1
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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. SCIENCE ADVANCES 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] [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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2
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Vierra NC, Ribeiro-Silva L, Kirmiz M, van der List D, Bhandari P, Mack OA, Carroll J, Le Monnier E, Aicher SA, Shigemoto R, Trimmer JS. Neuronal ER-plasma membrane junctions couple excitation to Ca 2+-activated PKA signaling. Nat Commun 2023; 14:5231. [PMID: 37633939 PMCID: PMC10460453 DOI: 10.1038/s41467-023-40930-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 08/16/2023] [Indexed: 08/28/2023] Open
Abstract
Junctions between the endoplasmic reticulum (ER) and the plasma membrane (PM) are specialized membrane contacts ubiquitous in eukaryotic cells. Concentration of intracellular signaling machinery near ER-PM junctions allows these domains to serve critical roles in lipid and Ca2+ signaling and homeostasis. Subcellular compartmentalization of protein kinase A (PKA) signaling also regulates essential cellular functions, however, no specific association between PKA and ER-PM junctional domains is known. Here, we show that in brain neurons type I PKA is directed to Kv2.1 channel-dependent ER-PM junctional domains via SPHKAP, a type I PKA-specific anchoring protein. SPHKAP association with type I PKA regulatory subunit RI and ER-resident VAP proteins results in the concentration of type I PKA between stacked ER cisternae associated with ER-PM junctions. This ER-associated PKA signalosome enables reciprocal regulation between PKA and Ca2+ signaling machinery to support Ca2+ influx and excitation-transcription coupling. These data reveal that neuronal ER-PM junctions support a receptor-independent form of PKA signaling driven by membrane depolarization and intracellular Ca2+, allowing conversion of information encoded in electrical signals into biochemical changes universally recognized throughout the cell.
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Affiliation(s)
- Nicholas C Vierra
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, USA.
| | - Luisa Ribeiro-Silva
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, USA
| | - Michael Kirmiz
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, USA
| | - Deborah van der List
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, USA
| | - Pradeep Bhandari
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Olivia A Mack
- Chemical Physiology and Biochemistry Department, Oregon Health & Science University, Portland, OR, USA
| | - James Carroll
- Chemical Physiology and Biochemistry Department, Oregon Health & Science University, Portland, OR, USA
| | - Elodie Le Monnier
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Sue A Aicher
- Chemical Physiology and Biochemistry Department, Oregon Health & Science University, Portland, OR, USA
| | - Ryuichi Shigemoto
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - James S Trimmer
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA, USA.
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3
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Gavagan M, Jameson N, Zalatan JG. The Axin scaffold protects the kinase GSK3β from cross-pathway inhibition. eLife 2023; 12:e85444. [PMID: 37548359 PMCID: PMC10442075 DOI: 10.7554/elife.85444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 08/04/2023] [Indexed: 08/08/2023] Open
Abstract
Multiple signaling pathways regulate the kinase GSK3β by inhibitory phosphorylation at Ser9, which then occupies the GSK3β priming pocket and blocks substrate binding. Since this mechanism should affect GSK3β activity toward all primed substrates, it is unclear why Ser9 phosphorylation does not affect other GSK3β-dependent pathways, such as Wnt signaling. We used biochemical reconstitution and cell culture assays to evaluate how Wnt-associated GSK3β is insulated from cross-activation by other signals. We found that the Wnt-specific scaffold protein Axin allosterically protects GSK3β from phosphorylation at Ser9 by upstream kinases, which prevents accumulation of pS9-GSK3β in the Axin•GSK3β complex. Scaffold proteins that protect bound proteins from alternative pathway reactions could provide a general mechanism to insulate signaling pathways from improper crosstalk.
