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Sun J, Shao Y, Pei L, Zhu Q, Yu X, Yao W. AKAP1 alleviates VSMC phenotypic modulation and neointima formation by inhibiting Drp1-dependent mitochondrial fission. Biomed Pharmacother 2024; 176:116858. [PMID: 38850669 DOI: 10.1016/j.biopha.2024.116858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 05/26/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024] Open
Abstract
The roles and mechanisms of A-kinase anchoring protein 1 (AKAP1) in vascular smooth muscle cell (VSMC) phenotypic modulation and neointima formation are currently unknown. AKAP1 is a mitochondrial PKA-anchored protein and maintains mitochondrial homeostasis. This study aimed to investigate how AKAP1/PKA signaling plays a protective role in inhibiting VSMC phenotypic transformation and neointima formation by regulating mitochondrial fission. The results showed that both PDGF-BB treatment and balloon injury reduced the transcription, expression, and mitochondrial anchoring of AKAP1. In vitro, the overexpression of AKAP1 significantly inhibited PDGF-BB mediated VSMC proliferation and migration, whereas AKAP1 knockdown further aggravated VSMC phenotypic transformation. Additionally, in the balloon injury model in vivo, AKAP1 overexpression reduced neointima formation, the muscle fiber area ratio, and rat VSMC proliferation and migration. Furthermore, PDGF-BB and balloon injury inhibited Drp1 phosphorylation at Ser637 and promoted Drp1 activity and mitochondrial midzone fission; AKAP1 overexpression reversed these effects. AKAP1 overexpression also inhibited the distribution of mitochondria at the plasma membrane and the reduction of PKARIIβ expression induced by PDGF-BB, as evidenced by an increase in mitochondria-plasma membrane distance as well as PKARIIβ protein levels. Moreover, the PKA agonist promoted Drp1 phosphorylation (Ser637) and inhibited PDGF-BB-mediated mitochondrial fission, cell proliferation, and migration. The PKA antagonist reversed the increase in Drp1 phosphorylation (Ser637) and the decline in mitochondrial midzone fission and VSMC phenotypic transformation caused by AKAP1 overexpression. The results of this study reveal that AKAP1 protects VSMCs against phenotypic modulation by improving Drp1 phosphorylation at Ser637 through PKA and inhibiting mitochondrial fission, thereby preventing neointima formation.
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MESH Headings
- Animals
- Male
- Rats
- A Kinase Anchor Proteins/metabolism
- A Kinase Anchor Proteins/genetics
- Becaplermin/pharmacology
- Cell Movement/drug effects
- Cell Proliferation/drug effects
- Cells, Cultured
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Dynamins/metabolism
- Mitochondrial Dynamics/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/drug effects
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/pathology
- Neointima/metabolism
- Neointima/pathology
- Phenotype
- Phosphorylation
- Rats, Sprague-Dawley
- Signal Transduction
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Affiliation(s)
- Jingwen Sun
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong 226001, China
| | - Yuting Shao
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong 226001, China
| | - Lele Pei
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong 226001, China
| | - Qingyu Zhu
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong 226001, China
| | - Xiaoqiang Yu
- Department of Vascular Surgery, The First People's Hospital of Nantong, Nantong 226001, China
| | - Wenjuan Yao
- School of Pharmacy, Nantong University, 19 QiXiu Road, Nantong 226001, China.
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2
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Feichtner A, Enzler F, Kugler V, Hoppe K, Mair S, Kremser L, Lindner H, Huber RG, Stelzl U, Stefan E, Torres-Quesada O. Phosphorylation of the compartmentalized PKA substrate TAF15 regulates RNA-protein interactions. Cell Mol Life Sci 2024; 81:162. [PMID: 38568213 PMCID: PMC10991009 DOI: 10.1007/s00018-024-05204-4] [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: 08/18/2023] [Revised: 03/08/2024] [Accepted: 03/09/2024] [Indexed: 04/05/2024]
Abstract
Spatiotemporal-controlled second messengers alter molecular interactions of central signaling nodes for ensuring physiological signal transmission. One prototypical second messenger molecule which modulates kinase signal transmission is the cyclic-adenosine monophosphate (cAMP). The main proteinogenic cellular effectors of cAMP are compartmentalized protein kinase A (PKA) complexes. Their cell-type specific compositions precisely coordinate substrate phosphorylation and proper signal propagation which is indispensable for numerous cell-type specific functions. Here we present evidence that TAF15, which is implicated in the etiology of amyotrophic lateral sclerosis, represents a novel nuclear PKA substrate. In cross-linking and immunoprecipitation experiments (iCLIP) we showed that TAF15 phosphorylation alters the binding to target transcripts related to mRNA maturation, splicing and protein-binding related functions. TAF15 appears to be one of multiple PKA substrates that undergo RNA-binding dynamics upon phosphorylation. We observed that the activation of the cAMP-PKA signaling axis caused a change in the composition of a collection of RNA species that interact with TAF15. This observation appears to be a broader principle in the regulation of molecular interactions, as we identified a significant enrichment of RNA-binding proteins within endogenous PKA complexes. We assume that phosphorylation of RNA-binding domains adds another layer of regulation to binary protein-RNAs interactions with consequences to RNA features including binding specificities, localization, abundance and composition.
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Affiliation(s)
- Andreas Feichtner
- Tyrolean Cancer Research Institute (TKFI), Innrain 66, 6020, Innsbruck, Austria
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Florian Enzler
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University of Innsbruck, Innrain 66/66a, 6020, Innsbruck, Austria
| | - Valentina Kugler
- Tyrolean Cancer Research Institute (TKFI), Innrain 66, 6020, Innsbruck, Austria
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Katharina Hoppe
- Institute of Developmental Immunology, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Sophia Mair
- Department of Cardiac Surgery, Medical University of Innsbruck, Innrain 66/66a, 6020, Innsbruck, Austria
- Vascage, Center of Clinical Stroke Research, 6020, Innsbruck, Austria
| | - Leopold Kremser
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Herbert Lindner
- Division of Clinical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria
| | - Roland G Huber
- Bioinformatics Institute, Agency for Science Technology and Research, Singapore, 138671, Singapore
| | - Ulrich Stelzl
- Institute of Pharmaceutical Sciences, University of Graz, Schubertstrasse 1, 8010, Graz, Austria
| | - Eduard Stefan
- Tyrolean Cancer Research Institute (TKFI), Innrain 66, 6020, Innsbruck, Austria.
- Institute of Molecular Biology and Center for Molecular Biosciences, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria.
| | - Omar Torres-Quesada
- Tyrolean Cancer Research Institute (TKFI), Innrain 66, 6020, Innsbruck, Austria.
- Division of Medical Biochemistry, Biocenter, Medical University of Innsbruck, Innrain 80/82, 6020, Innsbruck, Austria.
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3
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Kuschke S, Thon S, Sattler C, Schwabe T, Benndorf K, Schmauder R. cAMP binding to closed pacemaker ion channels is cooperative. Proc Natl Acad Sci U S A 2024; 121:e2315132121. [PMID: 38377199 PMCID: PMC10907242 DOI: 10.1073/pnas.2315132121] [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: 08/31/2023] [Accepted: 01/04/2024] [Indexed: 02/22/2024] Open
Abstract
The cooperative action of the subunits in oligomeric receptors enables fine-tuning of receptor activation, as demonstrated for the regulation of voltage-activated HCN pacemaker ion channels by relating cAMP binding to channel activation in ensemble signals. HCN channels generate electric rhythmicity in specialized brain neurons and cardiomyocytes. There is conflicting evidence on whether binding cooperativity does exist independent of channel activation or not, as recently reported for detergent-solubilized receptors positioned in zero-mode waveguides. Here, we show positive cooperativity in ligand binding to closed HCN2 channels in native cell membranes by following the binding of individual fluorescence-labeled cAMP molecules. Kinetic modeling reveals that the affinity of the still empty binding sites rises with increased degree of occupation and that the transition of the channel to a flip state is promoted accordingly. We conclude that ligand binding to the subunits in closed HCN2 channels not pre-activated by voltage is already cooperative. Hence, cooperativity is not causally linked to channel activation by voltage. Our analysis also shows that single-molecule binding measurements at equilibrium can quantify cooperativity in ligand binding to receptors in native membranes.
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Affiliation(s)
- Stefan Kuschke
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
| | - Susanne Thon
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
| | - Christian Sattler
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
| | - Tina Schwabe
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
| | - Klaus Benndorf
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
| | - Ralf Schmauder
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University, Jena07743, Germany
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4
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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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5
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Ju WK, Perkins GA, Kim KY, Bastola T, Choi WY, Choi SH. Glaucomatous optic neuropathy: Mitochondrial dynamics, dysfunction and protection in retinal ganglion cells. Prog Retin Eye Res 2023; 95:101136. [PMID: 36400670 DOI: 10.1016/j.preteyeres.2022.101136] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 10/04/2022] [Accepted: 11/03/2022] [Indexed: 11/18/2022]
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide and is characterized by a slow, progressive, and multifactorial degeneration of retinal ganglion cells (RGCs) and their axons, resulting in vision loss. Despite its high prevalence in individuals 60 years of age and older, the causing factors contributing to glaucoma progression are currently not well characterized. Intraocular pressure (IOP) is the only proven treatable risk factor. However, lowering IOP is insufficient for preventing disease progression. One of the significant interests in glaucoma pathogenesis is understanding the structural and functional impairment of mitochondria in RGCs and their axons and synapses. Glaucomatous risk factors such as IOP elevation, aging, genetic variation, neuroinflammation, neurotrophic factor deprivation, and vascular dysregulation, are potential inducers for mitochondrial dysfunction in glaucoma. Because oxidative phosphorylation stress-mediated mitochondrial dysfunction is associated with structural and functional impairment of mitochondria in glaucomatous RGCs, understanding the underlying mechanisms and relationship between structural and functional alterations in mitochondria would be beneficial to developing mitochondria-related neuroprotection in RGCs and their axons and synapses against glaucomatous neurodegeneration. Here, we review the current studies focusing on mitochondrial dynamics-based structural and functional alterations in the mitochondria of glaucomatous RGCs and therapeutic strategies to protect RGCs against glaucomatous neurodegeneration.
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Affiliation(s)
- Won-Kyu Ju
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA.
