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Omar MH, Byrne DP, Shrestha S, Lakey TM, Lee KS, Lauer SM, Collins KB, Daly LA, Eyers CE, Baird GS, Ong SE, Kannan N, Eyers PA, Scott JD. Discovery of a Cushing's syndrome protein kinase A mutant that biases signaling through type I AKAPs. Sci Adv 2024; 10:eadl1258. [PMID: 38381834 PMCID: PMC10881042 DOI: 10.1126/sciadv.adl1258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024]
Abstract
Adrenal Cushing's syndrome is a disease of cortisol hypersecretion often caused by mutations in protein kinase A catalytic subunit (PKAc). Using a personalized medicine screening platform, we discovered a Cushing's driver mutation, PKAc-W196G, in ~20% of patient samples analyzed. Proximity proteomics and photokinetic imaging reveal that PKAcW196G is unexpectedly distinct from other described Cushing's variants, exhibiting retained association with type I regulatory subunits (RI) and their corresponding A kinase anchoring proteins (AKAPs). Molecular dynamics simulations predict that substitution of tryptophan-196 with glycine creates a 653-cubic angstrom cleft between the catalytic core of PKAcW196G and type II regulatory subunits (RII), but only a 395-cubic angstrom cleft with RI. Endocrine measurements show that overexpression of RIα or redistribution of PKAcW196G via AKAP recruitment counteracts stress hormone overproduction. We conclude that a W196G mutation in the kinase catalytic core skews R subunit selectivity and biases AKAP association to drive Cushing's syndrome.
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Affiliation(s)
- Mitchell H. Omar
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Dominic P. Byrne
- Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Safal Shrestha
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Tyler M. Lakey
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Sophia M. Lauer
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kerrie B. Collins
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Leonard A. Daly
- Centre for Proteome Research, Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Claire E. Eyers
- Centre for Proteome Research, Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Geoffrey S. Baird
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Natarajan Kannan
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Patrick A. Eyers
- Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - John D. Scott
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
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Omar MH, Kihiu M, Byrne DP, Lee KS, Lakey TM, Butcher E, Eyers PA, Scott JD. Classification of Cushing's syndrome PKAc mutants based upon their ability to bind PKI. Biochem J 2023; 480:875-890. [PMID: 37306403 DOI: 10.1042/bcj20230183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/02/2023] [Accepted: 06/12/2023] [Indexed: 06/13/2023]
Abstract
Cushing's syndrome is an endocrine disorder caused by excess production of the stress hormone cortisol. Precision medicine strategies have identified single allele mutations within the PRKACA gene that drive adrenal Cushing's syndrome. These mutations promote perturbations in the catalytic core of protein kinase A (PKAc) that impair autoinhibition by regulatory subunits and compartmentalization via recruitment into AKAP signaling islands. PKAcL205R is found in ∼45% of patients, whereas PKAcE31V, PKAcW196R, and L198insW and C199insV insertion mutants are less prevalent. Mass spectrometry, cellular, and biochemical data indicate that Cushing's PKAc variants fall into two categories: those that interact with the heat-stable protein kinase inhibitor PKI, and those that do not. In vitro activity measurements show that wild-type PKAc and W196R activities are strongly inhibited by PKI (IC50 < 1 nM). In contrast, PKAcL205R activity is not blocked by the inhibitor. Immunofluorescent analyses show that the PKI-binding variants wild-type PKAc, E31V, and W196R are excluded from the nucleus and protected against proteolytic processing. Thermal stability measurements reveal that upon co-incubation with PKI and metal-bound nucleotide, the W196R variant tolerates melting temperatures 10°C higher than PKAcL205. Structural modeling maps PKI-interfering mutations to a ∼20 Å diameter area at the active site of the catalytic domain that interfaces with the pseudosubstrate of PKI. Thus, Cushing's kinases are individually controlled, compartmentalized, and processed through their differential association with PKI.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| | - Maryanne Kihiu
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| | - Dominic P Byrne
- Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| | - Tyler M Lakey
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| | - Erik Butcher
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
| | - Patrick A Eyers
- Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA 98195, U.S.A
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Omar MH, Byrne DP, Jones KN, Lakey TM, Collins KB, Lee KS, Daly LA, Forbush KA, Lau HT, Golkowski M, McKnight GS, Breault DT, Lefrançois-Martinez AM, Martinez A, Eyers CE, Baird GS, Ong SE, Smith FD, Eyers PA, Scott JD. Mislocalization of protein kinase A drives pathology in Cushing's syndrome. Cell Rep 2022; 40:111073. [PMID: 35830806 PMCID: PMC9311266 DOI: 10.1016/j.celrep.2022.111073] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/20/2022] [Accepted: 06/17/2022] [Indexed: 01/15/2023] Open
Abstract
Mutations in the catalytic subunit of protein kinase A (PKAc) drive the stress hormone disorder adrenal Cushing's syndrome. We define mechanisms of action for the PKAc-L205R and W196R variants. Proximity proteomic techniques demonstrate that both Cushing's mutants are excluded from A kinase-anchoring protein (AKAP)-signaling islands, whereas live-cell photoactivation microscopy reveals that these kinase mutants indiscriminately diffuse throughout the cell. Only cAMP analog drugs that displace native PKAc from AKAPs enhance cortisol release. Rescue experiments that incorporate PKAc mutants into AKAP complexes abolish cortisol overproduction, indicating that kinase anchoring restores normal endocrine function. Analyses of adrenal-specific PKAc-W196R knockin mice and Cushing's syndrome patient tissue reveal defective signaling mechanisms of the disease. Surprisingly each Cushing's mutant engages a different mitogenic-signaling pathway, with upregulation of YAP/TAZ by PKAc-L205R and ERK kinase activation by PKAc-W196R. Thus, aberrant spatiotemporal regulation of each Cushing's variant promotes the transmission of distinct downstream pathogenic signals.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
| | - Dominic P Byrne
- Department of Biochemistry & Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Kiana N Jones
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Tyler M Lakey
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kerrie B Collins
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Leonard A Daly
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Katherine A Forbush
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Martin Golkowski
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - G Stanley McKnight
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - David T Breault
- Division of Endocrinology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Anne-Marie Lefrançois-Martinez
- Génétique, Reproduction et Développement (GReD), CNRS, INSERM, Université Clermont Auvergne, 63001 Clermont-Ferrand, France
| | - Antoine Martinez
- Génétique, Reproduction et Développement (GReD), CNRS, INSERM, Université Clermont Auvergne, 63001 Clermont-Ferrand, France
| | - Claire E Eyers
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Geoffrey S Baird
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Shao-En Ong
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - F Donelson Smith
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Patrick A Eyers
- Department of Biochemistry & Systems Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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