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Affiliation(s)
- Maire Gavagan
- Department of Chemistry, University of WashingtonSeattleUnited States
| | - Noel Jameson
- Department of Chemistry, University of WashingtonSeattleUnited States
| | - Jesse G Zalatan
- Department of Chemistry, University of WashingtonSeattleUnited States
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4
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A non-catalytic scaffolding activity of hexokinase 2 contributes to EMT and metastasis. Nat Commun 2022; 13:899. [PMID: 35173161 PMCID: PMC8850586 DOI: 10.1038/s41467-022-28440-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 01/20/2022] [Indexed: 02/08/2023] Open
Abstract
Hexokinase 2 (HK2), which catalyzes the first committed step in glucose metabolism, is induced in cancer cells. HK2's role in tumorigenesis has been attributed to its glucose kinase activity. Here, we describe a kinase independent HK2 activity, which contributes to metastasis. HK2 binds and sequesters glycogen synthase kinase 3 (GSK3) and acts as a scaffold forming a ternary complex with the regulatory subunit of protein kinase A (PRKAR1a) and GSK3β to facilitate GSK3β phosphorylation and inhibition by PKA. Thus, HK2 functions as an A-kinase anchoring protein (AKAP). Phosphorylation by GSK3β targets proteins for degradation. Consistently, HK2 increases the level and stability of GSK3 targets, MCL1, NRF2, and particularly SNAIL. In addition to GSK3 inhibition, HK2 kinase activity mediates SNAIL glycosylation, which prohibits its phosphorylation by GSK3. Finally, in mouse models of breast cancer metastasis, HK2 deficiency decreases SNAIL protein levels and inhibits SNAIL-mediated epithelial mesenchymal transition and metastasis.
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5
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Gopalan J, Omar MH, Roy A, Cruz NM, Falcone J, Jones KN, Forbush KA, Himmelfarb J, Freedman BS, Scott JD. Targeting an anchored phosphatase-deacetylase unit restores renal ciliary homeostasis. eLife 2021; 10:e67828. [PMID: 34250905 PMCID: PMC8291974 DOI: 10.7554/elife.67828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/11/2021] [Indexed: 11/13/2022] Open
Abstract
Pathophysiological defects in water homeostasis can lead to renal failure. Likewise, common genetic disorders associated with abnormal cytoskeletal dynamics in the kidney collecting ducts and perturbed calcium and cAMP signaling in the ciliary compartment contribute to chronic kidney failure. We show that collecting ducts in mice lacking the A-Kinase anchoring protein AKAP220 exhibit enhanced development of primary cilia. Mechanistic studies reveal that AKAP220-associated protein phosphatase 1 (PP1) mediates this phenotype by promoting changes in the stability of histone deacetylase 6 (HDAC6) with concomitant defects in actin dynamics. This proceeds through a previously unrecognized adaptor function for PP1 as all ciliogenesis and cytoskeletal phenotypes are recapitulated in mIMCD3 knock-in cells expressing a phosphatase-targeting defective AKAP220-ΔPP1 mutant. Pharmacological blocking of local HDAC6 activity alters cilia development and reduces cystogenesis in kidney-on-chip and organoid models. These findings identify the AKAP220-PPI-HDAC6 pathway as a key effector in primary cilia development.
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Affiliation(s)
- Janani Gopalan
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Mitchell H Omar
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Ankita Roy
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Nelly M Cruz
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Jerome Falcone
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Kiana N Jones
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | | | - Jonathan Himmelfarb
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
| | - Benjamin S Freedman
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - John D Scott
- Department of Pharmacology, University of WashingtonSeattleUnited States
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6
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Kinase-anchoring proteins in ciliary signal transduction. Biochem J 2021; 478:1617-1629. [PMID: 33909027 DOI: 10.1042/bcj20200869] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/16/2022]
Abstract
Historically, the diffusion of chemical signals through the cell was thought to occur within a cytoplasmic soup bounded by the plasma membrane. This theory was predicated on the notion that all regulatory enzymes are soluble and moved with a Brownian motion. Although enzyme compartmentalization was initially rebuffed by biochemists as a 'last refuge of a scoundrel', signal relay through macromolecular complexes is now accepted as a fundamental tenet of the burgeoning field of spatial biology. A-Kinase anchoring proteins (AKAPs) are prototypic enzyme-organizing elements that position clusters of regulatory proteins at defined subcellular locations. In parallel, the primary cilium has gained recognition as a subcellular mechanosensory organelle that amplifies second messenger signals pertaining to metazoan development. This article highlights advances in our understanding of AKAP signaling within the primary cilium and how defective ciliary function contributes to an increasing number of diseases known as ciliopathies.
