title: Bimodal antagonism of PKA signalling by ARHGAP36.
abstract: Protein kinase A is a key mediator of cAMP signalling downstream of G-protein-coupled receptors, a signalling pathway conserved in all eukaryotes. cAMP binding to the regulatory subunits (PKAR) relieves their inhibition of the catalytic subunits (PKAC). Here we report that ARHGAP36 combines two distinct inhibitory mechanisms to antagonise PKA signalling. First, it blocks PKAC activity via a pseudosubstrate motif, akin to the mechanism employed by the protein kinase inhibitor proteins. Second, it targets PKAC for rapid ubiquitin-mediated lysosomal degradation, a pathway usually reserved for transmembrane receptors. ARHGAP36 thus dampens the sensitivity of cells to cAMP. We show that PKA inhibition by ARHGAP36 promotes derepression of the Hedgehog signalling pathway, thereby providing a simple rationale for the upregulation of ARHGAP36 in medulloblastoma. Our work reveals a new layer of PKA regulation that may play an important role in development and disease.
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Eccles
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.|Berlin Institute of Health (BIH), Kapelle-Ufer 2, 10117 Berlin, Germany.
authors.forename: Maciej T
authors.initials: MT
authors.lastname: Czajkowski
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Barth
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Paul Markus
authors.initials: PM
authors.lastname: Müller
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: McShane
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Grunwald
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Beaudette
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Nora
authors.initials: N
authors.lastname: Mecklenburg
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Volkmer
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Zühlke
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Dittmar
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Selbach
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Hammes
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.|Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Daumke
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.|DZHK, German Centre for Cardiovascular Research, Oudenarder Straße 16, 13347 Berlin, Germany.
authors.forename: Enno
authors.identifier: http://orcid.org/0000-0003-4004-5003
authors.initials: E
authors.lastname: Klussmann
authors.affiliation: Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Urbé
authors.affiliation: Max-Delbrück-Center for Molecular Medicine, Robert-Roessle-Straße 10, 13125 Berlin, Germany.
authors.forename: Oliver
authors.identifier: http://orcid.org/0000-0001-6349-9193
authors.initials: O
authors.lastname: Rocks
mesh_terms: D016475:3T3 Cells; D000818:Animals; D063646:Carcinogenesis / Q000473:pathology; D020134:Catalytic Domain / Q000502:physiology; D045744:Cell Line, Tumor; D002528:Cerebellar Neoplasms / Q000473:pathology; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D004285:Dogs; D020690:GTPase-Activating Proteins / Q000378:metabolism*; D057809:HEK293 Cells; D053823:Hedgehog Proteins / Q000378:metabolism*; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D008527:Medulloblastoma / Q000473:pathology*; D051379:Mice; D011485:Protein Binding / Q000502:physiology; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D059748:Proteolysis; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology; D054875:Ubiquitination / Q000502:physiology
chemical_list: C000628127:ARHGAP36 protein, human; D020690:GTPase-Activating Proteins; D053823:Hedgehog Proteins; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; C085379:rho GTPase-activating protein; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases