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Simmons SC, Flerlage WJ, Langlois LD, Shepard RD, Bouslog C, Thomas EH, Gouty KM, Sanderson JL, Gouty S, Cox BM, Dell'Acqua ML, Nugent FS. AKAP150-anchored PKA regulates synaptic transmission and plasticity, neuronal excitability and CRF neuromodulation in the mouse lateral habenula. Commun Biol 2024; 7:345. [PMID: 38509283 PMCID: PMC10954712 DOI: 10.1038/s42003-024-06041-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/08/2024] [Indexed: 03/22/2024] Open
Abstract
The scaffolding A-kinase anchoring protein 150 (AKAP150) is critically involved in kinase and phosphatase regulation of synaptic transmission/plasticity, and neuronal excitability. Emerging evidence also suggests that AKAP150 signaling may play a key role in brain's processing of rewarding/aversive experiences, however its role in the lateral habenula (LHb, as an important brain reward circuitry) is completely unknown. Using whole cell patch clamp recordings in LHb of male wildtype and ΔPKA knockin mice (with deficiency in AKAP-anchoring of PKA), here we show that the genetic disruption of PKA anchoring to AKAP150 significantly reduces AMPA receptor-mediated glutamatergic transmission and prevents the induction of presynaptic endocannabinoid-mediated long-term depression in LHb neurons. Moreover, ΔPKA mutation potentiates GABAA receptor-mediated inhibitory transmission while increasing LHb intrinsic excitability through suppression of medium afterhyperpolarizations. ΔPKA mutation-induced suppression of medium afterhyperpolarizations also blunts the synaptic and neuroexcitatory actions of the stress neuromodulator, corticotropin releasing factor (CRF), in mouse LHb. Altogether, our data suggest that AKAP150 complex signaling plays a critical role in regulation of AMPA and GABAA receptor synaptic strength, glutamatergic plasticity and CRF neuromodulation possibly through AMPA receptor and potassium channel trafficking and endocannabinoid signaling within the LHb.
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Affiliation(s)
- Sarah C Simmons
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - William J Flerlage
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Ludovic D Langlois
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Ryan D Shepard
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Christopher Bouslog
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Emily H Thomas
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Kaitlyn M Gouty
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Jennifer L Sanderson
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Shawn Gouty
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Brian M Cox
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, 80045, USA.
| | - Fereshteh S Nugent
- Uniformed Services University of the Health Sciences, Department of Pharmacology and Molecular Therapeutics, Bethesda, MD, 20814, USA.
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2
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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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3
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Amaya-Rodriguez CA, Carvajal-Zamorano K, Bustos D, Alegría-Arcos M, Castillo K. A journey from molecule to physiology and in silico tools for drug discovery targeting the transient receptor potential vanilloid type 1 (TRPV1) channel. Front Pharmacol 2024; 14:1251061. [PMID: 38328578 PMCID: PMC10847257 DOI: 10.3389/fphar.2023.1251061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 12/14/2023] [Indexed: 02/09/2024] Open
Abstract
The heat and capsaicin receptor TRPV1 channel is widely expressed in nerve terminals of dorsal root ganglia (DRGs) and trigeminal ganglia innervating the body and face, respectively, as well as in other tissues and organs including central nervous system. The TRPV1 channel is a versatile receptor that detects harmful heat, pain, and various internal and external ligands. Hence, it operates as a polymodal sensory channel. Many pathological conditions including neuroinflammation, cancer, psychiatric disorders, and pathological pain, are linked to the abnormal functioning of the TRPV1 in peripheral tissues. Intense biomedical research is underway to discover compounds that can modulate the channel and provide pain relief. The molecular mechanisms underlying temperature sensing remain largely unknown, although they are closely linked to pain transduction. Prolonged exposure to capsaicin generates analgesia, hence numerous capsaicin analogs have been developed to discover efficient analgesics for pain relief. The emergence of in silico tools offered significant techniques for molecular modeling and machine learning algorithms to indentify druggable sites in the channel and for repositioning of current drugs aimed at TRPV1. Here we recapitulate the physiological and pathophysiological functions of the TRPV1 channel, including structural models obtained through cryo-EM, pharmacological compounds tested on TRPV1, and the in silico tools for drug discovery and repositioning.
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Affiliation(s)
- Cesar A. Amaya-Rodriguez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Departamento de Fisiología y Comportamiento Animal, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá, Ciudad de Panamá, Panamá
| | - Karina Carvajal-Zamorano
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Daniel Bustos
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado Universidad Católica del Maule, Talca, Chile
- Laboratorio de Bioinformática y Química Computacional, Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca, Chile
| | - Melissa Alegría-Arcos
- Núcleo de Investigación en Data Science, Facultad de Ingeniería y Negocios, Universidad de las Américas, Santiago, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado Universidad Católica del Maule, Talca, Chile
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Collins KB, Scott JD. Phosphorylation, compartmentalization, and cardiac function. IUBMB Life 2023; 75:353-369. [PMID: 36177749 PMCID: PMC10049969 DOI: 10.1002/iub.2677] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 09/15/2022] [Indexed: 11/08/2022]
Abstract
Protein phosphorylation is a fundamental element of cell signaling. First discovered as a biochemical switch in glycogen metabolism, we now know that this posttranslational modification permeates all aspects of cellular behavior. In humans, over 540 protein kinases attach phosphate to acceptor amino acids, whereas around 160 phosphoprotein phosphatases remove phosphate to terminate signaling. Aberrant phosphorylation underlies disease, and kinase inhibitor drugs are increasingly used clinically as targeted therapies. Specificity in protein phosphorylation is achieved in part because kinases and phosphatases are spatially organized inside cells. A prototypic example is compartmentalization of the cyclic adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase A through association with A-kinase anchoring proteins. This configuration creates autonomous signaling islands where the anchored kinase is constrained in proximity to activators, effectors, and selected substates. This article primarily focuses on A kinase anchoring protein (AKAP) signaling in the heart with an emphasis on anchoring proteins that spatiotemporally coordinate excitation-contraction coupling and hypertrophic responses.
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Affiliation(s)
- Kerrie B. Collins
- Department of Pharmacology, University of Washington, School of Medicine, 1959 NE Pacific Ave, Seattle WA, 98195
| | - John D. Scott
- Department of Pharmacology, University of Washington, School of Medicine, 1959 NE Pacific Ave, Seattle WA, 98195
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5
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Zhang Y, Jeske NA. A-kinase anchoring protein 79/150 coordinates α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor sensitization in sensory neurons. Mol Pain 2023; 19:17448069231222406. [PMID: 38073552 PMCID: PMC10722943 DOI: 10.1177/17448069231222406] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/30/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023] Open
Abstract
Changes in sensory afferent activity contribute to the transition from acute to chronic pain. However, it is unlikely that a single sensory receptor is entirely responsible for persistent pain. It is more probable that extended changes to multiple receptor proteins expressed by afferent neurons support persistent pain. A-Kinase Anchoring Protein 79/150 (AKAP) is an intracellular scaffolding protein expressed in sensory neurons that spatially and temporally coordinates signaling events. Since AKAP scaffolds biochemical modifications of multiple TRP receptors linked to pain phenotypes, we probed for other ionotropic receptors that may be mediated by AKAP and contribute to persistent pain. Here, we identify a role for AKAP modulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid Receptor (AMPA-R) functionality in sensory neurons. Pharmacological manipulation of distinct AMPA-R subunits significantly reduces persistent mechanical hypersensitivity observed during hyperalgesic priming. Stimulation of both protein kinases C and A (PKC, PKA, respectively) modulate AMPA-R subunit GluR1 and GluR2 phosphorylation and surface expression in an AKAP-dependent manner in primary cultures of DRG neurons. Furthermore, AKAP knock out reduces sensitized AMPA-R responsivity in DRG neurons. Collectively, these data indicate that AKAP scaffolds AMPA-R subunit organization in DRG neurons that may contribute to the transition from acute-to-chronic pain.
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Affiliation(s)
- Yan Zhang
- Department of Oral and Maxillofacial Surgery, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Nathaniel A Jeske
- Department of Oral and Maxillofacial Surgery, University of Texas Health San Antonio, San Antonio, TX, USA
- Department of Pharmacology, University of Texas Health San Antonio, San Antonio, TX, USA
- Department of Physiology, University of Texas Health San Antonio, San Antonio, TX, USA
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6
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Emerging mechanisms involving brain Kv7 channel in the pathogenesis of hypertension. Biochem Pharmacol 2022; 206:115318. [PMID: 36283445 DOI: 10.1016/j.bcp.2022.115318] [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: 08/24/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022]
Abstract
Hypertension is a prevalent health problem inducing many organ damages. The pathogenesis of hypertension involves a complex integration of different organ systems including the brain. The elevated sympathetic nerve activity is closely related to the etiology of hypertension. Ion channels are critical regulators of neuronal excitability. Several mechanisms have been proposed to contribute to hypothalamic-driven elevated sympathetic activity, including altered ion channel function. Recent findings indicate one of the voltage-gated potassium channels, Kv7 channels (M channels), plays a vital role in regulating cardiovascular-related neurons activity, and the expression of Kv7 channels is downregulated in hypertension. This review highlights recent findings that the Kv7 channels in the brain, blood vessels, and kidneys are emerging targets involved in the pathogenesis of hypertension, suggesting new therapeutic targets for treating drug-resistant, neurogenic hypertension.
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7
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Chen X, Crosby KC, Feng A, Purkey AM, Aronova MA, Winters CA, Crocker VT, Leapman RD, Reese TS, Dell’Acqua ML. Palmitoylation of A-kinase anchoring protein 79/150 modulates its nanoscale organization, trafficking, and mobility in postsynaptic spines. Front Synaptic Neurosci 2022; 14:1004154. [PMID: 36186623 PMCID: PMC9521714 DOI: 10.3389/fnsyn.2022.1004154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
A-kinase anchoring protein 79-human/150-rodent (AKAP79/150) organizes signaling proteins to control synaptic plasticity. AKAP79/150 associates with the plasma membrane and endosomes through its N-terminal domain that contains three polybasic regions and two Cys residues that are reversibly palmitoylated. Mutations abolishing palmitoylation (AKAP79/150 CS) reduce its endosomal localization and association with the postsynaptic density (PSD). Here we combined advanced light and electron microscopy (EM) to characterize the effects of AKAP79/150 palmitoylation on its postsynaptic nanoscale organization, trafficking, and mobility in hippocampal neurons. Immunogold EM revealed prominent extrasynaptic membrane AKAP150 labeling with less labeling at the PSD. The label was at greater distances from the spine membrane for AKAP150 CS than WT in the PSD but not in extra-synaptic locations. Immunogold EM of GFP-tagged AKAP79 WT showed that AKAP79 adopts a vertical, extended conformation at the PSD with its N-terminus at the membrane, in contrast to extrasynaptic locations where it adopts a compact or open configurations of its N- and C-termini with parallel orientation to the membrane. In contrast, GFP-tagged AKAP79 CS was displaced from the PSD coincident with disruption of its vertical orientation, while proximity and orientation with respect to the extra-synaptic membrane was less impacted. Single-molecule localization microscopy (SMLM) revealed a heterogeneous distribution of AKAP150 with distinct high-density, nano-scale regions (HDRs) overlapping the PSD but more prominently located in the extrasynaptic membrane for WT and the CS mutant. Thick section scanning transmission electron microscopy (STEM) tomography revealed AKAP150 immunogold clusters similar in size to HDRs seen by SMLM and more AKAP150 labeled endosomes in spines for WT than for CS, consistent with the requirement for AKAP palmitoylation in endosomal trafficking. Hidden Markov modeling of single molecule tracking data revealed a bound/immobile fraction and two mobile fractions for AKAP79 in spines, with the CS mutant having shorter dwell times and faster transition rates between states than WT, suggesting that palmitoylation stabilizes individual AKAP molecules in various spine subpopulations. These data demonstrate that palmitoylation fine tunes the nanoscale localization, mobility, and trafficking of AKAP79/150 in dendritic spines, which might have profound effects on its regulation of synaptic plasticity.
