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Shetty MS, Ris L, Schindler RFR, Mizuno K, Fedele L, Giese KP, Brand T, Abel T. Mice Lacking the cAMP Effector Protein POPDC1 Show Enhanced Hippocampal Synaptic Plasticity. Cereb Cortex 2022; 32:3457-3471. [PMID: 34937090 PMCID: PMC9376866 DOI: 10.1093/cercor/bhab426] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/13/2022] Open
Abstract
Extensive research has uncovered diverse forms of synaptic plasticity and an array of molecular signaling mechanisms that act as positive or negative regulators. Specifically, cyclic 3',5'-cyclic adenosine monophosphate (cAMP)-dependent signaling pathways are crucially implicated in long-lasting synaptic plasticity. In this study, we examine the role of Popeye domain-containing protein 1 (POPDC1) (or blood vessel epicardial substance (BVES)), a cAMP effector protein, in modulating hippocampal synaptic plasticity. Unlike other cAMP effectors, such as protein kinase A (PKA) and exchange factor directly activated by cAMP, POPDC1 is membrane-bound and the sequence of the cAMP-binding cassette differs from canonical cAMP-binding domains, suggesting that POPDC1 may have an unique role in cAMP-mediated signaling. Our results show that Popdc1 is widely expressed in various brain regions including the hippocampus. Acute hippocampal slices from Popdc1 knockout (KO) mice exhibit PKA-dependent enhancement in CA1 long-term potentiation (LTP) in response to weaker stimulation paradigms, which in slices from wild-type mice induce only transient LTP. Loss of POPDC1, while not affecting basal transmission or input-specificity of LTP, results in altered response during high-frequency stimulation. Popdc1 KO mice also show enhanced forskolin-induced potentiation. Overall, these findings reveal POPDC1 as a novel negative regulator of hippocampal synaptic plasticity and, together with recent evidence for its interaction with phosphodiesterases (PDEs), suggest that POPDC1 is involved in modulating activity-dependent local cAMP-PKA-PDE signaling.
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Affiliation(s)
- Mahesh Shivarama Shetty
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Laurence Ris
- Department of Neuroscience, University of Mons, Research Institute for Health Sciences and Technology, 7000 Mons, Belgium
| | | | - Keiko Mizuno
- Department of Neuroscience, King’s College, London SE5 9NU, UK
| | - Laura Fedele
- National Heart and Lung Institute, Imperial College London, London W12 ONN, UK
| | | | - Thomas Brand
- National Heart and Lung Institute, Imperial College London, London W12 ONN, UK
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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2
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Li X, Fetter R, Schwabe T, Jung C, Liu L, Steller H, Gaul U. The cAMP effector PKA mediates Moody GPCR signaling in Drosophila blood-brain barrier formation and maturation. eLife 2021; 10:68275. [PMID: 34382936 PMCID: PMC8390003 DOI: 10.7554/elife.68275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/11/2021] [Indexed: 01/01/2023] Open
Abstract
The blood-brain barrier (BBB) of Drosophila comprises a thin epithelial layer of subperineural glia (SPG), which ensheath the nerve cord and insulate it against the potassium-rich hemolymph by forming intercellular septate junctions (SJs). Previously, we identified a novel Gi/Go protein-coupled receptor (GPCR), Moody, as a key factor in BBB formation at the embryonic stage. However, the molecular and cellular mechanisms of Moody signaling in BBB formation and maturation remain unclear. Here, we identify cAMP-dependent protein kinase A (PKA) as a crucial antagonistic Moody effector that is required for the formation, as well as for the continued SPG growth and BBB maintenance in the larva and adult stage. We show that PKA is enriched at the basal side of the SPG cell and that this polarized activity of the Moody/PKA pathway finely tunes the enormous cell growth and BBB integrity. Moody/PKA signaling precisely regulates the actomyosin contractility, vesicle trafficking, and the proper SJ organization in a highly coordinated spatiotemporal manner. These effects are mediated in part by PKA's molecular targets MLCK and Rho1. Moreover, 3D reconstruction of SJ ultrastructure demonstrates that the continuity of individual SJ segments, and not their total length, is crucial for generating a proper paracellular seal. Based on these findings, we propose that polarized Moody/PKA signaling plays a central role in controlling the cell growth and maintaining BBB integrity during the continuous morphogenesis of the SPG secondary epithelium, which is critical to maintain tissue size and brain homeostasis during organogenesis.
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Affiliation(s)
- Xiaoling Li
- Tianjin Cancer Hospital Airport Hospital, Tianjin Medical University Cancer Institute & Hospital, Tianjin, China.,Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany.,Rockefeller University, New York, United States
| | - Richard Fetter
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Tina Schwabe
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany
| | - Christophe Jung
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany
| | - Liren Liu
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy; Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | | | - Ulrike Gaul
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany.,Rockefeller University, New York, United States
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3
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Proteasomal-Mediated Degradation of AKAP150 Accompanies AMPAR Endocytosis during cLTD. eNeuro 2020; 7:ENEURO.0218-19.2020. [PMID: 32205379 PMCID: PMC7163082 DOI: 10.1523/eneuro.0218-19.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 02/17/2020] [Accepted: 03/02/2020] [Indexed: 12/26/2022] Open
Abstract
The number and function of synaptic AMPA receptors (AMPARs) tightly regulates excitatory synaptic transmission. Current evidence suggests that AMPARs are inserted into the postsynaptic membrane during long-term potentiation (LTP) and are removed from the membrane during long-term depression (LTD). Dephosphorylation of GluA1 at Ser-845 and enhanced endocytosis are critical events in the modulation of LTD. Moreover, changes in scaffold proteins from the postsynaptic density (PSD) could be also related to AMPAR regulation in LTD. In the present study we analyzed the effect of chemical LTD (cLTD) on A-kinase anchoring protein (AKAP)150 and AMPARs levels in mouse-cultured neurons. We show that cLTD induces AKAP150 protein degradation via proteasome, coinciding with GluA1 dephosphorylation at Ser-845 and endocytosis of GluA1-containing AMPARs. Pharmacological inhibition of proteasome activity, but not phosphatase calcineurin (CaN), reverted cLTD-induced AKAP150 protein degradation. Importantly, AKAP150 silencing induced dephosphorylation of GluA1 Ser-845 and GluA1-AMPARs endocytosis while AKAP150 overexpression blocked cLTD-mediated GluA1-AMPARs endocytosis. Our results provide direct evidence that cLTD-induced AKAP150 degradation by the proteasome contributes to synaptic AMPARs endocytosis.
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4
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Mirisis AA, Alexandrescu A, Carew TJ, Kopec AM. The Contribution of Spatial and Temporal Molecular Networks in the Induction of Long-term Memory and Its Underlying Synaptic Plasticity. AIMS Neurosci 2016; 3:356-384. [PMID: 27819030 PMCID: PMC5096789 DOI: 10.3934/neuroscience.2016.3.356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to form long-lasting memories is critical to survival and thus is highly conserved across the animal kingdom. By virtue of its complexity, this same ability is vulnerable to disruption by a wide variety of neuronal traumas and pathologies. To identify effective therapies with which to treat memory disorders, it is critical to have a clear understanding of the cellular and molecular mechanisms which subserve normal learning and memory. A significant challenge to achieving this level of understanding is posed by the wide range of distinct temporal and spatial profiles of molecular signaling induced by learning-related stimuli. In this review we propose that a useful framework within which to address this challenge is to view the molecular foundation of long-lasting plasticity as composed of unique spatial and temporal molecular networks that mediate signaling both within neurons (such as via kinase signaling) as well as between neurons (such as via growth factor signaling). We propose that evaluating how cells integrate and interpret these concurrent and interacting molecular networks has the potential to significantly advance our understanding of the mechanisms underlying learning and memory formation.
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Affiliation(s)
- Anastasios A. Mirisis
- Center for Neural Science, New York University, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Anamaria Alexandrescu
- Center for Neural Science, New York University, New York, NY, USA
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Thomas J. Carew
- Center for Neural Science, New York University, New York, NY, USA
| | - Ashley M. Kopec
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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5
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Poppinga WJ, Muñoz-Llancao P, González-Billault C, Schmidt M. A-kinase anchoring proteins: cAMP compartmentalization in neurodegenerative and obstructive pulmonary diseases. Br J Pharmacol 2014; 171:5603-23. [PMID: 25132049 PMCID: PMC4290705 DOI: 10.1111/bph.12882] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/14/2014] [Accepted: 08/10/2014] [Indexed: 12/25/2022] Open
Abstract
The universal second messenger cAMP is generated upon stimulation of Gs protein-coupled receptors, such as the β2 -adreneoceptor, and leads to the activation of PKA, the major cAMP effector protein. PKA oscillates between an on and off state and thereby regulates a plethora of distinct biological responses. The broad activation pattern of PKA and its contribution to several distinct cellular functions lead to the introduction of the concept of compartmentalization of cAMP. A-kinase anchoring proteins (AKAPs) are of central importance due to their unique ability to directly and/or indirectly interact with proteins that either determine the cellular content of cAMP, such as β2 -adrenoceptors, ACs and PDEs, or are regulated by cAMP such as the exchange protein directly activated by cAMP. We report on lessons learned from neurons indicating that maintenance of cAMP compartmentalization by AKAP5 is linked to neurotransmission, learning and memory. Disturbance of cAMP compartments seem to be linked to neurodegenerative disease including Alzheimer's disease. We translate this knowledge to compartmentalized cAMP signalling in the lung. Next to AKAP5, we focus here on AKAP12 and Ezrin (AKAP78). These topics will be highlighted in the context of the development of novel pharmacological interventions to tackle AKAP-dependent compartmentalization.