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA, 92093, USA
| | - Tonking Bastola
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA
| | - Woo-Young Choi
- Hamilton Glaucoma Center and Viterbi Family Department of Ophthalmology and Shiley Eye Institute, University of California San Diego, La Jolla, CA, 92093, USA; Department of Plastic Surgery, College of Medicine, Chosun University, Gwang-ju, South Korea
| | - Soo-Ho Choi
- Department of Medicine, University of California San Diego, La Jolla, CA, 92093, USA
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6
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Bastola T, Perkins GA, Kim KY, Choi S, Kwon JW, Shen Z, Strack S, Ju WK. Role of A-Kinase Anchoring Protein 1 in Retinal Ganglion Cells: Neurodegeneration and Neuroprotection. Cells 2023; 12:1539. [PMID: 37296658 PMCID: PMC10252895 DOI: 10.3390/cells12111539] [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: 03/25/2023] [Revised: 05/21/2023] [Accepted: 06/01/2023] [Indexed: 06/12/2023] Open
Abstract
A-Kinase anchoring protein 1 (AKAP1) is a multifunctional mitochondrial scaffold protein that regulates mitochondrial dynamics, bioenergetics, and calcium homeostasis by anchoring several proteins, including protein kinase A, to the outer mitochondrial membrane. Glaucoma is a complex, multifactorial disease characterized by a slow and progressive degeneration of the optic nerve and retinal ganglion cells (RGCs), ultimately resulting in vision loss. Impairment of the mitochondrial network and function is linked to glaucomatous neurodegeneration. Loss of AKAP1 induces dynamin-related protein 1 dephosphorylation-mediated mitochondrial fragmentation and loss of RGCs. Elevated intraocular pressure triggers a significant reduction in AKAP1 protein expression in the glaucomatous retina. Amplification of AKAP1 expression protects RGCs from oxidative stress. Hence, modulation of AKAP1 could be considered a potential therapeutic target for neuroprotective intervention in glaucoma and other mitochondria-associated optic neuropathies. This review covers the current research on the role of AKAP1 in the maintenance of mitochondrial dynamics, bioenergetics, and mitophagy in RGCs and provides a scientific basis to identify and develop new therapeutic strategies that could protect RGCs and their axons in glaucoma.
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Affiliation(s)
- Tonking Bastola
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Guy A. Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA; (G.A.P.); (K.-Y.K.)
| | - Seunghwan Choi
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Jin-Woo Kwon
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
- Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul 06591, Republic of Korea
- Department of Ophthalmology and Visual Science, St. Vincent’s Hospital, Jungbu-daero 93, Paldal-gu, Suwon 16247, Republic of Korea
| | - Ziyao Shen
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
| | - Stefan Strack
- Department of Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, USA;
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (S.C.); (J.-W.K.); (Z.S.)
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7
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Jia J, Tang S, Yue X, Jing S, Zhu L, Tan C, Gao J, Du Y, Lee I, Qian Y. An A-Kinase Anchoring Protein (ACBD3) Coordinates Traffic-Induced PKA Activation At The Golgi. J Biol Chem 2023; 299:104696. [PMID: 37044218 DOI: 10.1016/j.jbc.2023.104696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 03/23/2023] [Accepted: 03/25/2023] [Indexed: 04/14/2023] Open
Abstract
KDEL receptor (KDELR) is a key protein that recycles escaped ER resident proteins from the Golgi apparatus back to the ER and maintains a dynamic balance between these two organelles in the early secretory pathway. Studies have shown that this retrograde transport pathway is partly regulated by two KDELR-interacting proteins, Acyl-CoA-binding domain-containing 3 (ACBD3), and cyclic AMP-dependent protein kinase A (PKA). However, whether Golgi-localized ACBD3, which was first discovered as a PKA-anchoring protein in mitochondria, directly interacts with PKA at the Golgi and coordinates its signaling in Golgi-to-ER traffic has remained unclear. In this study, we showed that the GOLD domain of ACBD3 directly interacts with the regulatory subunit II (RII) of PKA and effectively recruits PKA holoenzyme to the Golgi. Forward trafficking of proteins from the ER triggers activation of PKA by releasing the catalytic subunit from RII. Furthermore, we determined that depletion of ACBD3 reduces the Golgi fraction of RII, resulting in moderate, but constitutive activation of PKA and KDELR retrograde transport, independent of cargo influx from the ER. Taken together, these data demonstrate that ACBD3 coordinates the protein secretory pathway at the Golgi by facilitating KDELR/PKA-containing protein complex formation.
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Affiliation(s)
- Jie Jia
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Shuocheng Tang
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xihua Yue
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Shuaiyang Jing
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Lianhui Zhu
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China
| | - Chuanting Tan
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Jingkai Gao
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Yulei Du
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China; University of Chinese Academy of Sciences, Beijing, China
| | - Intaek Lee
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.
| | - Yi Qian
- School of Life Science and Technology, ShanghaiTech University, Pudong, Shanghai, China.
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8
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Shendge AA, D’Souza JS. Strategic optimization of conditions for the solubilization of GST-tagged amphipathic helix-containing ciliary proteins overexpressed as inclusion bodies in E. coli. Microb Cell Fact 2022; 21:258. [PMID: 36510188 PMCID: PMC9746132 DOI: 10.1186/s12934-022-01979-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 11/24/2022] [Indexed: 12/14/2022] Open
Abstract
Expression of affinity-tagged recombinant proteins for crystallography, protein-protein interaction, antibody generation, therapeutic applications, etc. mandates the generation of high-yield soluble proteins. Although recent developments suggest the use of yeast, insect, and mammalian cell lines as protein expression platforms, Escherichia coli is still the most popular, due mainly to its ease of growth, feasibility in genetic manipulation and economy. However, some proteins have a spontaneous tendency to form inclusion bodies (IBs) when over-expressed in bacterial expression systems such as E. coli, thus posing a challenge in purification and yield. At times, small peptides undergo degradation during protein production and hence using suitable tags could circumvent the problem. Although several independent techniques have been used to solubilize IBs, these cannot always be applied in a generic sense. Although tagging a GST moiety is known to enhance the solubility of fusion proteins in E. coli, resulting in yields of 10-50 mg/L of the culture, the inherent nature of the protein sequence at times could lead to the formation of IBs. We have been working on a Myc Binding Protein-1 orthologue, viz. Flagellar Associated Protein 174 (FAP174) from the axoneme of Chlamydomonas reinhardtii that binds to an A-Kinase Anchoring Protein 240 (AKAP240) which has been annotated as Flagellar Associated Protein 65 (FAP65). Using an in-silico approach, we have identified two amphipathic helices on FAP65 (CrFAP65AH1 and CrFAP65AH2) that are predicted to bind to FAP174. To test this prediction, we have cloned the GST-tagged peptides, and overexpressed them in E. coli that have resulted in insoluble IBs. The yields of these over-expressed recombinant proteins dropped considerably due to IB formation, indicating aggregation. An integrated approach has been used to solubilize four highly hydrophobic polypeptides, viz. two amphipathic helices and the respective proline variants of FAP65. For solubilizing these polypeptides, variables such as non-denaturing detergents (IGEPAL CA-630), changing the ionic strength of the cell lysis and solubilization buffer, addition of BugBuster®, diluting the cell lysate and sonication were introduced. Our statistically viable results yielded highly soluble and functional polypeptides, indiscreet secondary structures, and a yield of ~ 20 mg/L of the E. coli culture. Our combinatorial strategy using chemical and physical methods to solubilize IBs could prove useful for hydrophobic peptides and proteins with amphipathic helices.
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Affiliation(s)
- Amruta A. Shendge
- grid.452882.10000 0004 1761 3305School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina campus, Santacruz (E), Mumbai, 400098 India
| | - Jacinta S. D’Souza
- grid.452882.10000 0004 1761 3305School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina campus, Santacruz (E), Mumbai, 400098 India
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9
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Wang Y, Liu M, Wei Q, Wu W, He Y, Gao J, Zhou R, Jiang L, Qu J, Xia J. Phase-Separated Multienzyme Compartmentalization for Terpene Biosynthesis in a Prokaryote. Angew Chem Int Ed Engl 2022; 61:e202203909. [PMID: 35562330 DOI: 10.1002/anie.202203909] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Indexed: 01/18/2023]
Abstract
Liquid-liquid phase separation (LLPS) forms biomolecular condensates or coacervates in cells. Metabolic enzymes can form phase-separated subcellular compartments that enrich enzymes, cofactors, and substrates. Herein, we report the construction of synthetic multienzyme condensates that catalyze the biosynthesis of a terpene, α-farnesene, in the prokaryote E. coli. RGGRGG derived from LAF-1 was used as the scaffold protein to form the condensates by LLPS. Multienzyme condensates were then formed by assembling two enzymes Idi and IspA through an RIAD/RIDD interaction. Multienzyme condensates constructed inside E. coli cells compartmentalized the cytosolic space into regions of high and low enzyme density and led to a significant enhancement of α-farnesene production. This work demonstrates LLPS-driven compartmentalization of the cytosolic space of prokaryotic cells, condensation of a biosynthetic pathway, and enhancement of the biosynthesis of α-farnesene.
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Affiliation(s)
- Yue Wang
- Department of Chemistry and Center for Cell & Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Min Liu
- Department of Chemistry and Center for Cell & Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Qixin Wei
- Department of Chemistry and Center for Cell & Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Wanjie Wu
- Departments of Electronic and Computer Engineering, Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Yanping He
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jiayang Gao
- Center for Cell & Developmental Biology, School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Renjie Zhou
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Liwen Jiang
- Center for Cell & Developmental Biology, School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jianan Qu
- Departments of Electronic and Computer Engineering, Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Jiang Xia
- Department of Chemistry and Center for Cell & Developmental Biology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
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10
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Wang Y, Liu M, Wei Q, Wu W, He Y, Gao J, Zhou R, Jiang L, Qu J, Xia J. Phase‐Separated Multienzyme Compartmentalization for Terpene Biosynthesis in a Prokaryote. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202203909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yue Wang
- Chinese University of Hong Kong Shaw College: The Chinese University of Hong Kong Chemistry HONG KONG
| | - Min Liu
- The Chinese University of Hong Kong Chemistry HONG KONG
| | - Qixin Wei
- The Chinese University of Hong Kong Chemistry HONG KONG
| | - Wanjie Wu
- Hong Kong University of Science and Technology School of Engineering Engineering HONG KONG
| | - Yanping He
- The Chinese University of Hong Kong Department of Biomedical Engineering HONG KONG
| | - Jiayang Gao
- The Chinese University of Hong Kong School of Life Sciences HONG KONG
| | - Renjie Zhou
- The Chinese University of Hong Kong Department of Biomedical Engineering HONG KONG
| | - Liwen Jiang
- The Chinese University of Hong Kong School of Life Sciences HONG KONG
| | - Jianan Qu
- Hong Kong University of Science and Technology School of Engineering Engineering HONG KONG
| | - Jiang Xia
- The Chinese University of Hong Kong Department of Chemistry SC G59, Department of ChemistryThe Chinese University of Hong Kong 00000 Shatin HONG KONG
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11
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The Role of Mitochondrial Dynamin in Stroke. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:2504798. [PMID: 35571256 PMCID: PMC9106451 DOI: 10.1155/2022/2504798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 04/17/2022] [Indexed: 11/25/2022]
Abstract
Stroke is one of the leading causes of death and disability in the world. However, the pathophysiological process of stroke is still not fully clarified. Mitochondria play an important role in promoting nerve survival and are an important drug target for the treatment of stroke. Mitochondrial dysfunction is one of the hallmarks of stroke. Mitochondria are in a state of continuous fission and fusion, which are termed as mitochondrial dynamics. Mitochondrial dynamics are very important for maintaining various functions of mitochondria. In this review, we will introduce the structure and functions of mitochondrial fission and fusion related proteins and discuss their role in the pathophysiologic process of stroke. A better understanding of mitochondrial dynamin in stroke will pave way for the development of new therapeutic options.