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Affiliation(s)
- Xiaobing Chen
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
- *Correspondence: Xiaobing Chen,
| | - Kevin C. Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Austin Feng
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Alicia M. Purkey
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
| | - Maria A. Aronova
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Christine A. Winters
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Virginia T. Crocker
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Richard D. Leapman
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Thomas S. Reese
- Laboratory of Neurobiology, National Institute of Neurological Diseases and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, United States
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
- Mark L. Dell’Acqua,
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Wu S, Li L, Wu X, Wong CKC, Sun F, Cheng CY. AKAP9 supports spermatogenesis through its effects on microtubule and actin cytoskeletons in the rat testis. FASEB J 2021; 35:e21925. [PMID: 34569663 DOI: 10.1096/fj.202100960r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/16/2021] [Accepted: 08/31/2021] [Indexed: 12/29/2022]
Abstract
In mammalian testes, extensive remodeling of the microtubule (MT) and actin cytoskeletons takes place in Sertoli cells across the seminiferous epithelium to support spermatogenesis. However, the mechanism(s) involving regulatory and signaling proteins remains poorly understood. Herein, A-kinase anchoring protein 9 (AKAP9, a member of the AKAP multivalent scaffold protein family) was shown to be one of these crucial regulatory proteins in the rat testis. Earlier studies have shown that AKAP9 serves as a signaling platform by recruiting multiple signaling and regulatory proteins to create a large protein complex that binds to the Golgi and centrosome to facilitate the assembly of the MT-nucleating γ-tubulin ring complex to initiate MT polymerization. We further expanded our earlier studies based on a Sertoli cell-specific AKAP9 knockout mouse model to probe the function of AKAP9 by using the techniques of immunofluorescence analysis, RNA interference (RNAi), and biochemical assays on an in vitro primary Sertoli cell culture model, and an adjudin-based animal model. AKAP9 robustly expressed across the seminiferous epithelium in adult rat testes, colocalizing with MT-based tracks, and laid perpendicular across the seminiferous epithelium, and prominently expressed at the Sertoli-spermatid cell-cell anchoring junction (called apical ectoplasmic specialization [ES]) and at the Sertoli cell-cell interface (called basal ES, which together with tight junction [TJ] created the blood-testis barrier [BTB]) stage specifically. AKAP9 knockdown in Sertoli cells by RNAi was found to perturb the TJ-permeability barrier through disruptive changes in the distribution of BTB-associated proteins at the Sertoli cell cortical zone, mediated by a considerable loss of ability to induce both MT polymerization and actin filament bundling. A considerable decline in AKAP9 expression and a disruptive distribution of AKAP9 across the seminiferous tubules was also noted during adjudin-induced germ cell (GC) exfoliation in this animal model, illustrating AKAP9 is essential to maintain the homeostasis of cytoskeletons to maintain Sertoli and GC adhesion in the testis.
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Affiliation(s)
- Siwen Wu
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, USA
| | - Linxi Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xiaolong Wu
- Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, China
| | - Chris K C Wong
- Department of Biology, Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Kowloon, China
| | - Fei Sun
- Institute of Reproductive Medicine, Nantong University School of Medicine, Nantong, China
| | - C Yan Cheng
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, China.,The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, New York, New York, USA
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9
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Gopalan J, Omar MH, Roy A, Cruz NM, Falcone J, Jones KN, Forbush KA, Himmelfarb J, Freedman BS, Scott JD. Targeting an anchored phosphatase-deacetylase unit restores renal ciliary homeostasis. eLife 2021; 10:e67828. [PMID: 34250905 PMCID: PMC8291974 DOI: 10.7554/elife.67828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/11/2021] [Indexed: 11/13/2022] Open
Abstract
Pathophysiological defects in water homeostasis can lead to renal failure. Likewise, common genetic disorders associated with abnormal cytoskeletal dynamics in the kidney collecting ducts and perturbed calcium and cAMP signaling in the ciliary compartment contribute to chronic kidney failure. We show that collecting ducts in mice lacking the A-Kinase anchoring protein AKAP220 exhibit enhanced development of primary cilia. Mechanistic studies reveal that AKAP220-associated protein phosphatase 1 (PP1) mediates this phenotype by promoting changes in the stability of histone deacetylase 6 (HDAC6) with concomitant defects in actin dynamics. This proceeds through a previously unrecognized adaptor function for PP1 as all ciliogenesis and cytoskeletal phenotypes are recapitulated in mIMCD3 knock-in cells expressing a phosphatase-targeting defective AKAP220-ΔPP1 mutant. Pharmacological blocking of local HDAC6 activity alters cilia development and reduces cystogenesis in kidney-on-chip and organoid models. These findings identify the AKAP220-PPI-HDAC6 pathway as a key effector in primary cilia development.
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Affiliation(s)
- Janani Gopalan
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Mitchell H Omar
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Ankita Roy
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Nelly M Cruz
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - Jerome Falcone
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | - Kiana N Jones
- Department of Pharmacology, University of WashingtonSeattleUnited States
| | | | - Jonathan Himmelfarb
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
| | - Benjamin S Freedman
- Kidney Research Institute, Division of Nephrology, Department of Laboratory Medicine and Pathology, University of WashingtonSeattleUnited States
- Institute for Stem Cell and Regenerative Medicine, University of WashingtonSeattleUnited States
| | - John D Scott
- Department of Pharmacology, University of WashingtonSeattleUnited States
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10
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Kinase-anchoring proteins in ciliary signal transduction. Biochem J 2021; 478:1617-1629. [PMID: 33909027 DOI: 10.1042/bcj20200869] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/16/2022]
Abstract
Historically, the diffusion of chemical signals through the cell was thought to occur within a cytoplasmic soup bounded by the plasma membrane. This theory was predicated on the notion that all regulatory enzymes are soluble and moved with a Brownian motion. Although enzyme compartmentalization was initially rebuffed by biochemists as a 'last refuge of a scoundrel', signal relay through macromolecular complexes is now accepted as a fundamental tenet of the burgeoning field of spatial biology. A-Kinase anchoring proteins (AKAPs) are prototypic enzyme-organizing elements that position clusters of regulatory proteins at defined subcellular locations. In parallel, the primary cilium has gained recognition as a subcellular mechanosensory organelle that amplifies second messenger signals pertaining to metazoan development. This article highlights advances in our understanding of AKAP signaling within the primary cilium and how defective ciliary function contributes to an increasing number of diseases known as ciliopathies.
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11
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AKAP79/150 coordinates leptin-induced PKA signaling to regulate K ATP channel trafficking in pancreatic β-cells. J Biol Chem 2021; 296:100442. [PMID: 33617875 PMCID: PMC8010710 DOI: 10.1016/j.jbc.2021.100442] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/11/2021] [Accepted: 02/17/2021] [Indexed: 01/21/2023] Open
Abstract
The adipocyte hormone leptin regulates glucose homeostasis both centrally and peripherally. A key peripheral target is the pancreatic β-cell, which secretes insulin upon glucose stimulation. Leptin is known to suppress glucose-stimulated insulin secretion by promoting trafficking of KATP channels to the β-cell surface, which increases K+ conductance and causes β-cell hyperpolarization. We have previously shown that leptin-induced KATP channel trafficking requires protein kinase A (PKA)-dependent actin remodeling. However, whether PKA is a downstream effector of leptin signaling or PKA plays a permissive role is unknown. Using FRET-based reporters of PKA activity, we show that leptin increases PKA activity at the cell membrane and that this effect is dependent on N-methyl-D-aspartate receptors, CaMKKβ, and AMPK, which are known to be involved in the leptin signaling pathway. Genetic knockdown and rescue experiments reveal that the increased PKA activity upon leptin stimulation requires the membrane-targeted PKA-anchoring protein AKAP79/150, indicating that PKA activated by leptin is anchored to AKAP79/150. Interestingly, disrupting protein phosphatase 2B (PP2B) anchoring to AKAP79/150, known to elevate basal PKA signaling, leads to increased surface KATP channels even in the absence of leptin stimulation. Our findings uncover a novel role of AKAP79/150 in coordinating leptin and PKA signaling to regulate KATP channel trafficking in β-cells, hence insulin secretion. The study further advances our knowledge of the downstream signaling events that may be targeted to restore insulin secretion regulation in β-cells defective in leptin signaling, such as those from obese individuals with type 2 diabetes.
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12
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Abstract
Kv7.1-Kv7.5 (KCNQ1-5) K+ channels are voltage-gated K+ channels with major roles in neurons, muscle cells and epithelia where they underlie physiologically important K+ currents, such as neuronal M current and cardiac IKs. Specific biophysical properties of Kv7 channels make them particularly well placed to control the activity of excitable cells. Indeed, these channels often work as 'excitability breaks' and are targeted by various hormones and modulators to regulate cellular activity outputs. Genetic deficiencies in all five KCNQ genes result in human excitability disorders, including epilepsy, arrhythmias, deafness and some others. Not surprisingly, this channel family attracts considerable attention as potential drug targets. Here we will review biophysical properties and tissue expression profile of Kv7 channels, discuss recent advances in the understanding of their structure as well as their role in various neurological, cardiovascular and other diseases and pathologies. We will also consider a scope for therapeutic targeting of Kv7 channels for treatment of the above health conditions.
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13
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Tenner B, Getz M, Ross B, Ohadi D, Bohrer CH, Greenwald E, Mehta S, Xiao J, Rangamani P, Zhang J. Spatially compartmentalized phase regulation of a Ca 2+-cAMP-PKA oscillatory circuit. eLife 2020; 9:e55013. [PMID: 33201801 PMCID: PMC7671691 DOI: 10.7554/elife.55013] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 10/07/2020] [Indexed: 01/31/2023] Open
Abstract
Signaling networks are spatiotemporally organized to sense diverse inputs, process information, and carry out specific cellular tasks. In β cells, Ca2+, cyclic adenosine monophosphate (cAMP), and Protein Kinase A (PKA) exist in an oscillatory circuit characterized by a high degree of feedback. Here, we describe a mode of regulation within this circuit involving a spatial dependence of the relative phase between cAMP, PKA, and Ca2+. We show that in mouse MIN6 β cells, nanodomain clustering of Ca2+-sensitive adenylyl cyclases (ACs) drives oscillations of local cAMP levels to be precisely in-phase with Ca2+ oscillations, whereas Ca2+-sensitive phosphodiesterases maintain out-of-phase oscillations outside of the nanodomain. Disruption of this precise phase relationship perturbs Ca2+ oscillations, suggesting the relative phase within an oscillatory circuit can encode specific functional information. This work unveils a novel mechanism of cAMP compartmentation utilized for localized tuning of an oscillatory circuit and has broad implications for the spatiotemporal regulation of signaling networks.