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Affiliation(s)
- W J Poppinga
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of GroningenGroningen, The Netherlands
| | - P Muñoz-Llancao
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Laboratory of Cell and Neuronal Dynamics (Cenedyn), Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile
- Department of Neuroscience, Section Medical Physiology, University Medical Center Groningen, University of GroningenGroningen, The Netherlands
| | - C González-Billault
- Laboratory of Cell and Neuronal Dynamics (Cenedyn), Department of Biology, Faculty of Sciences, Universidad de ChileSantiago, Chile
| | - M Schmidt
- Department of Molecular Pharmacology, University of GroningenGroningen, The Netherlands
- Groningen Research Institute for Asthma and COPD (GRIAC), University Medical Center Groningen, University of GroningenGroningen, The Netherlands
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6
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Logothetis DE, Petrou VI, Zhang M, Mahajan R, Meng XY, Adney SK, Cui M, Baki L. Phosphoinositide control of membrane protein function: a frontier led by studies on ion channels. Annu Rev Physiol 2014; 77:81-104. [PMID: 25293526 DOI: 10.1146/annurev-physiol-021113-170358] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Anionic phospholipids are critical constituents of the inner leaflet of the plasma membrane, ensuring appropriate membrane topology of transmembrane proteins. Additionally, in eukaryotes, the negatively charged phosphoinositides serve as key signals not only through their hydrolysis products but also through direct control of transmembrane protein function. Direct phosphoinositide control of the activity of ion channels and transporters has been the most convincing case of the critical importance of phospholipid-protein interactions in the functional control of membrane proteins. Furthermore, second messengers, such as [Ca(2+)]i, or posttranslational modifications, such as phosphorylation, can directly or allosterically fine-tune phospholipid-protein interactions and modulate activity. Recent advances in structure determination of membrane proteins have allowed investigators to obtain complexes of ion channels with phosphoinositides and to use computational and experimental approaches to probe the dynamic mechanisms by which lipid-protein interactions control active and inactive protein states.
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Affiliation(s)
- Diomedes E Logothetis
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298-0551;
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Radeva MY, Kugelmann D, Spindler V, Waschke J. PKA compartmentalization via AKAP220 and AKAP12 contributes to endothelial barrier regulation. PLoS One 2014; 9:e106733. [PMID: 25188285 PMCID: PMC4154725 DOI: 10.1371/journal.pone.0106733] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 08/07/2014] [Indexed: 01/14/2023] Open
Abstract
cAMP-mediated PKA signaling is the main known pathway involved in maintenance of the endothelial barrier. Tight regulation of PKA function can be achieved by discrete compartmentalization of the enzyme via physical interaction with A-kinase anchoring proteins (AKAPs). Here, we investigated the role of AKAPs 220 and 12 in endothelial barrier regulation. Analysis of human and mouse microvascular endothelial cells as well as isolated rat mesenteric microvessels was performed using TAT-Ahx-AKAPis peptide, designed to competitively inhibit PKA-AKAP interaction. In vivo microvessel hydraulic conductivity and in vitro transendothelial electrical resistance measurements showed that this peptide destabilized endothelial barrier properties, and dampened the cAMP-mediated endothelial barrier stabilization induced by forskolin and rolipram. Immunofluorescence analysis revealed that TAT-Ahx-AKAPis led to both adherens junctions and actin cytoskeleton reorganization. Those effects were paralleled by redistribution of PKA and Rac1 from endothelial junctions and by Rac1 inactivation. Similarly, membrane localization of AKAP220 was also reduced. In addition, depletion of either AKAP12 or AKAP220 significantly impaired endothelial barrier function and AKAP12 was also shown to interfere with cAMP-mediated barrier enhancement. Furthermore, immunoprecipitation analysis demonstrated that AKAP220 interacts not only with PKA but also with VE-cadherin and ß-catenin. Taken together, these results indicate that AKAP-mediated PKA subcellular compartmentalization is involved in endothelial barrier regulation. More specifically, AKAP220 and AKAP12 contribute to endothelial barrier function and AKAP12 is required for cAMP-mediated barrier stabilization.
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Affiliation(s)
- Mariya Y. Radeva
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Daniela Kugelmann
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Volker Spindler
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Jens Waschke
- Institute of Anatomy and Cell Biology, Ludwig-Maximilians-University Munich, Munich, Germany
- * E-mail:
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8
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Dittmer PJ, Dell'Acqua ML, Sather WA. Ca2+/calcineurin-dependent inactivation of neuronal L-type Ca2+ channels requires priming by AKAP-anchored protein kinase A. Cell Rep 2014; 7:1410-1416. [PMID: 24835998 DOI: 10.1016/j.celrep.2014.04.039] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 03/21/2014] [Accepted: 04/25/2014] [Indexed: 10/25/2022] Open
Abstract
Within neurons, Ca2+-dependent inactivation (CDI) of voltage-gated L-type Ca2+ channels shapes cytoplasmic Ca2+ signals. CDI is initiated by Ca2+ binding to channel-associated calmodulin and subsequent Ca2+/calmodulin activation of the Ca2+-dependent phosphatase, calcineurin (CaN), which is targeted to L channels by the A-kinase-anchoring protein AKAP79/150. Here, we report that CDI of neuronal L channels was abolished by inhibition of PKA activity or PKA anchoring to AKAP79/150 and that CDI was also suppressed by stimulation of PKA activity. Although CDI was reduced by positive or negative manipulation of PKA, interference with PKA anchoring or activity lowered Ca2+ current density whereas stimulation of PKA activity elevated it. In contrast, inhibition of CaN reduced CDI but had no effect on current density. These results suggest a model wherein PKA-dependent phosphorylation enhances neuronal L current, thereby priming channels to undergo CDI, and Ca2+/calmodulin-activated CaN actuates CDI by reversing PKA-mediated enhancement of channel activity.
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Affiliation(s)
- Philip J Dittmer
- Department of Pharmacology, University of Colorado School of Medicine, Mail Stop 8315, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Mail Stop 8315, 12800 East 19(th) Avenue, Aurora, CO 80045, USA
| | - William A Sather
- Department of Pharmacology, University of Colorado School of Medicine, Mail Stop 8315, 12800 East 19(th) Avenue, Aurora, CO 80045, USA.
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LRRK2 regulates synaptogenesis and dopamine receptor activation through modulation of PKA activity. Nat Neurosci 2014; 17:367-76. [PMID: 24464040 DOI: 10.1038/nn.3636] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/24/2013] [Indexed: 11/08/2022]
Abstract
Leucine-rich repeat kinase 2 (LRRK2) is enriched in the striatal projection neurons (SPNs). We found that LRRK2 negatively regulates protein kinase A (PKA) activity in the SPNs during synaptogenesis and in response to dopamine receptor Drd1 activation. LRRK2 interacted with PKA regulatory subunit IIβ (PKARIIβ). A lack of LRRK2 promoted the synaptic translocation of PKA and increased PKA-mediated phosphorylation of actin-disassembling enzyme cofilin and glutamate receptor GluR1, resulting in abnormal synaptogenesis and transmission in the developing SPNs. Furthermore, PKA-dependent phosphorylation of GluR1 was also aberrantly enhanced in the striatum of young and aged Lrrk2(-/-) mice after treatment with a Drd1 agonist. Notably, a Parkinson's disease-related Lrrk2 R1441C missense mutation that impaired the interaction of LRRK2 with PKARIIβ also induced excessive PKA activity in the SPNs. Our findings reveal a previously unknown regulatory role for LRRK2 in PKA signaling and suggest a pathogenic mechanism of SPN dysfunction in Parkinson's disease.
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Arora K, Sinha C, Zhang W, Ren A, Moon CS, Yarlagadda S, Naren AP. Compartmentalization of cyclic nucleotide signaling: a question of when, where, and why? Pflugers Arch 2013; 465:1397-407. [PMID: 23604972 DOI: 10.1007/s00424-013-1280-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/04/2013] [Accepted: 04/05/2013] [Indexed: 01/21/2023]
Abstract
Preciseness of cellular behavior depends upon how an extracellular cue mobilizes a correct orchestra of cellular messengers and effector proteins spatially and temporally. This concept, termed compartmentalization of cellular signaling, is now known to form the molecular basis of many aspects of cellular behavior in health and disease. The cyclic nucleotides cyclic adenosine monophosphate and cyclic guanosine monophosphate are ubiquitous cellular messengers that can be compartmentalized in three ways: first, by their physical containment; second, by formation of multiple protein signaling complexes; and third, by their selective depletion. Compartmentalized cyclic nucleotide signaling is a very prevalent response among all cell types. In order to understand how it becomes relevant to cellular behavior, it is important to know how it is executed in cells to regulate physiological responses and, also, how its execution or dysregulation can lead to a pathophysiological condition, which forms the scope of the presented review.
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Affiliation(s)
- Kavisha Arora
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
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11
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Hikida T, Gamo NJ, Sawa A. DISC1 as a therapeutic target for mental illnesses. Expert Opin Ther Targets 2012; 16:1151-60. [PMID: 23130881 DOI: 10.1517/14728222.2012.719879] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Many genetic studies have indicated that DISC1 is not merely "disrupted-in-schizophrenia," but is more generally implicated in various brain dysfunctions associated with aberrant neurodevelopment and intracellular signaling pathways. Thus, the DISC1 gene is mildly associated with a variety of brain disorders, including schizophrenia, mood disorders, and autism. This novel concept fits with the results from biological studies of DISC1, which include cell and animal models. AREAS COVERED We review the molecular structure and functions of DISC1, particularly those in conjunction with its important interactors. Functions of these interacting proteins are also introduced under the concept of the "DISC1 interactome." Finally, we discuss how the DISC1 interactome can provide potential therapeutic targets for mental illnesses. EXPERT OPINION Modulation of DISC1 stability and post-transcriptional modifications may be key targets to address DISC1-related pathology. In addition, modulation of DISC1 interactors and the mechanisms of their interactions with DISC1 may also provide drug targets. Disc1 rodent models can subsequently be used as templates for in vivo validations of compounds designed for DISC1 and its interacting proteins. Furthermore, these rodents will serve as genetic models for schizophrenia and related conditions, especially in conjunction with their pathologies during the neurodevelopmental trajectory.
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Affiliation(s)
- Takatoshi Hikida
- Kyoto University School of Medicine, Medical Innovation Center, Kyoto, Japan.
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12
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Rankovic V, Landgraf P, Kanyshkova T, Ehling P, Meuth SG, Kreutz MR, Budde T, Munsch T. Modulation of calcium-dependent inactivation of L-type Ca2+ channels via β-adrenergic signaling in thalamocortical relay neurons. PLoS One 2011; 6:e27474. [PMID: 22164209 PMCID: PMC3229489 DOI: 10.1371/journal.pone.0027474] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/17/2011] [Indexed: 01/01/2023] Open
Abstract
Neuronal high-voltage-activated (HVA) Ca(2+) channels are rapidly inactivated by a mechanism that is termed Ca(2+)-dependent inactivation (CDI). In this study we have shown that β-adrenergic receptor (βAR) stimulation inhibits CDI in rat thalamocortical (TC) relay neurons. This effect can be blocked by inhibition of cAMP-dependent protein kinase (PKA) with a cell-permeable inhibitor (myristoylated protein kinase inhibitor-(14-22)-amide) or A-kinase anchor protein (AKAP) St-Ht31 inhibitory peptide, suggesting a critical role of these molecules downstream of the receptor. Moreover, inhibition of protein phosphatases (PP) with okadaic acid revealed the involvement of phosphorylation events in modulation of CDI after βAR stimulation. Double fluorescence immunocytochemistry and pull down experiments further support the idea that modulation of CDI in TC neurons via βAR stimulation requires a protein complex consisting of Ca(V)1.2, PKA and proteins from the AKAP family. All together our data suggest that AKAPs mediate targeting of PKA to L-type Ca(2+) channels allowing their phosphorylation and thereby modulation of CDI.