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12
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Byrne DP, Omar MH, Kennedy EJ, Eyers PA, Scott JD. Biochemical Analysis of AKAP-Anchored PKA Signaling Complexes. Methods Mol Biol 2022; 2483:297-317. [PMID: 35286684 PMCID: PMC9518671 DOI: 10.1007/978-1-0716-2245-2_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Generation of the prototypic second messenger cAMP instigates numerous signaling events. A major intracellular target of cAMP is Protein kinase A (PKA), a Ser/Thr protein kinase. Where and when this enzyme is activated inside the cell has profound implications on the functional impact of PKA. It is now well established that PKA signaling is focused locally into subcellular signaling "islands" or "signalosomes." The A-Kinase Anchoring Proteins (AKAPs) play a critical role in this process by dictating spatial and temporal aspects of PKA action. Genetically encoded biosensors, small molecule and peptide-based disruptors of PKA signaling are valuable tools for rigorous investigation of local PKA action at the biochemical level. This chapter focuses on approaches to evaluate PKA signaling islands, including a simple assay for monitoring the interaction of an AKAP with a tunable PKA holoenzyme. The latter approach evaluates the composition of PKA holoenzymes, in which regulatory subunits and catalytic subunits can be visualized in the presence of test compounds and small-molecule inhibitors.
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Affiliation(s)
- Dominic P Byrne
- Department of Biochemistry and Systems Biology, ISMIB, University of Liverpool, Liverpool, UK
| | - Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA
| | - Patrick A Eyers
- Department of Biochemistry and Systems Biology, ISMIB, University of Liverpool, Liverpool, UK.
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA, USA.
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13
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A splicing factor phosphorylated by protein kinase A is increased in HL60 cells treated with retinoic acid. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1869:119142. [PMID: 34599982 DOI: 10.1016/j.bbamcr.2021.119142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/18/2021] [Accepted: 09/27/2021] [Indexed: 11/22/2022]
Abstract
Retinoic acid (RA) induces the differentiation of human promyelocytic leukemia HL60 cells into granulocytic cells and inhibits proliferation. Certain of actions of RA are mediated by RA nuclear receptors that regulate gene expression. However, it is also known that direct protein modification by RA (retinoylation) can occur. One such retinoylated protein in HL60 cells is a regulatory subunit of protein kinase A (PKA), which is increased in the nucleus following RA treatment and which then increases phosphorylation of other nuclear proteins. However, a complete understanding of which nuclear proteins are phosphorylated is lacking. In the current study, we employed mass spectrometry to identify one of the PKA-phosphorylated proteins as a serine/arginine-rich splicing factor 1 (SF2, SRSF1). We found that RA treatment increased the level of PKA-phosphorylated SF2 but decreased the level of SF2. While SF2 regulates myelogenous cell leukemia-1 (Mcl-1, anti-apoptotic factor), RA treatment reduced the level of Mcl-1L (full-length Mcl-1 long) and increased the level of Mcl-1S (Mcl-1 short; a short splicing variant of the Mcl-1). Furthermore, treatment with a PKA inhibitor reversed these effects on Mcl-1 and inhibited RA-induced cell differentiation. In contrast, treatment with a Mcl-1L inhibitor enhanced RA-induced cell differentiation. These results indicate that RA activates PKA in the nucleus, increases phosphorylation of SF2, raises levels of Mcl-1S and lowers levels of Mcl-1L, resulting in the induction of differentiation. RA-modified PKA may play an important role in inducing cell differentiation and suppressing cell proliferation.
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14
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Ramms DJ, Raimondi F, Arang N, Herberg FW, Taylor SS, Gutkind JS. G αs-Protein Kinase A (PKA) Pathway Signalopathies: The Emerging Genetic Landscape and Therapeutic Potential of Human Diseases Driven by Aberrant G αs-PKA Signaling. Pharmacol Rev 2021; 73:155-197. [PMID: 34663687 PMCID: PMC11060502 DOI: 10.1124/pharmrev.120.000269] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Many of the fundamental concepts of signal transduction and kinase activity are attributed to the discovery and crystallization of cAMP-dependent protein kinase, or protein kinase A. PKA is one of the best-studied kinases in human biology, with emphasis in biochemistry and biophysics, all the way to metabolism, hormone action, and gene expression regulation. It is surprising, however, that our understanding of PKA's role in disease is largely underappreciated. Although genetic mutations in the PKA holoenzyme are known to cause diseases such as Carney complex, Cushing syndrome, and acrodysostosis, the story largely stops there. With the recent explosion of genomic medicine, we can finally appreciate the broader role of the Gαs-PKA pathway in disease, with contributions from aberrant functioning G proteins and G protein-coupled receptors, as well as multiple alterations in other pathway components and negative regulators. Together, these represent a broad family of diseases we term the Gαs-PKA pathway signalopathies. The Gαs-PKA pathway signalopathies encompass diseases caused by germline, postzygotic, and somatic mutations in the Gαs-PKA pathway, with largely endocrine and neoplastic phenotypes. Here, we present a signaling-centric review of Gαs-PKA-driven pathophysiology and integrate computational and structural analysis to identify mutational themes commonly exploited by the Gαs-PKA pathway signalopathies. Major mutational themes include hotspot activating mutations in Gαs, encoded by GNAS, and mutations that destabilize the PKA holoenzyme. With this review, we hope to incite further study and ultimately the development of new therapeutic strategies in the treatment of a wide range of human diseases. SIGNIFICANCE STATEMENT: Little recognition is given to the causative role of Gαs-PKA pathway dysregulation in disease, with effects ranging from infectious disease, endocrine syndromes, and many cancers, yet these disparate diseases can all be understood by common genetic themes and biochemical signaling connections. By highlighting these common pathogenic mechanisms and bridging multiple disciplines, important progress can be made toward therapeutic advances in treating Gαs-PKA pathway-driven disease.
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Affiliation(s)
- Dana J Ramms
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Francesco Raimondi
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Nadia Arang
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Friedrich W Herberg
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - Susan S Taylor
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
| | - J Silvio Gutkind
- Department of Pharmacology (D.J.R., N.A., J.S.G.), Department of Chemistry and Biochemistry (S.S.T.), and Moores Cancer Center (D.J.R., N.A., J.S.G.), University of California, San Diego, La Jolla, California; Laboratorio di Biologia Bio@SNS, Scuola Normale Superiore, Pisa, Italy (F.R.); and Department of Biochemistry, University of Kassel, Kassel, Germany (F.W.H.)
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15
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Potential therapeutic applications of AKAP disrupting peptides. Clin Sci (Lond) 2021; 134:3259-3282. [PMID: 33346357 DOI: 10.1042/cs20201244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/16/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022]
Abstract
The 3'-5'-cyclic adenosine monophosphate (cAMP)/PKA pathway represents a major target for pharmacological intervention in multiple disease conditions. Although the last decade saw the concept of highly compartmentalized cAMP/PKA signaling consolidating, current means for the manipulation of this pathway still do not allow to specifically intervene on discrete cAMP/PKA microdomains. Since compartmentalization is crucial for action specificity, identifying new tools that allow local modulation of cAMP/PKA responses is an urgent need. Among key players of cAMP/PKA signaling compartmentalization, a major role is played by A-kinase anchoring proteins (AKAPs) that, by definition, anchor PKA, its substrates and its regulators within multiprotein complexes in well-confined subcellular compartments. Different tools have been conceived to interfere with AKAP-based protein-protein interactions (PPIs), and these primarily include peptides and peptidomimetics that disrupt AKAP-directed multiprotein complexes. While these molecules have been extensively used to understand the molecular mechanisms behind AKAP function in pathophysiological processes, less attention has been devoted to their potential application for therapy. In this review, we will discuss how AKAP-based PPIs can be pharmacologically targeted by synthetic peptides and peptidomimetics.
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16
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Asirvatham AL, Schworer CM, Stahl R, Heitzman D, Carey DJ. Role of A-kinase anchoring proteins in cyclic-AMP-mediated Schwann cell proliferation. Cell Signal 2021; 83:109977. [PMID: 33716104 DOI: 10.1016/j.cellsig.2021.109977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
Proliferation of Schwann cells during peripheral nerve development is stimulated by the heregulin/neuregulin family of growth factors expressed by neurons. However, for neonatal rat Schwann cells growing in culture, heregulins produce only a weak mitogenic response. Supplementing heregulin with forskolin, an agent that elevates cyclic AMP levels, produces a dramatic increase in the proliferation of cultured Schwann cells. The mechanisms underlying this synergistic effect required for Schwann cell proliferation in vivo is not well established. Characterizing the A-kinase anchoring proteins (AKAPs) in Schwann cells might help identify substrates tethered to and phosphorylated by the cAMP-dependent protein kinase A (PKA). Using an RII overlay assay that detects AKAPs that are bound to the type II regulatory subunits of PKA, we identified AKAP150 in Schwann cells. Western blot analysis revealed that additional AKAPs, specifically AKAP95, and yotiao were also present. Disruption of PKA/AKAP interaction with Ht-31 peptide resulted in an increase in luciferase-conjugated cyclin D3 promoter activity. Transfection with sequence-specific AKAP siRNAs for AKAP150 and AKAP95 produced a marked reduction in cell proliferation. Immunoblot analysis revealed that knock down of AKAP95 protein caused a significant decrease in expression of the cell cycle regulatory proteins cyclin D2, cyclin D3 and the cell survival signal Akt/Protein Kinase B (Akt/PKB). Morphological characterization of Schwann cell AKAPs indicated the presence of nuclear (AKAP95), cytoplasm-associated (AKAP150) and perinuclear (yotiao) A-kinase anchoring proteins. These results indicate a role for AKAP95 and AKAP150 in the synergistic response of Schwann cells to treatment with heregulin and forskolin.
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Affiliation(s)
- Angela L Asirvatham
- Department of Biology, Misericordia University, 301 Lake Street Dallas, PA 18612, United States of America.
| | - Charles M Schworer
- Geisinger Medical Center Weis Center for Research, 100 N Academy Avenue, Danville, PA 17822, United States of America
| | - Rick Stahl
- Geisinger Medical Center Weis Center for Research, 100 N Academy Avenue, Danville, PA 17822, United States of America
| | - Deborah Heitzman
- Department of Biology, Bloomsburg University, 400 E. Second Street, Bloomsburg, PA 17815, United States of America
| | - David J Carey
- Geisinger Medical Center Weis Center for Research, 100 N Academy Avenue, Danville, PA 17822, United States of America
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17
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Zhang J, Zhang C, Chen X, Wang B, Ma W, Yang Y, Zheng R, Huang Z. PKA-RIIβ autophosphorylation modulates PKA activity and seizure phenotypes in mice. Commun Biol 2021; 4:263. [PMID: 33649504 PMCID: PMC7921646 DOI: 10.1038/s42003-021-01748-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 12/22/2020] [Indexed: 11/20/2022] Open
Abstract
Temporal lobe epilepsy (TLE) is one of the most common and intractable neurological disorders in adults. Dysfunctional PKA signaling is causally linked to the TLE. However, the mechanism underlying PKA involves in epileptogenesis is still poorly understood. In the present study, we found the autophosphorylation level at serine 114 site (serine 112 site in mice) of PKA-RIIβ subunit was robustly decreased in the epileptic foci obtained from both surgical specimens of TLE patients and seizure model mice. The p-RIIβ level was negatively correlated with the activities of PKA. Notably, by using a P-site mutant that cannot be autophosphorylated and thus results in the released catalytic subunit to exert persistent phosphorylation, an increase in PKA activities through transduction with AAV-RIIβ-S112A in hippocampal DG granule cells decreased mIPSC frequency but not mEPSC, enhanced neuronal intrinsic excitability and seizure susceptibility. In contrast, a reduction of PKA activities by RIIβ knockout led to an increased mIPSC frequency, a reduction in neuronal excitability, and mice less prone to experimental seizure onset. Collectively, our data demonstrated that the autophosphorylation of RIIβ subunit plays a critical role in controlling neuronal and network excitabilities by regulating the activities of PKA, providing a potential therapeutic target for TLE.
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Affiliation(s)
- Jingliang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Chenyu Zhang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Xiaoling Chen
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China
| | - Bingwei Wang
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Weining Ma
- Department of Neurology, Shengjing Hospital Affiliated to China Medical University, Shenyang, China
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University College of Pharmacy, West Lafayette, IN, USA
| | - Ruimao Zheng
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
- Neuroscience Research Institute, Peking University, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education, Beijing, China.
- Key Laboratory for Neuroscience of National Health Commission, Beijing, China.
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, China.
- Key Laboratory for Neuroscience, Ministry of Education, Beijing, China.
- Key Laboratory for Neuroscience of National Health Commission, Beijing, China.
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18
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Abstract
The field of cAMP signaling is witnessing exciting developments with the recognition that cAMP is compartmentalized and that spatial regulation of cAMP is critical for faithful signal coding. This realization has changed our understanding of cAMP signaling from a model in which cAMP connects a receptor at the plasma membrane to an intracellular effector in a linear pathway to a model in which cAMP signals propagate within a complex network of alternative branches and the specific functional outcome strictly depends on local regulation of cAMP levels and on selective activation of a limited number of branches within the network. In this review, we cover some of the early studies and summarize more recent evidence supporting the model of compartmentalized cAMP signaling, and we discuss how this knowledge is starting to provide original mechanistic insight into cell physiology and a novel framework for the identification of disease mechanisms that potentially opens new avenues for therapeutic interventions. SIGNIFICANCE STATEMENT: cAMP mediates the intracellular response to multiple hormones and neurotransmitters. Signal fidelity and accurate coordination of a plethora of different cellular functions is achieved via organization of multiprotein signalosomes and cAMP compartmentalization in subcellular nanodomains. Defining the organization and regulation of subcellular cAMP nanocompartments is necessary if we want to understand the complex functional ramifications of pharmacological treatments that target G protein-coupled receptors and for generating a blueprint that can be used to develop precision medicine interventions.
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Affiliation(s)
- Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Zerio
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Miguel J Lobo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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19
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Moreno-Corona NC, Lopez-Ortega O, Flores Hermenegildo JM, Berron-Ruiz L, Rodriguez-Alba JC, Santos-Argumedo L, Lopez-Herrera G. Lipopolysaccharide-responsive beige-like anchor acts as a cAMP-dependent protein kinase anchoring protein in B cells. Scand J Immunol 2020; 92:e12922. [PMID: 32592188 DOI: 10.1111/sji.12922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 05/15/2020] [Accepted: 06/21/2020] [Indexed: 01/04/2023]
Abstract
Lipopolysaccharide (LPS)-responsive beige-like anchor (LRBA) protein was initially described as a monogenetic cause for common variable immune deficiency, a syndrome characterized by low levels of B cells, defects in memory B cell differentiation and hypogammaglobulinaemia. LRBA was identified as an LPS up-regulated gene in B cells, macrophages and T cells. LRBA weighs 320 kDa and has 2863 amino acids. Its sequence contains multiple domains, suggesting that LRBA can act as a scaffolding protein. It contains two putative binding sites for cAMP-dependent kinase (PKA) regulatory subunits, suggesting this protein can act as A-kinase anchor protein (AKAP); however, physical interactions involving LRBA and PKA have not been demonstrated to date, and functional roles for such interactions are unexplored. In this work, we investigated physical interactions involving LRBA with regulatory subunits of PKA in human B cell lines and primary human B cells. PKA is a holoenzyme composed of two regulatory subunits, which can be RIα, RIβ, RIIα or RIIβ, and two catalytic subunits, Cα or Cβ. We co-immunoprecipitated LRBA using Ramos B cell lymphoma cells and observed that LRBA interacts with RIIβ. Interestingly, St-Ht31, an inhibitory peptide that disrupts AKAP interactions with regulatory subunits, reduced the amount of interacting protein. Furthermore, in primary human B cells, LRBA was induced after CD40L and IL-4 stimulation, and under such activation, we found that LRBA interacts with RIIα and RIIβ, suggesting that LRBA acts as an AKAP and binds RII subunits. Interestingly, we also identified that LRBA interacts with activation-induced cytidine deaminase in primary B cells, suggesting that it is involved in B cell function.
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Affiliation(s)
- Nidia Carolina Moreno-Corona
- Biomedicina Molecular, Centro de Investigacion y de Estudios Avanzados, Mexico City, Mexico.,Unidad de Investigacion en Inmunodeficiencias, Instituto Nacional de Pediatria, Mexico City, Mexico
| | - Orestes Lopez-Ortega
- Biomedicina Molecular, Centro de Investigacion y de Estudios Avanzados, Mexico City, Mexico
| | - Jose Mizael Flores Hermenegildo
- Biomedicina Molecular, Centro de Investigacion y de Estudios Avanzados, Mexico City, Mexico.,Unidad de Investigacion en Inmunodeficiencias, Instituto Nacional de Pediatria, Mexico City, Mexico
| | - Laura Berron-Ruiz
- Unidad de Investigacion en Inmunodeficiencias, Instituto Nacional de Pediatria, Mexico City, Mexico
| | - Juan Carlos Rodriguez-Alba
- Unidad de Citometria de Flujo, Instituto de Ciencias de la Salud, Universidad Veracruzana, Xalapa, Veracruz, Mexico
| | | | - Gabriela Lopez-Herrera
- Unidad de Investigacion en Inmunodeficiencias, Instituto Nacional de Pediatria, Mexico City, Mexico
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20
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Edwards G, Perkins GA, Kim KY, Kong Y, Lee Y, Choi SH, Liu Y, Skowronska-Krawczyk D, Weinreb RN, Zangwill L, Strack S, Ju WK. Loss of AKAP1 triggers Drp1 dephosphorylation-mediated mitochondrial fission and loss in retinal ganglion cells. Cell Death Dis 2020; 11:254. [PMID: 32312949 PMCID: PMC7170863 DOI: 10.1038/s41419-020-2456-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 04/06/2020] [Accepted: 04/07/2020] [Indexed: 12/14/2022]
Abstract
Impairment of mitochondrial structure and function is strongly linked to glaucoma pathogenesis. Despite the widely appreciated disease relevance of mitochondrial dysfunction and loss, the molecular mechanisms underlying mitochondrial fragmentation and metabolic stress in glaucoma are poorly understood. We demonstrate here that glaucomatous retinal ganglion cells (RGCs) show loss of A-kinase anchoring protein 1 (AKAP1), activation of calcineurin (CaN) and reduction of dynamin-related protein 1 (Drp1) phosphorylation at serine 637 (Ser637). These findings suggest that AKAP1-mediated phosphorylation of Drp1 at Ser637 has a critical role in RGC survival in glaucomatous neurodegeneration. Male mice lacking AKAP1 show increases in CaN and total Drp1 levels, as well as a decrease in Drp1 phosphorylation at Ser637 in the retina. Ultrastructural analysis of mitochondria shows that loss of AKAP1 triggers mitochondrial fragmentation and loss, as well as mitophagosome formation in RGCs. Loss of AKAP1 deregulates oxidative phosphorylation (OXPHOS) complexes (Cxs) by increasing CxII and decreasing CxIII-V, leading to metabolic and oxidative stress. Also, loss of AKAP1 decreases Akt phosphorylation at Serine 473 (Ser473) and threonine 308 (Thr308) and activates the Bim/Bax signaling pathway in the retina. These results suggest that loss of AKAP1 has a critical role in RGC dysfunction by decreasing Drp1 phosphorylation at Ser637, deregulating OXPHOS, decreasing Akt phosphorylation at Ser473 and Thr308, and activating the Bim/Bax pathway in glaucomatous neurodegeneration. Thus, we propose that overexpression of AKAP1 or modulation of Drp1 phosphorylation at Ser637 are potential therapeutic strategies for neuroprotective intervention in glaucoma and other mitochondria-related optic neuropathies.
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Affiliation(s)
- Genea Edwards
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Guy A Perkins
- National Center for Microscopy and Imaging Research and Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research and Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - YeEun Kong
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Yonghoon Lee
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Soo-Ho Choi
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Yujia Liu
- Department of Pharmacology and Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Dorota Skowronska-Krawczyk
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Linda Zangwill
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA
| | - Stefan Strack
- Department of Pharmacology and Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Center, The Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA, USA.
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Marin W. A-kinase anchoring protein 1 (AKAP1) and its role in some cardiovascular diseases. J Mol Cell Cardiol 2019; 138:99-109. [PMID: 31783032 DOI: 10.1016/j.yjmcc.2019.11.154] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 11/08/2019] [Accepted: 11/22/2019] [Indexed: 01/09/2023]
Abstract
A-kinase anchoring proteins (AKAPs) play crucial roles in regulating compartmentalized multi-protein signaling networks related to PKA-mediated phosphorylation. The mitochondrial AKAP - AKAP1 proteins are enriched in heart and play cardiac protective roles. This review aims to thoroughly summarize AKAP1 variants from their sequence features to the structure-function relationships between AKAP1 and its binding partners, as well as the molecular mechanisms of AKAP1 in cardiac hypertrophy, hypoxia-induced myocardial infarction and endothelial cells dysfunction, suggesting AKAP1 as a candidate for cardiovascular therapy.
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Affiliation(s)
- Wenwen Marin
- Institute for Translational Medicine, Medical Faculty of Qingdao University, Qingdao 266021, China.
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22
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Van Laar VS, Otero PA, Hastings TG, Berman SB. Potential Role of Mic60/Mitofilin in Parkinson's Disease. Front Neurosci 2019; 12:898. [PMID: 30740041 PMCID: PMC6357844 DOI: 10.3389/fnins.2018.00898] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/16/2018] [Indexed: 12/21/2022] Open
Abstract
There are currently no treatments that hinder or halt the inexorable progression of Parkinson's disease (PD). While the etiology of PD remains elusive, evidence suggests that early dysfunction of mitochondrial respiration and homeostasis play a major role in PD pathogenesis. The mitochondrial structural protein Mic60, also known as mitofilin, is critical for maintaining mitochondrial architecture and function. Loss of Mic60 is associated with detrimental effects on mitochondrial homeostasis. Growing evidence now implicates Mic60 in the pathogenesis of PD. In this review, we discuss the data supporting a role of Mic60 and mitochondrial dysfunction in PD. We will also consider the potential of Mic60 as a therapeutic target for treating neurological disorders.
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Affiliation(s)
- Victor S Van Laar
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, United States
| | - P Anthony Otero
- Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, United States.,Division of Neuropathology, Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Cellular and Molecular Pathology (CMP) Program, Department of Pathology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Teresa G Hastings
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sarah B Berman
- Department of Neurology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, United States.,Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, United States
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23
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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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24
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Fyn Regulates Binding Partners of Cyclic-AMP Dependent Protein Kinase A. Proteomes 2018; 6:proteomes6040037. [PMID: 30274258 PMCID: PMC6313912 DOI: 10.3390/proteomes6040037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 12/03/2022] Open
Abstract
The cAMP-dependent protein kinase A (PKA) is a serine/threonine kinase involved in many fundamental cellular processes, including migration and proliferation. Recently, we found that the Src family kinase Fyn phosphorylates the catalytic subunit of PKA (PKA-C) at Y69, thereby increasing PKA kinase activity. We also showed that Fyn induced the phosphorylation of cellular proteins within the PKA preferred target motif. This led to the hypothesis that Fyn could affect proteins in complex with PKA. To test this, we employed a quantitative mass spectrometry approach to identify Fyn-dependent binding partners in complex with PKA-C. We found Fyn enhanced the binding of PKA-C to several cytoskeletal regulators that localize to the centrosome and Golgi apparatus. Three of these Fyn-induced PKA interactors, AKAP9, PDE4DIP, and CDK5RAP2, were validated biochemically and were shown to exist in complex with Fyn and PKA in a glioblastoma cell line. Intriguingly, the complexes formed between PKA-C and these known AKAPs were dependent upon Fyn catalytic activity and expression levels. In addition, we identified Fyn-regulated phosphorylation sites on proteins in complex with PKA-C. We also identified and biochemically validated a novel PKA-C interactor, LARP4, which complexed with PKA in the absence of Fyn. These results demonstrate the ability of Fyn to influence the docking of PKA to specific cellular scaffolds and suggest that Fyn may affect the downstream substrates targeted by PKA.
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25
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AKAP1 Protects from Cerebral Ischemic Stroke by Inhibiting Drp1-Dependent Mitochondrial Fission. J Neurosci 2018; 38:8233-8242. [PMID: 30093535 PMCID: PMC6146498 DOI: 10.1523/jneurosci.0649-18.2018] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 07/29/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial fission and fusion impact numerous cellular functions and neurons are particularly sensitive to perturbations in mitochondrial dynamics. Here we describe that male mice lacking the mitochondrial A-kinase anchoring protein 1 (AKAP1) exhibit increased sensitivity in the transient middle cerebral artery occlusion model of focal ischemia. At the ultrastructural level, AKAP1-/- mice have smaller mitochondria and increased contacts between mitochondria and the endoplasmic reticulum in the brain. Mechanistically, deletion of AKAP1 dysregulates complex II of the electron transport chain, increases superoxide production, and impairs Ca2+ homeostasis in neurons subjected to excitotoxic glutamate. Ca2+ deregulation in neurons lacking AKAP1 can be attributed to loss of inhibitory phosphorylation of the mitochondrial fission enzyme dynamin-related protein 1 (Drp1) at the protein kinase A (PKA) site Ser637. Our results indicate that inhibition of Drp1-dependent mitochondrial fission by the outer mitochondrial AKAP1/PKA complex protects neurons from ischemic stroke by maintaining respiratory chain activity, inhibiting superoxide production, and delaying Ca2+ deregulation. They also provide the first genetic evidence that Drp1 inhibition may be of therapeutic relevance for the treatment of stroke and neurodegeneration.SIGNIFICANCE STATEMENT Previous work suggests that activation of dynamin-related protein 1 (Drp1) and mitochondrial fission contribute to ischemic injury in the brain. However, the specificity and efficacy of the pharmacological Drp1 inhibitor mdivi-1 that was used has now been discredited by several high-profile studies. Our report is timely and highly impactful because it provides the first evidence that genetic disinhibition of Drp1 via knock-out of the mitochondrial protein kinase A (PKA) scaffold AKAP1 exacerbates stroke injury in mice. Mechanistically, we show that electron transport deficiency, increased superoxide production, and Ca2+ overload result from genetic disinhibition of Drp1. In summary, our work settles current controversies regarding the role of mitochondrial fission in neuronal injury, provides mechanisms, and suggests that fission inhibitors hold promise as future therapeutic agents.
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Wang X, Miao J, Xia J, Chang T, E G, Bao J, Jin S, Xu L, Zhang L, Zhu B, Gao X, Chen Y, Li J, Gao H. Identifying novel genes for carcass traits by testing G × E interaction through genome-wide meta-analysis in Chinese Simmental beef cattle. Livest Sci 2018. [DOI: 10.1016/j.livsci.2018.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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27
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AKAPs-PKA disruptors increase AQP2 activity independently of vasopressin in a model of nephrogenic diabetes insipidus. Nat Commun 2018; 9:1411. [PMID: 29650969 PMCID: PMC5897355 DOI: 10.1038/s41467-018-03771-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/09/2018] [Indexed: 02/08/2023] Open
Abstract
Congenital nephrogenic diabetes insipidus (NDI) is characterized by the inability of the kidney to concentrate urine. Congenital NDI is mainly caused by loss-of-function mutations in the vasopressin type 2 receptor (V2R), leading to impaired aquaporin-2 (AQP2) water channel activity. So far, treatment options of congenital NDI either by rescuing mutant V2R with chemical chaperones or by elevating cyclic adenosine monophosphate (cAMP) levels have failed to yield effective therapies. Here we show that inhibition of A-kinase anchoring proteins (AKAPs) binding to PKA increases PKA activity and activates AQP2 channels in cortical collecting duct cells. In vivo, the low molecular weight compound 3,3′-diamino-4,4′-dihydroxydiphenylmethane (FMP-API-1) and its derivatives increase AQP2 activity to the same extent as vasopressin, and increase urine osmolality in the context of V2R inhibition. We therefore suggest that FMP-API-1 may constitute a promising lead compound for the treatment of congenital NDI caused by V2R mutations. Patients suffering from congenital nephrogenic diabetes insipidus (NDI) fail to concentrate urine due to mutations in vasopressin type 2 receptor (V2R). Here Ando et al. show that agents disrupting the interaction between PKA and AKAPs restore aquaporin-2 activity downstream of V2R, offering a therapeutic approach for the treatment of NDI.
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28
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Investigating PKA-RII specificity using analogs of the PKA:AKAP peptide inhibitor STAD-2. Bioorg Med Chem 2018; 26:1174-1178. [PMID: 29449124 DOI: 10.1016/j.bmc.2018.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 01/31/2018] [Accepted: 02/01/2018] [Indexed: 11/20/2022]
Abstract
Generation of the second messenger molecule cAMP mediates a variety of cellular responses which are essential for critical cellular processes. In response to elevated cAMP levels, cAMP dependent protein kinase (PKA) phosphorylates serine and threonine residues on a wide variety of target substrates. In order to enhance the precision and directionality of these signaling events, PKA is localized to discrete locations within the cell by A-kinase anchoring proteins (AKAPs). The interaction between PKA and AKAPs is mediated via an amphipathic α-helix derived from AKAPs which binds to a stable hydrophobic groove formed in the dimerization/docking (D/D) domain of PKA-R in an isoform-specific fashion. Although numerous AKAP disruptors have previously been identified that can inhibit either RI- or RII-selective AKAPs, no AKAP disruptors have been identified that have isoform specificity for RIα versus RIβ or RIIα versus RIIβ. As a strategy to identify isoform-specific AKAP inhibitors, a library of chemically stapled protein-protein interaction (PPI) disruptors was developed based on the RII-selective AKAP disruptor, STAD-2. An alanine was substituted at each position in the sequence, and from this library it was possible to delineate the importance of longer aliphatic residues in the formation of a region which complements the hydrophobic cleft formed by the D/D domain. Interestingly, lysine residues that were added to both terminal ends of the peptide sequence to facilitate water solubility appear to contribute to isoform specificity for RIIα over RIIβ while having only weak interaction with RI. This work supports current hypotheses on the mechanisms of AKAP binding and highlights the significance of particular residue positions that aid in distinguishing between the RII isoforms and may provide insight into future design of isoform-selective AKAP disruptors.
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29
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Bieluszewska A, Weglewska M, Bieluszewski T, Lesniewicz K, Poreba E. PKA
‐binding domain of
AKAP
8 is essential for direct interaction with
DPY
30 protein. FEBS J 2018; 285:947-964. [DOI: 10.1111/febs.14378] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 12/01/2017] [Accepted: 12/22/2017] [Indexed: 11/27/2022]
Affiliation(s)
- Anna Bieluszewska
- Department of Molecular Virology Institute of Experimental Biology Faculty of Biology Adam Mickiewicz University in Poznan Poland
| | - Martyna Weglewska
- Department of Molecular Virology Institute of Experimental Biology Faculty of Biology Adam Mickiewicz University in Poznan Poland
| | - Tomasz Bieluszewski
- Department of Genome Biology Institute of Molecular Biology and Biotechnology Faculty of Biology Adam Mickiewicz University in Poznan Poland
| | - Krzysztof Lesniewicz
- Department of Molecular and Cellular Biology Institute of Molecular Biology and Biotechnology Faculty of Biology Adam Mickiewicz University in Poznan Poland
| | - Elzbieta Poreba
- Department of Molecular Virology Institute of Experimental Biology Faculty of Biology Adam Mickiewicz University in Poznan Poland
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30
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Gu Y, Xu W, Zhuang B, Fu W. Role of A-kinase anchoring protein 95 in the regulation of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) in human ovarian granulosa cells. Reprod Fertil Dev 2018; 30:1128-1136. [DOI: 10.1071/rd17313] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 01/02/2018] [Indexed: 11/23/2022] Open
Abstract
Irregular expression of cytochrome P450 family 19 subfamily A member 1 (CYP19A1) is involved in the development of polycystic ovary syndrome (PCOS). Activation of the cAMP/protein kinase A (PKA)/cAMP response element-binding protein (CREB) pathway plays a crucial role in FSH regulation of CYP19A1 in human ovarian granulosa cells. A-Kinase anchor protein 95 (AKAP95) is known to confine PKA to the nucleus. However, it is unclear whether anchoring PKA to the nucleus is essential for the induction of CYP19A1 by FSH in human ovarian granulosa cells. Using the human granulosa cell line KGN and primary cultured human luteinised granulosa cells (hLGCs), we found that knockdown of AKAP8, the gene encoding AKAP95, or inhibition of AKAP95 reduced the amount of PKA anchored in the nucleus and attenuated the phosphorylation of CREB by either FSH or activation of the cAMP/PKA pathway. Moreover, knockdown of AKAP8 or inhibition of AKAP95 also significantly attenuated FSH-induced CYP19A1 expression and oestrogen synthesis. Furthermore, significant decreases in AKAP95 and CYP19A1 were observed in hLGCs obtained from PCOS patients. The results of the present study demonstrate a crucial role for AKAP95 in CYP19A1 expression and oestrogen synthesis in hLGCs, which implies that AKAP95 may be involved in the pathogenesis of PCOS.