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Affiliation(s)
- Brian Tenner
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Pharmacology, University of California, San DiegoLa JollaUnited States
| | - Michael Getz
- Chemical Engineering Graduate Program, University of California, San DiegoLa JollaUnited States
| | - Brian Ross
- Department of Pharmacology, University of California, San DiegoLa JollaUnited States
| | - Donya Ohadi
- Department of Mechanical and Aerospace Engineering, University of California, San DiegoLa JollaUnited States
| | - Christopher H Bohrer
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Eric Greenwald
- Department of Pharmacology, University of California, San DiegoLa JollaUnited States
| | - Sohum Mehta
- Department of Pharmacology, University of California, San DiegoLa JollaUnited States
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Padmini Rangamani
- Chemical Engineering Graduate Program, University of California, San DiegoLa JollaUnited States
- Department of Mechanical and Aerospace Engineering, University of California, San DiegoLa JollaUnited States
| | - Jin Zhang
- Department of Pharmacology, University of California, San DiegoLa JollaUnited States
- Department of Chemistry and Biochemistry, University of California, San DiegoLa JollaUnited States
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14
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Omar MH, Scott JD. AKAP Signaling Islands: Venues for Precision Pharmacology. Trends Pharmacol Sci 2020; 41:933-946. [PMID: 33082006 DOI: 10.1016/j.tips.2020.09.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/19/2022]
Abstract
Regulatory enzymes often have different roles in distinct subcellular compartments. Yet, most drugs indiscriminately saturate the cell. Thus, subcellular drug-delivery holds promise as a means to reduce off-target pharmacological effects. A-kinase anchoring proteins (AKAPs) sequester combinations of signaling enzymes within subcellular microdomains. Targeting drugs to these 'signaling islands' offers an opportunity for more precise delivery of therapeutics. Here, we review mechanisms that bestow protein kinase A (PKA) versatility inside the cell, appraise recent advances in exploiting AKAPs as platforms for precision pharmacology, and explore the impact of methodological innovations on AKAP research.
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Affiliation(s)
- Mitchell H Omar
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA.
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15
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Cytosolic and intra-organellar Ca2+ oscillations: mechanisms and function. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Bucko PJ, Scott JD. Drugs That Regulate Local Cell Signaling: AKAP Targeting as a Therapeutic Option. Annu Rev Pharmacol Toxicol 2020; 61:361-379. [PMID: 32628872 DOI: 10.1146/annurev-pharmtox-022420-112134] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells respond to environmental cues by mobilizing signal transduction cascades that engage protein kinases and phosphoprotein phosphatases. Correct organization of these enzymes in space and time enables the efficient and precise transmission of chemical signals. The cyclic AMP-dependent protein kinase A is compartmentalized through its association with A-kinase anchoring proteins (AKAPs). AKAPs are a family of multivalent scaffolds that constrain signaling enzymes and effectors at subcellular locations to drive essential physiological events. More recently, it has been recognized that defective signaling in certain endocrine disorders and cancers proceeds through pathological AKAP complexes. Consequently, pharmacologically targeting these macromolecular complexes unlocks new therapeutic opportunities for a growing number of clinical indications. This review highlights recent findings on AKAP signaling in disease, particularly in certain cancers, and offers an overview of peptides and small molecules that locally regulate AKAP-binding partners.
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Affiliation(s)
- Paula J Bucko
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
| | - John D Scott
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA; ,
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17
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van der Horst J, Greenwood IA, Jepps TA. Cyclic AMP-Dependent Regulation of Kv7 Voltage-Gated Potassium Channels. Front Physiol 2020; 11:727. [PMID: 32695022 PMCID: PMC7338754 DOI: 10.3389/fphys.2020.00727] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/04/2020] [Indexed: 01/08/2023] Open
Abstract
Voltage-gated Kv7 potassium channels, encoded by KCNQ genes, have major physiological impacts cardiac myocytes, neurons, epithelial cells, and smooth muscle cells. Cyclic adenosine monophosphate (cAMP), a well-known intracellular secondary messenger, can activate numerous downstream effector proteins, generating downstream signaling pathways that regulate many functions in cells. A role for cAMP in ion channel regulation has been established, and recent findings show that cAMP signaling plays a role in Kv7 channel regulation. Although cAMP signaling is recognized to regulate Kv7 channels, the precise molecular mechanism behind the cAMP-dependent regulation of Kv7 channels is complex. This review will summarize recent research findings that support the mechanisms of cAMP-dependent regulation of Kv7 channels.
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Affiliation(s)
- Jennifer van der Horst
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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18
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In Vivo Attenuation of M-Current Suppression Impairs Consolidation of Object Recognition Memory. J Neurosci 2020; 40:5847-5856. [PMID: 32554550 DOI: 10.1523/jneurosci.0348-20.2020] [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: 02/13/2020] [Revised: 05/08/2020] [Accepted: 06/06/2020] [Indexed: 11/21/2022] Open
Abstract
The M-current is a low voltage-activated potassium current generated by neuronal Kv7 channels. A prominent role of the M-current is to a create transient increase of neuronal excitability in response to neurotransmitters through the suppression of this current. Accordingly, M-current suppression is assumed to be involved in higher brain functions including learning and memory. However, there is little evidence supporting such a role to date. To address this gap, we examined behavioral tasks to assess learning and memory in homozygous Kv7.2 knock-in mice, Kv7.2(S559A), which show reduced M-current suppression while maintaining a normal basal M-current activity in neurons. We found that Kv7.2(S559A) mice had normal object location memory and contextual fear memory, but impaired long-term object recognition memory. Furthermore, short-term memory for object recognition was intact in Kv7.2(S559A) mice. The deficit in long-term object recognition memory was restored by the administration of a selective Kv7 channel inhibitor, XE991, when delivered during the memory consolidation phase. Lastly, c-Fos induction 2 h after training in Kv7.2(S559A) mice was normal in the hippocampus, which corresponds to intact object location memory, but was reduced in the perirhinal cortex, which corresponds to impaired long-term object recognition memory. Together, these results support the overall conclusion that M-current suppression is important for memory consolidation of specific types of memories.SIGNIFICANCE STATEMENT Dynamic regulation of neuronal excitation is a fundamental mechanism for information processing in the brain, which is mediated by changes in synaptic transmissions or by changes in ion channel activity. Some neurotransmitters can facilitate action potential firing by suppression of a low voltage-activated potassium current, M-current. We demonstrate that M-current suppression is critical for establishment of long-term object recognition memory, but is not required for establishment of hippocampus-dependent location memory or contextual memory. This study suggests that M-current suppression is important for stable encoding of specific types of memories.
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19
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Hoshi N. M-Current Suppression, Seizures and Lipid Metabolism: A Potential Link Between Neuronal Kv7 Channel Regulation and Dietary Therapies for Epilepsy. Front Physiol 2020; 11:513. [PMID: 32523549 PMCID: PMC7261926 DOI: 10.3389/fphys.2020.00513] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 04/27/2020] [Indexed: 12/28/2022] Open
Abstract
Neuronal Kv7 channel generates a low voltage-activated potassium current known as the M-current. The M-current can be suppressed by various neurotransmitters that activate Gq-coupled receptors. Because the M-current stabilizes membrane potential at the resting membrane potential, its suppression transiently increase neuronal excitability. However, its physiological and pathological roles in vivo is not well understood to date. This review summarizes the molecular mechanism underlying M-current suppression, and why it remained elusive for many years. I also summarize how regulation of neuronal Kv7 channel contributes to anti-seizure action of valproic acid through inhibition of palmitoylation of a Kv7 channel binding protein, and discuss about a potential link with anti-seizure mechanisms of medium chain triglyceride ketogenic diet.
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Affiliation(s)
- Naoto Hoshi
- Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, United States.,Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, United States
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20
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Wild AR, Sinnen BL, Dittmer PJ, Kennedy MJ, Sather WA, Dell'Acqua ML. Synapse-to-Nucleus Communication through NFAT Is Mediated by L-type Ca 2+ Channel Ca 2+ Spike Propagation to the Soma. Cell Rep 2020; 26:3537-3550.e4. [PMID: 30917310 PMCID: PMC6521872 DOI: 10.1016/j.celrep.2019.03.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 12/11/2018] [Accepted: 02/28/2019] [Indexed: 12/21/2022] Open
Abstract
Long-term information storage in the brain requires continual modification of the neuronal transcriptome. Synaptic inputs located hundreds of micrometers from the nucleus can regulate gene transcription, requiring high-fidelity, long-range signaling from synapses in dendrites to the nucleus in the cell soma. Here, we describe a synapse-to-nucleus signaling mechanism for the activity-dependent transcription factor NFAT. NMDA receptors activated on distal dendrites were found to initiate L-type Ca2+ channel (LTCC) spikes that quickly propagated the length of the dendrite to the soma. Surprisingly, LTCC propagation did not require voltage-gated Na+ channels or back-propagating action potentials. NFAT nuclear recruitment and transcriptional activation only occurred when LTCC spikes invaded the somatic compartment, and the degree of NFAT activation correlated with the number of somatic LTCC Ca2+ spikes. Together, these data support a model for synapse to nucleus communication where NFAT integrates somatic LTCC Ca2+ spikes to alter transcription during periods of heightened neuronal activity. Signaling from synapse to nucleus can alter transcription and consolidate long-term changes in neuronal function. Wild et al. uncover a mechanism for rapid long-distance signaling from distal dendrites to the nucleus that utilizes L-type voltage-gated Ca2+ channel Ca2+ spikes to activate the transcription factor NFAT.
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Affiliation(s)
- Angela R Wild
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Brooke L Sinnen
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Philip J Dittmer
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Matthew J Kennedy
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - William A Sather
- 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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21
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Purkey AM, Dell’Acqua ML. Phosphorylation-Dependent Regulation of Ca 2+-Permeable AMPA Receptors During Hippocampal Synaptic Plasticity. Front Synaptic Neurosci 2020; 12:8. [PMID: 32292336 PMCID: PMC7119613 DOI: 10.3389/fnsyn.2020.00008] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/18/2020] [Indexed: 01/28/2023] Open
Abstract
Experience-dependent learning and memory require multiple forms of plasticity at hippocampal and cortical synapses that are regulated by N-methyl-D-aspartate receptors (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type ionotropic glutamate receptors (NMDAR, AMPAR). These plasticity mechanisms include long-term potentiation (LTP) and depression (LTD), which are Hebbian input-specific mechanisms that rapidly increase or decrease AMPAR synaptic strength at specific inputs, and homeostatic plasticity that globally scales-up or -down AMPAR synaptic strength across many or even all inputs. Frequently, these changes in synaptic strength are also accompanied by a change in the subunit composition of AMPARs at the synapse due to the trafficking to and from the synapse of receptors lacking GluA2 subunits. These GluA2-lacking receptors are most often GluA1 homomeric receptors that exhibit higher single-channel conductance and are Ca2+-permeable (CP-AMPAR). This review article will focus on the role of protein phosphorylation in regulation of GluA1 CP-AMPAR recruitment and removal from hippocampal synapses during synaptic plasticity with an emphasis on the crucial role of local signaling by the cAMP-dependent protein kinase (PKA) and the Ca2+calmodulin-dependent protein phosphatase 2B/calcineurin (CaN) that is coordinated by the postsynaptic scaffold protein A-kinase anchoring protein 79/150 (AKAP79/150).
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Affiliation(s)
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
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22
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Abstract
Here, I recount some adventures that I and my colleagues have had over some 60 years since 1957 studying the effects of drugs and neurotransmitters on neuronal excitability and ion channel function, largely, but not exclusively, using sympathetic neurons as test objects. Studies include effects of centrally active drugs on sympathetic transmission; neuronal action and neuroglial uptake of GABA in the ganglia and brain; the action of muscarinic agonists on sympathetic neurons; the action of bradykinin on neuroblastoma-derived cells; and the identification of M-current as a target for muscarinic action, including experiments to determine its distribution, molecular composition, neurotransmitter sensitivity, and intracellular regulation by phospholipids and their hydrolysis products. Techniques used include electrophysiological recording (extracellular, intracellular microelectrode, whole-cell, and single-channel patch-clamp), autoradiography, messenger RNA and complementary DNA expression, antibody injection, antisense knockdown, and membrane-targeted lipidated peptides. I finish with some recollections about my scientific career, funding, and changes in laboratory life and pharmacology research over the past 60 years.