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Affiliation(s)
- Vladan Rankovic
- Institute of Physiology, Otto-von-Guericke University Magdeburg, Germany.
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13
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Abstract
Voltage-gated M-type (KCNQ) K+ channels play critical roles in regulation of neuronal excitability. Previous work showed A-kinase-anchoring protein (AKAP)79/150-mediated protein kinase C (PKC) phosphorylation of M channels to be involved in M current (I(M)) suppression by muscarinic M1, but not bradykinin B2, receptors. In this study, we first explored whether purinergic and angiotensin suppression of I(M) in superior cervical ganglion (SCG) sympathetic neurons involves AKAP79/150. Transfection into rat SCG neurons of ΔA-AKAP79, which lacks the A domain necessary for PKC binding, or the absence of AKAP150 in AKAP150(-/-) mice, did not affect I(M) suppression by purinergic agonist or by bradykinin, but reduced I(M) suppression by muscarinic agonist and angiotensin II. Transfection of AKAP79, but not ΔA-AKAP79 or AKAP15, rescued suppression of I(M) by muscarinic receptors in AKAP150(-/-) neurons. We also tested association of AKAP79 with M(1), B(2), P2Y(6), and AT(1) receptors, and KCNQ2 and KCNQ3 channels, via Förster resonance energy transfer (FRET) on Chinese hamster ovary cells under total internal refection fluorescence microscopy, which revealed substantial FRET between AKAP79 and M1 or AT1 receptors, and with the channels, but only weak FRET with P2Y(6) or B2 receptors. The involvement of AKAP79/150 in G(q/11)-coupled muscarinic regulation of N- and L-type Ca2+) channels and by cAMP/protein kinase A was also studied. We found AKAP79/150 to not play a role in the former, but to be necessary for forskolin-induced upregulation of L-current. Thus, AKAP79/150 action correlates with the PIP(2) (phosphatidylinositol 4,5-bisphosphate)-depletion mode of I(M) suppression, but does not generalize to G(q/11)-mediated inhibition of N- or L-type Ca2+ channels.
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Nakataki M, Iga JI, Numata S, Yoshimoto E, Kodera K, Watanabe SY, Song H, Ueno SI, Ohmori T. Gene expression and association analysis of the epithelial membrane protein 1 gene in major depressive disorder in the Japanese population. Neurosci Lett 2010; 489:126-30. [PMID: 21146590 DOI: 10.1016/j.neulet.2010.12.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 11/17/2010] [Accepted: 12/02/2010] [Indexed: 11/16/2022]
Abstract
The epithelial membrane protein 1 (EMP1) plays a role in neuronal differentiation and neurite outgrowth, which are involved in the pathogenesis of major depressive disorder (MDD). We sought to determine whether the EMP1 gene is implicated in MDD. We determined the mRNA expression levels of the EMP1 gene in peripheral-blood leukocytes of patients and control subjects (n=27 each). Next, we performed case-control association analyses (MDD, n=182; controls, n=350) in the Japanese population. The level of expression of the EMP1 mRNA was significantly lower in medication-free patients compared with control subjects (P<0.001). The association analysis revealed an absence of association between the polymorphisms studied and MDD, whereas a gender-specific association was observed between male controls and male patients for marker rs7315725 (permutation P=0.039). Our results suggest that the EMP1 gene may be implicated in the pathophysiology of MDD in the Japanese population.
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Affiliation(s)
- Masahito Nakataki
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, 18-15 Kuramoto-cho 3, Tokushima 770-8509, Japan.
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15
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A calcineurin/AKAP complex is required for NMDA receptor-dependent long-term depression. Nat Neurosci 2010; 13:1053-5. [PMID: 20694001 PMCID: PMC2943866 DOI: 10.1038/nn.2613] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 07/07/2010] [Indexed: 02/05/2023]
Abstract
AKAP79/150 is a protein scaffold thought to position specific kinases (PKA, PKC) and phosphastases (calcineurin) in appropriate synaptic domains so that their activities can regulate excitatory synaptic strength. Using a viral-mediated molecular replacement strategy in rat hippocampal slices, we found that AKAP is required for NMDA receptor-dependent LTD solely due to its interaction with calcineurin.
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Friedrich MW, Aramuni G, Mank M, Mackinnon JAG, Griesbeck O. Imaging CREB activation in living cells. J Biol Chem 2010; 285:23285-95. [PMID: 20484048 DOI: 10.1074/jbc.m110.124545] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The Ca(2+)- and cAMP-responsive element-binding protein (CREB) and the related ATF-1 and CREM are stimulus-inducible transcription factors that link certain forms of cellular activity to changes in gene expression. They are attributed to complex integrative activation characteristics, but current biochemical technology does not allow dynamic imaging of CREB activation in single cells. Using fluorescence resonance energy transfer between mutants of green fluorescent protein we here develop a signal-optimized genetically encoded indicator that enables imaging activation of CREB due to phosphorylation of the critical serine 133. The indicator of CREB activation due to phosphorylation (ICAP) was used to investigate the role of the scaffold and anchoring protein AKAP79/150 in regulating signal pathways converging on CREB. We show that disruption of AKAP79/150-mediated protein kinase A anchoring or knock-down of AKAP150 dramatically reduces the ability of protein kinase A to activate CREB. In contrast, AKAP79/150 regulation of CREB via L-type channels may only have minor importance. ICAP allows dynamic and reversible imaging in living cells and may become useful in studying molecular components and cell-type specificity of activity-dependent gene expression.
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Affiliation(s)
- Michael W Friedrich
- Max-Planck-Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany
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17
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Temporal sensitivity of protein kinase a activation in late-phase long term potentiation. PLoS Comput Biol 2010; 6:e1000691. [PMID: 20195498 PMCID: PMC2829045 DOI: 10.1371/journal.pcbi.1000691] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 01/26/2010] [Indexed: 01/22/2023] Open
Abstract
Protein kinases play critical roles in learning and memory and in long term potentiation (LTP), a form of synaptic plasticity. The induction of late-phase LTP (L-LTP) in the CA1 region of the hippocampus requires several kinases, including CaMKII and PKA, which are activated by calcium-dependent signaling processes and other intracellular signaling pathways. The requirement for PKA is limited to L-LTP induced using spaced stimuli, but not massed stimuli. To investigate this temporal sensitivity of PKA, a computational biochemical model of L-LTP induction in CA1 pyramidal neurons was developed. The model describes the interactions of calcium and cAMP signaling pathways and is based on published biochemical measurements of two key synaptic signaling molecules, PKA and CaMKII. The model is stimulated using four 100 Hz tetani separated by 3 sec (massed) or 300 sec (spaced), identical to experimental L-LTP induction protocols. Simulations show that spaced stimulation activates more PKA than massed stimulation, and makes a key experimental prediction, that L-LTP is PKA-dependent for intervals larger than 60 sec. Experimental measurements of L-LTP demonstrate that intervals of 80 sec, but not 40 sec, produce PKA-dependent L-LTP, thereby confirming the model prediction. Examination of CaMKII reveals that its temporal sensitivity is opposite that of PKA, suggesting that PKA is required after spaced stimulation to compensate for a decrease in CaMKII. In addition to explaining the temporal sensitivity of PKA, these simulations suggest that the use of several kinases for memory storage allows each to respond optimally to different temporal patterns. The hippocampus is a part of the cerebral cortex intimately involved in learning and memory behavior. A common cellular model of learning is a long lasting form of long term potentiation (L-LTP) in the hippocampus, because it shares several characteristics with learning. For example, both learning and long term potentiation exhibit sensitivity to temporal patterns of synaptic inputs and share common intracellular events such as activation of specific intracellular signaling pathways. Therefore, understanding the pivotal molecules in the intracellular signaling pathways underlying temporal sensitivity of L-LTP in the hippocampus may illuminate mechanisms underlying learning. We developed a computational model to evaluate whether the signaling pathways leading to activation of the two critical enzymes: protein kinase A and calcium-calmodulin-dependent kinase II are sufficient to explain the experimentally observed temporal sensitivity. Indeed, the simulations demonstrate that these enzymes exhibit different temporal sensitivities, and make a key experimental prediction, that L-LTP is dependent on protein kinase A for intervals larger than 60 sec. Measurements of hippocampal L-LTP confirm this prediction, demonstrating the value of a systems biology approach to computational neuroscience.
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Azorsa DO, Robeson RH, Frost D, Meec hoovet B, Brautigam GR, Dickey C, Beaudry C, Basu GD, Holz DR, Hernandez JA, Bisanz KM, Gwinn L, Grover A, Rogers J, Reiman EM, Hutton M, Stephan DA, Mousses S, Dunckley T. High-content siRNA screening of the kinome identifies kinases involved in Alzheimer's disease-related tau hyperphosphorylation. BMC Genomics 2010; 11:25. [PMID: 20067632 PMCID: PMC2820455 DOI: 10.1186/1471-2164-11-25] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 01/12/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neurofibrillary tangles (NFT), a cardinal neuropathological feature of Alzheimer's disease (AD) that is highly correlated with synaptic loss and dementia severity, appear to be partly attributable to increased phosphorylation of the microtubule stabilizing protein tau at certain AD-related residues. Identifying the kinases involved in the pathologic phosphorylation of tau may provide targets at which to aim new AD-modifying treatments. RESULTS We report results from a screen of 572 kinases in the human genome for effects on tau hyperphosphorylation using a loss of function, high-throughput RNAi approach. We confirm effects of three kinases from this screen, the eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2), the dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (DYRK1A), and the A-kinase anchor protein 13 (AKAP13) on tau phosphorylation at the 12E8 epitope (serine 262/serine 356). We provide evidence that EIF2AK2 effects may result from effects on tau protein expression, whereas DYRK1A and AKAP13 are likely more specifically involved in tau phosphorylation pathways. CONCLUSIONS These findings identify novel kinases that phosphorylate tau protein and provide a valuable reference data set describing the kinases involved in phosphorylating tau at an AD-relevant epitope.
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Affiliation(s)
- David O Azorsa
- Pharmaceutical Genomics Division, Translational Genomics Research Institute, Scottsdale, Arizona 85251, USA
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19
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Mechanisms of protein kinase A anchoring. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 283:235-330. [PMID: 20801421 DOI: 10.1016/s1937-6448(10)83005-9] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP), which is produced by adenylyl cyclases following stimulation of G-protein-coupled receptors, exerts its effect mainly through the cAMP-dependent serine/threonine protein kinase A (PKA). Due to the ubiquitous nature of the cAMP/PKA system, PKA signaling pathways underlie strict spatial and temporal control to achieve specificity. A-kinase anchoring proteins (AKAPs) bind to the regulatory subunit dimer of the tetrameric PKA holoenzyme and thereby target PKA to defined cellular compartments in the vicinity of its substrates. AKAPs promote the termination of cAMP signals by recruiting phosphodiesterases and protein phosphatases, and the integration of signaling pathways by binding additional signaling proteins. AKAPs are a heterogeneous family of proteins that only display similarity within their PKA-binding domains, amphipathic helixes docking into a hydrophobic groove formed by the PKA regulatory subunit dimer. This review summarizes the current state of information on compartmentalized cAMP/PKA signaling with a major focus on structural aspects, evolution, diversity, and (patho)physiological functions of AKAPs and intends to outline newly emerging directions of the field, such as the elucidation of AKAP mutations and alterations of AKAP expression in human diseases, and the validation of AKAP-dependent protein-protein interactions as new drug targets. In addition, alternative PKA anchoring mechanisms employed by noncanonical AKAPs and PKA catalytic subunit-interacting proteins are illustrated.
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Chen Q, Weiner RI, Blackman BE. Decreased expression of A-kinase anchoring protein 150 in GT1 neurons decreases neuron excitability and frequency of intrinsic gonadotropin-releasing hormone pulses. Endocrinology 2010; 151:281-90. [PMID: 19887564 PMCID: PMC2803148 DOI: 10.1210/en.2009-0894] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The frequency of intrinsic pulsatile GnRH secretion from endogenous GnRH neurons and GT1 GnRH cell lines is stimulated by increased intracellular cAMP levels. The downstream molecules comprising the cAMP signaling pathway are organized in microdomains by a family of scaffolding proteins, A-kinase anchoring proteins (AKAPs). These molecules tether protein kinase A, cAMP-specific phosphodiesterases, phosphatases to known substrates. In neurons AKAP150 organizes many of the signaling molecules known to regulate the excitability and intrinsic pulsatile activity of GnRH neurons. AKAP150 was expressed in both the GT1-1 and GT1-7 cells. We determined the role of AKAP150 in coordinating GT1-1 cell excitability and intrinsic GnRH pulsatile secretion by lowering AKAP150 levels with a small interfering RNA (siRNA) adenovirus construct to AKAP150 (Ad-AKAP150-siRNA). Infection with Ad-AKAP150-siRNA specifically decreased AKAP150 mRNA levels by 74% and protein levels by 53% relative to uninfected cells or cells infected with a luciferase control adenovirus siRNA vector. In GT1 cells, spontaneous Ca(2+) oscillations, an index of neuron excitability, are stimulated by increased levels of intracellular cAMP and lowered by decreased levels. The frequency of spontaneous Ca(2+) oscillations in Ad-AKAP150-siRNA-treated GT1-1 cells decreased by 47.2% relative to controls. A dramatic decrease in the number of spontaneous GnRH pulses was also observed after infection with Ad-AKAP150-siRNA. The interpulse interval increased to 143 +/- 20.25 min in Ad-AKAP150-siRNA infected cells from 32.2 +/- 7.3 min in luciferase control adenovirus siRNA vector-infected cells. These data demonstrate an important role of AKAP150 in coordinating signaling events regulating the frequency of intrinsic pulsatile GnRH secretion.
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Affiliation(s)
- Qiumei Chen
- Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, California 94143, USA
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21
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HAGEWOUD ROELINA, HAVEKES ROBBERT, NOVATI ARIANNA, KEIJSER JANN, VAN DER ZEE EDDYA, MEERLO PETER. Sleep deprivation impairs spatial working memory and reduces hippocampal AMPA receptor phosphorylation. J Sleep Res 2009; 19:280-8. [DOI: 10.1111/j.1365-2869.2009.00799.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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22
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Carnegie GK, Means CK, Scott JD. A-kinase anchoring proteins: from protein complexes to physiology and disease. IUBMB Life 2009; 61:394-406. [PMID: 19319965 DOI: 10.1002/iub.168] [Citation(s) in RCA: 140] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein scaffold complexes are a key mechanism by which a common signaling pathway can serve many different functions. Sequestering a signaling enzyme to a specific subcellular environment not only ensures that the enzyme is near its relevant targets, but also segregates this activity to prevent indiscriminate phosphorylation of other substrates. One family of diverse, well-studied scaffolding proteins are the A-kinase anchoring proteins (AKAPs). These anchoring proteins form multi-protein complexes that integrate cAMP signaling with other pathways and signaling events. In this review, we focus on recent advances in the elucidation of AKAP function.
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Affiliation(s)
- Graeme K Carnegie
- Department of Pharmacology, Howard Hughes Medical Institute, University of Washington, School of Medicine, Seattle, Washington 98195, USA.
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23
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Signal transduction cross talk mediated by Jun N-terminal kinase-interacting protein and insulin receptor substrate scaffold protein complexes. Mol Cell Biol 2009; 29:4831-40. [PMID: 19564410 DOI: 10.1128/mcb.00155-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Scaffold proteins have been established as important mediators of signal transduction specificity. The insulin receptor substrate (IRS) proteins represent a critical group of scaffold proteins that are required for signal transduction by the insulin receptor, including the activation of phosphatidylinositol 3 kinase. The c-Jun NH(2)-terminal kinase (JNK)-interacting proteins (JIPs) represent a different group of scaffold molecules that are implicated in the regulation of the JNK. These two signaling pathways are functionally linked because JNK can phosphorylate IRS1 on the negative regulatory site Ser-307. Here we demonstrate the physical association of these signaling pathways using a proteomic approach that identified insulin-regulated complexes of JIPs together with IRS scaffold proteins. Studies using mice with JIP scaffold protein defects confirm that the JIP1 and JIP2 proteins are required for normal glucose homeostasis. Together, these observations demonstrate that JIP proteins can influence insulin-stimulated signal transduction mediated by IRS proteins.
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Zhong H, Sia GM, Sato TR, Gray NW, Mao T, Khuchua Z, Huganir RL, Svoboda K. Subcellular dynamics of type II PKA in neurons. Neuron 2009; 62:363-74. [PMID: 19447092 PMCID: PMC2702487 DOI: 10.1016/j.neuron.2009.03.013] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2008] [Revised: 11/12/2008] [Accepted: 03/18/2009] [Indexed: 02/05/2023]
Abstract
Protein kinase A (PKA) plays multiple roles in neurons. The localization and specificity of PKA are largely controlled by A-kinase anchoring proteins (AKAPs). However, the dynamics of PKA in neurons and the roles of specific AKAPs are poorly understood. We imaged the distribution of type II PKA in hippocampal and cortical layer 2/3 pyramidal neurons in vitro and in vivo. PKA was concentrated in dendritic shafts compared to the soma, axons, and dendritic spines. This spatial distribution was imposed by the microtubule-binding protein MAP2, indicating that MAP2 is the dominant AKAP in neurons. Following cAMP elevation, catalytic subunits dissociated from the MAP2-tethered regulatory subunits and rapidly became enriched in nearby spines. The spatial gradient of type II PKA between dendritic shafts and spines was critical for the regulation of synaptic strength and long-term potentiation. Therefore, the localization and activity-dependent translocation of type II PKA are important determinants of PKA function.
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Affiliation(s)
- Haining Zhong
- Howard Hughes Medical Institute Janelia Farm Research Campus, Ashburn, VA 20147, USA.
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25
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Numata S, Iga JI, Nakataki M, Tayoshi S, Taniguchi K, Sumitani S, Tomotake M, Tanahashi T, Itakura M, Kamegaya Y, Tatsumi M, Sano A, Asada T, Kunugi H, Ueno SI, Ohmori T. Gene expression and association analyses of the phosphodiesterase 4B (PDE4B) gene in major depressive disorder in the Japanese population. Am J Med Genet B Neuropsychiatr Genet 2009; 150B:527-34. [PMID: 18785206 DOI: 10.1002/ajmg.b.30852] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The phosphodiesterase 4B (PDE4B) interacts with disrupted-in-schizophrenia 1 (DISC1), which is a known genetic risk factor for schizophrenia, bipolar disorder and major depressive disorder (MDD). PDE4B is also important in the regulation of cAMP signaling, a second messenger implicated in learning, memory, and mood. In this study, we determined mRNA expression levels of the PDE4B gene in the peripheral blood leukocytes of patients with MDD and control subjects (n = 33, each). Next we performed two-stage case-controlled association analyses (first set; case = 174, controls = 348; second set; case = 481, controls = 812) in the Japanese population to determine if the PDE4B gene is implicated in MDD. In the leukocytes, a significantly higher expression of the PDE4B mRNA was observed in the drug-naïve MDD patients compared with control subjects (P < 0.0001) and the expression of the MDD patients significantly decreased after antidepressant treatment (P = 0.030). In the association analysis, we observed significant allelic associations of four SNPs (the most significant, rs472952; P = 0.002) and a significant haplotypic association (permutation P = 0.019) between the PDE4B gene and MDD in the first-set samples. However, we could not confirm these significant associations in the following independent second-set of samples. Our results suggest that the PDE4B gene itself does not link to MDD but the elevated mRNA levels of PDE4B might be implicated in the pathophysiology of MDD.
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Affiliation(s)
- Shusuke Numata
- Department of Psychiatry, Course of Integrated Brain Sciences, Medical Informatics, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
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26
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Hines R, El-Husseini A. Excitatory Amino Acid Neurotransmitter Regulation. Mol Pain 2009. [DOI: 10.1007/978-0-387-75269-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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27
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Stable membrane expression of postsynaptic CaV1.2 calcium channel clusters is independent of interactions with AKAP79/150 and PDZ proteins. J Neurosci 2009; 28:13845-55. [PMID: 19091974 DOI: 10.1523/jneurosci.3213-08.2008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In neurons L-type calcium currents contribute to synaptic plasticity and to activity-dependent gene regulation. The subcellular localization of Ca(V)1.2 and its association with upstream and downstream signaling proteins is important for efficient and specific signal transduction. Here we tested the hypothesis that A-kinase anchoring proteins (AKAPs) or PDZ-proteins are responsible for the targeting and anchoring of Ca(V)1.2 in the postsynaptic compartment of glutamatergic neurons. Double-immunofluorescence labeling of hippocampal neurons transfected with external HA epitope-tagged Ca(V)1.2 demonstrated that clusters of membrane-incorporated Ca(V)1.2-HA were colocalized with AKAP79/150 but not with PSD-95 in the spines and shafts of dendrites. To disrupt the interactions with these scaffold proteins, we mutated known binding sequences for AKAP79/150 and PDZ proteins in the C terminus of Ca(V)1.2-HA. Unexpectedly, the distribution pattern, the density, and the fluorescence intensity of clusters were similar for wild-type and mutant Ca(V)1.2-HA, indicating that interactions with AKAP and PDZ proteins are not essential for the correct targeting of Ca(V)1.2. In agreement, brief treatment with NMDA (a chemical LTD paradigm) caused the degradation of PSD-95 and the redistribution of AKAP79/150 and alpha-actinin from dendritic spines into the shaft, without a concurrent loss or redistribution of Ca(V)1.2-HA clusters. Thus, in the postsynaptic compartment of hippocampal neurons Ca(V)1.2 calcium channels form signaling complexes apart from those of glutamate receptors and PSD-95. Their number and distribution in dendritic spines is not altered upon NMDA-induced disruption of the glutamate receptor signaling complex, and targeting and anchoring of Ca(V)1.2 is independent of its interactions with AKAP79/150 and PDZ proteins.
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28
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Kurosu T, Hernández AI, Wolk J, Liu J, Schwartz JH. α/β-tubulin are A kinase anchor proteins for type I PKA in neurons. Brain Res 2009; 1251:53-64. [DOI: 10.1016/j.brainres.2008.11.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 10/30/2008] [Accepted: 11/01/2008] [Indexed: 12/15/2022]
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29
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Hardingham N, Wright N, Dachtler J, Fox K. Sensory deprivation unmasks a PKA-dependent synaptic plasticity mechanism that operates in parallel with CaMKII. Neuron 2008; 60:861-74. [PMID: 19081380 DOI: 10.1016/j.neuron.2008.10.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2008] [Revised: 10/03/2008] [Accepted: 10/03/2008] [Indexed: 10/21/2022]
Abstract
Calcium/calmodulin kinase II (CaMKII) is required for LTP and experience-dependent potentiation in the barrel cortex. Here, we find that whisker deprivation increases LTP in the layer IV to II/III pathway and that PKA antagonists block the additional LTP. No LTP was seen in undeprived CaMKII-T286A mice, but whisker deprivation again unmasked PKA-sensitive LTP. Infusion of a PKA agonist potentiated EPSPs in deprived wild-types and deprived CaMKII-T286A point mutants but not in undeprived animals of either genotype. The PKA-dependent potentiation mechanism was not present in GluR1 knockouts. Infusion of a PKA antagonist caused depression of EPSPs in undeprived but not deprived cortex. LTD was occluded by whisker deprivation and blocked by PKA manipulation, but not blocked by cannabinoid antagonists. NMDA receptor currents were unaffected by sensory deprivation. These results suggest that sensory deprivation causes synaptic depression by reversing a PKA-dependent process that may act via GluR1.
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Affiliation(s)
- Neil Hardingham
- School of Bioscience, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK
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30
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Wojtal KA, Hoekstra D, van Ijzendoorn SCD. cAMP-dependent protein kinase A and the dynamics of epithelial cell surface domains: moving membranes to keep in shape. Bioessays 2008; 30:146-55. [PMID: 18200529 DOI: 10.1002/bies.20705] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cyclic adenosine monophosphate (cAMP) and cAMP-dependent protein kinase A (PKA) are evolutionary conserved molecules with a well-established position in the complex network of signal transduction pathways. cAMP/PKA-mediated signaling pathways are implicated in many biological processes that cooperate in organ development including the motility, survival, proliferation and differentiation of epithelial cells. Cell surface polarity, here defined as the anisotropic organisation of cellular membranes, is a critical parameter for most of these processes. Changes in the activity of cAMP/PKA elicit a variety of effects on intracellular membrane dynamics, including membrane sorting and trafficking. One of the most intriguing aspects of cAMP/PKA signaling is its evolutionary conserved abundance on the one hand and its precise spatial-temporal actions on the other. Here, we review recent developments with regard to the role of cAMP/PKA in the regulation of intracellular membrane trafficking in relation to the dynamics of epithelial surface domains.
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Affiliation(s)
- Kacper A Wojtal
- Division of Clinical Pharmacology and Toxicology, University Hospital Zurich, Zurich, Switzerland
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31
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Abel T, Nguyen PV. Regulation of hippocampus-dependent memory by cyclic AMP-dependent protein kinase. PROGRESS IN BRAIN RESEARCH 2008; 169:97-115. [PMID: 18394470 DOI: 10.1016/s0079-6123(07)00006-4] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The hippocampus is crucial for the consolidation of new declarative long-term memories. Genetic and behavioral experimentation have revealed that several protein kinases are critical for the formation of hippocampus-dependent long-term memories. Cyclic-AMP dependent protein kinase (PKA) is a serine-threonine kinase that has been strongly implicated in the expression of specific forms of hippocampus-dependent memory. We review evidence that PKA is required for hippocampus-dependent memory in mammals, and we highlight some of the proteins that have been implicated as targets of PKA. Future directions and open questions regarding the role of PKA in memory storage are also described.
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Affiliation(s)
- Ted Abel
- University of Pennsylvania, Department of Biology, Biological Basis of Behavior Program, Philadelphia, PA 19104, USA
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32
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Oliveria SF, Dell'Acqua ML, Sather WA. AKAP79/150 anchoring of calcineurin controls neuronal L-type Ca2+ channel activity and nuclear signaling. Neuron 2007; 55:261-75. [PMID: 17640527 PMCID: PMC2698451 DOI: 10.1016/j.neuron.2007.06.032] [Citation(s) in RCA: 267] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Revised: 03/27/2007] [Accepted: 06/27/2007] [Indexed: 10/23/2022]
Abstract
Neuronal L-type calcium channels contribute to dendritic excitability and activity-dependent changes in gene expression that influence synaptic strength. Phosphorylation-mediated enhancement of L-type channels containing the CaV1.2 pore-forming subunit is promoted by A-kinase anchoring proteins (AKAPs) that target cAMP-dependent protein kinase (PKA) to the channel. Although PKA increases L-type channel activity in dendrites and dendritic spines, the mechanism of enhancement in neurons remains poorly understood. Here, we show that CaV1.2 interacts directly with AKAP79/150, which binds both PKA and the Ca2+/calmodulin-activated phosphatase calcineurin (CaN). Cotargeting of PKA and CaN by AKAP79/150 confers bidirectional regulation of L-type current amplitude in transfected HEK293 cells and hippocampal neurons. However, anchored CaN dominantly suppresses PKA enhancement of the channel. Additionally, activation of the transcription factor NFATc4 via local Ca2+ influx through L-type channels requires AKAP79/150, suggesting that this signaling complex promotes neuronal L channel signaling to the nucleus through NFATc4.
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Affiliation(s)
- Seth F Oliveria
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
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33
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Lu Y, Lu YS, Shuai Y, Feng C, Tully T, Xie Z, Zhong Y, Zhou HM. The AKAP Yu is required for olfactory long-term memory formation in Drosophila. Proc Natl Acad Sci U S A 2007; 104:13792-7. [PMID: 17690248 PMCID: PMC1959461 DOI: 10.1073/pnas.0700439104] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extensive neurogenetic analysis has shown that memory formation depends critically on cAMP-protein kinase A (PKA) signaling. Details of how this pathway is involved in memory formation, however, remain to be fully elucidated. From a large-scale behavioral screen in Drosophila, we identified the yu mutant to be defective in one-day memory after spaced training. The yu mutation disrupts a gene encoding an A-kinase anchoring protein (AKAP). AKAPs comprise a family of proteins, which determine the subcellular localization of PKAs and thereby critically restrict cAMP signaling within a cell. Further behavioral characterizations revealed that long-term memory (LTM) was disrupted specifically in the yu mutant, whereas learning, short-term memory and anesthesia-resistant memory all appeared normal. Another independently isolated mutation of the yu gene failed to complement the LTM defect associated with the yu mutation, and this phenotypic defect could be rescued by induced acute expression of a yu(+) transgene, suggesting that yu functions physiologically during memory formation. AKAP Yu is expressed preferentially in the mushroom body (MB) neuroanatomical structure, and expression of a yu(+) transgene to the MB, but not to other brain regions, is sufficient to rescue the LTM defect of the yu mutant. These observations lead us to conclude that proper localization of PKA by Yu AKAP in MB neurons is required for the formation of LTM.
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Affiliation(s)
- Yubing Lu
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
| | - Yi-Sheng Lu
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
| | - Yichun Shuai
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
| | | | - Tim Tully
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
| | - Zuoping Xie
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
| | - Yi Zhong
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724
- To whom correspondence may be addressed. E-mail: or
| | - Hai-Meng Zhou
- *Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
- To whom correspondence may be addressed. E-mail: or
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Shcherbakova OG, Hurt CM, Xiang Y, Dell'Acqua ML, Zhang Q, Tsien RW, Kobilka BK. Organization of beta-adrenoceptor signaling compartments by sympathetic innervation of cardiac myocytes. ACTA ACUST UNITED AC 2007; 176:521-33. [PMID: 17296797 PMCID: PMC2063986 DOI: 10.1083/jcb.200604167] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The sympathetic nervous system regulates cardiac function through the activation of adrenergic receptors (ARs). β1 and β2ARs are the primary sympathetic receptors in the heart and play different roles in regulating cardiac contractile function and remodeling in response to injury. In this study, we examine the targeting and trafficking of β1 and β2ARs at cardiac sympathetic synapses in vitro. Sympathetic neurons form functional synapses with neonatal cardiac myocytes in culture. The myocyte membrane develops into specialized zones that surround contacting axons and contain accumulations of the scaffold proteins SAP97 and AKAP79/150 but are deficient in caveolin-3. The β1ARs are enriched within these zones, whereas β2ARs are excluded from them after stimulation of neuronal activity. The results indicate that specialized signaling domains are organized in cardiac myocytes at sites of contact with sympathetic neurons and that these domains are likely to play a role in the subtype-specific regulation of cardiac function by β1 and β2ARs in vivo.
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MESH Headings
- A Kinase Anchor Proteins
- Adaptor Proteins, Signal Transducing/metabolism
- Animals
- Caveolin 3/metabolism
- Cell Compartmentation
- Cells, Cultured
- Coculture Techniques
- Discs Large Homolog 1 Protein
- Guanylate Kinases
- Heart/innervation
- Heart/physiology
- Membrane Microdomains/metabolism
- Membrane Microdomains/ultrastructure
- Membrane Proteins/metabolism
- Mice
- Myocardium/metabolism
- Myocardium/ultrastructure
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/ultrastructure
- Neuromuscular Junction/metabolism
- Neuromuscular Junction/ultrastructure
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Receptors, Adrenergic, beta-1/drug effects
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/drug effects
- Receptors, Adrenergic, beta-2/metabolism
- Signal Transduction/physiology
- Sympathetic Fibers, Postganglionic/metabolism
- Sympathetic Fibers, Postganglionic/ultrastructure
- Synaptic Membranes/metabolism
- Synaptic Membranes/ultrastructure
- Synaptic Transmission/physiology
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Affiliation(s)
- Olga G Shcherbakova
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 95305, USA
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Han J, Han L, Tiwari P, Wen Z, Zheng JQ. Spatial targeting of type II protein kinase A to filopodia mediates the regulation of growth cone guidance by cAMP. ACTA ACUST UNITED AC 2007; 176:101-11. [PMID: 17200417 PMCID: PMC2063631 DOI: 10.1083/jcb.200607128] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The second messenger cyclic adenosine monophosphate (cAMP) plays a pivotal role in axonal growth and guidance, but its downstream mechanisms remain elusive. In this study, we report that type II protein kinase A (PKA) is highly enriched in growth cone filopodia, and this spatial localization enables the coupling of cAMP signaling to its specific effectors to regulate guidance responses. Disrupting the localization of PKA to filopodia impairs cAMP-mediated growth cone attraction and prevents the switching of repulsive responses to attraction by elevated cAMP. Our data further show that PKA targets protein phosphatase-1 (PP1) through the phosphorylation of a regulatory protein inhibitor-1 (I-1) to promote growth cone attraction. Finally, we find that I-1 and PP1 mediate growth cone repulsion induced by myelin-associated glycoprotein. These findings demonstrate that the spatial localization of type II PKA to growth cone filopodia plays an important role in the regulation of growth cone motility and guidance by cAMP.
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Affiliation(s)
- Jianzhong Han
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA
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36
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Schubert V, Dotti CG. Transmitting on actin: synaptic control of dendritic architecture. J Cell Sci 2007; 120:205-12. [PMID: 17215449 DOI: 10.1242/jcs.03337] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Excitatory synaptic transmission in the central nervous system mainly takes place at dendritic spines, highly motile protrusions on the dendritic surface. Depending on the stimuli received, dendritic spines undergo rapid actin-based changes in their morphology. This plasticity appears to involve signaling through numerous proteins that control the organization of the actin cytoskeleton (actin regulators). At least in part, recruitment and activation of these depends on neurotransmitter receptors at the post-synapse, which directly link neurotransmission to changes in dendritic spine architecture. However, other, non-neurotransmitter-receptors present at dendritic spines also participate. It is likely that several receptor types can control the activity of a single actin-regulatory pathway and it is the complex integration of numerous signals that determines the overall architecture of a dendritic spine.
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Affiliation(s)
- Vanessa Schubert
- Cavalieri Ottolenghi Scientific Institute, Universita degli Studi di Torino, A.O. San Luigi Gonzaga, Regione Gonzole 10, 10043 Orbassano (Torino), Italy.
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Lindskog M, Kim M, Wikström MA, Blackwell KT, Kotaleski JH. Transient calcium and dopamine increase PKA activity and DARPP-32 phosphorylation. PLoS Comput Biol 2006; 2:e119. [PMID: 16965177 PMCID: PMC1562452 DOI: 10.1371/journal.pcbi.0020119] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 07/27/2006] [Indexed: 12/03/2022] Open
Abstract
Reinforcement learning theorizes that strengthening of synaptic connections in medium spiny neurons of the striatum occurs when glutamatergic input (from cortex) and dopaminergic input (from substantia nigra) are received simultaneously. Subsequent to learning, medium spiny neurons with strengthened synapses are more likely to fire in response to cortical input alone. This synaptic plasticity is produced by phosphorylation of AMPA receptors, caused by phosphorylation of various signalling molecules. A key signalling molecule is the phosphoprotein DARPP-32, highly expressed in striatal medium spiny neurons. DARPP-32 is regulated by several neurotransmitters through a complex network of intracellular signalling pathways involving cAMP (increased through dopamine stimulation) and calcium (increased through glutamate stimulation). Since DARPP-32 controls several kinases and phosphatases involved in striatal synaptic plasticity, understanding the interactions between cAMP and calcium, in particular the effect of transient stimuli on DARPP-32 phosphorylation, has major implications for understanding reinforcement learning. We developed a computer model of the biochemical reaction pathways involved in the phosphorylation of DARPP-32 on Thr34 and Thr75. Ordinary differential equations describing the biochemical reactions were implemented in a single compartment model using the software XPPAUT. Reaction rate constants were obtained from the biochemical literature. The first set of simulations using sustained elevations of dopamine and calcium produced phosphorylation levels of DARPP-32 similar to that measured experimentally, thereby validating the model. The second set of simulations, using the validated model, showed that transient dopamine elevations increased the phosphorylation of Thr34 as expected, but transient calcium elevations also increased the phosphorylation of Thr34, contrary to what is believed. When transient calcium and dopamine stimuli were paired, PKA activation and Thr34 phosphorylation increased compared with dopamine alone. This result, which is robust to variation in model parameters, supports reinforcement learning theories in which activity-dependent long-term synaptic plasticity requires paired glutamate and dopamine inputs. Reinforcement learning, based on the association of a stimulus-triggered movement with a reward, involves changes in connection strength between neurons. Memory storage occurs in the striatum, the input stage of the basal ganglia, when a stimulus or movement signal originating from the cortex and a reward signal originating from the midbrain reach the target striatal cells together. Repetitive pairing of these two signals strengthens the connection between cortical and striatal cells. The strengthening of the connections is caused by activation of biochemical signalling pathways inside the striatal cells. These intracellular signalling pathways are explored in a quantitative computational model describing the biochemical pathways important for reinforcement learning. Lindskog et al.'s study shows that when brief reward and stimuli signals are paired, a stronger response in the intracellular signalling occurs compared with the situation when each signal is given alone. This result illustrates mechanisms whereby paired stimuli, but not unpaired stimuli, can cause learning. Furthermore, the model predicts that the biochemical responses are different after brief stimulation as compared with prolonged stimulation. This result highlights the difficulties in predicting the nonlinear interactions within signalling cascades based on prolonged stimulations, which often are used in biochemical experiments.
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Affiliation(s)
- Maria Lindskog
- School of Computer Science and Communication, Royal Institute of Technology, Stockholm, Sweden
| | - MyungSook Kim
- School of Computational Sciences, George Mason University, Fairfax, Virginia, United States of America
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia, United States of America
| | - Martin A Wikström
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Kim T Blackwell
- School of Computational Sciences, George Mason University, Fairfax, Virginia, United States of America
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia, United States of America
| | - Jeanette Hellgren Kotaleski
- School of Computer Science and Communication, Royal Institute of Technology, Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * To whom correspondence should be addressed. E-mail:
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Sandoz G, Thümmler S, Duprat F, Feliciangeli S, Vinh J, Escoubas P, Guy N, Lazdunski M, Lesage F. AKAP150, a switch to convert mechano-, pH- and arachidonic acid-sensitive TREK K(+) channels into open leak channels. EMBO J 2006; 25:5864-72. [PMID: 17110924 PMCID: PMC1698884 DOI: 10.1038/sj.emboj.7601437] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 10/16/2006] [Indexed: 11/09/2022] Open
Abstract
TREK channels are unique among two-pore-domain K(+) channels. They are activated by polyunsaturated fatty acids (PUFAs) including arachidonic acid (AA), phospholipids, mechanical stretch and intracellular acidification. They are inhibited by neurotransmitters and hormones. TREK-1 knockout mice have impaired PUFA-mediated neuroprotection to ischemia, reduced sensitivity to volatile anesthetics and altered perception of pain. Here, we show that the A-kinase-anchoring protein AKAP150 is a constituent of native TREK-1 channels. Its binding to a key regulatory domain of TREK-1 transforms low-activity outwardly rectifying currents into robust leak conductances insensitive to AA, stretch and acidification. Inhibition of the TREK-1/AKAP150 complex by Gs-coupled receptors such as serotonin 5HT4sR and noradrenaline beta2AR is as extensive as for TREK-1 alone, but is faster. Inhibition of TREK-1/AKAP150 by Gq-coupled receptors such as serotonin 5HT2bR and glutamate mGluR5 is much reduced when compared to TREK-1 alone. The association of AKAP150 with TREK channels integrates them into a postsynaptic scaffold where both G-protein-coupled membrane receptors (as demonstrated here for beta2AR) and TREK-1 dock simultaneously.
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MESH Headings
- Adaptor Proteins, Signal Transducing/analysis
- Adaptor Proteins, Signal Transducing/metabolism
- Amino Acid Sequence
- Animals
- Arachidonic Acid/metabolism
- COS Cells
- Chlorocebus aethiops
- Dogs
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Hydrogen-Ion Concentration
- Mice
- Mice, Inbred C57BL
- Molecular Sequence Data
- Oocytes
- Potassium Channels, Tandem Pore Domain/chemistry
- Potassium Channels, Tandem Pore Domain/metabolism
- Protein Binding
- Protein Structure, Tertiary
- Proteomics
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Cell Surface/metabolism
- Up-Regulation/genetics
- Xenopus
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Affiliation(s)
- Guillaume Sandoz
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Susanne Thümmler
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Fabrice Duprat
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Sylvain Feliciangeli
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | | | - Pierre Escoubas
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Nicolas Guy
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Michel Lazdunski
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
| | - Florian Lesage
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, Valbonne, France
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS UMR6097, Institut Paul Hamel, 660, route des lucioles, 06560 Valbonne, France. Tel.: +33 4 93 95 77 32; Fax: +33 4 93 95 77 32; E-mail:
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Porteous DJ, Thomson P, Brandon NJ, Millar JK. The genetics and biology of DISC1--an emerging role in psychosis and cognition. Biol Psychiatry 2006; 60:123-31. [PMID: 16843095 DOI: 10.1016/j.biopsych.2006.04.008] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 03/31/2006] [Accepted: 04/04/2006] [Indexed: 11/24/2022]
Abstract
In the developing field of biological psychiatry, DISC1 stands out by virtue of there being credible evidence, both genetic and biological, for a role in determining susceptibility to schizophrenia and related disorders. We highlight the methodologic paradigm that led to identification of DISC1 and review the supporting genetic and biological evidence. The original finding of DISC1 as a gene disrupted by a balanced translocation on chromosome 1q42 that segregates with schizophrenia, bipolar disorder, and recurrent major depression has sparked a number of confirmatory linkage and association studies. These indicate that DISC1 is a generalizable genetic risk factor for psychiatric illness that also influences cognition in healthy subjects. DISC1 has also been shown to interact with a number of proteins with neurobiological pedigrees, including Ndel1 (NUDEL), a key regulator of neuronal migration with endo-oligopeptidase activity, and PDE4B, a phosphodiesterase that is critical for cyclic adenosine monophosphate signaling and that is directly linked to learning, memory, and mood. Both are potential "drug" targets. DISC1 has thus emerged as a key molecular player in the etiology of major mental illness and in normal brain processes.