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31
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Wild AR, Dell'Acqua ML. Potential for therapeutic targeting of AKAP signaling complexes in nervous system disorders. Pharmacol Ther 2017; 185:99-121. [PMID: 29262295 DOI: 10.1016/j.pharmthera.2017.12.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A common feature of neurological and neuropsychiatric disorders is a breakdown in the integrity of intracellular signal transduction pathways. Dysregulation of ion channels and receptors in the cell membrane and the enzymatic mediators that link them to intracellular effectors can lead to synaptic dysfunction and neuronal death. However, therapeutic targeting of these ubiquitous signaling elements can lead to off-target side effects due to their widespread expression in multiple systems of the body. A-kinase anchoring proteins (AKAPs) are multivalent scaffolding proteins that compartmentalize a diverse range of receptor and effector proteins to streamline signaling within nanodomain signalosomes. A number of essential neurological processes are known to critically depend on AKAP-directed signaling and an understanding of the role AKAPs play in nervous system disorders has emerged in recent years. Selective targeting of AKAP protein-protein interactions may be a means to uncouple pathologically active signaling pathways in neurological disorders with a greater degree of specificity. In this review we will discuss the role of AKAPs in both regulating normal nervous system function and dysfunction associated with disease, and the potential for therapeutic targeting of AKAP signaling complexes.
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Affiliation(s)
- Angela R Wild
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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32
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Lu J, Wang W, Mi Y, Zhang C, Ying H, Wang L, Wang Y, Myatt L, Sun K. AKAP95-mediated nuclear anchoring of PKA mediates cortisol-induced PTGS2 expression in human amnion fibroblasts. Sci Signal 2017; 10:10/506/eaac6160. [PMID: 29162743 DOI: 10.1126/scisignal.aac6160] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phosphorylation of the transcription factors cyclic adenosine monophosphate response element-binding protein (CREB) and signal transducer and activator of transcription 3 (STAT3) by protein kinase A (PKA) is required for the cortisol-induced production of cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) in human amnion fibroblasts, which critically mediates human parturition (labor). We found that PKA was confined in the nucleus by A-kinase-anchoring protein 95 (AKAP95) in amnion fibroblasts and that this localization was key to the cortisol-induced expression of PTGS2, the gene encoding COX-2. Cortisol increased the abundance of nuclear PKA by stimulating the expression of the gene encoding AKAP95. Knockdown of AKAP95 not only reduced the amounts of nuclear PKA and phosphorylated CREB but also attenuated the induction of PTGS2 expression in primary human amnion fibroblasts treated with cortisol, whereas the phosphorylation of STAT3 in response to cortisol was not affected. The abundances of AKAP95, phosphorylated CREB, and COX-2 were markedly increased in human amnion tissue after labor compared to those in amnion tissues from cesarean sections without labor. These results highlight an essential role for PKA that is anchored in the nucleus by AKAP95 in the phosphorylation of CREB and the consequent induction of COX-2 expression by cortisol in amnion fibroblasts, which may be important in human parturition.
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Affiliation(s)
- Jiangwen Lu
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P. R. China.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200135, P. R. China
| | - Wangsheng Wang
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P. R. China.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200135, P. R. China
| | - Yabing Mi
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P. R. China.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200135, P. R. China
| | - Chuyue Zhang
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P. R. China.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200135, P. R. China
| | - Hao Ying
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201204, P. R. China
| | - Luyao Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201204, P. R. China
| | - Yawei Wang
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201204, P. R. China
| | - Leslie Myatt
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Kang Sun
- Center for Reproductive Medicine, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200135, P. R. China. .,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Shanghai 200135, P. R. China
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Xu Z, Feng X, Dong J, Wang ZM, Lee J, Furdui C, Files DC, Beavers KM, Kritchevsky S, Milligan C, Jin JP, Delbono O, Zhang T. Cardiac troponin T and fast skeletal muscle denervation in ageing. J Cachexia Sarcopenia Muscle 2017; 8:808-823. [PMID: 28419739 PMCID: PMC5659053 DOI: 10.1002/jcsm.12204] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/13/2017] [Accepted: 03/01/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Ageing skeletal muscle undergoes chronic denervation, and the neuromuscular junction (NMJ), the key structure that connects motor neuron nerves with muscle cells, shows increased defects with ageing. Previous studies in various species have shown that with ageing, type II fast-twitch skeletal muscle fibres show more atrophy and NMJ deterioration than type I slow-twitch fibres. However, how this process is regulated is largely unknown. A better understanding of the mechanisms regulating skeletal muscle fibre-type specific denervation at the NMJ could be critical to identifying novel treatments for sarcopenia. Cardiac troponin T (cTnT), the heart muscle-specific isoform of TnT, is a key component of the mechanisms of muscle contraction. It is expressed in skeletal muscle during early development, after acute sciatic nerve denervation, in various neuromuscular diseases and possibly in ageing muscle. Yet the subcellular localization and function of cTnT in skeletal muscle is largely unknown. METHODS Studies were carried out on isolated skeletal muscles from mice, vervet monkeys, and humans. Immunoblotting, immunoprecipitation, and mass spectrometry were used to analyse protein expression, real-time reverse transcription polymerase chain reaction was used to measure gene expression, immunofluorescence staining was performed for subcellular distribution assay of proteins, and electromyographic recording was used to analyse neurotransmission at the NMJ. RESULTS Levels of cTnT expression in skeletal muscle increased with ageing in mice. In addition, cTnT was highly enriched at the NMJ region-but mainly in the fast-twitch, not the slow-twitch, muscle of old mice. We further found that the protein kinase A (PKA) RIα subunit was largely removed from, while PKA RIIα and RIIβ are enriched at, the NMJ-again, preferentially in fast-twitch but not slow-twitch muscle in old mice. Knocking down cTnT in fast skeletal muscle of old mice: (i) increased PKA RIα and reduced PKA RIIα at the NMJ; (ii) decreased the levels of gene expression of muscle denervation markers; and (iii) enhanced neurotransmission efficiency at NMJ. CONCLUSIONS Cardiac troponin T at the NMJ region contributes to NMJ functional decline with ageing mainly in the fast-twitch skeletal muscle through interfering with PKA signalling. This knowledge could inform useful targets for prevention and therapy of age-related decline in muscle function.
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Affiliation(s)
- Zherong Xu
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Department of Geriatrics, First Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Xin Feng
- Department of Otolaryngology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Juan Dong
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Zhong-Min Wang
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jingyun Lee
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Cristina Furdui
- Department of Internal Medicine, Section on Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Daniel Clark Files
- Internal Medicine-Pulmonary, Critical Care, Allergy and Immunology, Gerontology and Geriatric Medicine and the Critical Illness Injury and Recovery Research Center, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Kristen M Beavers
- Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC, USA
| | - Stephen Kritchevsky
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Carolanne Milligan
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Jian-Ping Jin
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Osvaldo Delbono
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Tan Zhang
- Department of Internal Medicine, Section on Gerontology and Geriatic Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA.,Sticht Center for Healthy Aging and Alzheimer's Prevention, Wake Forest School of Medicine, Winston-Salem, NC, USA
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Torres-Quesada O, Mayrhofer JE, Stefan E. The many faces of compartmentalized PKA signalosomes. Cell Signal 2017; 37:1-11. [PMID: 28528970 DOI: 10.1016/j.cellsig.2017.05.012] [Citation(s) in RCA: 119] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/03/2023]
Abstract
Cellular signal transmission requires the dynamic formation of spatiotemporally controlled molecular interactions. At the cell surface information is received by receptor complexes and relayed through intracellular signaling platforms which organize the actions of functionally interacting signaling enzymes and substrates. The list of hormone or neurotransmitter pathways that utilize the ubiquitous cAMP-sensing protein kinase A (PKA) system is expansive. This requires that the specificity, duration, and intensity of PKA responses are spatially and temporally restricted. Hereby, scaffolding proteins take the center stage for ensuring proper signal transmission. They unite second messenger sensors, activators, effectors, and kinase substrates within cellular micro-domains to precisely control and route signal propagation. A-kinase anchoring proteins (AKAPs) organize such subcellular signalosomes by tethering the PKA holoenzyme to distinct cell compartments. AKAPs differ in their modular organization showing pathway specific arrangements of interaction motifs or domains. This enables the cell- and compartment- guided assembly of signalosomes with unique enzyme composition and function. The AKAP-mediated clustering of cAMP and other second messenger sensing and interacting signaling components along with functional successive enzymes facilitates the rapid and precise dissemination of incoming signals. This review article delineates examples for different means of PKA regulation and for snapshots of compartmentalized PKA signalosomes.
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Affiliation(s)
- Omar Torres-Quesada
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Johanna E Mayrhofer
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, Innrain 80/82, 6020 Innsbruck, Austria.
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Protein kinase A activation by retinoic acid in the nuclei of HL60 cells. Biochim Biophys Acta Gen Subj 2017; 1861:276-285. [DOI: 10.1016/j.bbagen.2016.11.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/21/2016] [Accepted: 11/28/2016] [Indexed: 11/23/2022]
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36
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Yang H, Yang L. Targeting cAMP/PKA pathway for glycemic control and type 2 diabetes therapy. J Mol Endocrinol 2016; 57:R93-R108. [PMID: 27194812 DOI: 10.1530/jme-15-0316] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 05/18/2016] [Indexed: 12/11/2022]
Abstract
In mammals, cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is usually elicited by binding of hormones and neurotransmitters to G protein-coupled receptors (GPCRs). cAMP exerts many of its physiological effects by activating cAMP-dependent protein kinase (PKA), which in turn phosphorylates and regulates the functions of downstream protein targets including ion channels, enzymes, and transcription factors. cAMP/PKA signaling pathway regulates glucose homeostasis at multiple levels including insulin and glucagon secretion, glucose uptake, glycogen synthesis and breakdown, gluconeogenesis, and neural control of glucose homeostasis. This review summarizes recent genetic and pharmacological studies concerning the regulation of glucose homeostasis by cAMP/PKA in pancreas, liver, skeletal muscle, adipose tissues, and brain. We also discuss the strategies for targeting cAMP/PKA pathway for research and potential therapeutic treatment of type 2 diabetes mellitus (T2D).
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Affiliation(s)
- Haihua Yang
- Division of EndocrinologyZhengzhou Children's Hospital, Zhengzhou, Henan, China
| | - Linghai Yang
- Department of PharmacologyUniversity of Washington, Seattle, Washington, USA
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37
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Ivan T, Enkvist E, Viira B, Manoharan GB, Raidaru G, Pflug A, Alam KA, Zaccolo M, Engh RA, Uri A. Bifunctional Ligands for Inhibition of Tight-Binding Protein-Protein Interactions. Bioconjug Chem 2016; 27:1900-10. [PMID: 27389935 DOI: 10.1021/acs.bioconjchem.6b00293] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The acknowledged potential of small-molecule therapeutics targeting disease-related protein-protein interactions (PPIs) has promoted active research in this field. The strategy of using small molecule inhibitors (SMIs) to fight strong (tight-binding) PPIs tends to fall short due to the flat and wide interfaces of PPIs. Here we propose a biligand approach for disruption of strong PPIs. The potential of this approach was realized for disruption of the tight-binding (KD = 100 pM) tetrameric holoenzyme of cAMP-dependent protein kinase (PKA). Supported by X-ray analysis of cocrystals, bifunctional inhibitors (ARC-inhibitors) were constructed that simultaneously associated with both the ATP-pocket and the PPI interface area of the catalytic subunit of PKA (PKAc). Bifunctional inhibitor ARC-1411, possessing a KD value of 3 pM toward PKAc, induced the dissociation of the PKA holoenzyme with a low-nanomolar IC50, whereas the ATP-competitive inhibitor H89 bound to the PKA holoenzyme without disruption of the protein tetramer.