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Affiliation(s)
- David A. Brown
- Departments of Neuroscience, Physiology, and Pharmacology, University College London, London WC1E 6BT, United Kingdom
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23
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Carboplatin Enhances the Activity of Human Transient Receptor Potential Ankyrin 1 through the Cyclic AMP-Protein Kinase A-A-Kinase Anchoring Protein (AKAP) Pathways. Int J Mol Sci 2019; 20:ijms20133271. [PMID: 31277262 PMCID: PMC6651390 DOI: 10.3390/ijms20133271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 02/06/2023] Open
Abstract
Carboplatin, an anticancer drug, often causes chemotherapy-induced peripheral neuropathy (PN). Transient receptor potential ankyrin 1 (TRPA1), a non-selective cation channel, is a polymodal nociceptor expressed in sensory neurons. TRPA1 is not only involved in pain transmission, but also in allodynia or hyperalgesia development. However, the effects of TRPA1 on carboplatin-induced PN is unclear. We revealed that carboplatin induced mechanical allodynia and cold hyperalgesia, and the pains observed in carboplatin-induced PN models were significantly suppressed by the TRPA1 antagonist HC-030031 without a change in the level of TRPA1 protein. In cells expressing human TRPA, carboplatin had no effects on changes in intracellular Ca2+ concentration ([Ca2+]i); however, carboplatin pretreatment enhanced the increase in [Ca2+]i induced by the TRPA1 agonist, allyl isothiocyanate (AITC). These effects were suppressed by an inhibitor of protein kinase A (PKA). The PKA activator forskolin enhanced AITC-induced increase in [Ca2+]i and carboplatin itself increased intracellular cyclic adenosine monophosphate (cAMP) levels. Moreover, inhibition of A-kinase anchoring protein (AKAP) significantly decreased the carboplatin-induced enhancement of [Ca2+]i induced by AITC and improved carboplatin-induced mechanical allodynia and cold hyperalgesia. These results suggested that carboplatin induced mechanical allodynia and cold hyperalgesia by increasing sensitivity to TRPA1 via the cAMP-PKA-AKAP pathway.
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24
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Dittmer PJ, Dell'Acqua ML, Sather WA. Synaptic crosstalk conferred by a zone of differentially regulated Ca 2+ signaling in the dendritic shaft adjoining a potentiated spine. Proc Natl Acad Sci U S A 2019; 116:13611-13620. [PMID: 31209051 PMCID: PMC6613087 DOI: 10.1073/pnas.1902461116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Patterns of postsynaptic activity that induce long-term potentiation of fast excitatory transmission at glutamatergic synapses between hippocampal neurons cause enlargement of the dendritic spine and promote growth in spine endoplasmic reticulum (ER) content. Such postsynaptic activity patterns also impact Ca2+ signaling in the adjoining dendritic shaft, in a zone centered on the spine-shaft junction and extending ∼10-20 µm in either direction along the shaft. Comparing this specialized zone in the shaft with the dendrite in general, plasticity-inducing stimulation of a single spine causes more profound depletion of Ca2+ stores in the ER, a greater degree of interaction between stromal interaction molecule 1 (STIM1) and L-type Ca2+ channels, and thus stronger STIM1 inhibition of these channels. Here we show that the length of this zone along the dendritic axis can be approximately doubled through the neuromodulatory action of β-adrenergic receptors (βARs). The mechanism of βAR enlargement of the zone arises from protein kinase A-mediated enhancement of L-type Ca2+ current, which in turn lowers [Ca2+]ER through ryanodine receptor-dependent Ca2+-induced Ca2+ release and activates STIM1 feedback inhibition of L-type Ca2+ channels. An important function of this dendritic zone is to support crosstalk between spines along its length such that spines neighboring a strongly stimulated spine are enabled to undergo structural plasticity in response to stimulation that would otherwise be subthreshold for spine structural plasticity. This form of crosstalk requires L-type Ca2+ channel current to activate STIM1, and βAR activity extends the range along the shaft over which such spine-to-spine communication can occur.
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Affiliation(s)
- Philip J Dittmer
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - William A Sather
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
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25
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Murphy JG, Crosby KC, Dittmer PJ, Sather WA, Dell'Acqua ML. AKAP79/150 recruits the transcription factor NFAT to regulate signaling to the nucleus by neuronal L-type Ca 2+ channels. Mol Biol Cell 2019; 30:1743-1756. [PMID: 31091162 PMCID: PMC6727748 DOI: 10.1091/mbc.e19-01-0060] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In neurons, regulation of activity-dependent transcription by the nuclear factor of activated T-cells (NFAT) depends upon Ca2+ influx through voltage-gated L-type calcium channels (LTCC) and NFAT translocation to the nucleus following its dephosphorylation by the Ca2+-dependent phosphatase calcineurin (CaN). CaN is recruited to the channel by A-kinase anchoring protein (AKAP) 79/150, which binds to the LTCC C-terminus via a modified leucine-zipper (LZ) interaction. Here we sought to gain new insights into how LTCCs and signaling to NFAT are regulated by this LZ interaction. RNA interference–mediated knockdown of endogenous AKAP150 and replacement with human AKAP79 lacking its C-terminal LZ domain resulted in loss of depolarization-stimulated NFAT signaling in rat hippocampal neurons. However, the LZ mutation had little impact on the AKAP–LTCC interaction or LTCC function, as measured by Förster resonance energy transfer, Ca2+ imaging, and electrophysiological recordings. AKAP79 and NFAT coimmunoprecipitated when coexpressed in heterologous cells, and the LZ mutation disrupted this association. Critically, measurements of NFAT mobility in neurons employing fluorescence recovery after photobleaching and fluorescence correlation spectroscopy provided further evidence for an AKAP79 LZ interaction with NFAT. These findings suggest that the AKAP79/150 LZ motif functions to recruit NFAT to the LTCC signaling complex to promote its activation by AKAP-anchored calcineurin.
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Affiliation(s)
- Jonathan G Murphy
- Eunice Kennedy Shriver Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892.,Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Kevin C Crosby
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Philip J Dittmer
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - William A Sather
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045
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26
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Gq-Coupled Muscarinic Receptor Enhancement of KCNQ2/3 Channels and Activation of TRPC Channels in Multimodal Control of Excitability in Dentate Gyrus Granule Cells. J Neurosci 2018; 39:1566-1587. [PMID: 30593498 DOI: 10.1523/jneurosci.1781-18.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/21/2022] Open
Abstract
KCNQ (Kv7, "M-type") K+ channels and TRPC (transient receptor potential, "canonical") cation channels are coupled to neuronal discharge properties and are regulated via Gq/11-protein-mediated signals. Stimulation of Gq/11-coupled receptors both consumes phosphatidylinositol 4,5-bisphosphate (PIP2) via phosphalipase Cβ hydrolysis and stimulates PIP2 synthesis via rises in Ca2+ i and other signals. Using brain-slice electrophysiology and Ca2+ imaging from male and female mice, we characterized threshold K+ currents in dentate gyrus granule cells (DGGCs) and CA1 pyramidal cells, the effects of Gq/11-coupled muscarinic M1 acetylcholine (M1R) stimulation on M current and on neuronal discharge properties, and elucidated the intracellular signaling mechanisms involved. We observed disparate signaling cascades between DGGCs and CA1 neurons. DGGCs displayed M1R enhancement of M-current, rather than suppression, due to stimulation of PIP2 synthesis, which was paralleled by increased PIP2-gated G-protein coupled inwardly rectifying K+ currents as well. Deficiency of KCNQ2-containing M-channels ablated the M1R-induced enhancement of M-current in DGGCs. Simultaneously, M1R stimulation in DGGCs induced robust increases in [Ca2+]i, mostly due to TRPC currents, consistent with, and contributing to, neuronal depolarization and hyperexcitability. CA1 neurons did not display such multimodal signaling, but rather M current was suppressed by M1R stimulation in these cells, similar to the previously described actions of M1R stimulation on M-current in peripheral ganglia that mostly involves PIP2 depletion. Therefore, these results point to a pleiotropic network of cholinergic signals that direct cell-type-specific, precise control of hippocampal function with strong implications for hyperexcitability and epilepsy.SIGNIFICANCE STATEMENT At the neuronal membrane, protein signaling cascades consisting of ion channels and metabotropic receptors govern the electrical properties and neurotransmission of neuronal networks. Muscarinic acetylcholine receptors are G-protein-coupled metabotropic receptors that control the excitability of neurons through regulating ion channels, intracellular Ca2+ signals, and other second-messenger cascades. We have illuminated previously unknown actions of muscarinic stimulation on the excitability of hippocampal principal neurons that include M channels, TRPC (transient receptor potential, "canonical") cation channels, and powerful regulation of lipid metabolism. Our results show that these signaling pathways, and mechanisms of excitability, are starkly distinct between peripheral ganglia and brain, and even between different principal neurons in the hippocampus.
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27
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Patriarchi T, Buonarati OR, Hell JW. Postsynaptic localization and regulation of AMPA receptors and Cav1.2 by β2 adrenergic receptor/PKA and Ca 2+/CaMKII signaling. EMBO J 2018; 37:e99771. [PMID: 30249603 PMCID: PMC6187224 DOI: 10.15252/embj.201899771] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/25/2018] [Accepted: 08/17/2018] [Indexed: 11/09/2022] Open
Abstract
The synapse transmits, processes, and stores data within its tiny space. Effective and specific signaling requires precise alignment of the relevant components. This review examines current insights into mechanisms of AMPAR and NMDAR localization by PSD-95 and their spatial distribution at postsynaptic sites to illuminate the structural and functional framework of postsynaptic signaling. It subsequently delineates how β2 adrenergic receptor (β2 AR) signaling via adenylyl cyclase and the cAMP-dependent protein kinase PKA is organized within nanodomains. Here, we discuss targeting of β2 AR, adenylyl cyclase, and PKA to defined signaling complexes at postsynaptic sites, i.e., AMPARs and the L-type Ca2+ channel Cav1.2, and other subcellular surface localizations, the role of A kinase anchor proteins, the physiological relevance of the spatial restriction of corresponding signaling, and their interplay with signal transduction by the Ca2+- and calmodulin-dependent kinase CaMKII How localized and specific signaling by cAMP occurs is a central cellular question. The dendritic spine constitutes an ideal paradigm for elucidating the dimensions of spatially restricted signaling because of their small size and defined protein composition.