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Affiliation(s)
- David J Porteous
- Medical Genetics Section, Molecular Medicine Centre, University of Edinburgh, Crewe Road South, Edinburgh.
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40
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Inan M, Lu HC, Albright MJ, She WC, Crair MC. Barrel map development relies on protein kinase A regulatory subunit II beta-mediated cAMP signaling. J Neurosci 2006; 26:4338-49. [PMID: 16624954 PMCID: PMC6674004 DOI: 10.1523/jneurosci.3745-05.2006] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The cellular and molecular mechanisms mediating the activity-dependent development of brain circuitry are still incompletely understood. Here, we examine the role of cAMP-dependent protein kinase [protein kinase A (PKA)] signaling in cortical development and plasticity, focusing on its role in thalamocortical synapse and barrel map development. We provide direct evidence that PKA activity mediates barrel map formation using knock-out mice that lack type IIbeta regulatory subunits of PKA (PKARIIbeta). We show that PKARIIbeta-mediated PKA function is required for proper dendritogenesis and the organization of cortical layer IV neurons into barrels, but not for the development and plasticity of thalamocortical afferent clustering into a barrel pattern. We localize PKARIIbeta function to postsynaptic processes in barrel cortex and show that postsynaptic PKA targets, but not presynaptic PKA targets, have decreased phosphorylation in pkar2b knock-out (PKARIIbeta(-/-)) mice. We also show that long-term potentiation at TC synapses and the associated developmental increase in AMPA receptor function at these synapses, which normally occurs as barrels form, is absent in PKARIIbeta(-/-) mice. Together, these experiments support an activity-dependent model for barrel map development in which the selective addition and elimination of thalamocortical synapses based on Hebbian mechanisms for synapse formation is mediated by a cAMP/PKA-dependent pathway that relies on PKARIIbeta function.
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Huang T, McDonough CB, Abel T. Compartmentalized PKA signaling events are required for synaptic tagging and capture during hippocampal late-phase long-term potentiation. Eur J Cell Biol 2006; 85:635-42. [PMID: 16600423 PMCID: PMC2914317 DOI: 10.1016/j.ejcb.2006.02.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Synaptic plasticity, the activity-dependent change in the strength of neuronal connections, is a proposed cellular mechanism of memory storage that is critically regulated by protein kinases such as cAMP-dependent protein kinase (PKA). Despite the fact that a neuron contains thousands of synapses, the expression of synaptic plasticity can be specific to subsets of synapses. This is surprising because signal transduction pathways underlying synaptic plasticity involve diffusible second messenger molecules such as cAMP and diffusible proteins such as the catalytic subunit of PKA. One way in which this specificity can be achieved is by the localization of signal transduction molecules to specific subcellular domains. Spatial compartmentalization of PKA signaling is achieved via binding to A kinase-anchoring proteins (AKAPs). We report here that pharmacological inhibition of PKA anchoring impairs synaptically activated late-phase long-term potentiation (L-LTP) in hippocampal slices. In contrast, potentiation that is induced by the pharmacological activation of the cAMP/PKA pathway, which can potentially affect all synapses within the neuron, is not impaired by inhibition of PKA anchoring. These results suggest that PKA anchoring may be particularly important for events that occur at the synapse during the induction of L-LTP, such as synaptic tagging and capture. Indeed, our results demonstrate that blocking PKA anchoring impairs synaptic tagging and capture. Thus our data highlight the idea that PKA anchoring may allow for specific populations of synapses to change in synaptic strength in the face of plasticity-related transcription that is cell-wide.
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Affiliation(s)
| | | | - Ted Abel
- Corresponding author. Tel.: +215 898 5614; fax: +215 898 8780. (T. Abel)
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42
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Smith KE, Gibson ES, Dell’Acqua ML. cAMP-dependent protein kinase postsynaptic localization regulated by NMDA receptor activation through translocation of an A-kinase anchoring protein scaffold protein. J Neurosci 2006; 26:2391-402. [PMID: 16510716 PMCID: PMC6793655 DOI: 10.1523/jneurosci.3092-05.2006] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Revised: 01/18/2006] [Accepted: 01/19/2006] [Indexed: 11/21/2022] Open
Abstract
NMDA receptor-dependent long-term potentiation and long-term depression (LTD) involve changes in AMPA receptor activity and postsynaptic localization that are in part controlled by glutamate receptor 1 (GluR1) subunit phosphorylation. The scaffolding molecule A-kinase anchoring protein (AKAP)79/150 targets both the cAMP-dependent protein kinase (PKA) and protein phosphatase 2B/calcineurin (PP2B/CaN) to AMPA receptors to regulate GluR1 phosphorylation. Here, we report that brief NMDA receptor activation leads to persistent redistribution of AKAP79/150 and PKA-RII, but not PP2B/CaN, from postsynaptic membranes to the cytoplasm in hippocampal slices. Similar to LTD, AKAP79/150 redistribution requires PP2B/CaN activation and is accompanied by GluR1 dephosphorylation and internalization. Using fluorescence resonance energy transfer microscopy in hippocampal neurons, we demonstrate that PKA anchoring to AKAP79/150 is required for NMDA receptor regulation of PKA-RII localization and that movement of AKAP-PKA complexes underlies PKA redistribution. These findings suggest that LTD involves removal of AKAP79/150 and PKA from synapses in addition to activation of PP2B/CaN. Movement of AKAP79/150-PKA complexes from the synapse could further favor the actions of phosphatases in maintaining dephosphorylation of postsynaptic substrates, such as GluR1, that are important for LTD induction and expression. In addition, our observations demonstrate that AKAPs serve not solely as stationary anchors in cells but also as dynamic signaling components.
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Dell'Acqua ML, Smith KE, Gorski JA, Horne EA, Gibson ES, Gomez LL. Regulation of neuronal PKA signaling through AKAP targeting dynamics. Eur J Cell Biol 2006; 85:627-33. [PMID: 16504338 DOI: 10.1016/j.ejcb.2006.01.010] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Central to organization of signaling pathways are scaffolding, anchoring and adaptor proteins that mediate localized assembly of multi-protein complexes containing receptors, second messenger-generating enzymes, kinases, phosphatases, and substrates. At the postsynaptic density (PSD) of excitatory synapses, AMPA (AMPAR) and NMDA (NMDAR) glutamate receptors are linked to signaling proteins, the actin cytoskeleton, and synaptic adhesion molecules on dendritic spines through a network of scaffolding proteins that may play important roles regulating synaptic structure and receptor functions in synaptic plasticity underlying learning and memory. AMPARs are rapidly recruited to dendritic spines through NMDAR activation during induction of long-term potentiation (LTP) through pathways that also increase the size and F-actin content of spines. Phosphorylation of AMPAR-GluR1 subunits by the cAMP-dependent protein kinase (PKA) helps stabilize AMPARs recruited during LTP. In contrast, induction of long-term depression (LTD) leads to rapid calcineurin-protein phosphatase 2B (CaN) mediated dephosphorylation of PKA-phosphorylated GluR1 receptors, endocytic removal of AMPAR from synapses, and a reduction in spine size. However, mechanisms for coordinately regulating AMPAR localization, phosphorylation, and synaptic structure by PKA and CaN are not well understood. A kinase-anchoring protein (AKAP) 79/150 is a PKA- and CaN-anchoring protein that is linked to NMDARs and AMPARs through PSD-95 and SAP97 membrane-associated guanylate kinase (MAGUK) scaffolds. Importantly, disruption of PKA-anchoring in neurons and functional analysis of GluR1-MAGUK-AKAP79 complexes in heterologous cells suggests that AKAP79/150-anchored PKA and CaN may regulate AMPARs in LTD. In the work presented at the "First International Meeting on Anchored cAMP Signaling Pathways" (Berlin-Buch, Germany, October 15-16, 2005), we demonstrate that AKAP79/150 is targeted to dendritic spines by an N-terminal basic region that binds phosphatidylinositol-4,5-bisphosphate (PIP(2)), F-actin, and actin-linked cadherin adhesion molecules. Thus, anchoring of PKA and CaN as well as physical linkage of the AKAP to both cadherin-cytoskeletal and MAGUK-receptor complexes could play roles in coordinating changes in synaptic structure and receptor signaling functions underlying plasticity. Importantly, we provide evidence showing that NMDAR-CaN signaling pathways implicated in AMPAR regulation during LTD lead to a disruption of AKAP79/150 interactions with actin, MAGUKs, and cadherins and lead to a loss of the AKAP and anchored PKA from postsynapses. Our studies thus far indicate that this AKAP79/150 translocation depends on activation of CaN, F-actin reorganization, and possibly Ca(2+)-CaM binding to the N-terminal basic regions. Importantly, this tranlocation of the AKAP79/150-PKA complex from spines may shift the balance of PKA kinase and CaN/PP1 phosphatase activity at the postsynapse in favor of the phosphatases. This loss of PKA could then promote actions of CaN and PP1 during induction of LTD including maintaining AMPAR dephosphorylation, promoting AMPAR endocytosis, and preventing AMPAR recycling. Overall, these findings challenge the accepted notion that AKAPs are static anchors that position signaling proteins near fixed target substrates and instead suggest that AKAPs can function in more dynamic manners to regulate local signaling events.
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Affiliation(s)
- Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center at Fitzsimons, P.O. Box 6511, Mail Stop 8303, Aurora, CO 80045-0508, USA.
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45
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Millar JK, Pickard BS, Mackie S, James R, Christie S, Buchanan SR, Malloy MP, Chubb JE, Huston E, Baillie GS, Thomson PA, Hill EV, Brandon NJ, Rain JC, Camargo LM, Whiting PJ, Houslay MD, Blackwood DHR, Muir WJ, Porteous DJ. DISC1 and PDE4B are interacting genetic factors in schizophrenia that regulate cAMP signaling. Science 2005; 310:1187-91. [PMID: 16293762 DOI: 10.1126/science.1112915] [Citation(s) in RCA: 503] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The disrupted in schizophrenia 1 (DISC1) gene is a candidate susceptibility factor for schizophrenia, but its mechanistic role in the disorder is unknown. Here we report that the gene encoding phosphodiesterase 4B (PDE4B) is disrupted by a balanced translocation in a subject diagnosed with schizophrenia and a relative with chronic psychiatric illness. The PDEs inactivate adenosine 3',5'-monophosphate (cAMP), a second messenger implicated in learning, memory, and mood. We show that DISC1 interacts with the UCR2 domain of PDE4B and that elevation of cellular cAMP leads to dissociation of PDE4B from DISC1 and an increase in PDE4B activity. We propose a mechanistic model whereby DISC1 sequesters PDE4B in resting cells and releases it in an activated state in response to elevated cAMP.
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MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/genetics
- 3',5'-Cyclic-AMP Phosphodiesterases/metabolism
- Adult
- Affective Disorders, Psychotic/genetics
- Affective Disorders, Psychotic/metabolism
- Animals
- Cadherins/genetics
- Cell Line
- Chromosomes, Human, Pair 1
- Chromosomes, Human, Pair 16
- Cyclic AMP/metabolism
- Cyclic Nucleotide Phosphodiesterases, Type 4
- Enzyme Activation
- Genetic Predisposition to Disease
- Humans
- Male
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Protein Binding
- Rats
- Schizophrenia/enzymology
- Schizophrenia/genetics
- Schizophrenia/metabolism
- Signal Transduction
- Translocation, Genetic
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Affiliation(s)
- J Kirsty Millar
- Medical Genetics Section, Molecular Medicine Centre, University of Edinburgh, Edinburgh EH4 2XU, UK.
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46
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Chen L, Kurokawa J, Kass RS. Phosphorylation of the A-kinase-anchoring Protein Yotiao Contributes to Protein Kinase A Regulation of a Heart Potassium Channel. J Biol Chem 2005; 280:31347-52. [PMID: 16002409 DOI: 10.1074/jbc.m505191200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of the heart by the sympathetic nervous system, fundamental to the physiological response to stress and exercise, requires coordinated phosphorylation of multiple downstream molecular targets, including the I(Ks) (slowly activating potassium current) channel. Sympathetic nervous system stimulation increases intracellular cAMP for which targeted regulation is directed in large part by distinct scaffold or anchoring proteins. Yotiao is an A-kinase-anchoring protein (AKAP) that recruits the cyclic AMP-dependent protein kinase (protein kinase A (PKA)) and protein phosphatase 1 to the carboxyl terminus of the I(Ks) channel to form a molecular complex and control its phosphorylation state, crucial to the cardiac cellular response to sympathetic nervous system stimulation. Here we report that Yotiao itself is a substrate for PKA phosphorylation, and we identify a Yotiao amino-terminal (N-T) residue (Ser-43) that is PKA-phosphorylated in response to beta-adrenergic receptor stimulation. The replacement of Ser-43 by Ala ablates the PKA phosphorylation of N-T Yotiao and markedly diminishes the functional response of the wild type and pseudo-phosphorylated I(Ks) channel to cAMP but neither prevents the PKA phosphorylation of KCNQ1 nor its binding to Yotiao. These results suggest, for the first time, a critical role for the PKA phosphorylation of an AKAP in the functional regulation of an ion channel protein and postphosphorylation allosteric modulation of the I(Ks) channel by Yotiao.
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Affiliation(s)
- Lei Chen
- Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA
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47
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Gamper N, Reznikov V, Yamada Y, Yang J, Shapiro MS. Phosphatidylinositol [correction] 4,5-bisphosphate signals underlie receptor-specific Gq/11-mediated modulation of N-type Ca2+ channels. J Neurosci 2005; 24:10980-92. [PMID: 15574748 PMCID: PMC6730206 DOI: 10.1523/jneurosci.3869-04.2004] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Modulation of voltage-gated Ca2+ channels via G-protein-coupled receptors is a prime mechanism regulating neurotransmitter release and synaptic plasticity. Despite extensive studies, the molecular mechanism underlying Gq/11-mediated modulation remains unclear. We found cloned and native N-type Ca2+ channels to be regulated by phosphatidylinositol [correction] 4,5-bisphosphate (PIP2). In inside-out oocyte patches, PIP2 greatly attenuated or reversed the observed rundown of expressed channels. In sympathetic neurons, muscarinic M1 ACh receptor suppression of the Ca2+ current (ICa) was temporally correlated with PIP2 hydrolysis, blunted by PIP2 in whole-cell pipettes, attenuated by expression of PIP2-sequestering proteins, and became irreversible when PIP2 synthesis was blocked. We also probed mechanisms of receptor specificity. Although bradykinin also induced PIP2 hydrolysis, it did not inhibit ICa. However, bradykinin receptors became nearly as effective as M1 receptors when PIP2 synthesis, IP3 receptors, or the activity of neuronal Ca2+ sensor-1 were blocked, suggesting that bradykinin receptor-induced intracellular Ca2+ increases stimulate PIP2 synthesis, compensating for PIP2 hydrolysis. We suggest that differential use of PIP2 signals underlies specificity of Gq/11-coupled receptor actions on the channels
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MESH Headings
- 1-Phosphatidylinositol 4-Kinase/physiology
- Animals
- Biolistics
- Bradykinin/pharmacology
- Calcium/metabolism
- Calcium Channels, N-Type/chemistry
- Calcium Channels, N-Type/physiology
- Calcium Signaling
- Calcium-Binding Proteins/physiology
- Cells, Cultured
- Female
- GTP-Binding Protein alpha Subunits, Gq-G11/chemistry
- GTP-Binding Protein alpha Subunits, Gq-G11/physiology
- Ion Transport
- Isoenzymes/physiology
- Male
- Nerve Tissue Proteins/chemistry
- Nerve Tissue Proteins/physiology
- Neurons/physiology
- Oocytes
- Patch-Clamp Techniques
- Phosphatidylinositol 4,5-Diphosphate/biosynthesis
- Phosphatidylinositol 4,5-Diphosphate/physiology
- Phospholipase C delta
- Rabbits
- Rats
- Rats, Sprague-Dawley
- Receptors, Muscarinic/drug effects
- Receptors, Muscarinic/physiology
- Recombinant Fusion Proteins/physiology
- Superior Cervical Ganglion/cytology
- Transfection
- Type C Phospholipases/physiology
- Xenopus laevis
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Affiliation(s)
- Nikita Gamper
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229, USA
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Gorski JA, Gomez LL, Scott JD, Dell'Acqua ML. Association of an A-kinase-anchoring protein signaling scaffold with cadherin adhesion molecules in neurons and epithelial cells. Mol Biol Cell 2005; 16:3574-90. [PMID: 15930126 PMCID: PMC1182299 DOI: 10.1091/mbc.e05-02-0134] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A-kinase-anchoring protein (AKAP) 79/150 organizes a scaffold of cAMP-dependent protein kinase (PKA), protein kinase C (PKC), and protein phosphatase 2B/calcineurin that regulates phosphorylation pathways underlying neuronal long-term potentiation and long-term depression (LTD) synaptic plasticity. AKAP79/150 postsynaptic targeting requires three N-terminal basic domains that bind F-actin and acidic phospholipids. Here, we report a novel interaction of these domains with cadherin adhesion molecules that are linked to actin through beta-catenin (beta-cat) at neuronal synapses and epithelial adherens junctions. Mapping the AKAP binding site in cadherins identified overlap with beta-cat binding; however, no competition between AKAP and beta-cat binding to cadherins was detected in vitro. Accordingly, AKAP79/150 exhibited polarized localization with beta-cat and cadherins in epithelial cell lateral membranes, and beta-cat was present in AKAP-cadherin complexes isolated from epithelial cells, cultured neurons, and rat brain synaptic membranes. Inhibition of epithelial cell cadherin adhesion and actin polymerization redistributed intact AKAP-cadherin complexes from lateral membranes to intracellular compartments. In contrast, stimulation of neuronal pathways implicated in LTD that depolymerize postsynaptic F-actin disrupted AKAP-cadherin interactions and resulted in loss of the AKAP, but not cadherins, from synapses. This neuronal regulation of AKAP79/150 targeting to cadherins may be important in functional and structural synaptic modifications underlying plasticity.
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Affiliation(s)
- Jessica A Gorski
- Department of Pharmacology, University of Colorado at Denver and Health Sciences Center, Aurora, CO 80045, USA
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Schulman H. Activity-dependent regulation of calcium/calmodulin-dependent protein kinase II localization. J Neurosci 2005; 24:8399-403. [PMID: 15456811 PMCID: PMC6729891 DOI: 10.1523/jneurosci.3606-04.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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50
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Grönholm M, Teesalu T, Tyynelä J, Piltti K, Böhling T, Wartiovaara K, Vaheri A, Carpén O. Characterization of the NF2 protein merlin and the ERM protein ezrin in human, rat, and mouse central nervous system. Mol Cell Neurosci 2005; 28:683-93. [PMID: 15797715 DOI: 10.1016/j.mcn.2004.11.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Revised: 11/12/2004] [Accepted: 11/19/2004] [Indexed: 11/28/2022] Open
Abstract
The neurofibromatosis 2 (NF2) protein, merlin, is structurally related to the ERM (ezrin-radixin-moesin) protein family of membrane-cytoskeleton linkers and is mutated in nervous system tumors. Apart from tumor suppressor activity, merlin's functions are poorly understood. We compared the localization and expression of merlin and ezrin in developing and adult brain and in brain-derived progenitor cells. Both proteins were widely but differentially expressed in human, rat, and mouse brain. In brain tissue and neuronal progenitor cell cultures merlin was predominantly found in neurons while ezrin was expressed in astrocytes. Merlin expression was seen from E11 in mouse embryos, whereas ezrin was present earlier. Both proteins were expressed in embryonic mouse neurospheres, where ezrin was specifically localized in filopodia of adherent neuronal progenitor cells. Subcellular analysis demonstrated ezrin in fine filopodial structures in astrocytes, while merlin was detected in neuronal synaptic junctions. The widespread expression of merlin in brain and its association with protein kinase A suggest a role for merlin in brain biology.
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Affiliation(s)
- Mikaela Grönholm
- Neuroscience Program, Biomedicum Helsinki, University of Helsinki and Helsinki University Central Hospital, PB 63, Haartmaninkatu 8, 00014 Helsinki, Finland.
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