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7
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Omar MH, Scott JD. AKAP Signaling Islands: Venues for Precision Pharmacology. Trends Pharmacol Sci 2020; 41:933-946. [PMID: 33082006 DOI: 10.1016/j.tips.2020.09.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022]
Abstract
Regulatory enzymes often have different roles in distinct subcellular compartments. Yet, most drugs indiscriminately saturate the cell. Thus, subcellular drug-delivery holds promise as a means to reduce off-target pharmacological effects. A-kinase anchoring proteins (AKAPs) sequester combinations of signaling enzymes within subcellular microdomains. Targeting drugs to these 'signaling islands' offers an opportunity for more precise delivery of therapeutics. Here, we review mechanisms that bestow protein kinase A (PKA) versatility inside the cell, appraise recent advances in exploiting AKAPs as platforms for precision pharmacology, and explore the impact of methodological innovations on AKAP research.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA.
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Bucko PJ, Scott JD. Drugs That Regulate Local Cell Signaling: AKAP Targeting as a Therapeutic Option. Annu Rev Pharmacol Toxicol 2020; 61:361-379. [PMID: 32628872 DOI: 10.1146/annurev-pharmtox-022420-112134] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells respond to environmental cues by mobilizing signal transduction cascades that engage protein kinases and phosphoprotein phosphatases. Correct organization of these enzymes in space and time enables the efficient and precise transmission of chemical signals. The cyclic AMP-dependent protein kinase A is compartmentalized through its association with A-kinase anchoring proteins (AKAPs). AKAPs are a family of multivalent scaffolds that constrain signaling enzymes and effectors at subcellular locations to drive essential physiological events. More recently, it has been recognized that defective signaling in certain endocrine disorders and cancers proceeds through pathological AKAP complexes. Consequently, pharmacologically targeting these macromolecular complexes unlocks new therapeutic opportunities for a growing number of clinical indications. This review highlights recent findings on AKAP signaling in disease, particularly in certain cancers, and offers an overview of peptides and small molecules that locally regulate AKAP-binding partners.
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Affiliation(s)
- Paula J Bucko
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
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9
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Cerioni L, Guidarelli A, Fiorani M, Cantoni O. Prostaglandin E 2 Signals Through E Prostanoid Receptor 2 to Inhibit Mitochondrial Superoxide Formation and the Ensuing Downstream Cytotoxic and Genotoxic Effects Induced by Arsenite. Front Pharmacol 2019; 10:781. [PMID: 31354495 PMCID: PMC6640088 DOI: 10.3389/fphar.2019.00781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 06/17/2019] [Indexed: 12/02/2022] Open
Abstract
We investigated the effects of prostaglandin E2 (PGE2), an important inflammatory lipid mediator, on the cytotoxicity–genotoxicity induced by arsenite. With the use of a toxicity paradigm in which the metalloid uniquely induces mitochondrial superoxide (mitoO2−.) formation, PGE2 promoted conditions favoring the cytosolic accumulation of Bad and Bax and abolished mitochondrial permeability transition (MPT) and the ensuing lethal response through an E prostanoid receptor 2/adenylyl cyclase/protein kinase A (PKA) dependent signaling. It was, however, interesting to observe that, under the same conditions, PGE2 also abolished the DNA-damaging effects of arsenite and that this response was associated with an unexpected suppression of mitoO2−. formation. We conclude that PGE2 promotes PKA-dependent inhibition of mitoO2−. formation, thereby blunting the downstream responses mediated by these species, leading to DNA strand scission and MPT-dependent apoptosis. These findings are therefore consistent with the possibility that, in cells responding to arsenite with mitoO2−. formation, PGE2 fails to enhance—but rather decreases—the risk of neoplastic transformation associated with genotoxic events.