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MESH Headings
- Animals
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/physiology
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/genetics
- Calcium-Calmodulin-Dependent Protein Kinase Type 2/metabolism
- Cyclic AMP-Dependent Protein Kinases/genetics
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Humans
- Receptors, AMPA/genetics
- Receptors, AMPA/metabolism
- Receptors, Adrenergic, beta-2/genetics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, N-Methyl-D-Aspartate/metabolism
- Synapses/genetics
- Synapses/metabolism
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Affiliation(s)
- Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, CA, USA
- Department of Biochemistry and Molecular Medicine, University of California, Davis, CA, USA
| | | | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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28
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Civciristov S, Ellisdon AM, Suderman R, Pon CK, Evans BA, Kleifeld O, Charlton SJ, Hlavacek WS, Canals M, Halls ML. Preassembled GPCR signaling complexes mediate distinct cellular responses to ultralow ligand concentrations. Sci Signal 2018; 11:eaan1188. [PMID: 30301787 PMCID: PMC7416780 DOI: 10.1126/scisignal.aan1188] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
G protein-coupled receptors (GPCRs) are the largest class of cell surface signaling proteins, participate in nearly all physiological processes, and are the targets of 30% of marketed drugs. Typically, nanomolar to micromolar concentrations of ligand are used to activate GPCRs in experimental systems. We detected GPCR responses to a wide range of ligand concentrations, from attomolar to millimolar, by measuring GPCR-stimulated production of cyclic adenosine monophosphate (cAMP) with high spatial and temporal resolution. Mathematical modeling showed that femtomolar concentrations of ligand activated, on average, 40% of the cells in a population provided that a cell was activated by one to two binding events. Furthermore, activation of the endogenous β2-adrenergic receptor (β2AR) and muscarinic acetylcholine M3 receptor (M3R) by femtomolar concentrations of ligand in cell lines and human cardiac fibroblasts caused sustained increases in nuclear translocation of extracellular signal-regulated kinase (ERK) and cytosolic protein kinase C (PKC) activity, respectively. These responses were spatially and temporally distinct from those that occurred in response to higher concentrations of ligand and resulted in a distinct cellular proteomic profile. This highly sensitive signaling depended on the GPCRs forming preassembled, higher-order signaling complexes at the plasma membrane. Recognizing that GPCRs respond to ultralow concentrations of neurotransmitters and hormones challenges established paradigms of drug action and provides a previously unappreciated aspect of GPCR activation that is quite distinct from that typically observed with higher ligand concentrations.
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Affiliation(s)
- Srgjan Civciristov
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Andrew M Ellisdon
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
| | - Ryan Suderman
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Cindy K Pon
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Bronwyn A Evans
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Oded Kleifeld
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, Haifa 3200003, Israel
| | - Steven J Charlton
- Cell Signalling Research Group, School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
- Excellerate Bioscience Ltd, MediCity, Nottingham NG90 6BH, UK
| | - William S Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Meritxell Canals
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Michelle L Halls
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
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29
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Greene DL, Kosenko A, Hoshi N. Attenuating M-current suppression in vivo by a mutant Kcnq2 gene knock-in reduces seizure burden and prevents status epilepticus-induced neuronal death and epileptogenesis. Epilepsia 2018; 59:1908-1918. [PMID: 30146722 DOI: 10.1111/epi.14541] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 02/06/2023]
Abstract
OBJECTIVES The M-current is a low-threshold voltage-gated potassium current generated by Kv7 subunits that regulates neural excitation. It is important to note that M-current suppression, induced by activation of Gq-coupled neurotransmitter receptors, can dynamically regulate the threshold of action-potential firing and firing frequency. Here we sought to directly examine whether M-current suppression is involved in seizures and epileptogenesis. METHODS Kv7.2 knock-in mice lacking the key protein kinase C (PKC) phosphorylation acceptor site for M-current suppression were generated by introducing an alanine substitution at serine residue 559 of mouse Kv7.2, mKv7.2(S559A). Basic electrophysiologic properties of the M-current between wild-type and Kv7.2(S559A) knock-in mice were analyzed in primary cultured neurons. Homozygous Kv7.2(S559A) knock-in mice were used to evaluate the protective effect of mutant Kv7.2 channel against chemoconvulsant-induced seizures. In addition, pilocarpine-induced neuronal damage and spontaneously recurrent seizures were evaluated after equivalent chemoconvulsant-induced status epilepticus was achieved by coadministration of the M-current-specific channel inhibitor, XE991. RESULT Neurons from Kv7.2(S559A) knock-in mice showed normal basal M-currents. Knock-in mice displayed reduced M-current suppression when challenged by a muscarinic agonist, oxotremorine-M. Kv7.2(S559A) mice were resistant to chemoconvulsant-induced seizures with no mortality. Administration of XE991 transiently exacerbated seizures in knock-in mice equivalent to those of wild-type mice. Valproate, which disrupts neurotransmitter-induced M-current suppression, showed no additional anticonvulsant effect in Kv7.2(S559A) mice. After experiencing status epilepticus, Kv7.2(S559A) knock-in mice did not show seizure-induced cell death or spontaneous recurring seizures. SIGNIFICANCE This study provides evidence that neurotransmitter-induced suppression of M-current generated by Kv7.2-containing channels exacerbates behavioral seizures. In addition, prompt recovery of M-current after status epilepticus prevents subsequent neuronal death and the development of spontaneously recurrent seizures. Therefore, prompt restoration of M-current activity may have a therapeutic benefit for epilepsy.
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Affiliation(s)
- Derek L Greene
- Department of Pharmacology, University of California, Irvine, Irvine, California
| | - Anastasia Kosenko
- Department of Pharmacology, University of California, Irvine, Irvine, California
| | - Naoto Hoshi
- Department of Pharmacology, University of California, Irvine, Irvine, California.,Department of Physiology and Biophysics, University of California, Irvine, Irvine, California
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30
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Kim EC, Zhang J, Pang W, Wang S, Lee KY, Cavaretta JP, Walters J, Procko E, Tsai NP, Chung HJ. Reduced axonal surface expression and phosphoinositide sensitivity in K v7 channels disrupts their function to inhibit neuronal excitability in Kcnq2 epileptic encephalopathy. Neurobiol Dis 2018; 118:76-93. [PMID: 30008368 DOI: 10.1016/j.nbd.2018.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 07/04/2018] [Indexed: 01/08/2023] Open
Abstract
Neuronal Kv7/KCNQ channels are voltage-gated potassium channels composed of Kv7.2/KCNQ2 and Kv7.3/KCNQ3 subunits. Enriched at the axonal membrane, they potently suppress neuronal excitability. De novo and inherited dominant mutations in Kv7.2 cause early onset epileptic encephalopathy characterized by drug resistant seizures and profound psychomotor delay. However, their precise pathogenic mechanisms remain elusive. Here, we investigated selected epileptic encephalopathy causing mutations in calmodulin (CaM)-binding helices A and B of Kv7.2. We discovered that R333W, K526N, and R532W mutations located peripheral to CaM contact sites decreased axonal surface expression of heteromeric channels although only R333W mutation reduced CaM binding to Kv7.2. These mutations also altered gating modulation by phosphatidylinositol 4,5-bisphosphate (PIP2), revealing novel PIP2 binding residues. While these mutations disrupted Kv7 function to suppress excitability, hyperexcitability was observed in neurons expressing Kv7.2-R532W that displayed severe impairment in voltage-dependent activation. The M518 V mutation at the CaM contact site in helix B caused most defects in Kv7 channels by severely reducing their CaM binding, K+ currents, and axonal surface expression. Interestingly, the M518 V mutation induced ubiquitination and accelerated proteasome-dependent degradation of Kv7.2, whereas the presence of Kv7.3 blocked this degradation. Furthermore, expression of Kv7.2-M518V increased neuronal death. Together, our results demonstrate that epileptic encephalopathy mutations in helices A and B of Kv7.2 cause abnormal Kv7 expression and function by disrupting Kv7.2 binding to CaM and/or modulation by PIP2. We propose that such multiple Kv7 channel defects could exert more severe impacts on neuronal excitability and health, and thus serve as pathogenic mechanisms underlying Kcnq2 epileptic encephalopathy.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Weilun Pang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shuwei Wang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kwan Young Lee
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - John P Cavaretta
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jennifer Walters
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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31
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Control of Homeostatic Synaptic Plasticity by AKAP-Anchored Kinase and Phosphatase Regulation of Ca 2+-Permeable AMPA Receptors. J Neurosci 2018; 38:2863-2876. [PMID: 29440558 DOI: 10.1523/jneurosci.2362-17.2018] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/17/2018] [Accepted: 02/06/2018] [Indexed: 12/31/2022] Open
Abstract
Neuronal information processing requires multiple forms of synaptic plasticity mediated by NMDARs and AMPA-type glutamate receptors (AMPARs). These plasticity mechanisms include long-term potentiation (LTP) and long-term depression (LTD), which are Hebbian, homosynaptic mechanisms locally regulating synaptic strength of specific inputs, and homeostatic synaptic scaling, which is a heterosynaptic mechanism globally regulating synaptic strength across all inputs. In many cases, LTP and homeostatic scaling regulate AMPAR subunit composition to increase synaptic strength via incorporation of Ca2+-permeable receptors (CP-AMPAR) containing GluA1, but lacking GluA2, subunits. Previous work by our group and others demonstrated that anchoring of the kinase PKA and the phosphatase calcineurin (CaN) to A-kinase anchoring protein (AKAP) 150 play opposing roles in regulation of GluA1 Ser845 phosphorylation and CP-AMPAR synaptic incorporation during hippocampal LTP and LTD. Here, using both male and female knock-in mice that are deficient in PKA or CaN anchoring, we show that AKAP150-anchored PKA and CaN also play novel roles in controlling CP-AMPAR synaptic incorporation during homeostatic plasticity in hippocampal neurons. We found that genetic disruption of AKAP-PKA anchoring prevented increases in Ser845 phosphorylation and CP-AMPAR synaptic recruitment during rapid homeostatic synaptic scaling-up induced by combined blockade of action potential firing and NMDAR activity. In contrast, genetic disruption of AKAP-CaN anchoring resulted in basal increases in Ser845 phosphorylation and CP-AMPAR synaptic activity that blocked subsequent scaling-up by preventing additional CP-AMPAR recruitment. Thus, the balanced, opposing phospho-regulation provided by AKAP-anchored PKA and CaN is essential for control of both Hebbian and homeostatic plasticity mechanisms that require CP-AMPARs.SIGNIFICANCE STATEMENT Neuronal circuit function is shaped by multiple forms of activity-dependent plasticity that control excitatory synaptic strength, including LTP/LTD that adjusts strength of individual synapses and homeostatic plasticity that adjusts overall strength of all synapses. Mechanisms controlling LTP/LTD and homeostatic plasticity were originally thought to be distinct; however, recent studies suggest that CP-AMPAR phosphorylation regulation is important during both LTP/LTD and homeostatic plasticity. Here we show that CP-AMPAR regulation by the kinase PKA and phosphatase CaN coanchored to the scaffold protein AKAP150, a mechanism previously implicated in LTP/LTD, is also crucial for controlling synaptic strength during homeostatic plasticity. These novel findings significantly expand our understanding of homeostatic plasticity mechanisms and further emphasize how intertwined they are with LTP and LTD.