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Affiliation(s)
- Taavi Ivan
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Erki Enkvist
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Birgit Viira
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | | | - Gerda Raidaru
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
| | - Alexander Pflug
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Kazi Asraful Alam
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford , OX1 3QX Oxford, United Kingdom
| | - Richard Alan Engh
- The Norwegian Structural Biology Centre, Department of Chemistry, University of Tromsø , N-9019 Tromsø, Norway
| | - Asko Uri
- Institute of Chemistry, University of Tartu , 50410 Tartu, Estonia
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38
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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.
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Wehbi VL, Taskén K. Molecular Mechanisms for cAMP-Mediated Immunoregulation in T cells - Role of Anchored Protein Kinase A Signaling Units. Front Immunol 2016; 7:222. [PMID: 27375620 PMCID: PMC4896925 DOI: 10.3389/fimmu.2016.00222] [Citation(s) in RCA: 127] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/23/2016] [Indexed: 12/20/2022] Open
Abstract
The cyclic AMP/protein kinase A (cAMP/PKA) pathway is one of the most common and versatile signal pathways in eukaryotic cells. A-kinase anchoring proteins (AKAPs) target PKA to specific substrates and distinct subcellular compartments providing spatial and temporal specificity for mediation of biological effects channeled through the cAMP/PKA pathway. In the immune system, cAMP is a potent negative regulator of T cell receptor-mediated activation of effector T cells (Teff) acting through a proximal PKA/Csk/Lck pathway anchored via a scaffold consisting of the AKAP Ezrin holding PKA, the linker protein EBP50, and the anchoring protein phosphoprotein associated with glycosphingolipid-enriched microdomains holding Csk. As PKA activates Csk and Csk inhibits Lck, this pathway in response to cAMP shuts down proximal T cell activation. This immunomodulating pathway in Teff mediates clinically important responses to regulatory T cell (Treg) suppression and inflammatory mediators, such as prostaglandins (PGs), adrenergic stimuli, adenosine, and a number of other ligands. A major inducer of T cell cAMP levels is PG E2 (PGE2) acting through EP2 and EP4 prostanoid receptors. PGE2 plays a crucial role in the normal physiological control of immune homeostasis as well as in inflammation and cancer immune evasion. Peripherally induced Tregs express cyclooxygenase-2, secrete PGE2, and elicit the immunosuppressive cAMP pathway in Teff as one tumor immune evasion mechanism. Moreover, a cAMP increase can also be induced by indirect mechanisms, such as intercellular transfer between T cells. Indeed, Treg, known to have elevated levels of intracellular cAMP, may mediate their suppressive function by transferring cAMP to Teff through gap junctions, which we speculate could also be regulated by PKA/AKAP complexes. In this review, we present an updated overview on the influence of cAMP-mediated immunoregulatory mechanisms acting through localized cAMP signaling and the therapeutical increasing prospects of AKAPs disruptors in T-cell immune function.
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Affiliation(s)
- Vanessa L. Wehbi
- Nordic EMBL Partnership, Centre for Molecular Medicine Norway, Oslo University Hospital, University of Oslo, Oslo, Norway
- Jebsen Inflammation Research Centre, Oslo University Hospital, Oslo, Norway
- Biotechnology Centre, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Kjetil Taskén
- Nordic EMBL Partnership, Centre for Molecular Medicine Norway, Oslo University Hospital, University of Oslo, Oslo, Norway
- Jebsen Inflammation Research Centre, Oslo University Hospital, Oslo, Norway
- Biotechnology Centre, Oslo University Hospital, University of Oslo, Oslo, Norway
- Jebsen Centre for Cancer Immunotherapy, Oslo University Hospital, Oslo, Norway
- Department of Infectious Diseases, Oslo University Hospital, Oslo, Norway
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40
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AKAP18:PKA-RIIα structure reveals crucial anchor points for recognition of regulatory subunits of PKA. Biochem J 2016; 473:1881-94. [PMID: 27102985 DOI: 10.1042/bcj20160242] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 04/20/2016] [Indexed: 12/25/2022]
Abstract
A-kinase anchoring proteins (AKAPs) interact with the dimerization/docking (D/D) domains of regulatory subunits of the ubiquitous protein kinase A (PKA). AKAPs tether PKA to defined cellular compartments establishing distinct pools to increase the specificity of PKA signalling. Here, we elucidated the structure of an extended PKA-binding domain of AKAP18β bound to the D/D domain of the regulatory RIIα subunits of PKA. We identified three hydrophilic anchor points in AKAP18β outside the core PKA-binding domain, which mediate contacts with the D/D domain. Such anchor points are conserved within AKAPs that bind regulatory RII subunits of PKA. We derived a different set of anchor points in AKAPs binding regulatory RI subunits of PKA. In vitro and cell-based experiments confirm the relevance of these sites for the interaction of RII subunits with AKAP18 and of RI subunits with the RI-specific smAKAP. Thus we report a novel mechanism governing interactions of AKAPs with PKA. The sequence specificity of each AKAP around the anchor points and the requirement of these points for the tight binding of PKA allow the development of selective inhibitors to unequivocally ascribe cellular functions to the AKAP18-PKA and other AKAP-PKA interactions.
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41
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Autenrieth K, Bendzunas NG, Bertinetti D, Herberg FW, Kennedy EJ. Defining A-Kinase Anchoring Protein (AKAP) Specificity for the Protein Kinase A Subunit RI (PKA-RI). Chembiochem 2016; 17:693-697. [PMID: 26611881 PMCID: PMC4836982 DOI: 10.1002/cbic.201500632] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Indexed: 01/18/2023]
Abstract
A-Kinase anchoring proteins (AKAPs) act as spatial and temporal regulators of protein kinase A (PKA) by localizing PKA along with multiple proteins into discrete signaling complexes. AKAPs interact with the PKA holoenzyme through an α-helix that docks into a groove formed on the dimerization/docking domain of PKA-R in an isoform-dependent fashion. In an effort to understand isoform selectivity at the molecular level, a library of protein-protein interaction (PPI) disruptors was designed to systematically probe the significance of an aromatic residue on the AKAP docking sequence for RI selectivity. The stapled peptide library was designed based on a high affinity, RI-selective disruptor of AKAP binding, RI-STAD-2. Phe, Trp and Leu were all found to maintain RI selectivity, whereas multiple intermediate-sized hydrophobic substitutions at this position either resulted in loss of isoform selectivity (Ile) or a reversal of selectivity (Val). As a limited number of RI-selective sequences are currently known, this study aids in our understanding of isoform selectivity and establishing parameters for discovering additional RI-selective AKAPs.
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Affiliation(s)
- Karolin Autenrieth
- Dept. of Biochemistry, Universitat Kassel, Heinrich Plett Strasse 40, Kassel 34132 (Germany)
| | - N. George Bendzunas
- Dept. of Pharmaceutical and Biomedical Sciences, University of Georgia, College of Pharmacy, 240 W. Green St, Athens, GA 30602 (USA)
| | - Daniela Bertinetti
- Dept. of Biochemistry, Universitat Kassel, Heinrich Plett Strasse 40, Kassel 34132 (Germany)
| | - Friedrich W. Herberg
- Dept. of Biochemistry, Universitat Kassel, Heinrich Plett Strasse 40, Kassel 34132 (Germany)
| | - Eileen J. Kennedy
- Dept. of Pharmaceutical and Biomedical Sciences, University of Georgia, College of Pharmacy, 240 W. Green St, Athens, GA 30602 (USA)
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42
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Calabokis M, González Y, Merchán A, Escalona JL, Araujo NA, Sanz-Rodríguez CE, Cywiak C, Spencer LM, Martínez JC, Bubis J. Immunological identification of a cAMP-dependent protein kinase regulatory subunit-like protein from theTrypanosoma equiperdumTeAp-N/D1 isolate. J Immunoassay Immunochem 2016; 37:485-514. [DOI: 10.1080/15321819.2016.1162799] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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43
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Marstad A, Landsverk OJB, Strømme O, Otterlei M, Collas P, Sundan A, Brede G. A-kinase anchoring protein AKAP95 is a novel regulator of ribosomal RNA synthesis. FEBS J 2016; 283:757-70. [PMID: 26683827 DOI: 10.1111/febs.13630] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 11/23/2015] [Accepted: 12/14/2015] [Indexed: 11/30/2022]
Abstract
The RNA polymerase I transcription apparatus acquires and integrates the combined information from multiple cellular signalling cascades to regulate ribosome production essential for cell growth and proliferation. In the present study, we show that a subpopulation of A-kinase anchoring protein 95 (AKAP95) targets the nucleolus during interphase and is involved in regulating rRNA production. We show that AKAP95 co-localizes with the nucleolar upstream binding factor, an essential rRNA transcription factor. Similar to other members of the C2 H2 -zinc finger family, we show, using systematic selection and evolution of ligands by exponential enrichment and in vitro binding analysis, that AKAP95 has a preference for GC-rich DNA in vitro, whereas fluorescence recovery after photobleaching analysis reveals AKAP95 to be a highly mobile protein that exhibits RNA polymerase I and II dependent nucleolar trafficking. In line with its GC-binding features, chromatin immunoprecipitation analysis revealed AKAP95 to be associated with ribosomal chromatin in vivo. Manipulation of AKAP95-expression in U2OS cells revealed a reciprocal relationship between the expression of AKAP95 and 47S rRNA. Taken together, our data indicate that AKAP95 is a novel nucleolus-associated protein with a regulatory role on rRNA production.
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Affiliation(s)
- Anne Marstad
- Centre of Molecular Inflammation Research (CEMIR), Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ole Jørgen B Landsverk
- Department of Pathology, Centre for Immune Regulation, Oslo University Hospital Norway, Norway
| | - Olaf Strømme
- Centre of Molecular Inflammation Research (CEMIR), Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Marit Otterlei
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Philippe Collas
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Anders Sundan
- Centre of Molecular Inflammation Research (CEMIR), Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.,KG Jebsen Centre for Myeloma Research, Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gaute Brede
- Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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44
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Kennedy EJ, Scott JD. Selective disruption of the AKAP signaling complexes. Methods Mol Biol 2015; 1294:137-50. [PMID: 25783883 DOI: 10.1007/978-1-4939-2537-7_11] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Synthesis of the second messenger cAMP activates a variety of signaling pathways critical for all facets of intracellular regulation. Protein kinase A (PKA) is the major cAMP-responsive effector. Where and when this enzyme is activated has profound implications on the cellular role of PKA. A-Kinase Anchoring Proteins (AKAPs) play a critical role in this process by orchestrating spatial and temporal aspects of PKA action. A popular means of evaluating the impact of these anchored signaling events is to biochemically interfere with the PKA-AKAP interface. Hence, peptide disruptors of PKA anchoring are valuable tools in the investigation of local PKA action. This article outlines the development of PKA isoform-selective disruptor peptides, documents the optimization of cell-soluble peptide derivatives, and introduces alternative cell-based approaches that interrogate other aspects of the PKA-AKAP interface.
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Affiliation(s)
- Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA, USA
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45
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Dema A, Perets E, Schulz MS, Deák VA, Klussmann E. Pharmacological targeting of AKAP-directed compartmentalized cAMP signalling. Cell Signal 2015; 27:2474-87. [PMID: 26386412 DOI: 10.1016/j.cellsig.2015.09.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/08/2015] [Accepted: 09/14/2015] [Indexed: 01/26/2023]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP) can bind and activate protein kinase A (PKA). The cAMP/PKA system is ubiquitous and involved in a wide array of biological processes and therefore requires tight spatial and temporal regulation. Important components of the safeguard system are the A-kinase anchoring proteins (AKAPs), a heterogeneous family of scaffolding proteins defined by its ability to directly bind PKA. AKAPs tether PKA to specific subcellular compartments, and they bind further interaction partners to create local signalling hubs. The recent discovery of new AKAPs and advances in the field that shed light on the relevance of these hubs for human disease highlight unique opportunities for pharmacological modulation. This review exemplifies how interference with signalling, particularly cAMP signalling, at such hubs can reshape signalling responses and discusses how this could lead to novel pharmacological concepts for the treatment of disease with an unmet medical need such as cardiovascular disease and cancer.
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Affiliation(s)
- Alessandro Dema
- Max Delbrück Center for Molecular Medicine Berlin in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Ekaterina Perets
- Max Delbrück Center for Molecular Medicine Berlin in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Maike Svenja Schulz
- Max Delbrück Center for Molecular Medicine Berlin in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Veronika Anita Deák
- Max Delbrück Center for Molecular Medicine Berlin in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany
| | - Enno Klussmann
- Max Delbrück Center for Molecular Medicine Berlin in the Helmholtz Association (MDC), Robert-Rössle-Straße 10, 13125 Berlin, Germany; DZHK, German Centre for Cardiovascular Research, Oudenarder Straße 16, 13347 Berlin, Germany.
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46
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Calejo AI, Taskén K. Targeting protein-protein interactions in complexes organized by A kinase anchoring proteins. Front Pharmacol 2015; 6:192. [PMID: 26441649 PMCID: PMC4562273 DOI: 10.3389/fphar.2015.00192] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/24/2015] [Indexed: 01/06/2023] Open
Abstract
Cyclic AMP is a ubiquitous intracellular second messenger involved in the regulation of a wide variety of cellular processes, a majority of which act through the cAMP – protein kinase A (PKA) signaling pathway and involve PKA phosphorylation of specific substrates. PKA phosphorylation events are typically spatially restricted and temporally well controlled. A-kinase anchoring proteins (AKAPs) directly bind PKA and recruit it to specific subcellular loci targeting the kinase activity toward particular substrates, and thereby provide discrete spatiotemporal control of downstream phosphorylation events. AKAPs also scaffold other signaling molecules into multi-protein complexes that function as crossroads between different signaling pathways. Targeting AKAP coordinated protein complexes with high-affinity peptidomimetics or small molecules to tease apart distinct protein–protein interactions (PPIs) therefore offers important means to disrupt binding of specific components of the complex to better understand the molecular mechanisms involved in the function of individual signalosomes and their pathophysiological role. Furthermore, development of novel classes of small molecules involved in displacement of AKAP-bound signal molecules is now emerging. Here, we will focus on mechanisms for targeting PPI, disruptors that modulate downstream cAMP signaling and their role, especially in the heart.
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Affiliation(s)
- Ana I Calejo
- Biotechnology Centre, University of Oslo Oslo, Norway ; Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership, University of Oslo and Oslo University Hospital Oslo, Norway
| | - Kjetil Taskén
- Biotechnology Centre, University of Oslo Oslo, Norway ; Centre for Molecular Medicine Norway, Nordic European Molecular Biology Laboratory Partnership, University of Oslo and Oslo University Hospital Oslo, Norway
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47
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Rinaldi L, Sepe M, Donne RD, Feliciello A. A dynamic interface between ubiquitylation and cAMP signaling. Front Pharmacol 2015; 6:177. [PMID: 26388770 PMCID: PMC4559665 DOI: 10.3389/fphar.2015.00177] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 08/06/2015] [Indexed: 01/01/2023] Open
Abstract
Phosphorylation waves drive the propagation of signals generated in response to hormones and growth factors in target cells. cAMP is an ancient second messenger implicated in key biological functions. In mammals, most of the effects elicited by cAMP are mediated by protein kinase A (PKA). Activation of the kinase by cAMP results in the phosphorylation of a variety of cellular substrates, leading to differentiation, proliferation, survival, metabolism. The identification of scaffold proteins, namely A-Kinase Anchor proteins (AKAPs), that localize PKA in specific cellular districts, provided critical cues for our understanding of the role played by cAMP in cell biology. Multivalent complexes are assembled by AKAPs and include signaling enzymes, mRNAs, adapter molecules, receptors and ion channels. A novel development derived from the molecular analysis of these complexes nucleated by AKAPs is represented by the presence of components of the ubiquitin-proteasome system (UPS). More to it, the AKAP complex can be regulated by the UPS, eliciting relevant effects on downstream cAMP signals. This represents a novel, yet previously unpredicted interface between compartmentalized signaling and the UPS. We anticipate that impairment of these regulatory mechanisms could promote cell dysfunction and disease. Here, we will focus on the reciprocal regulation between cAMP signaling and UPS, and its relevance to human degenerative and proliferative disorders.
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Affiliation(s)
- Laura Rinaldi
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, University of Naples Federico II , Naples, Italy
| | - Maria Sepe
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, University of Naples Federico II , Naples, Italy
| | - Rossella Delle Donne
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, University of Naples Federico II , Naples, Italy
| | - Antonio Feliciello
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, University of Naples Federico II , Naples, Italy
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48
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Abstract
Cell division relies on coordinated regulation of the cell cycle. A process including a well-defined series of strictly regulated molecular mechanisms involving cyclin-dependent kinases, retinoblastoma protein, and polo-like kinases. Dysfunctions in cell cycle regulation are associated with disease such as cancer, diabetes, and neurodegeneration. Compartmentalization of cellular signaling is a common strategy used to ensure the accuracy and efficiency of cellular responses. Compartmentalization of intracellular signaling is maintained by scaffolding proteins, such as A-kinase anchoring proteins (AKAPs). AKAPs are characterized by their ability to anchor the regulatory subunits of protein kinase A (PKA), and thereby achieve guidance to different cellular locations via various targeting domains. Next to PKA, AKAPs also associate with several other signaling elements including receptors, ion channels, protein kinases, phosphatases, small GTPases, and phosphodiesterases. Taking the amount of possible AKAP signaling complexes and their diverse localization into account, it is rational to believe that such AKAP-based complexes regulate several critical cellular events of the cell cycle. In fact, several AKAPs are assigned as tumor suppressors due to their vital roles in cell cycle regulation. Here, we first briefly discuss the most important players of cell cycle progression. After that, we will review our recent knowledge of AKAPs linked to the regulation and progression of the cell cycle, with special focus on AKAP12, AKAP8, and Ezrin. At last, we will discuss this specific AKAP subset in relation to diseases with focus on a diverse subset of cancer.
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Affiliation(s)
- B Han
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands. .,Groningen Research Institute for Asthma and COPD, GRIAC, Groningen, The Netherlands.
| | - W J Poppinga
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.,Groningen Research Institute for Asthma and COPD, GRIAC, Groningen, The Netherlands
| | - M Schmidt
- Department of Molecular Pharmacology, University of Groningen, Groningen, The Netherlands.,Groningen Research Institute for Asthma and COPD, GRIAC, Groningen, The Netherlands
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49
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Wang Y, Ho TG, Franz E, Hermann JS, Smith FD, Hehnly H, Esseltine JL, Hanold LE, Murph MM, Bertinetti D, Scott JD, Herberg FW, Kennedy EJ. PKA-type I selective constrained peptide disruptors of AKAP complexes. ACS Chem Biol 2015; 10:1502-10. [PMID: 25765284 DOI: 10.1021/acschembio.5b00009] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A-Kinase Anchoring Proteins (AKAPs) coordinate complex signaling events by serving as spatiotemporal modulators of cAMP-dependent protein kinase activity in cells. Although AKAPs organize a plethora of diverse pathways, their cellular roles are often elusive due to the dynamic nature of these signaling complexes. AKAPs can interact with the type I or type II PKA holoenzymes by virtue of high-affinity interactions with the R-subunits. As a means to delineate AKAP-mediated PKA signaling in cells, we sought to develop isoform-selective disruptors of AKAP signaling. Here, we report the development of conformationally constrained peptides named RI-STapled Anchoring Disruptors (RI-STADs) that target the docking/dimerization domain of the type 1 regulatory subunit of PKA. These high-affinity peptides are isoform-selective for the RI isoforms, can outcompete binding by the classical AKAP disruptor Ht31, and can selectively displace RIα, but not RIIα, from binding the dual-specific AKAP149 complex. Importantly, these peptides are cell-permeable and disrupt Type I PKA-mediated phosphorylation events in the context of live cells. Hence, RI-STAD peptides are versatile cellular tools to selectively probe anchored type I PKA signaling events.
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Affiliation(s)
- Yuxiao Wang
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Tienhuei G. Ho
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Eugen Franz
- Department
of Biochemistry, University of Kassel, 34132 Kassel, Germany
| | | | - F. Donelson Smith
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Heidi Hehnly
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Jessica L. Esseltine
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Laura E. Hanold
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Mandi M. Murph
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | | | - John D. Scott
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | | | - Eileen J. Kennedy
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
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Neurochondrin is an atypical RIIα-specific A-kinase anchoring protein. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1667-75. [PMID: 25916936 DOI: 10.1016/j.bbapap.2015.04.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/13/2015] [Accepted: 04/15/2015] [Indexed: 12/25/2022]
Abstract
Protein kinase activity is regulated not only by direct strategies affecting activity but also by spatial and temporal regulatory mechanisms. Kinase signaling pathways are coordinated by scaffolding proteins that orchestrate the assembly of multi-protein complexes. One family of such scaffolding proteins are the A-kinase anchoring proteins (AKAPs). AKAPs share the commonality of binding cAMP-dependent protein kinase (PKA). In addition, they bind further signaling proteins and kinase substrates and tether such multi-protein complexes to subcellular locations. The A-kinase binding (AKB) domain of AKAPs typically contains a conserved helical motif that interacts directly with the dimerization/docking (D/D) domain of the regulatory subunits of PKA. Based on a pull-down proteomics approach, we identified neurochondrin (neurite-outgrowth promoting protein) as a previously unidentified AKAP. Here, we show that neurochondrin interacts directly with PKA through a novel mechanism that involves two distinct binding regions. In addition, we demonstrate that neurochondrin has strong isoform selectivity towards the RIIα subunit of PKA with nanomolar affinity. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases.
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