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Affiliation(s)
- Liana Cerioni
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Andrea Guidarelli
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Mara Fiorani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Orazio Cantoni
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
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10
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Turnham RE, Smith FD, Kenerson HL, Omar MH, Golkowski M, Garcia I, Bauer R, Lau HT, Sullivan KM, Langeberg LK, Ong SE, Riehle KJ, Yeung RS, Scott JD. An acquired scaffolding function of the DNAJ-PKAc fusion contributes to oncogenic signaling in fibrolamellar carcinoma. eLife 2019; 8:44187. [PMID: 31063128 PMCID: PMC6533061 DOI: 10.7554/elife.44187] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 05/05/2019] [Indexed: 12/22/2022] Open
Abstract
Fibrolamellar carcinoma (FLC) is a rare liver cancer. FLCs uniquely produce DNAJ-PKAc, a chimeric enzyme consisting of a chaperonin-binding domain fused to the Cα subunit of protein kinase A. Biochemical analyses of clinical samples reveal that a unique property of this fusion enzyme is the ability to recruit heat shock protein 70 (Hsp70). This cellular chaperonin is frequently up-regulated in cancers. Gene-editing of mouse hepatocytes generated disease-relevant AML12DNAJ-PKAc cell lines. Further analyses indicate that the proto-oncogene A-kinase anchoring protein-Lbc is up-regulated in FLC and functions to cluster DNAJ-PKAc/Hsp70 sub-complexes with a RAF-MEK-ERK kinase module. Drug screening reveals Hsp70 and MEK inhibitor combinations that selectively block proliferation of AML12DNAJ-PKAc cells. Phosphoproteomic profiling demonstrates that DNAJ-PKAc biases the signaling landscape toward ERK activation and engages downstream kinase cascades. Thus, the oncogenic action of DNAJ-PKAc involves an acquired scaffolding function that permits recruitment of Hsp70 and mobilization of local ERK signaling. Fibrolamellar carcinoma (or FLC for short) is a rare type of liver cancer that affects teenagers and young adults. FLC tumors are often resistant to standard radiotherapy or chemotherapy treatments. The only way to treat FLC is to remove tumors by surgery. However, often the tumors come back after initial treatment and spread to other locations. Therefore, there is a genuine need to improve the treatment options available to FLC patients. The tumor cells of FLC patients contain a genetic defect that fuses together two genes, which produce proteins called DNAJ and PKAc. Normally, DNAJ helps other proteins in the cell to fold into their correct shapes, while PKAc is an enzyme that can control how cells communicate. However, it is not clear what the abnormal DNAJ-PKAc fusion protein does, or how it causes FLC. Turnham, Smith et al. have now used gene editing to make mouse liver cells that mimic the human FLC mutation. Biochemical experiments on these cells showed that the DNAJ-PKAc protein brings together unique combinations of enzymes that drive uncontrolled cell growth. Analyzing cells taken from tumors in FLC patients confirmed that these enzymes are also activated in the human disease. Turnham, Smith et al. also found that combinations of drugs that simultaneously target the DNAJ-PKAc protein and the recruited enzymes slowed down the growth of FLC cells. More experiments are now needed to test these drug combinations on human FLC cells or in mice.
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Affiliation(s)
- Rigney E Turnham
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - F Donelson Smith
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Heidi L Kenerson
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Martin Golkowski
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Irvin Garcia
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Renay Bauer
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Ho-Tak Lau
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Kevin M Sullivan
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Lorene K Langeberg
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Shao-En Ong
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
| | - Kimberly J Riehle
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - Raymond S Yeung
- Department of Surgery, University of Washington Medical Center, Seattle, United States
| | - John D Scott
- Department of Pharmacology, University of Washington Medical Center, Seattle, United States
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11
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Single nucleotide polymorphisms alter kinase anchoring and the subcellular targeting of A-kinase anchoring proteins. Proc Natl Acad Sci U S A 2018; 115:E11465-E11474. [PMID: 30455320 DOI: 10.1073/pnas.1816614115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A-kinase anchoring proteins (AKAPs) shape second-messenger signaling responses by constraining protein kinase A (PKA) at precise intracellular locations. A defining feature of AKAPs is a helical region that binds to regulatory subunits (RII) of PKA. Mining patient-derived databases has identified 42 nonsynonymous SNPs in the PKA-anchoring helices of five AKAPs. Solid-phase RII binding assays confirmed that 21 of these amino acid substitutions disrupt PKA anchoring. The most deleterious side-chain modifications are situated toward C-termini of AKAP helices. More extensive analysis was conducted on a valine-to-methionine variant in the PKA-anchoring helix of AKAP18. Molecular modeling indicates that additional density provided by methionine at position 282 in the AKAP18γ isoform deflects the pitch of the helical anchoring surface outward by 6.6°. Fluorescence polarization measurements show that this subtle topological change reduces RII-binding affinity 8.8-fold and impairs cAMP responsive potentiation of L-type Ca2+ currents in situ. Live-cell imaging of AKAP18γ V282M-GFP adducts led to the unexpected discovery that loss of PKA anchoring promotes nuclear accumulation of this polymorphic variant. Targeting proceeds via a mechanism whereby association with the PKA holoenzyme masks a polybasic nuclear localization signal on the anchoring protein. This led to the discovery of AKAP18ε: an exclusively nuclear isoform that lacks a PKA-anchoring helix. Enzyme-mediated proximity-proteomics reveal that compartment-selective variants of AKAP18 associate with distinct binding partners. Thus, naturally occurring PKA-anchoring-defective AKAP variants not only perturb dissemination of local second-messenger responses, but also may influence the intracellular distribution of certain AKAP18 isoforms.