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32
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Nie B, Liu C, Bai X, Chen X, Wu S, Zhang S, Huang Z, Xie M, Xu T, Xin W, Zeng W, Ouyang H. AKAP150 involved in paclitaxel-induced neuropathic pain via inhibiting CN/NFAT2 pathway and downregulating IL-4. Brain Behav Immun 2018; 68:158-168. [PMID: 29056557 DOI: 10.1016/j.bbi.2017.10.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 10/03/2017] [Accepted: 10/17/2017] [Indexed: 12/31/2022] Open
Abstract
Antitubulin chemotherapeutics agents, such as paclitaxel, are effective chemotherapy drugs for cancer treatment. However, painful neuropathy is a major adverse effect limiting the wider application of chemotherapeutics. In this study, we found that A-kinase anchor protein 150 (AKAP150) was significantly upregulated after paclitaxel injection. Inhibition of AKAP150 via siRNA or AKAP150flox/flox in rodents alleviated the pain behavior induced by paclitaxel, and partly restored the decreased calcineurin (CN) phosphatase activity after paclitaxel treatment. Paclitaxel decreased the expression of anti-inflammatory cytokine interleukin-4 (IL-4), and intrathecal injections of IL-4 effectively alleviated paclitaxel-induced hypersensitivity and the frequency of dorsal root ganglion (DRG) neurons action potential. The decreased CN enzyme activity, resulted in reduced protein expression of nuclear factor of activated T cells 2 (NFAT2) in cell nuclei. Chromatin immunoprecipitation showed that, NFAT2 binds to the IL-4 gene promoter regulating the protein expression of IL-4. Overexpression of NFAT2 by intrathecal injection of the AAV5-NFAT2-GFP virus alleviated the pain behavior induced by paclitaxel via increasing the expression of IL-4. Knocked down AKAP150 by siRNA or AAV5-Cre-GFP partly restored the expression of IL-4 in DRG. Our results indicated that regulation of IL-4 via the CN/NFAT2 pathway mediated by AKAP150 could be a pivotal treatment target for paclitaxel-induced neuropathic pain and or other neuropsychiatric disorders.
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Affiliation(s)
- Bilin Nie
- Department of Anesthesiology, Guangdong Women and Children Hospital, Guangzhou, China; Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Cuicui Liu
- Department of Rehabilitation Medicine and Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaohui Bai
- Department of Rehabilitation Medicine and Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaodi Chen
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Shaoyong Wu
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Subo Zhang
- Department of Rehabilitation Medicine and Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhuxi Huang
- Department of Rehabilitation Medicine and Anesthesiology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Manxiu Xie
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Ting Xu
- Zhongshan Medicine School, Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-sen University, Guangzhou, China.
| | - Wenjun Xin
- Zhongshan Medicine School, Guangdong Province Key Laboratory of Brain Function and Disease, Sun Yat-sen University, Guangzhou, China
| | - Weian Zeng
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Handong Ouyang
- Department of Anesthesiology, State Key Laboratory of Oncology in Southern China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China.
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33
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Smith FD, Esseltine JL, Nygren PJ, Veesler D, Byrne DP, Vonderach M, Strashnov I, Eyers CE, Eyers PA, Langeberg LK, Scott JD. Local protein kinase A action proceeds through intact holoenzymes. Science 2018. [PMID: 28642438 DOI: 10.1126/science.aaj1669] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hormones can transmit signals through adenosine 3',5'-monophosphate (cAMP) to precise intracellular locations. The fidelity of these responses relies on the activation of localized protein kinase A (PKA) holoenzymes. Association of PKA regulatory type II (RII) subunits with A-kinase-anchoring proteins (AKAPs) confers location, and catalytic (C) subunits phosphorylate substrates. Single-particle electron microscopy demonstrated that AKAP79 constrains RII-C subassemblies within 150 to 250 angstroms of its targets. Native mass spectrometry established that these macromolecular assemblies incorporated stoichiometric amounts of cAMP. Chemical-biology- and live cell-imaging techniques revealed that catalytically active PKA holoenzymes remained intact within the cytoplasm. These findings indicate that the parameters of anchored PKA holoenzyme action are much more restricted than originally anticipated.
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Affiliation(s)
- F Donelson Smith
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Jessica L Esseltine
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Patrick J Nygren
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Dominic P Byrne
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Matthias Vonderach
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Ilya Strashnov
- School of Chemistry, The University of Manchester, Manchester M13 9PL, UK
| | - Claire E Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Patrick A Eyers
- Department of Biochemistry, Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Lorene K Langeberg
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - John D Scott
- Howard Hughes Medical Institute, Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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34
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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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35
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A-Kinase Anchoring Protein 79/150 Scaffolds Transient Receptor Potential A 1 Phosphorylation and Sensitization by Metabotropic Glutamate Receptor Activation. Sci Rep 2017; 7:1842. [PMID: 28500286 PMCID: PMC5431798 DOI: 10.1038/s41598-017-01999-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 04/05/2017] [Indexed: 01/20/2023] Open
Abstract
Mechanical pain serves as a base clinical symptom for many of the world’s most debilitating syndromes. Ion channels expressed by peripheral sensory neurons largely contribute to mechanical hypersensitivity. Transient Receptor Potential A 1 (TRPA1) is a ligand-gated ion channel that contributes to inflammatory mechanical hypersensitivity, yet little is known as to the post-translational mechanism behind its somatosensitization. Here, we utilize biochemical, electrophysiological, and behavioral measures to demonstrate that metabotropic glutamate receptor-induced sensitization of TRPA1 nociceptors stimulates targeted modification of the receptor. Type 1 mGluR5 activation increases TRPA1 receptor agonist sensitivity in an AKA-dependent manner. As a scaffolding protein for Protein Kinases A and C (PKA and PKC, respectively), AKAP facilitates phosphorylation and sensitization of TRPA1 in ex vivo sensory neuronal preparations. Furthermore, hyperalgesic priming of mechanical hypersensitivity requires both TRPA1 and AKAP. Collectively, these results identify a novel AKAP-mediated biochemical mechanism that increases TRPA1 sensitivity in peripheral sensory neurons, and likely contributes to persistent mechanical hypersensitivity.
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36
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Nystoriak MA, Nieves-Cintrón M, Patriarchi T, Buonarati OR, Prada MP, Morotti S, Grandi E, Fernandes JDS, Forbush K, Hofmann F, Sasse KC, Scott JD, Ward SM, Hell JW, Navedo MF. Ser1928 phosphorylation by PKA stimulates the L-type Ca2+ channel CaV1.2 and vasoconstriction during acute hyperglycemia and diabetes. Sci Signal 2017; 10:10/463/eaaf9647. [PMID: 28119464 DOI: 10.1126/scisignal.aaf9647] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hypercontractility of arterial myocytes and enhanced vascular tone during diabetes are, in part, attributed to the effects of increased glucose (hyperglycemia) on L-type CaV1.2 channels. In murine arterial myocytes, kinase-dependent mechanisms mediate the increase in CaV1.2 activity in response to increased extracellular glucose. We identified a subpopulation of the CaV1.2 channel pore-forming subunit (α1C) within nanometer proximity of protein kinase A (PKA) at the sarcolemma of murine and human arterial myocytes. This arrangement depended upon scaffolding of PKA by an A-kinase anchoring protein 150 (AKAP150) in mice. Glucose-mediated increases in CaV1.2 channel activity were associated with PKA activity, leading to α1C phosphorylation at Ser1928 Compared to arteries from low-fat diet (LFD)-fed mice and nondiabetic patients, arteries from high-fat diet (HFD)-fed mice and from diabetic patients had increased Ser1928 phosphorylation and CaV1.2 activity. Arterial myocytes and arteries from mice lacking AKAP150 or expressing mutant AKAP150 unable to bind PKA did not exhibit increased Ser1928 phosphorylation and CaV1.2 current density in response to increased glucose or to HFD. Consistent with a functional role for Ser1928 phosphorylation, arterial myocytes and arteries from knockin mice expressing a CaV1.2 with Ser1928 mutated to alanine (S1928A) lacked glucose-mediated increases in CaV1.2 activity and vasoconstriction. Furthermore, the HFD-induced increases in CaV1.2 current density and myogenic tone were prevented in S1928A knockin mice. These findings reveal an essential role for α1C phosphorylation at Ser1928 in stimulating CaV1.2 channel activity and vasoconstriction by AKAP-targeted PKA upon exposure to increased glucose and in diabetes.
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Affiliation(s)
- Matthew A Nystoriak
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | | | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Olivia R Buonarati
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Maria Paz Prada
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Stefano Morotti
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | | | - Katherine Forbush
- Howard Hughes Medical Institute and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Franz Hofmann
- Department of Pharmacology and Toxicology, Technical University of Munich, Munich D80802, Germany
| | | | - John D Scott
- Howard Hughes Medical Institute and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Sean M Ward
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV 89557, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, Davis, CA 95616, USA.
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37
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Zhang J, Carver CM, Choveau FS, Shapiro MS. Clustering and Functional Coupling of Diverse Ion Channels and Signaling Proteins Revealed by Super-resolution STORM Microscopy in Neurons. Neuron 2016; 92:461-478. [PMID: 27693258 DOI: 10.1016/j.neuron.2016.09.014] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/24/2016] [Accepted: 08/26/2016] [Indexed: 11/25/2022]
Abstract
The fidelity of neuronal signaling requires organization of signaling molecules into macromolecular complexes, whose components are in intimate proximity. The intrinsic diffraction limit of light makes visualization of individual signaling complexes using visible light extremely difficult. However, using super-resolution stochastic optical reconstruction microscopy (STORM), we observed intimate association of individual molecules within signaling complexes containing ion channels (M-type K+, L-type Ca2+, or TRPV1 channels) and G protein-coupled receptors coupled by the scaffolding protein A-kinase-anchoring protein (AKAP)79/150. Some channels assembled as multi-channel supercomplexes. Surprisingly, we identified novel layers of interplay within macromolecular complexes containing diverse channel types at the single-complex level in sensory neurons, dependent on AKAP79/150. Electrophysiological studies revealed that such ion channels are functionally coupled as well. Our findings illustrate the novel role of AKAP79/150 as a molecular coupler of different channels that conveys crosstalk between channel activities within single microdomains in tuning the physiological response of neurons.
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Affiliation(s)
- Jie Zhang
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Chase M Carver
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Frank S Choveau
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Mark S Shapiro
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
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Greene DL, Hoshi N. Modulation of Kv7 channels and excitability in the brain. Cell Mol Life Sci 2016; 74:495-508. [PMID: 27645822 DOI: 10.1007/s00018-016-2359-y] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 11/26/2022]
Abstract
Neuronal Kv7 channels underlie a voltage-gated non-inactivating potassium current known as the M-current. Due to its particular characteristics, Kv7 channels show pronounced control over the excitability of neurons. We will discuss various factors that have been shown to drastically alter the activity of this channel such as protein and phospholipid interactions, phosphorylation, calcium, and numerous neurotransmitters. Kv7 channels locate to key areas for the control of action potential initiation and propagation. Moreover, we will explore the dynamic surface expression of the channel modulated by neurotransmitters and neural activity. We will also focus on known principle functions of neural Kv7 channels: control of resting membrane potential and spiking threshold, setting the firing frequency, afterhyperpolarization after burst firing, theta resonance, and transient hyperexcitability from neurotransmitter-induced suppression of the M-current. Finally, we will discuss the contribution of altered Kv7 activity to pathologies such as epilepsy and cognitive deficits.
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Affiliation(s)
- Derek L Greene
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA
| | - Naoto Hoshi
- Department of Pharmacology, University of California, 360 Med Surge II, Irvine, CA, 92697, USA.
- Department of Physiology and Biophysics, University of California, Irvine, USA.
