promotes the compartmentalization of Gpr161 to the plasma membrane. Moreover, we show that Gpr161, functioning as an AKAP, recruits PKA RI to primary cilia in zebrafish embryos. We also show that Gpr161 is a target of PKA phosphorylation, and that mutation of the PKA phosphorylation site affects ciliary receptor localization. Thus, we propose that Gpr161 is itself an AKAP and that the cAMP-sensing Gpr161:PKA complex acts as cilium-compartmentalized signalosome, a concept that now needs to be considered in the analyzing, interpreting, and pharmaceutical targeting of PKA-associated functions.
authors.affiliation: Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Verena A
authors.initials: VA
authors.lastname: Bachmann
authors.affiliation: Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Johanna E
authors.initials: JE
authors.lastname: Mayrhofer
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093;
authors.forename: Ronit
authors.initials: R
authors.lastname: Ilouz
authors.affiliation: Institute of Molecular Biology, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Philipp
authors.initials: P
authors.lastname: Tschaikner
authors.affiliation: Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Philipp
authors.initials: P
authors.lastname: Raffeiner
authors.affiliation: Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Ruth
authors.initials: R
authors.lastname: Röck
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, Canada H3C 3J7; Département de Biochimie, Université de Montréal, Montreal, QC, Canada H3C 3J7;
authors.forename: Mathieu
authors.initials: M
authors.lastname: Courcelles
authors.affiliation: Otto-Warburg Laboratory, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany;
authors.forename: Federico
authors.initials: F
authors.lastname: Apelt
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093; Department of Pharmacology, University of California, San Diego, CA 92093;
authors.forename: Tsan-Wen
authors.initials: TW
authors.lastname: Lu
authors.affiliation: Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom;
authors.forename: George S
authors.initials: GS
authors.lastname: Baillie
authors.affiliation: Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, QC, Canada H3C 3J7; Department of Chemistry, Université de Montréal, Montreal, QC, Canada H3C 3J7;
authors.forename: Pierre
authors.initials: P
authors.lastname: Thibault
authors.affiliation: Institute of Molecular Biology, University of Innsbruck, 6020 Innsbruck, Austria;
authors.forename: Pia
authors.initials: P
authors.lastname: Aanstad
authors.affiliation: Otto-Warburg Laboratory, Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany; Institute of Pharmaceutical Sciences, Pharmaceutical Chemistry, University of Graz, 8010 Graz, Austria.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stelzl
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, CA 92093; Department of Pharmacology, University of California, San Diego, CA 92093; staylor@ucsd.edu eduard.stefan@uibk.ac.at.
authors.forename: Susan S
authors.initials: SS
authors.lastname: Taylor
authors.affiliation: Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, 6020 Innsbruck, Austria; staylor@ucsd.edu eduard.stefan@uibk.ac.at.
authors.forename: Eduard
authors.initials: E
authors.lastname: Stefan
mesh_terms: D054758:A Kinase Anchor Proteins / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D000242:Cyclic AMP / Q000378:metabolism*; D054743:Cyclic AMP-Dependent Protein Kinase Type I / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D049410:Luciferases, Renilla; D051379:Mice; D010766:Phosphorylation; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015027:Zebrafish
chemical_list: D054758:A Kinase Anchor Proteins; C000588604:GPR161 protein, human; D043562:Receptors, G-Protein-Coupled; D000242:Cyclic AMP; D049410:Luciferases, Renilla; D054743:Cyclic AMP-Dependent Protein Kinase Type I
keywords: interaction network; molecular interactions; phosphorylation; primary cilium; scaffolding function