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12
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Wang S, Yang F, Petyuk VA, Shukla AK, Monroe ME, Gritsenko MA, Rodland KD, Smith RD, Qian WJ, Gong CX, Liu T. Quantitative proteomics identifies altered O-GlcNAcylation of structural, synaptic and memory-associated proteins in Alzheimer's disease. J Pathol 2017; 243:78-88. [PMID: 28657654 DOI: 10.1002/path.4929] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 06/05/2017] [Accepted: 06/13/2017] [Indexed: 12/30/2022]
Abstract
Protein modification by O-linked β-N-acetylglucosamine (O-GlcNAc) is emerging as an important factor in the pathogenesis of sporadic Alzheimer's disease (AD); however, detailed molecular characterization of this important protein post-translational modification at the proteome level has been highly challenging, owing to its low stoichiometry and labile nature. Herein, we report the most comprehensive, quantitative proteomics analysis for protein O-GlcNAcylation in postmortem human brain tissues with and without AD by the use of isobaric tandem mass tag labelling, chemoenzymatic photocleavage enrichment, and liquid chromatography coupled to mass spectrometry. A total of 1850 O-GlcNAc peptides covering 1094 O-GlcNAcylation sites were identified from 530 proteins in the human brain. One hundred and thirty-one O-GlcNAc peptides covering 81 proteins were altered in AD brains as compared with controls (q < 0.05). Moreover, alteration of O-GlcNAc peptide abundance could be attributed more to O-GlcNAcylation level than to protein level changes. The altered O-GlcNAcylated proteins belong to several structural and functional categories, including synaptic proteins, cytoskeleton proteins, and memory-associated proteins. These findings suggest that dysregulation of O-GlcNAcylation of multiple brain proteins may be involved in the development of sporadic AD. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Sheng Wang
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Feng Yang
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Vladislav A Petyuk
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Anil K Shukla
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Matthew E Monroe
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Marina A Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Karin D Rodland
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Wei-Jun Qian
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Cheng-Xin Gong
- New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York, USA
| | - Tao Liu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
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13
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Miyoshi H, VanDussen KL, Malvin NP, Ryu SH, Wang Y, Sonnek NM, Lai CW, Stappenbeck TS. Prostaglandin E2 promotes intestinal repair through an adaptive cellular response of the epithelium. EMBO J 2016; 36:5-24. [PMID: 27797821 DOI: 10.15252/embj.201694660] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 09/21/2016] [Accepted: 09/22/2016] [Indexed: 12/18/2022] Open
Abstract
Adaptive cellular responses are often required during wound repair. Following disruption of the intestinal epithelium, wound-associated epithelial (WAE) cells form the initial barrier over the wound. Our goal was to determine the critical factor that promotes WAE cell differentiation. Using an adaptation of our in vitro primary epithelial cell culture system, we found that prostaglandin E2 (PGE2) signaling through one of its receptors, Ptger4, was sufficient to drive a differentiation state morphologically and transcriptionally similar to in vivo WAE cells. WAE cell differentiation was a permanent state and dominant over enterocyte differentiation in plasticity experiments. WAE cell differentiation was triggered by nuclear β-catenin signaling independent of canonical Wnt signaling. Creation of WAE cells via the PGE2-Ptger4 pathway was required in vivo, as mice with loss of Ptger4 in the intestinal epithelium did not produce WAE cells and exhibited impaired wound repair. Our results demonstrate a mechanism by which WAE cells are formed by PGE2 and suggest a process of adaptive cellular reprogramming of the intestinal epithelium that occurs to ensure proper repair to injury.