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Hamamoto M, Kiyokage E, Sohn J, Hioki H, Harada T, Toida K. Structural basis for cholinergic regulation of neural circuits in the mouse olfactory bulb. J Comp Neurol 2016; 525:574-591. [PMID: 27491021 DOI: 10.1002/cne.24088] [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: 03/24/2016] [Revised: 06/30/2016] [Accepted: 07/08/2016] [Indexed: 01/10/2023]
Abstract
Odor information is regulated by olfactory inputs, bulbar interneurons, and centrifugal inputs in the olfactory bulb (OB). Cholinergic neurons projecting from the nucleus of the horizontal limb of the diagonal band of Broca and the magnocellular preoptic nucleus are one of the primary centrifugal inputs to the OB. In this study, we focused on cholinergic regulation of the OB and analyzed neural morphology with a particular emphasis on the projection pathways of cholinergic neurons. Single-cell imaging of a specific neuron within dense fibers is critical to evaluate the structure and function of the neural circuits. We labeled cholinergic neurons by infection with virus vector and then reconstructed them three-dimensionally. We also examined the ultramicrostructure of synapses by electron microscopy tomography. To further clarify the function of cholinergic neurons, we performed confocal laser scanning microscopy to investigate whether other neurotransmitters are present within cholinergic axons in the OB. Our results showed the first visualization of complete cholinergic neurons, including axons projecting to the OB, and also revealed frequent axonal branching within the OB where it innervated multiple glomeruli in different areas. Furthermore, electron tomography demonstrated that cholinergic axons formed asymmetrical synapses with a morphological variety of thicknesses of the postsynaptic density. Although we have not yet detected the presence of other neurotransmitters, the range of synaptic morphology suggests multiple modes of transmission. The present study elucidates the ways that cholinergic neurons could contribute to the elaborate mechanisms involved in olfactory processing in the OB. J. Comp. Neurol. 525:574-591, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Masakazu Hamamoto
- Department of Anatomy, Kawasaki Medical School, Okayama, 701-0192, Japan.,Department of Otolaryngology, Kawasaki Medical School, Okayama, 701-0192, Japan
| | - Emi Kiyokage
- Department of Anatomy, Kawasaki Medical School, Okayama, 701-0192, Japan
| | - Jaerin Sohn
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan.,Division of Cerebral Circuitry, National Institute for Physiological Sciences, Aichi, 444-8787, Japan
| | - Hiroyuki Hioki
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Tamotsu Harada
- Department of Otolaryngology, Kawasaki Medical School, Okayama, 701-0192, Japan
| | - Kazunori Toida
- Department of Anatomy, Kawasaki Medical School, Okayama, 701-0192, Japan.,Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Osaka, 567-0047, Japan
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40
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Compartmentalization of GPCR signalling controls unique cellular responses. Biochem Soc Trans 2016; 44:562-7. [DOI: 10.1042/bst20150236] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Indexed: 02/08/2023]
Abstract
With >800 members, G protein-coupled receptors (GPCRs) are the largest class of cell-surface signalling proteins, and their activation mediates diverse physiological processes. GPCRs are ubiquitously distributed across all cell types, involved in many diseases and are major drug targets. However, GPCR drug discovery is still characterized by very high attrition rates. New avenues for GPCR drug discovery may be provided by a recent shift away from the traditional view of signal transduction as a simple chain of events initiated from the plasma membrane. It is now apparent that GPCR signalling is restricted to highly organized compartments within the cell, and that GPCRs activate distinct signalling pathways once internalized. A high-resolution understanding of how compartmentalized signalling is controlled will probably provide unique opportunities to selectively and therapeutically target GPCRs.
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41
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Oruganty K, Talevich EE, Neuwald AF, Kannan N. Identification and classification of small molecule kinases: insights into substrate recognition and specificity. BMC Evol Biol 2016; 16:7. [PMID: 26738562 PMCID: PMC4702295 DOI: 10.1186/s12862-015-0576-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 12/21/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Many prokaryotic kinases that phosphorylate small molecule substrates, such as antibiotics, lipids and sugars, are evolutionarily related to Eukaryotic Protein Kinases (EPKs). These Eukaryotic-Like Kinases (ELKs) share the same overall structural fold as EPKs, but differ in their modes of regulation, substrate recognition and specificity-the sequence and structural determinants of which are poorly understood. RESULTS To better understand the basis for ELK specificity, we applied a Bayesian classification procedure designed to identify sequence determinants responsible for functional divergence. This reveals that a large and diverse family of aminoglycoside kinases, characterized members of which are involved in antibiotic resistance, fall into major sub-groups based on differences in putative substrate recognition motifs. Aminoglycoside kinase substrate specificity follows simple rules of alternating hydroxyl and amino groups that is strongly correlated with variations at the DFG + 1 position. CONCLUSIONS Substrate specificity determining features in small molecule kinases are mostly confined to the catalytic core and can be identified based on quantitative sequence and crystal structure comparisons.
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Affiliation(s)
- Krishnadev Oruganty
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
| | - Eric E Talevich
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, 94158, USA.
| | - Andrew F Neuwald
- Institute for Genome Sciences and Department of Biochemistry & Molecular Biology, School of Medicine, University of Maryland, Baltimore, MD, 21201, USA.
| | - Natarajan Kannan
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
- Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA.
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Jiang L, Kosenko A, Yu C, Huang L, Li X, Hoshi N. Activation of m1 muscarinic acetylcholine receptor induces surface transport of KCNQ channels through a CRMP-2-mediated pathway. J Cell Sci 2015; 128:4235-45. [PMID: 26446259 DOI: 10.1242/jcs.175547] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 09/28/2015] [Indexed: 01/10/2023] Open
Abstract
Neuronal excitability is strictly regulated by various mechanisms, including modulation of ion channel activity and trafficking. Stimulation of m1 muscarinic acetylcholine receptor (also known as CHRM1) increases neuronal excitability by suppressing the M-current generated by the Kv7/KCNQ channel family. We found that m1 muscarinic acetylcholine receptor stimulation also triggers surface transport of KCNQ subunits. This receptor-induced surface transport was observed with KCNQ2 as well as KCNQ3 homomeric channels, but not with Kv3.1 channels. Deletion analyses identified that a conserved domain in a proximal region of the N-terminal tail of KCNQ protein is crucial for this surface transport--the translocation domain. Proteins that bind to this domain were identified as α- and β-tubulin and collapsin response mediator protein 2 (CRMP-2; also known as DPYSL2). An inhibitor of casein kinase 2 (CK2) reduced tubulin binding to the translocation domain, whereas an inhibitor of glycogen synthase kinase 3 (GSK3) facilitated CRMP-2 binding to the translocation domain. Consistently, treatment with the GSK3 inhibitor enhanced receptor-induced KCNQ2 surface transport. M-current recordings from neurons showed that treatment with a GSK3 inhibitor shortened the duration of muscarinic suppression and led to over-recovery of the M-current. These results suggest that m1 muscarinic acetylcholine receptor stimulates surface transport of KCNQ channels through a CRMP-2-mediated pathway.
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Affiliation(s)
- Ling Jiang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, and Beijing Key Laboratory of Tumor Systems Biology, Peking University, Beijing 100191, China Department of Pharmacology, University of California, Irvine, 360 Med Surge II, Irvine, CA 92617, USA
| | - Anastasia Kosenko
- Department of Pharmacology, University of California, Irvine, 360 Med Surge II, Irvine, CA 92617, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, D340 Medical Science I, Irvine, CA 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, D340 Medical Science I, Irvine, CA 92697, USA
| | - Xuejun Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, and Beijing Key Laboratory of Tumor Systems Biology, Peking University, Beijing 100191, China
| | - Naoto Hoshi
- Department of Pharmacology, University of California, Irvine, 360 Med Surge II, Irvine, CA 92617, USA Department of Physiology and Biophysics, University of California, Irvine, D340 Medical Science I, Irvine, CA 92697, USA
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43
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Kay HY, Greene DL, Kang S, Kosenko A, Hoshi N. M-current preservation contributes to anticonvulsant effects of valproic acid. J Clin Invest 2015; 125:3904-14. [PMID: 26348896 DOI: 10.1172/jci79727] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 07/30/2015] [Indexed: 01/04/2023] Open
Abstract
Valproic acid (VPA) has been widely used for decades to treat epilepsy; however, its mechanism of action remains poorly understood. Here, we report that the anticonvulsant effects of nonacute VPA treatment involve preservation of the M-current, a low-threshold noninactivating potassium current, during seizures. In a wide variety of neurons, activation of Gq-coupled receptors, such as the m1 muscarinic acetylcholine receptor, suppresses the M-current and induces hyperexcitability. We demonstrated that VPA treatment disrupts muscarinic suppression of the M-current and prevents resultant agonist-induced neuronal hyperexcitability. We also determined that VPA treatment interferes with M-channel signaling by inhibiting palmitoylation of a signaling scaffold protein, AKAP79/150, in cultured neurons. In a kainate-induced murine seizure model, administration of a dose of an M-channel inhibitor that did not affect kainate-induced seizure transiently eliminated the anticonvulsant effects of VPA. Retigabine, an M-channel opener that does not open receptor-suppressed M-channels, provided anticonvulsant effects only when administered prior to seizure induction in control animals. In contrast, treatment of VPA-treated mice with retigabine induced anticonvulsant effects even when administered after seizure induction. Together, these results suggest that receptor-induced M-current suppression plays a role in the pathophysiology of seizures and that preservation of the M-current during seizures has potential as an effective therapeutic strategy.
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44
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Neuromodulatory effect of Gαs- or Gαq-coupled G-protein-coupled receptor on NMDA receptor selectively activates the NMDA receptor/Ca2+/calcineurin/cAMP response element-binding protein-regulated transcriptional coactivator 1 pathway to effectively induce brain-derived neurotrophic factor expression in neurons. J Neurosci 2015; 35:5606-24. [PMID: 25855176 DOI: 10.1523/jneurosci.3650-14.2015] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although coordinated molecular signaling through excitatory and modulatory neurotransmissions is critical for the induction of immediate early genes (IEGs), which lead to effective changes in synaptic plasticity, the intracellular mechanisms responsible remain obscure. Here we measured the expression of IEGs and used bioluminescence imaging to visualize the expression of Bdnf when GPCRs, major neuromodulator receptors, were stimulated. Stimulation of pituitary adenylate cyclase-activating polypeptide (PACAP)-specific receptor (PAC1), a Gαs/q-protein-coupled GPCR, with PACAP selectively activated the calcineurin (CN) pathway that is controlled by calcium signals evoked via NMDAR. This signaling pathway then induced the expression of Bdnf and CN-dependent IEGs through the nuclear translocation of CREB-regulated transcriptional coactivator 1 (CRTC1). Intracerebroventricular injection of PACAP and intraperitoneal administration of MK801 in mice demonstrated that functional interactions between PAC1 and NMDAR induced the expression of Bdnf in the brain. Coactivation of NMDAR and PAC1 synergistically induced the expression of Bdnf attributable to selective activation of the CN pathway. This CN pathway-controlled expression of Bdnf was also induced by stimulating other Gαs- or Gαq-coupled GPCRs, such as dopamine D1, adrenaline β, CRF, and neurotensin receptors, either with their cognate agonists or by direct stimulation of the protein kinase A (PKA)/PKC pathway with chemical activators. Thus, the GPCR-induced expression of IEGs in coordination with NMDAR might occur via the selective activation of the CN/CRTC1/CREB pathway under simultaneous excitatory and modulatory synaptic transmissions in neurons if either the Gαs/adenylate cyclase/PKA or Gαq/PLC/PKC-mediated pathway is activated.
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45
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Samelson BK, Gore BB, Whiting JL, Nygren PJ, Purkey AM, Colledge M, Langeberg LK, Dell'Acqua ML, Zweifel LS, Scott JD. A-kinase Anchoring Protein 79/150 Recruits Protein Kinase C to Phosphorylate Roundabout Receptors. J Biol Chem 2015; 290:14107-19. [PMID: 25882844 DOI: 10.1074/jbc.m115.637470] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Indexed: 01/08/2023] Open
Abstract
Anchoring proteins direct protein kinases and phosphoprotein phosphatases toward selected substrates to control the efficacy, context, and duration of neuronal phosphorylation events. The A-kinase anchoring protein AKAP79/150 interacts with protein kinase A (PKA), protein kinase C (PKC), and protein phosphatase 2B (calcineurin) to modulate second messenger signaling events. In a mass spectrometry-based screen for additional AKAP79/150 binding partners, we have identified the Roundabout axonal guidance receptor Robo2 and its ligands Slit2 and Slit3. Biochemical and cellular approaches confirm that a linear sequence located in the cytoplasmic tail of Robo2 (residues 991-1070) interfaces directly with sites on the anchoring protein. Parallel studies show that AKAP79/150 interacts with the Robo3 receptor in a similar manner. Immunofluorescent staining detects overlapping expression patterns for murine AKAP150, Robo2, and Robo3 in a variety of brain regions, including hippocampal region CA1 and the islands of Calleja. In vitro kinase assays, peptide spot array mapping, and proximity ligation assay staining approaches establish that human AKAP79-anchored PKC selectively phosphorylates the Robo3.1 receptor subtype on serine 1330. These findings imply that anchored PKC locally modulates the phosphorylation status of Robo3.1 in brain regions governing learning and memory and reward.
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Affiliation(s)
- Bret K Samelson
- From the Howard Hughes Medical Institute, Department of Pharmacology, and
| | - Bryan B Gore
- the Departments of Pharmacology and Psychiatry, University of Washington, Seattle, Washington 98195-7290
| | - Jennifer L Whiting
- From the Howard Hughes Medical Institute, Department of Pharmacology, and
| | - Patrick J Nygren
- From the Howard Hughes Medical Institute, Department of Pharmacology, and
| | - Alicia M Purkey
- the Department of Pharmacology, University of Colorado, Aurora, Colorado 80045, and
| | | | - Lorene K Langeberg
- From the Howard Hughes Medical Institute, Department of Pharmacology, and
| | - Mark L Dell'Acqua
- the Department of Pharmacology, University of Colorado, Aurora, Colorado 80045, and
| | - Larry S Zweifel
- the Departments of Pharmacology and Psychiatry, University of Washington, Seattle, Washington 98195-7290
| | - John D Scott
- From the Howard Hughes Medical Institute, Department of Pharmacology, and
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Abstract
Cellular responses to environmental cues involve the mobilization of GTPases, protein kinases and phosphoprotein phosphatases. The spatial organization of these signalling enzymes by scaffold proteins helps to guide the flow of molecular information. Allosteric modulation of scaffolded enzymes can alter their catalytic activity or sensitivity to second messengers in a manner that augments, insulates or terminates local cellular events. This Review examines the features of scaffold proteins and highlights examples of locally organized groups of signalling enzymes that drive essential physiological processes, including hormone action, heart rate, cell division, organelle movement and synaptic transmission.
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47
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Krenz WDC, Rodgers EW, Baro DJ. Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin. PLoS One 2015; 10:e0117965. [PMID: 25692473 PMCID: PMC4333293 DOI: 10.1371/journal.pone.0117965] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/05/2015] [Indexed: 01/11/2023] Open
Abstract
Volume transmission results in phasic and tonic modulatory signals. The actions of tonic dopamine (DA) at type 1 DA receptors (D1Rs) are largely undefined. Here we show that tonic 5nM DA acts at D1Rs to stabilize neuronal output over minutes by enabling activity-dependent regulation of the hyperpolarization activated current (I h). In the presence but not absence of 5nM DA, I h maximal conductance (G max) was adjusted according to changes in slow wave activity in order to maintain spike timing. Our study on the lateral pyloric neuron (LP), which undergoes rhythmic oscillations in membrane potential with depolarized plateaus, demonstrated that incremental, bi-directional changes in plateau duration produced corresponding alterations in LP I hG max when preparations were superfused with saline containing 5nM DA. However, when preparations were superfused with saline alone there was no linear correlation between LP I hGmax and duty cycle. Thus, tonic nM DA modulated the capacity for activity to modulate LP I h G max; this exemplifies metamodulation (modulation of modulation). Pretreatment with the Ca2+-chelator, BAPTA, or the specific PKA inhibitor, PKI, prevented all changes in LP I h in 5nM DA. Calcineurin inhibitors blocked activity-dependent changes enabled by DA and revealed a PKA-mediated, activity-independent enhancement of LP I hG max. These data suggested that tonic 5nM DA produced two simultaneous, PKA-dependent effects: a direct increase in LP I h G max and a priming event that permitted calcineurin regulation of LP I h. The latter produced graded reductions in LP I hG max with increasing duty cycles. We also demonstrated that this metamodulation preserved the timing of LP’s first spike when network output was perturbed with bath-applied 4AP. In sum, 5nM DA permits slow wave activity to provide feedback that maintains spike timing, suggesting that one function of low-level, tonic modulation is to stabilize specific features of a dynamic output.
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Affiliation(s)
- Wulf-Dieter C. Krenz
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Edmund W. Rodgers
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Deborah J. Baro
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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Jeske NA. Peripheral scaffolding and signaling pathways in inflammatory pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:31-52. [PMID: 25744669 DOI: 10.1016/bs.pmbts.2014.11.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Peripheral injury precipitates the release and accumulation of extracellular molecules at the site of injury. Although these molecules exist in various forms, they activate specific receptor classes expressed on primary afferent neurons to mediate cellular and behavioral responses to both nonpainful and painful stimuli. These inflammatory mediators and subsequent receptor-mediated effects exist to warn an organism of future injury, thereby resulting in protection and rehabilitation of the wounded tissue. In this chapter, inflammatory mediators, their target receptor classes, and downstream signaling pathways are identified and discussed within the context of inflammatory hyperalgesia. Furthermore, scaffolding mechanisms that exist to support inflammatory signaling in peripheral afferent neuronal tissues specifically are identified and discussed. Together, the mediators, pathways, and scaffolding mechanisms involved in inflammatory hyperalgesia provide a unique knowledge point from which new therapeutic targets can be understood.
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Affiliation(s)
- Nathaniel A Jeske
- Department of Oral and Maxillofacial Surgery, UT Health Science Center, San Antonio, Texas, USA.
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49
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Thompson JL, Shuttleworth TJ. Anchoring protein AKAP79-mediated PKA phosphorylation of STIM1 determines selective activation of the ARC channel, a store-independent Orai channel. J Physiol 2015; 593:559-72. [PMID: 25504574 PMCID: PMC4324705 DOI: 10.1113/jphysiol.2014.284182] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 12/02/2014] [Indexed: 02/02/2023] Open
Abstract
KEY POINTS Although both the calcium store-dependent CRAC channels and the store-independent ARC channels are regulated by the protein STIM1, CRAC channels are regulated by STIM1 in the endoplasmic reticulum, whilst ARC channels are regulated by the STIM1 constitutively resident in the plasma membrane. We now demonstrate that activation of the ARC channels, but not CRAC channels, is uniquely dependent on phosphorylation of a single residue (T389) in the extensive cytosolic domain of STIM1 by protein kinase A. We further demonstrate that the phosphorylation of the T389 residue by protein kinase A is mediated by the association of plasma membrane STIM1 with the scaffolding protein AKAP79. Together, these findings indicate that the phosphorylation status of this single residue in STIM1 represents a key molecular determinant of the relative activities of these two co-existing Ca(2+) entry channels that are known to play critical, but distinct, roles in modulating a variety of physiologically relevant activities. ABSTRACT The low-conductance, highly calcium-selective channels encoded by the Orai family of proteins represent a major pathway for the agonist-induced entry of calcium associated with the generation and modulation of the key intracellular calcium signals that initiate and control a wide variety of physiologically important processes in cells. There are two distinct members of this channel family that co-exist endogenously in many cell types: the store-operated Ca(2+) release-activated CRAC channels and the store-independent arachidonic acid-regulated ARC channels. Although the activities of both channels are regulated by the stromal-interacting molecule-1 (STIM1) protein, two distinct pools of this protein are responsible, with the major pool of STIM1 in the endoplasmic reticulum membrane regulating CRAC channel activity, whilst the minor pool of plasma membrane STIM1 regulates ARC channel activity. We now show that a critical feature in determining this selective activation of the two channels is the phosphorylation status of a single threonine residue (T389) within the extensive (∼450 residue) cytosolic domain of STIM1. Specifically, protein kinase A (PKA)-mediated phosphorylation of T389 of STIM1 is necessary for effective activation of the ARC channels, whilst phosphorylation of the same residue actually inhibits the ability of STIM1 to activate the CRAC channels. We further demonstrate that the PKA-mediated phosphorylation of T389 occurs at the plasma membrane via the involvement of the anchoring protein AKAP79, which is constitutively associated with the pool of STIM1 in the plasma membrane. The novel mechanism we have described provides a means for the cell to precisely regulate the relative activities of these two channels to independently modulate the resulting intracellular calcium signals in a physiologically relevant manner.
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Affiliation(s)
- Jill L Thompson
- Department of Pharmacology and Physiology, University of Rochester Medical CenterRochester, NY, 14642, USA
| | - Trevor J Shuttleworth
- Department of Pharmacology and Physiology, University of Rochester Medical CenterRochester, NY, 14642, USA
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50
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Garcia-Alvarez G, Lu B, Yap KAF, Wong LC, Thevathasan JV, Lim L, Ji F, Tan KW, Mancuso JJ, Tang W, Poon SY, Augustine GJ, Fivaz M. STIM2 regulates PKA-dependent phosphorylation and trafficking of AMPARs. Mol Biol Cell 2015; 26:1141-59. [PMID: 25609091 PMCID: PMC4357513 DOI: 10.1091/mbc.e14-07-1222] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum and regulate store-operated Ca2+ entry. STIM2 mediates cAMP/PKA-dependent phosphorylation of the AMPA receptor subunit GluA1 in excitatory neurons. In addition, STIM2 promotes cAMP-dependent surface delivery of GluA1. STIMs (STIM1 and STIM2 in mammals) are transmembrane proteins that reside in the endoplasmic reticulum (ER) and regulate store-operated Ca2+ entry (SOCE). The function of STIMs in the brain is only beginning to be explored, and the relevance of SOCE in nerve cells is being debated. Here we identify STIM2 as a central organizer of excitatory synapses. STIM2, but not its paralogue STIM1, influences the formation of dendritic spines and shapes basal synaptic transmission in excitatory neurons. We further demonstrate that STIM2 is essential for cAMP/PKA-dependent phosphorylation of the AMPA receptor (AMPAR) subunit GluA1. cAMP triggers rapid migration of STIM2 to ER–plasma membrane (PM) contact sites, enhances recruitment of GluA1 to these ER-PM junctions, and promotes localization of STIM2 in dendritic spines. Both biochemical and imaging data suggest that STIM2 regulates GluA1 phosphorylation by coupling PKA to the AMPAR in a SOCE-independent manner. Consistent with a central role of STIM2 in regulating AMPAR phosphorylation, STIM2 promotes cAMP-dependent surface delivery of GluA1 through combined effects on exocytosis and endocytosis. Collectively our results point to a unique mechanism of synaptic plasticity driven by dynamic assembly of a STIM2 signaling complex at ER-PM contact sites.
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Affiliation(s)
- Gisela Garcia-Alvarez
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Bo Lu
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Kenrick An Fu Yap
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Loo Chin Wong
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Jervis Vermal Thevathasan
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Lynette Lim
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Fang Ji
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Kia Wee Tan
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - James J Mancuso
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Willcyn Tang
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - Shou Yu Poon
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857
| | - George J Augustine
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637553 Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
| | - Marc Fivaz
- Program in Neuroscience and Behavioral Disorders, DUKE-NUS Graduate Medical School, Singapore 169857 Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
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