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Affiliation(s)
- Hiroyuki Miyoshi
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kelli L VanDussen
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nicole P Malvin
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Stacy H Ryu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yi Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Naomi M Sonnek
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Chin-Wen Lai
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Thaddeus S Stappenbeck
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
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14
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Dema A, Schröter MF, Perets E, Skroblin P, Moutty MC, Deàk VA, Birchmeier W, Klussmann E. The A-Kinase Anchoring Protein (AKAP) Glycogen Synthase Kinase 3β Interaction Protein (GSKIP) Regulates β-Catenin through Its Interactions with Both Protein Kinase A (PKA) and GSK3β. J Biol Chem 2016; 291:19618-30. [PMID: 27484798 DOI: 10.1074/jbc.m116.738047] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 01/24/2023] Open
Abstract
The A-kinase anchoring protein (AKAP) GSK3β interaction protein (GSKIP) is a cytosolic scaffolding protein binding protein kinase A (PKA) and glycogen synthase kinase 3β (GSK3β). Here we show that both the AKAP function of GSKIP, i.e. its direct interaction with PKA, and its direct interaction with GSK3β are required for the regulation of β-catenin and thus Wnt signaling. A cytoplasmic destruction complex targets β-catenin for degradation and thus prevents Wnt signaling. Wnt signals cause β-catenin accumulation and translocation into the nucleus, where it induces Wnt target gene expression. GSKIP facilitates control of the β-catenin stabilizing phosphorylation at Ser-675 by PKA. Its interaction with GSK3β facilitates control of the destabilizing phosphorylation of β-catenin at Ser-33/Ser-37/Thr-41. The influence of GSKIP on β-catenin is explained by its scavenger function; it recruits the kinases away from the destruction complex without forming a complex with β-catenin. The regulation of β-catenin by GSKIP is specific for this AKAP as AKAP220, which also binds PKA and GSK3β, did not affect Wnt signaling. We find that the binding domain of AKAP220 for GSK3β is a conserved GSK3β interaction domain (GID), which is also present in GSKIP. Our findings highlight an essential compartmentalization of both PKA and GSK3β by GSKIP, and ascribe a function to a cytosolic AKAP-PKA interaction as a regulatory factor in the control of canonical Wnt signaling. Wnt signaling controls different biological processes, including embryonic development, cell cycle progression, glycogen metabolism, and immune regulation; deregulation is associated with diseases such as cancer, type 2 diabetes, inflammatory, and Alzheimer's and Parkinson's diseases.
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Affiliation(s)
- Alessandro Dema
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Micha Friedemann Schröter
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Ekaterina Perets
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Philipp Skroblin
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Marie Christine Moutty
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Veronika Anita Deàk
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Walter Birchmeier
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and
| | - Enno Klussmann
- From the Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Strasse 10, 13125 Berlin, Germany and the DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Oudenarder Strasse 16, 13347 Berlin, Germany
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15
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AKAP220 manages apical actin networks that coordinate aquaporin-2 location and renal water reabsorption. Proc Natl Acad Sci U S A 2016; 113:E4328-37. [PMID: 27402760 DOI: 10.1073/pnas.1607745113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Filtration through the kidney eliminates toxins, manages electrolyte balance, and controls water homeostasis. Reabsorption of water from the luminal fluid of the nephron occurs through aquaporin-2 (AQP2) water pores in principal cells that line the kidney-collecting duct. This vital process is impeded by formation of an "actin barrier" that obstructs the passive transit of AQP2 to the plasma membrane. Bidirectional control of AQP2 trafficking is managed by hormones and signaling enzymes. We have discovered that vasopressin-independent facets of this homeostatic mechanism are under the control of A-Kinase Anchoring Protein 220 (AKAP220; product of the Akap11 gene). CRISPR/Cas9 gene editing and imaging approaches show that loss of AKAP220 disrupts apical actin networks in organoid cultures. Similar defects are evident in tissue sections from AKAP220-KO mice. Biochemical analysis of AKAP220-null kidney extracts detected reduced levels of active RhoA GTPase, a well-known modulator of the actin cytoskeleton. Fluorescent imaging of kidney sections from these genetically modified mice revealed that RhoA and AQP2 accumulate at the apical surface of the collecting duct. Consequently, these animals are unable to appropriately dilute urine in response to overhydration. We propose that membrane-proximal signaling complexes constrained by AKAP220 impact the actin barrier dynamics and AQP2 trafficking to ensure water homeostasis.
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16
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Levine TP, Patel S. Signalling at membrane contact sites: two membranes come together to handle second messengers. Curr Opin Cell Biol 2016; 39:77-83. [PMID: 26922871 DOI: 10.1016/j.ceb.2016.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 12/22/2022]
Abstract
It is now clear that many intracellular signals result from multiple membrane-bound compartments acting in concert. Membrane contact sites, regions of close apposition between organelles, have emerged as major points of convergence during signalling, as these are places where material is exchanged. The material exchanged can be either water-insoluble molecules such as membrane lipids that are passed directly between organelles, or ions such as Ca(2+). Here we highlight new insights into the role of contacts in signalling by second messengers, including lipid traffic that underpins re-generation of IP3, the regulation of NAADP and store-operated Ca(2+) signals, and possible involvement in cyclic AMP signalling.
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Affiliation(s)
- Tim P Levine
- UCL Institute of Ophthalmology, London EC1V 9EL, UK.
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK.
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17
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VAP, a Versatile Access Point for the Endoplasmic Reticulum: Review and analysis of FFAT-like motifs in the VAPome. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:952-961. [PMID: 26898182 DOI: 10.1016/j.bbalip.2016.02.009] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/12/2016] [Accepted: 02/12/2016] [Indexed: 11/24/2022]
Abstract
Dysfunction of VAMP-associated protein (VAP) is associated with neurodegeneration, both Amyotrophic Lateral Sclerosis and Parkinson's disease. Here we summarize what is known about the intracellular interactions of VAP in humans and model organisms. VAP is a simple, small and highly conserved protein on the cytoplasmic face of the endoplasmic reticulum (ER). It is the sole protein on that large organelle that acts as a receptor for cytoplasmic proteins. This may explain the extremely wide range of interacting partners of VAP, with components of many cellular pathways binding it to access the ER. Many proteins that bind VAP also target other intracellular membranes, so VAP is a component of multiple molecular bridges at membrane contact sites between the ER and other organelles. So far approximately 100 proteins have been identified in the VAP interactome (VAPome), of which a small minority have a "two phenylalanines in an acidic tract" (FFAT) motif as it was originally defined. We have analyzed the entire VAPome in humans and yeast using a simple algorithm that identifies many more FFAT-like motifs. We show that approximately 50% of the VAPome binds directly or indirectly via the VAP-FFAT interaction. We also review evidence on pathogenesis in genetic disorders of VAP, which appear to arise from reduced overall VAP levels, leading to ER stress. It is not possible to identify one single interaction that underlies disease. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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18
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Nygren PJ, Scott JD. Therapeutic strategies for anchored kinases and phosphatases: exploiting short linear motifs and intrinsic disorder. Front Pharmacol 2015; 6:158. [PMID: 26283967 PMCID: PMC4516873 DOI: 10.3389/fphar.2015.00158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 07/16/2015] [Indexed: 12/17/2022] Open
Abstract
Phosphorylation events that occur in response to the second messenger cAMP are controlled spatially and temporally by protein kinase A (PKA) interacting with A-kinase anchoring proteins (AKAPs). Recent advances in understanding the structural basis for this interaction have reinforced the hypothesis that AKAPs create spatially constrained signaling microdomains. This has led to the realization that the PKA/AKAP interface is a potential drug target for modulating a plethora of cell-signaling events. Pharmacological disruption of kinase–AKAP interactions has previously been explored for disease treatment and remains an interesting area of research. However, disrupting or enhancing the association of phosphatases with AKAPs is a therapeutic concept of equal promise, particularly since they oppose the actions of many anchored kinases. Accordingly, numerous AKAPs bind phosphatases such as protein phosphatase 1 (PP1), calcineurin (PP2B), and PP2A. These multimodal signaling hubs are equally able to control the addition of phosphate groups onto target substrates, as well as the removal of these phosphate groups. In this review, we describe recent advances in structural analysis of kinase and phosphatase interactions with AKAPs, and suggest future possibilities for targeting these interactions for therapeutic benefit.
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Affiliation(s)
- Patrick J Nygren
- Department of Pharmacology, University of Washington Seattle, WA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
| | - John D Scott
- Department of Pharmacology, University of Washington Seattle, WA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
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