51
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Gorshkov K, Mehta S, Ramamurthy S, Ronnett GV, Zhou FQ, Zhang J. AKAP-mediated feedback control of cAMP gradients in developing hippocampal neurons. Nat Chem Biol 2017; 13:425-431. [PMID: 28192412 PMCID: PMC5362298 DOI: 10.1038/nchembio.2298] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/06/2016] [Indexed: 01/06/2023]
Abstract
Cyclic AMP (cAMP) and protein kinase A (PKA), classical examples of spatially compartmentalized signaling molecules, are critical axon determinants that regulate neuronal polarity and axon formation, yet little is known about micro-compartmentalization of cAMP and PKA signaling and its role in developing neurons. Here, we revealed that cAMP forms a gradient in developing hippocampal neurons, with higher cAMP levels in more distal regions of the axon compared to other regions of the cell. Interestingly, this cAMP gradient changed according to the developmental stage and depended on proper anchoring of PKA by A-kinase anchoring proteins (AKAPs). Disrupting PKA anchoring to AKAPs increased the cAMP gradient in early-stage neurons and led to enhanced axon elongation. Our results provide new evidence for a local negative feedback loop, assembled by AKAPs, for the precise control of a growth-stage-dependent cAMP gradient to ensure proper axon growth.
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Affiliation(s)
- Kirill Gorshkov
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
| | - Santosh Ramamurthy
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Gabriele V Ronnett
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Departments of Neurology and Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Feng-Quan Zhou
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Orthopedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Pharmacology, University of California, San Diego, La Jolla, California, USA
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52
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Qian H, Patriarchi T, Price JL, Matt L, Lee B, Nieves-Cintrón M, Buonarati OR, Chowdhury D, Nanou E, Nystoriak MA, Catterall WA, Poomvanicha M, Hofmann F, Navedo MF, Hell JW. Phosphorylation of Ser1928 mediates the enhanced activity of the L-type Ca2+ channel Cav1.2 by the β2-adrenergic receptor in neurons. Sci Signal 2017; 10:10/463/eaaf9659. [PMID: 28119465 DOI: 10.1126/scisignal.aaf9659] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The L-type Ca2+ channel Cav1.2 controls multiple functions throughout the body including heart rate and neuronal excitability. It is a key mediator of fight-or-flight stress responses triggered by a signaling pathway involving β-adrenergic receptors (βARs), cyclic adenosine monophosphate (cAMP), and protein kinase A (PKA). PKA readily phosphorylates Ser1928 in Cav1.2 in vitro and in vivo, including in rodents and humans. However, S1928A knock-in (KI) mice have normal PKA-mediated L-type channel regulation in the heart, indicating that Ser1928 is not required for regulation of cardiac Cav1.2 by PKA in this tissue. We report that augmentation of L-type currents by PKA in neurons was absent in S1928A KI mice. Furthermore, S1928A KI mice failed to induce long-term potentiation in response to prolonged theta-tetanus (PTT-LTP), a form of synaptic plasticity that requires Cav1.2 and enhancement of its activity by the β2-adrenergic receptor (β2AR)-cAMP-PKA cascade. Thus, there is an unexpected dichotomy in the control of Cav1.2 by PKA in cardiomyocytes and hippocampal neurons.
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Affiliation(s)
- Hai Qian
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - Jennifer L Price
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - Lucas Matt
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - Boram Lee
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | | | - Olivia R Buonarati
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | | | - Evanthia Nanou
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Matthew A Nystoriak
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Montatip Poomvanicha
- Department of Pharmacology and Toxicology, Technical University of Munich, D-80802 Munich, Germany
| | - Franz Hofmann
- Department of Pharmacology and Toxicology, Technical University of Munich, D-80802 Munich, Germany
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA 95616-8636, USA.
| | - Johannes W Hell
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242-1109, USA. .,Department of Pharmacology, University of California, Davis, CA 95616-8636, USA
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53
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Jones BW, Deem J, Younts TJ, Weisenhaus M, Sanford CA, Slack MC, Chin J, Nachmanson D, McKennon A, Castillo PE, McKnight GS. Targeted deletion of AKAP7 in dentate granule cells impairs spatial discrimination. eLife 2016; 5. [PMID: 27911261 PMCID: PMC5135391 DOI: 10.7554/elife.20695] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 11/23/2016] [Indexed: 01/26/2023] Open
Abstract
Protein Kinase A (PKA) mediates synaptic plasticity and is widely implicated in learning and memory. The hippocampal dentate gyrus (DG) is thought to be responsible for processing and encoding distinct contextual associations in response to highly similar inputs. The mossy fiber (MF) axons of the dentate granule cells convey strong excitatory drive to CA3 pyramidal neurons and express presynaptic, PKA-dependent forms of plasticity. Here, we demonstrate an essential role for the PKA anchoring protein, AKAP7, in mouse MF axons and terminals. Genetic ablation of AKAP7 specifically from dentate granule cells results in disruption of MF-CA3 LTP directly initiated by cAMP, and the AKAP7 mutant mice are selectively deficient in pattern separation behaviors. Our results suggest that the AKAP7/PKA complex in the MF projections plays an essential role in synaptic plasticity and contextual memory formation. DOI:http://dx.doi.org/10.7554/eLife.20695.001
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Affiliation(s)
- Brian W Jones
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Jennifer Deem
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Thomas J Younts
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| | - Michael Weisenhaus
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Christina A Sanford
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Margaret C Slack
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Jenesa Chin
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Daniela Nachmanson
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Alex McKennon
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
| | - Pablo E Castillo
- Dominick P Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, United States
| | - G Stanley McKnight
- Department of Pharmacology, University of Washington School of Medicine, Seattle, United States
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AMPA Receptor Antagonist NBQX Decreased Seizures by Normalization of Perineuronal Nets. PLoS One 2016; 11:e0166672. [PMID: 27880801 PMCID: PMC5120819 DOI: 10.1371/journal.pone.0166672] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 11/02/2016] [Indexed: 12/15/2022] Open
Abstract
Epilepsy is a serious brain disorder with diverse seizure types and epileptic syndromes. AMPA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzoquinoxaline-2,3-dione (NBQX) attenuates spontaneous recurrent seizures in rats. However, the anti-epileptic effect of NBQX in chronic epilepsy model is poorly understood. Perineuronal nets (PNNs), specialized extracellular matrix structures, surround parvalbumin-positive inhibitory interneurons, and play a critical role in neuronal cell development and synaptic plasticity. Here, we focused on the potential involvement of PNNs in the treatment of epilepsy by NBQX. Rats were intraperitoneally (i.p.) injected with pentylenetetrazole (PTZ, 50 mg/kg) for 28 consecutive days to establish chronic epilepsy models. Subsequently, NBQX (20 mg/kg, i.p.) was injected for 3 days for the observation of behavioral measurements of epilepsy. The Wisteria floribundi agglutinin (WFA)-labeled PNNs were measured by immunohistochemical staining to evaluate the PNNs. The levels of three components of PNNs such as tenascin-R, aggrecan and neurocan were assayed by Western blot assay. The results showed that there are reduction of PNNs and decrease of tenascin-R, aggrecan and neurocan in the medial prefrontal cortex (mPFC) in the rats injected with PTZ. However, NBQX treatment normalized PNNs, tenascin-R, aggrecan and neurocan levels. NBQX was sufficient to decrease seizures through increasing the latency to seizures, decrease the duration of seizure onset, and reduce the scores for the severity of seizures. Furthermore, the degradation of mPFC PNNs by chondroitinase ABC (ChABC) exacerbated seizures in PTZ-treated rats. Finally, the anti-epileptic effect of NBQX was reversed by pretreatment with ChABC into mPFC. These findings revealed that PNNs degradation in mPFC is involved in the pathophysiology of epilepsy and enhancement of PNNs may be effective for the treatment of epilepsy.
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55
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Bennett MR, Arnold J, Hatton SN, Lagopoulos J. Regulation of fear extinction by long-term depression: The roles of endocannabinoids and brain derived neurotrophic factor. Behav Brain Res 2016; 319:148-164. [PMID: 27867101 DOI: 10.1016/j.bbr.2016.11.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 11/10/2016] [Accepted: 11/15/2016] [Indexed: 11/19/2022]
Abstract
The extinction of a conditioned fear response is of great interest in the search for a means of ameliorating adverse neurobiological changes resulting from stress. The discovery that endocannibinoid (EC) levels are inversely related to the extent of such stress, and that the amygdala is a primary site mediating stress, suggests that ECs in this brain region might play a major role in extinction. Supporting this are the observations that the basolateral complex of the amygdala shows an increase in ECs only during extinction and that early clinical trials indicate that cannabinoid-like agents, when taken orally by patients suffering from post traumatic stress disorder (PTSD), reduce insomnia and nightmares. In order to optimize the potential of these agents to ameliorate symptoms of PTSD four important questions need to be answered: first, what is the identity of the cells that release ECs in the amygdala during extinction; second, what are their sites of action; third, what roles do the ECs play in the alleviation of long- depression (LTD), a process central to extinction; and finally, to what extent does brain derived neurotrophic factor (BDNF) facilitate the release of ECs? A review of the relevant literature is presented in an attempt to answer these questions. It is suggested that the principal cell involved in EC synthesis and release during extinction is the so-called excitatory extinction neuron in the basal nucleus of the amygdala. Furthermore that the main site of action of the ECs is the adjacent calcitonin gene-related peptide inhibitory interneurons, whose normal role of blocking the excitatory neurons is greatly diminished. The molecular pathways leading (during extinction trials) to the synthesis and release of ECs from synaptic spines of extinction neurons, that is potentiated by BDNF, are also delineated in this review. Finally, consideration is given to how the autocrine action of BDNF, linked to the release of ECs, can lead to the sustained release of these, so maintaining extinction over long times.
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Affiliation(s)
- Maxwell R Bennett
- The Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW, Australia.
| | - Jonathon Arnold
- The Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW, Australia
| | - Sean N Hatton
- The Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW, Australia
| | - Jim Lagopoulos
- The Brain and Mind Centre, University of Sydney, 94 Mallett Street, Camperdown, NSW, Australia; The Sunshine Coast Mind and Neuroscience, Thompson Institute, The University of the Sunshine Coast, QLD, Australia
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56
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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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57
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Protein kinase C gamma-mediated phosphorylation of GluA1 in the postsynaptic density of spinal dorsal horn neurons accompanies neuropathic pain, and dephosphorylation by calcineurin is associated with prolonged analgesia. Pain 2016; 156:2514-2520. [PMID: 26270583 DOI: 10.1097/j.pain.0000000000000323] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Loss of calcineurin (protein phosphatase 3) activity and protein content in the postsynaptic density (PSD) of spinal dorsal horn neurons was associated with pain behavior after chronic constriction injury (CCI) of the rat sciatic nerve, and intrathecal administration of the phosphatase provided prolonged analgesia (Miletic et al. 2013). In this study, we examined whether one consequence of the loss of calcineurin was the persistent phosphorylation of the GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropioinic acid (AMPAR) receptors in the PSD. This would allow continual activation of AMPAR receptors at the synapse to help maintain a long-lasting enhancement of synaptic function, ie, neuropathic pain. We also investigated if the phosphorylation was mediated by protein kinase A (PKA), protein kinase C gamma (PKCγ), or calcium-calmodulin dependent kinase II (CaMKII), and if the prolonged calcineurin analgesia was associated with GluA1 dephosphorylation. Mechanical thresholds and thermal latencies were obtained before CCI. Seven days later, the behavioral testing was repeated before saline, calcineurin, or the specific peptide inhibitors of PKA (PKI-tide), PKCγ (PKC 19-31), or CaMKII (autocamtide-2-related inhibitory peptide) were injected intrathecally. The behavior was retested before the animals were euthanized and their PSD isolated. All CCI animals developed mechanical and thermal hypersensitivity. This was associated with phosphorylation of GluA1 in the ipsilateral PSD at Ser831 (but not Ser845) by PKCγ and not by PKA or CaMKII. Intrathecal treatment with calcineurin provided prolonged analgesia, and this was accompanied by GluA1 dephosphorylation. Therapy with calcineurin may prove useful in the prolonged clinical management of well-established neuropathic pain.
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58
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Zhuo M. Contribution of synaptic plasticity in the insular cortex to chronic pain. Neuroscience 2016; 338:220-229. [PMID: 27530697 DOI: 10.1016/j.neuroscience.2016.08.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/03/2016] [Accepted: 08/04/2016] [Indexed: 12/20/2022]
Abstract
Animal and human studies have consistently demonstrated that cortical regions are important for pain perception and pain-related emotional changes. Studies of the anterior cingulate cortex (ACC) have shown that adult cortical synapses can be modified after peripheral injuries, and long-term changes at synaptic level may contribute to long-lasting suffering in patients. It also explains why chronic pain is resistant to conventional analgesics that act by inhibiting synaptic transmission. Insular cortex (IC), another critical cortical area, is found to be highly plastic and can undergo long-term potentiation (LTP) after injury. Inhibiting IC LTP reduces behavioral sensitization caused by injury. LTP of glutamatergic transmission in pain related cortical areas serves as a key mechanism for chronic pain.
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Affiliation(s)
- Min Zhuo
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China; Centre for the Study of Pain, University of Toronto, Ontario M5S 1A8, Canada.
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59
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Saccà SC, Gandolfi S, Bagnis A, Manni G, Damonte G, Traverso CE, Izzotti A. From DNA damage to functional changes of the trabecular meshwork in aging and glaucoma. Ageing Res Rev 2016; 29:26-41. [PMID: 27242026 DOI: 10.1016/j.arr.2016.05.012] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/25/2016] [Accepted: 05/26/2016] [Indexed: 12/24/2022]
Abstract
Glaucoma is a degenerative disease of the eye. Both the anterior and posterior segments of the eye are affected, extensive damage being detectable in the trabecular meshwork and the inner retina-central visual pathway complex. Oxidative stress is claimed to be mainly responsible for molecular damage in the anterior chamber. Indeed, oxidation harms the trabecular meshwork, leading eventually to endothelial cell decay, tissue malfunction, subclinical inflammation, changes in the extracellular matrix and cytoskeleton, altered motility, reduced outflow facility and (ultimately) increased IOP. Moreover, free radicals are involved in aging and can be produced in the brain (as well as in the eye) as a result of ischemia, leading to oxidation of the surrounding neurons. Glaucoma-related cell death occurs by means of apoptosis, and apoptosis is triggered by oxidative stress via (a) mitochondrial damage, (b) inflammation, (c) endothelial dysregulation and dysfunction, and (d) hypoxia. The proteomics of the aqueous humor is significantly altered in glaucoma as a result of oxidation-induced trabecular damage. Those proteins whose aqueous humor levels are increased in glaucoma are biomarkers of trabecular meshwork impairment. Their diffusion from the anterior to the posterior segment of the eye may be relevant in the cascade of events triggering apoptosis in the inner retinal layers, including the ganglion cells.
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Affiliation(s)
- Sergio Claudio Saccà
- IRCCS San Martino University Hospital, Department of Neuroscience and Sense Organs, San Martino Hospital, Ophthalmology Unit, Viale Benedetto XV, 16132 Genoa, Italy.
| | - Stefano Gandolfi
- Ophthalmology Unit, Department of Biological, Biotechnological and Translational Sciences, University of Parma, Parma, Italy
| | - Alessandro Bagnis
- University of Genoa, Eye Clinic, Department of Neuroscience and Sense Organs, Viale Benedetto XV, 5, 16148 Genoa, Italy
| | - Gianluca Manni
- Dept. of Clinical Science and Translational Medicine, University Tor Vergata, Rome, Italy
| | - Gianluca Damonte
- Dept. of Experimental Medicine, Section of Biochemistry and Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV 1, 16132 Genoa, Italy
| | - Carlo Enrico Traverso
- University of Genoa, Eye Clinic, Department of Neuroscience and Sense Organs, Viale Benedetto XV, 5, 16148 Genoa, Italy
| | - Alberto Izzotti
- Mutagenesis Unit, IRCCS San Martino University Hospital, IST National Institute for Cancer Research, Department of Health Sciences, University of Genoa, Via A. Pastore 1, Genoa I-16132, Italy
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60
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AKAP220 manages apical actin networks that coordinate aquaporin-2 location and renal water reabsorption. Proc Natl Acad Sci U S A 2016; 113:E4328-37. [PMID: 27402760 DOI: 10.1073/pnas.1607745113] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Filtration through the kidney eliminates toxins, manages electrolyte balance, and controls water homeostasis. Reabsorption of water from the luminal fluid of the nephron occurs through aquaporin-2 (AQP2) water pores in principal cells that line the kidney-collecting duct. This vital process is impeded by formation of an "actin barrier" that obstructs the passive transit of AQP2 to the plasma membrane. Bidirectional control of AQP2 trafficking is managed by hormones and signaling enzymes. We have discovered that vasopressin-independent facets of this homeostatic mechanism are under the control of A-Kinase Anchoring Protein 220 (AKAP220; product of the Akap11 gene). CRISPR/Cas9 gene editing and imaging approaches show that loss of AKAP220 disrupts apical actin networks in organoid cultures. Similar defects are evident in tissue sections from AKAP220-KO mice. Biochemical analysis of AKAP220-null kidney extracts detected reduced levels of active RhoA GTPase, a well-known modulator of the actin cytoskeleton. Fluorescent imaging of kidney sections from these genetically modified mice revealed that RhoA and AQP2 accumulate at the apical surface of the collecting duct. Consequently, these animals are unable to appropriately dilute urine in response to overhydration. We propose that membrane-proximal signaling complexes constrained by AKAP220 impact the actin barrier dynamics and AQP2 trafficking to ensure water homeostasis.
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61
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Down-regulation of adenylate kinase 5 in temporal lobe epilepsy patients and rat model. J Neurol Sci 2016; 366:20-26. [DOI: 10.1016/j.jns.2016.04.037] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/01/2016] [Accepted: 04/19/2016] [Indexed: 11/19/2022]
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62
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Authement ME, Langlois LD, Kassis H, Gouty S, Dacher M, Shepard RD, Cox BM, Nugent FS. Morphine-induced synaptic plasticity in the VTA is reversed by HDAC inhibition. J Neurophysiol 2016; 116:1093-103. [PMID: 27306674 DOI: 10.1152/jn.00238.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 06/13/2016] [Indexed: 12/14/2022] Open
Abstract
Dopamine (DA) dysfunction originating from the ventral tegmental area (VTA) occurs as a result of synaptic abnormalities following consumption of drugs of abuse and underlies behavioral plasticity associated with drug abuse. Drugs of abuse can cause changes in gene expression through epigenetic mechanisms in the brain that underlie some of the lasting neuroplasticity and behavior associated with addiction. Here we investigated the function of histone acetylation and histone deacetylase (HDAC)2 in the VTA in recovery of morphine-induced synaptic modifications following a single in vivo exposure to morphine. Using a combination of immunohistochemistry, Western blot, and whole cell patch-clamp recording in rat midbrain slices, we show that morphine increased HDAC2 activity in VTA DA neurons and reduced histone H3 acetylation at lysine 9 (Ac-H3K9) in the VTA 24 h after the injection. Morphine-induced synaptic changes at glutamatergic synapses involved endocannabinoid signaling to reduce GABAergic synaptic strength onto VTA DA neurons. Both plasticities were recovered by in vitro incubation of midbrain slices with a class I-specific HDAC inhibitor (HDACi), CI-994, through an increase in acetylation of histone H3K9. Interestingly, HDACi incubation also increased levels of Ac-H3K9 and triggered GABAergic and glutamatergic plasticities in DA neurons of saline-treated rats. Our results suggest that acute morphine-induced changes in VTA DA activity and synaptic transmission engage HDAC2 activity locally in the VTA to maintain synaptic modifications through histone hypoacetylation.
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Affiliation(s)
- Michael E Authement
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Ludovic D Langlois
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Haifa Kassis
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Shawn Gouty
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Matthieu Dacher
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Ryan D Shepard
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Brian M Cox
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Fereshteh S Nugent
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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63
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Neis VB, Moretti M, Bettio LEB, Ribeiro CM, Rosa PB, Gonçalves FM, Lopes MW, Leal RB, Rodrigues ALS. Agmatine produces antidepressant-like effects by activating AMPA receptors and mTOR signaling. Eur Neuropsychopharmacol 2016; 26:959-71. [PMID: 27061850 DOI: 10.1016/j.euroneuro.2016.03.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 02/19/2016] [Accepted: 03/18/2016] [Indexed: 12/16/2022]
Abstract
The activation of AMPA receptors and mTOR signaling has been reported as mechanisms underlying the antidepressant effects of fast-acting agents, specially the NMDA receptor antagonist ketamine. In the present study, oral administration of agmatine (0.1mg/kg), a neuromodulator that has been reported to modulate NMDA receptors, caused a significant reduction in the immobility time of mice submitted to the tail suspension test (TST), an effect prevented by the administration of DNQX (AMPA receptor antagonist, 2.5μg/site, i.c.v.), BDNF antibody (1μg/site, i.c.v.), K-252a (TrkB receptor antagonist, 1μg/site, i.c.v.), LY294002 (PI3K inhibitor, 10nmol/site, i.c.v.) or rapamycin (selective mTOR inhibitor, 0.2nmol/site, i.c.v.). Moreover, the administration of lithium chloride (non-selective GSK-3β inhibitor, 10mg/kg, p.o.) or AR-A014418 (selective GSK-3β inhibitor, 0.01μg/site, i.c.v.) in combination with a sub-effective dose of agmatine (0.0001mg/kg, p.o.) reduced the immobility time in the TST when compared with either drug alone. Furthermore, increased immunocontents of BDNF, PSD-95 and GluA1 were found in the prefrontal cortex of mice just 1h after agmatine administration. These results indicate that the antidepressant-like effect of agmatine in the TST may be dependent on the activation of AMPA and TrkB receptors, PI3K and mTOR signaling as well as inhibition of GSK-3β, and increase in synaptic proteins. The results contribute to elucidate the complex signaling pathways involved in the antidepressant effect of agmatine and reinforce the pivotal role of these molecular targets for antidepressant responses.
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Affiliation(s)
- Vivian Binder Neis
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Morgana Moretti
- Post-Graduate Nutrition Program, Center of Health Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Luis Eduardo B Bettio
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Camille M Ribeiro
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Priscila Batista Rosa
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Filipe Marques Gonçalves
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Mark William Lopes
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Rodrigo Bainy Leal
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil
| | - Ana Lúcia S Rodrigues
- Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
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Montersino A, Thomas GM. Slippery signaling: Palmitoylation-dependent control of neuronal kinase localization and activity. Mol Membr Biol 2016; 32:179-88. [PMID: 27241460 DOI: 10.1080/09687688.2016.1182652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Modification of proteins with the lipid palmitate, a process called palmitoylation, is important for the normal function of neuronal cells. However, most attention has focused on how palmitoylation regulates the targeting and trafficking of neurotransmitter receptors and non-enzymatic scaffold proteins. In this review we discuss recent studies that suggest that palmitoylation also plays additional roles in neurons by controlling the localization, interactions and perhaps even the activity of protein kinases that play key roles in physiological neuronal regulation and in neuropathological processes.
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Affiliation(s)
- Audrey Montersino
- a Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair) and
| | - Gareth M Thomas
- a Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair) and.,b Department of Anatomy and Cell Biology , Temple University School of Medicine , Philadelphia , PA , USA
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65
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Kähne T, Richter S, Kolodziej A, Smalla KH, Pielot R, Engler A, Ohl FW, Dieterich DC, Seidenbecher C, Tischmeyer W, Naumann M, Gundelfinger ED. Proteome rearrangements after auditory learning: high-resolution profiling of synapse-enriched protein fractions from mouse brain. J Neurochem 2016; 138:124-38. [PMID: 27062398 PMCID: PMC5089584 DOI: 10.1111/jnc.13636] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 03/23/2016] [Accepted: 04/01/2016] [Indexed: 01/09/2023]
Abstract
Learning and memory processes are accompanied by rearrangements of synaptic protein networks. While various studies have demonstrated the regulation of individual synaptic proteins during these processes, much less is known about the complex regulation of synaptic proteomes. Recently, we reported that auditory discrimination learning in mice is associated with a relative down-regulation of proteins involved in the structural organization of synapses in various brain regions. Aiming at the identification of biological processes and signaling pathways involved in auditory memory formation, here, a label-free quantification approach was utilized to identify regulated synaptic junctional proteins and phosphoproteins in the auditory cortex, frontal cortex, hippocampus, and striatum of mice 24 h after the learning experiment. Twenty proteins, including postsynaptic scaffolds, actin-remodeling proteins, and RNA-binding proteins, were regulated in at least three brain regions pointing to common, cross-regional mechanisms. Most of the detected synaptic proteome changes were, however, restricted to individual brain regions. For example, several members of the Septin family of cytoskeletal proteins were up-regulated only in the hippocampus, while Septin-9 was down-regulated in the hippocampus, the frontal cortex, and the striatum. Meta analyses utilizing several databases were employed to identify underlying cellular functions and biological pathways. Data are available via ProteomeExchange with identifier PXD003089. How does the protein composition of synapses change in different brain areas upon auditory learning? We unravel discrete proteome changes in mouse auditory cortex, frontal cortex, hippocampus, and striatum functionally implicated in the learning process. We identify not only common but also area-specific biological pathways and cellular processes modulated 24 h after training, indicating individual contributions of the regions to memory processing.
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Affiliation(s)
- Thilo Kähne
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Sandra Richter
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Angela Kolodziej
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Institute of Biology, Otto von Guericke University, Magdeburg, Germany
| | - Karl-Heinz Smalla
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Rainer Pielot
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | | | - Frank W Ohl
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Institute of Biology, Otto von Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Daniela C Dieterich
- Center for Behavioral Brain Sciences, Magdeburg, Germany.,Institute of Pharmacology and Toxicology, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Constanze Seidenbecher
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Wolfgang Tischmeyer
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Michael Naumann
- Institute of Experimental Internal Medicine, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Eckart D Gundelfinger
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Molecular Neuroscience, Medical School, Otto von Guericke University, Magdeburg, Germany.,German Center for Neurodegenerative Diseases, Magdeburg, Germany
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66
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Reyland ME, Jones DNM. Multifunctional roles of PKCδ: Opportunities for targeted therapy in human disease. Pharmacol Ther 2016; 165:1-13. [PMID: 27179744 DOI: 10.1016/j.pharmthera.2016.05.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The serine-threonine protein kinase, protein kinase C-δ (PKCδ), is emerging as a bi-functional regulator of cell death and proliferation. Studies in PKCδ-/- mice have confirmed a pro-apoptotic role for this kinase in response to DNA damage and a tumor promoter role in some oncogenic contexts. In non-transformed cells, inhibition of PKCδ suppresses the release of cytochrome c and caspase activation, indicating a function upstream of apoptotic pathways. Data from PKCδ-/- mice demonstrate a role for PKCδ in the execution of DNA damage-induced and physiologic apoptosis. This has led to the important finding that inhibitors of PKCδ can be used therapeutically to reduce irradiation and chemotherapy-induced toxicity. By contrast, PKCδ is a tumor promoter in mouse models of mammary gland and lung cancer, and increased PKCδ expression is a negative prognostic indicator in Her2+ and other subtypes of human breast cancer. Understanding how these distinct functions of PKCδ are regulated is critical for the design of therapeutics to target this pathway. This review will discuss what is currently known about biological roles of PKCδ and prospects for targeting PKCδ in human disease.
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Affiliation(s)
- Mary E Reyland
- Department of Craniofacial Biology, School of Dental Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - David N M Jones
- Department of Pharmacology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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67
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Patriarchi T, Qian H, Di Biase V, Malik ZA, Chowdhury D, Price JL, Hammes EA, Buonarati OR, Westenbroek RE, Catterall WA, Hofmann F, Xiang YK, Murphy GG, Chen CY, Navedo MF, Hell JW. Phosphorylation of Cav1.2 on S1928 uncouples the L-type Ca2+ channel from the β2 adrenergic receptor. EMBO J 2016; 35:1330-45. [PMID: 27103070 DOI: 10.15252/embj.201593409] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 03/24/2016] [Indexed: 01/07/2023] Open
Abstract
Agonist-triggered downregulation of β-adrenergic receptors (ARs) constitutes vital negative feedback to prevent cellular overexcitation. Here, we report a novel downregulation of β2AR signaling highly specific for Cav1.2. We find that β2-AR binding to Cav1.2 residues 1923-1942 is required for β-adrenergic regulation of Cav1.2. Despite the prominence of PKA-mediated phosphorylation of Cav1.2 S1928 within the newly identified β2AR binding site, its physiological function has so far escaped identification. We show that phosphorylation of S1928 displaces the β2AR from Cav1.2 upon β-adrenergic stimulation rendering Cav1.2 refractory for several minutes from further β-adrenergic stimulation. This effect is lost in S1928A knock-in mice. Although AMPARs are clustered at postsynaptic sites like Cav1.2, β2AR association with and regulation of AMPARs do not show such dissociation. Accordingly, displacement of the β2AR from Cav1.2 is a uniquely specific desensitization mechanism of Cav1.2 regulation by highly localized β2AR/cAMP/PKA/S1928 signaling. The physiological implications of this mechanism are underscored by our finding that LTP induced by prolonged theta tetanus (PTT-LTP) depends on Cav1.2 and its regulation by channel-associated β2AR.
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Affiliation(s)
| | - Hai Qian
- Department of Pharmacology, University of Iowa, Iowa City, IA, USA
| | | | - Zulfiquar A Malik
- Department of Pharmacology, University of California, Davis, CA, USA Department of Pharmacology, University of Iowa, Iowa City, IA, USA
| | | | - Jennifer L Price
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Erik A Hammes
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | | | | | - Franz Hofmann
- Department of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany
| | - Yang K Xiang
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Geoffrey G Murphy
- Department of Molecular & Integrative Physiology, Molecular & Behavioral Neuroscience Institute University of Michigan, Ann Arbor, MI, USA
| | - Chao-Ye Chen
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA Department of Pharmacology, University of Iowa, Iowa City, IA, USA
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68
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Cassoli JS, Iwata K, Steiner J, Guest PC, Turck CW, Nascimento JM, Martins-de-Souza D. Effect of MK-801 and Clozapine on the Proteome of Cultured Human Oligodendrocytes. Front Cell Neurosci 2016; 10:52. [PMID: 26973466 PMCID: PMC4776125 DOI: 10.3389/fncel.2016.00052] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 02/15/2016] [Indexed: 01/06/2023] Open
Abstract
Separate lines of evidence have demonstrated the involvement of N-methyl-D-aspartate (NMDA) receptor and oligodendrocyte dysfunctions in schizophrenia. Here, we have carried out shotgun mass spectrometry proteome analysis of oligodendrocytes treated with the NMDA receptor antagonist MK-801 to gain potential insights into these effects at the molecular level. The MK-801 treatment led to alterations in the levels of 68 proteins, which are associated with seven distinct biological processes. Most of these proteins are involved in energy metabolism and many have been found to be dysregulated in previous proteomic studies of post-mortem brain tissues from schizophrenia patients. Finally, addition of the antipsychotic clozapine to MK-801-treated oligodendrocyte cultures resulted in changes in the levels of 45 proteins and treatment with clozapine alone altered 122 proteins and many of these showed opposite changes to the MK-801 effects. Therefore, these proteins and the associated energy metabolism pathways should be explored as potential biomarkers of antipsychotic efficacy. In conclusion, MK-801 treatment of oligodendrocytes may provide a useful model for testing the efficacy of novel treatment approaches.
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Affiliation(s)
- Juliana S Cassoli
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas Campinas, Brazil
| | - Keiko Iwata
- United Graduate School of Child Development, Department of Development of Functional Brain Activities, Research Center for Child Mental Development, Hamamatsu University School of Medicine, Osaka University and Kanazawa University and Chiba University and University of Fukui Fukui, Japan
| | - Johann Steiner
- Department of Psychiatry, University of Magdeburg Magdeburg, Germany
| | - Paul C Guest
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas Campinas, Brazil
| | - Christoph W Turck
- Department of Translational Research in Psychiatry, Max Planck Institute of Psychiatry Munich, Germany
| | - Juliana M Nascimento
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of CampinasCampinas, Brazil; D'Or Institute for Research and Education Rio de Janeiro, Brazil
| | - Daniel Martins-de-Souza
- Laboratory of Neuroproteomics, Department of Biochemistry and Tissue Biology, Institute of Biology, University of CampinasCampinas, Brazil; UNICAMP Neurobiology CenterCampinas, Brazil
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69
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McClatchy DB, Savas JN, Martínez-Bartolomé S, Park SK, Maher P, Powell SB, Yates JR. Global quantitative analysis of phosphorylation underlying phencyclidine signaling and sensorimotor gating in the prefrontal cortex. Mol Psychiatry 2016; 21:205-15. [PMID: 25869802 PMCID: PMC4605830 DOI: 10.1038/mp.2015.41] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/27/2015] [Accepted: 03/02/2015] [Indexed: 01/09/2023]
Abstract
Prepulse inhibition (PPI) is an example of sensorimotor gating and deficits in PPI have been demonstrated in schizophrenia patients. Phencyclidine (PCP) suppression of PPI in animals has been studied to elucidate the pathological elements of schizophrenia. However, the molecular mechanisms underlying PCP treatment or PPI in the brain are still poorly understood. In this study, quantitative phosphoproteomic analysis was performed on the prefrontal cortex from rats that were subjected to PPI after being systemically injected with PCP or saline. PCP downregulated phosphorylation events were significantly enriched in proteins associated with long-term potentiation (LTP). Importantly, this data set identifies functionally novel phosphorylation sites on known LTP-associated signaling molecules. In addition, mutagenesis of a significantly altered phosphorylation site on xCT (SLC7A11), the light chain of system xc-, the cystine/glutamate antiporter, suggests that PCP also regulates the activity of this protein. Finally, new insights were also derived on PPI signaling independent of PCP treatment. This is the first quantitative phosphorylation proteomic analysis providing new molecular insights into sensorimotor gating.
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Affiliation(s)
| | - Jeffrey N. Savas
- Department of Chemical Physiology, The Scripps Research Institute
| | | | - Sung Kyu Park
- Department of Chemical Physiology, The Scripps Research Institute
| | - Pamela Maher
- Cellular Neurobiology Laboratory, Salk Institute
| | | | - John R. Yates
- Department of Chemical Physiology, The Scripps Research Institute
- Corresponding Author:
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70
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Kennedy EJ, Scott JD. Selective disruption of the AKAP signaling complexes. Methods Mol Biol 2015; 1294:137-50. [PMID: 25783883 DOI: 10.1007/978-1-4939-2537-7_11] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Synthesis of the second messenger cAMP activates a variety of signaling pathways critical for all facets of intracellular regulation. Protein kinase A (PKA) is the major cAMP-responsive effector. Where and when this enzyme is activated has profound implications on the cellular role of PKA. A-Kinase Anchoring Proteins (AKAPs) play a critical role in this process by orchestrating spatial and temporal aspects of PKA action. A popular means of evaluating the impact of these anchored signaling events is to biochemically interfere with the PKA-AKAP interface. Hence, peptide disruptors of PKA anchoring are valuable tools in the investigation of local PKA action. This article outlines the development of PKA isoform-selective disruptor peptides, documents the optimization of cell-soluble peptide derivatives, and introduces alternative cell-based approaches that interrogate other aspects of the PKA-AKAP interface.
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Affiliation(s)
- Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, Athens, GA, USA
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71
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Increased expression of copine VI in patients with refractory epilepsy and a rat model. J Neurol Sci 2015; 360:30-6. [PMID: 26723968 DOI: 10.1016/j.jns.2015.11.041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 10/25/2015] [Accepted: 11/20/2015] [Indexed: 02/06/2023]
Abstract
Copine VI (CPNE6) is a member of copines family, a calcium-dependent phospholipids-binding protein group found in many diverse eukaryotic organisms. Although earlier studies have shown that CPNE6 is almost exclusively expressed in brain, the exact biological functions remain unclear. The purpose of this study is to explore the relationship between epilepsy and CPNE6 expression. In present study, we investigated the expression pattern and distribution of CPNE6 in patients with refractory epilepsy and in a chronic pilocarpine-induced epileptic rat model by quantitative real-time PCR, Western blot and immunofluorescence. The results showed that the expression of CPNE6 increased remarkably in epileptic patients and in experimental epileptic rats. Double immunofluorescence labeling studies have revealed that CPNE6 protein is mainly expressed in neurons, demonstrated by co-localization with the dendritic marker, MAP2. Our results are the first to indicate that the abnormal expression of the CPNE6 in epileptic brain tissue may play an important role in epilepsy, especially refractory epilepsy.
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72
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Womersley JS, Uys JD. S-Glutathionylation and Redox Protein Signaling in Drug Addiction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 137:87-121. [PMID: 26809999 DOI: 10.1016/bs.pmbts.2015.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drug addiction is a chronic relapsing disorder that comes at a high cost to individuals and society. Therefore understanding the mechanisms by which drugs exert their effects is of prime importance. Drugs of abuse increase the production of reactive oxygen and nitrogen species resulting in oxidative stress. This change in redox homeostasis increases the conjugation of glutathione to protein cysteine residues; a process called S-glutathionylation. Although traditionally regarded as a protective mechanism against irreversible protein oxidation, accumulated evidence suggests a more nuanced role for S-glutathionylation, namely as a mediator in redox-sensitive protein signaling. The reversible modification of protein thiols leading to alteration in function under different physiologic/pathologic conditions provides a mechanism whereby change in redox status can be translated into a functional response. As such, S-glutathionylation represents an understudied means of post-translational protein modification that may be important in the mechanisms underlying drug addiction. This review will discuss the evidence for S-glutathionylation as a redox-sensing mechanism and how this may be involved in the response to drug-induced oxidative stress. The function of S-glutathionylated proteins involved in neurotransmission, dendritic spine structure, and drug-induced behavioral outputs will be reviewed with specific reference to alcohol, cocaine, and heroin.
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Affiliation(s)
- Jacqueline S Womersley
- Department of Cellular and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Joachim D Uys
- Department of Cellular and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, South Carolina, USA.
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73
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Woolfrey KM, Dell'Acqua ML. Coordination of Protein Phosphorylation and Dephosphorylation in Synaptic Plasticity. J Biol Chem 2015; 290:28604-12. [PMID: 26453308 DOI: 10.1074/jbc.r115.657262] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A central theme in nervous system function is equilibrium: synaptic strengths wax and wane, neuronal firing rates adjust up and down, and neural circuits balance excitation with inhibition. This push/pull regulatory theme carries through to the molecular level at excitatory synapses, where protein function is controlled through phosphorylation and dephosphorylation by kinases and phosphatases. However, these opposing enzymatic activities are only part of the equation as scaffolding interactions and assembly of multi-protein complexes are further required for efficient, localized synaptic signaling. This review will focus on coordination of postsynaptic serine/threonine kinase and phosphatase signaling by scaffold proteins during synaptic plasticity.
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Affiliation(s)
- Kevin M Woolfrey
- From the Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado 80045
| | - Mark L Dell'Acqua
- From the Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado 80045
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74
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Ma J, Duan Y, Qin Z, Wang J, Liu W, Xu M, Zhou S, Cao X. Overexpression of αCaMKII impairs behavioral flexibility and NMDAR-dependent long-term depression in the medial prefrontal cortex. Neuroscience 2015; 310:528-40. [PMID: 26415772 DOI: 10.1016/j.neuroscience.2015.09.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 09/02/2015] [Accepted: 09/20/2015] [Indexed: 01/24/2023]
Abstract
The medial prefrontal cortex (mPFC) participates in the behavioral flexibility. As a major downstream molecule in the NMDA receptor signaling, alpha-Ca(2+)/calmodulin-dependent protein kinase II (αCaMKII) is crucial for hippocampal long-term potentiation (LTP) and hippocampus-related memory. However, the role of αCaMKII in mPFC-related behavioral flexibility and mPFC synaptic plasticity remains elusive. In the present study, using chemical-genetic approaches to temporally up-regulate αCaMKII activity, we found that αCaMKII-F89G transgenic mice exhibited impaired behavioral flexibility in Y-water maze arm reversal task. Notably, in vitro electrophysiological analysis showed normal basal synaptic transmission, LTP and depotentiation, but selectively impaired NMDAR-dependent long-term depression (LTD) in the mPFC of αCaMKII-F89G transgenic mice. In accordance with the deficit in NMDAR-dependent LTD, αCaMKII-F89G transgenic mice exhibited impaired AMPAR internalization during NMDAR-dependent chemical LTD expression in the mPFC. Furthermore, the above deficits in behavioral flexibility, NMDAR-dependent LTD and AMPAR internalization could all be reversed by 1-naphthylmethyl (NM)-PP1, a specific inhibitor of exogenous αCaMKII-F89G activity. Taken together, our results for the first time indicate that αCaMKII overexpression in the forebrain impairs behavioral flexibility and NMDAR-dependent LTD in the mPFC, and supports the notion that there is a close relationship between NMDAR-dependent LTD and behavioral flexibility.
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Affiliation(s)
- J Ma
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - Y Duan
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - Z Qin
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - J Wang
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - W Liu
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - M Xu
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - S Zhou
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China
| | - X Cao
- Key Laboratory of Brain Functional Genomics (East China Normal University), Ministry of Education, Shanghai Key Laboratory of Brain Functional Genomics (East China Normal University), School of Life Sciences, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China.
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75
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Wu XL, Huang H, Huang YY, Yuan JX, Zhou X, Chen YM. Reduced Pumilio-2 expression in patients with temporal lobe epilepsy and in the lithium-pilocarpine induced epilepsy rat model. Epilepsy Behav 2015; 50:31-9. [PMID: 26101106 DOI: 10.1016/j.yebeh.2015.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/08/2015] [Accepted: 05/09/2015] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Drosophila Pumilio (Pum), a homolog of mammalian Pum2, plays an important role in translational regulation in the central nervous system (CNS), particularly for dendrite outgrowth and neuronal excitability. We investigated the expression pattern and cellular distribution of Pum2 in patients with drug-refractory temporal lobe epilepsy (TLE) and rats with lithium chloride-pilocarpine-induced epilepsy. METHODS Real-time quantitative PCR (RT-qPCR), Western blot, immunohistochemistry, and double-labeled immunofluorescence were utilized to determine the expression level and distribution of Pum2 in temporal neocortex tissues from patients with intractable TLE (n=20) and patients with severe head trauma (n=20) in addition to the hippocampus and adjacent cortex of rats with lithium chloride-pilocarpine-induced TLE and controls. RESULTS Pum2 was expressed in the cell bodies and dendrites of neurons but did not colocalize with glial fibrillary acidic protein-positive astrocytes or propidium iodide (PI) in nuclei. The expression of Pum2 was significantly reduced in patients and rats with TLE in comparison to controls (P<0.05). CONCLUSION Pum2 expression was less in patients with TLE and a rodent model of epilepsy, suggesting that decreased expression of Pum2 may be involved in the pathogenesis of TLE.
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Affiliation(s)
- Xu-Ling Wu
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Hao Huang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Yun-Yi Huang
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Jin-Xian Yuan
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Xin Zhou
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China
| | - Yang-Mei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 74 Lin Jiang Road, Chongqing 400010, China.
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Region-specific alterations of AMPA receptor phosphorylation and signaling pathways in the pilocarpine model of epilepsy. Neurochem Int 2015; 87:22-33. [DOI: 10.1016/j.neuint.2015.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 05/06/2015] [Accepted: 05/07/2015] [Indexed: 01/27/2023]
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77
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Nygren PJ, Scott JD. Therapeutic strategies for anchored kinases and phosphatases: exploiting short linear motifs and intrinsic disorder. Front Pharmacol 2015; 6:158. [PMID: 26283967 PMCID: PMC4516873 DOI: 10.3389/fphar.2015.00158] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 07/16/2015] [Indexed: 12/17/2022] Open
Abstract
Phosphorylation events that occur in response to the second messenger cAMP are controlled spatially and temporally by protein kinase A (PKA) interacting with A-kinase anchoring proteins (AKAPs). Recent advances in understanding the structural basis for this interaction have reinforced the hypothesis that AKAPs create spatially constrained signaling microdomains. This has led to the realization that the PKA/AKAP interface is a potential drug target for modulating a plethora of cell-signaling events. Pharmacological disruption of kinase–AKAP interactions has previously been explored for disease treatment and remains an interesting area of research. However, disrupting or enhancing the association of phosphatases with AKAPs is a therapeutic concept of equal promise, particularly since they oppose the actions of many anchored kinases. Accordingly, numerous AKAPs bind phosphatases such as protein phosphatase 1 (PP1), calcineurin (PP2B), and PP2A. These multimodal signaling hubs are equally able to control the addition of phosphate groups onto target substrates, as well as the removal of these phosphate groups. In this review, we describe recent advances in structural analysis of kinase and phosphatase interactions with AKAPs, and suggest future possibilities for targeting these interactions for therapeutic benefit.
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Affiliation(s)
- Patrick J Nygren
- Department of Pharmacology, University of Washington Seattle, WA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
| | - John D Scott
- Department of Pharmacology, University of Washington Seattle, WA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
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78
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Wang Y, Ho TG, Franz E, Hermann JS, Smith FD, Hehnly H, Esseltine JL, Hanold LE, Murph MM, Bertinetti D, Scott JD, Herberg FW, Kennedy EJ. PKA-type I selective constrained peptide disruptors of AKAP complexes. ACS Chem Biol 2015; 10:1502-10. [PMID: 25765284 DOI: 10.1021/acschembio.5b00009] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A-Kinase Anchoring Proteins (AKAPs) coordinate complex signaling events by serving as spatiotemporal modulators of cAMP-dependent protein kinase activity in cells. Although AKAPs organize a plethora of diverse pathways, their cellular roles are often elusive due to the dynamic nature of these signaling complexes. AKAPs can interact with the type I or type II PKA holoenzymes by virtue of high-affinity interactions with the R-subunits. As a means to delineate AKAP-mediated PKA signaling in cells, we sought to develop isoform-selective disruptors of AKAP signaling. Here, we report the development of conformationally constrained peptides named RI-STapled Anchoring Disruptors (RI-STADs) that target the docking/dimerization domain of the type 1 regulatory subunit of PKA. These high-affinity peptides are isoform-selective for the RI isoforms, can outcompete binding by the classical AKAP disruptor Ht31, and can selectively displace RIα, but not RIIα, from binding the dual-specific AKAP149 complex. Importantly, these peptides are cell-permeable and disrupt Type I PKA-mediated phosphorylation events in the context of live cells. Hence, RI-STAD peptides are versatile cellular tools to selectively probe anchored type I PKA signaling events.
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Affiliation(s)
- Yuxiao Wang
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Tienhuei G. Ho
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Eugen Franz
- Department
of Biochemistry, University of Kassel, 34132 Kassel, Germany
| | | | - F. Donelson Smith
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Heidi Hehnly
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Jessica L. Esseltine
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | - Laura E. Hanold
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Mandi M. Murph
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | | | - John D. Scott
- Howard
Hughes Medical Institute, Department of Pharmacology, University of Washington School of Medicine, Seattle, Washington 98195, United States
| | | | - Eileen J. Kennedy
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
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79
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Microglia-dependent alteration of glutamatergic synaptic transmission and plasticity in the hippocampus during peripheral inflammation. J Neurosci 2015; 35:4942-52. [PMID: 25810524 DOI: 10.1523/jneurosci.4485-14.2015] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Peripheral inflammatory diseases are often associated with behavioral comorbidities including anxiety, depression, and cognitive dysfunction, but the mechanism for these is not well understood. Changes in the neuronal and synaptic functions associated with neuroinflammation may underlie these behavioral abnormalities. We have used a model of colonic inflammation induced by 2,4,6-trinitrobenzenesulfonic acid in Sprague Dawley rats to identify inflammation-induced changes in hippocampal synaptic transmission. Hippocampal slices obtained 4 d after the induction of inflammation revealed enhanced Schaffer collateral-induced excitatory field potentials in CA1 stratum radiatum. This was associated with larger-amplitude mEPSCs, but unchanged mEPSC frequencies and paired-pulse ratios, suggesting altered postsynaptic effects. Both AMPA- and NMDA-mediated synaptic currents were enhanced, and analysis of AMPA-mediated currents revealed increased contributions of GluR2-lacking receptors. In keeping with this, both transcripts and protein levels of the GluR2 subunit were reduced in hippocampus. Both long-term potentiation (LTP) and depression (LTD) were significantly reduced in hippocampal slices taken from inflamed animals. Chronic administration of the microglial/macrophage activation inhibitor minocycline to the inflamed animals both lowered the level of the cytokine tumor necrosis factor α in the hippocampus and completely abolished the effect of peripheral inflammation on the field potentials and synaptic plasticity (LTP and LTD). Our results reveal profound synaptic changes caused by a mirror microglia-mediated inflammatory response in hippocampus during peripheral organ inflammation. These synaptic changes may underlie the behavioral comorbidities seen in patients.
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80
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Challenor M, O'Hare Doig R, Fuller P, Giacci M, Bartlett C, Wale CH, Cozens GS, Hool L, Dunlop S, Swaminathan Iyer K, Rodger J, Fitzgerald M. Prolonged glutamate excitotoxicity increases GluR1 immunoreactivity but decreases mRNA of GluR1 and associated regulatory proteins in dissociated rat retinae in vitro. Biochimie 2015; 112:160-71. [DOI: 10.1016/j.biochi.2015.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/06/2015] [Indexed: 12/15/2022]
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81
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Kantamneni S. Cross-talk and regulation between glutamate and GABAB receptors. Front Cell Neurosci 2015; 9:135. [PMID: 25914625 PMCID: PMC4392697 DOI: 10.3389/fncel.2015.00135] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 03/23/2015] [Indexed: 12/16/2022] Open
Abstract
Brain function depends on co-ordinated transmission of signals from both excitatory and inhibitory neurotransmitters acting upon target neurons. NMDA, AMPA and mGluR receptors are the major subclasses of glutamate receptors that are involved in excitatory transmission at synapses, mechanisms of activity dependent synaptic plasticity, brain development and many neurological diseases. In addition to canonical role of regulating presynaptic release and activating postsynaptic potassium channels, GABAB receptors also regulate glutamate receptors. There is increasing evidence that metabotropic GABAB receptors are now known to play an important role in modulating the excitability of circuits throughout the brain by directly influencing different types of postsynaptic glutamate receptors. Specifically, GABAB receptors affect the expression, activity and signaling of glutamate receptors under physiological and pathological conditions. Conversely, NMDA receptor activity differentially regulates GABAB receptor subunit expression, signaling and function. In this review I will describe how GABAB receptor activity influence glutamate receptor function and vice versa. Such a modulation has widespread implications for the control of neurotransmission, calcium-dependent neuronal function, pain pathways and in various psychiatric and neurodegenerative diseases.
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Affiliation(s)
- Sriharsha Kantamneni
- Bradford School of Pharmacy, School of Life Sciences, University of Bradford Bradford, West Yorkshire, UK
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82
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The palmitoyl acyltransferase DHHC2 regulates recycling endosome exocytosis and synaptic potentiation through palmitoylation of AKAP79/150. J Neurosci 2015; 35:442-56. [PMID: 25589740 DOI: 10.1523/jneurosci.2243-14.2015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Phosphorylation and dephosphorylation of AMPA-type ionotropic glutamate receptors (AMPARs) by kinases and phosphatases and interactions with scaffold proteins play essential roles in regulating channel biophysical properties and trafficking events that control synaptic strength during NMDA receptor-dependent synaptic plasticity, such as LTP and LTD. We previously demonstrated that palmitoylation of the AMPAR-linked scaffold protein A-kinase anchoring protein (AKAP) 79/150 is required for its targeting to recycling endosomes in dendrites, where it regulates exocytosis from these compartments that is required for LTP-stimulated enlargement of postsynaptic dendritic spines, delivery of AMPARs to the plasma membrane, and maintenance of synaptic potentiation. Here, we report that the recycling endosome-resident palmitoyl acyltransferase DHHC2 interacts with and palmitoylates AKAP79/150 to regulate these plasticity signaling mechanisms. In particular, RNAi-mediated knockdown of DHHC2 expression in rat hippocampal neurons disrupted stimulation of exocytosis from recycling endosomes, enlargement of dendritic spines, AKAP recruitment to spines, and potentiation of AMPAR-mediated synaptic currents that occur during LTP. Importantly, expression of a palmitoylation-independent lipidated AKAP mutant in DHHC2-deficient neurons largely restored normal plasticity regulation. Thus, we conclude that DHHC2-AKAP79/150 signaling is an essential regulator of dendritic recycling endosome exocytosis that controls both structural and functional plasticity at excitatory synapses.
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83
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Zhang J, Shapiro MS. Mechanisms and dynamics of AKAP79/150-orchestrated multi-protein signalling complexes in brain and peripheral nerve. J Physiol 2015; 594:31-7. [PMID: 25653013 DOI: 10.1113/jphysiol.2014.287698] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 01/30/2015] [Indexed: 01/24/2023] Open
Abstract
A-kinase anchoring proteins (AKAPs) have emerged as a converging point of diverse signals to achieve spatiotemporal resolution of directed cellular regulation. With the extensive studies of AKAP79/150 in regulation of ion channel activity, the major questions to be posed centre on the mechanism and functional role of synergistic regulation of ion channels by such signalling proteins. In this review, we summarize recent discoveries of AKAP79/150-mediated modulation of voltage-gated neuronal M-type (KCNQ, Kv7) K(+) channels and L-type CaV 1 Ca(2+) channels, on both short- and longer-term time scales, highlighting the dynamics of the macromolecular signalling complexes in brain and peripheral nerve We also discuss several models for the possible mechanisms of these multi-protein assemblies and how they serve the agenda of the neurons in which they occur.
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Affiliation(s)
- Jie Zhang
- Department of Physiology, University of Texas Health Science Centre at San Antonio, San Antonio, TX, USA
| | - Mark S Shapiro
- Department of Physiology, University of Texas Health Science Centre at San Antonio, San Antonio, TX, USA
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84
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Krenz WDC, Rodgers EW, Baro DJ. Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin. PLoS One 2015; 10:e0117965. [PMID: 25692473 PMCID: PMC4333293 DOI: 10.1371/journal.pone.0117965] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/05/2015] [Indexed: 01/11/2023] Open
Abstract
Volume transmission results in phasic and tonic modulatory signals. The actions of tonic dopamine (DA) at type 1 DA receptors (D1Rs) are largely undefined. Here we show that tonic 5nM DA acts at D1Rs to stabilize neuronal output over minutes by enabling activity-dependent regulation of the hyperpolarization activated current (I h). In the presence but not absence of 5nM DA, I h maximal conductance (G max) was adjusted according to changes in slow wave activity in order to maintain spike timing. Our study on the lateral pyloric neuron (LP), which undergoes rhythmic oscillations in membrane potential with depolarized plateaus, demonstrated that incremental, bi-directional changes in plateau duration produced corresponding alterations in LP I hG max when preparations were superfused with saline containing 5nM DA. However, when preparations were superfused with saline alone there was no linear correlation between LP I hGmax and duty cycle. Thus, tonic nM DA modulated the capacity for activity to modulate LP I h G max; this exemplifies metamodulation (modulation of modulation). Pretreatment with the Ca2+-chelator, BAPTA, or the specific PKA inhibitor, PKI, prevented all changes in LP I h in 5nM DA. Calcineurin inhibitors blocked activity-dependent changes enabled by DA and revealed a PKA-mediated, activity-independent enhancement of LP I hG max. These data suggested that tonic 5nM DA produced two simultaneous, PKA-dependent effects: a direct increase in LP I h G max and a priming event that permitted calcineurin regulation of LP I h. The latter produced graded reductions in LP I hG max with increasing duty cycles. We also demonstrated that this metamodulation preserved the timing of LP’s first spike when network output was perturbed with bath-applied 4AP. In sum, 5nM DA permits slow wave activity to provide feedback that maintains spike timing, suggesting that one function of low-level, tonic modulation is to stabilize specific features of a dynamic output.
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Affiliation(s)
- Wulf-Dieter C. Krenz
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Edmund W. Rodgers
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
| | - Deborah J. Baro
- Department of Biology, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
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85
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Fukuda M, Aizawa Y. Hypothetical geneC18orf42encodes a novel protein kinase A-binding protein. Genes Cells 2015; 20:267-80. [DOI: 10.1111/gtc.12217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 12/11/2014] [Indexed: 11/27/2022]
Affiliation(s)
- Makiha Fukuda
- Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Yokohama 226-8501 Japan
| | - Yasunori Aizawa
- Graduate School of Bioscience and Biotechnology; Tokyo Institute of Technology; Yokohama 226-8501 Japan
- Centre for Biological Resources and Informatics; Tokyo Institute of Technology; Yokohama 226-8501 Japan
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86
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Galván EJ, Pérez-Rosello T, Gómez-Lira G, Lara E, Gutiérrez R, Barrionuevo G. Synapse-specific compartmentalization of signaling cascades for LTP induction in CA3 interneurons. Neuroscience 2015; 290:332-45. [PMID: 25637803 DOI: 10.1016/j.neuroscience.2015.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/15/2015] [Accepted: 01/15/2015] [Indexed: 11/28/2022]
Abstract
Inhibitory interneurons with somata in strata radiatum and lacunosum-molecular (SR/L-M) of hippocampal area CA3 receive excitatory input from pyramidal cells via the recurrent collaterals (RCs), and the dentate gyrus granule cells via the mossy fibers (MFs). Here we demonstrate that Hebbian long-term potentiation (LTP) at RC synapses on SR/L-M interneurons requires the concomitant activation of calcium-impermeable AMPARs (CI-AMPARs) and N-methyl-d-aspartate receptors (NMDARs). RC LTP was prevented by voltage clamping the postsynaptic cell during high-frequency stimulation (HFS; 3 trains of 100 pulses delivered at 100 Hz every 10s), with intracellular injections of the Ca(2+) chelator BAPTA (20mM), and with the NMDAR antagonist D-AP5. In separate experiments, RC and MF inputs converging onto the same interneuron were sequentially activated. We found that RC LTP induction was blocked by inhibitors of the calcium/calmodulin-dependent protein kinase II (CaMKII; KN-62, 10 μM or KN-93, 10 μM) but MF LTP was CaMKII independent. Conversely, the application of the protein kinase A (PKA) activators forskolin/IBMX (50 μM/25 μM) potentiated MF EPSPs but not RC EPSPs. Together these data indicate that the aspiny dendrites of SR/L-M interneurons compartmentalize synapse-specific Ca(2+) signaling required for LTP induction at RC and MF synapses. We also show that the two signal transduction cascades converge to activate a common effector, protein kinase C (PKC). Specifically, LTP at RC and MF synapses on the same SR/LM interneuron was blocked by postsynaptic injections of chelerythrine (10 μM). These data indicate that both forms of LTP share a common mechanism involving PKC-dependent signaling modulation.
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Affiliation(s)
- E J Galván
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, Mexico.
| | - T Pérez-Rosello
- Department of Physiology, Northwestern University, Chicago, IL, USA
| | - G Gómez-Lira
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, Mexico
| | - E Lara
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, Mexico
| | - R Gutiérrez
- Departamento de Farmacobiología, Cinvestav Sede Sur, México City, Mexico
| | - G Barrionuevo
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
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87
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GluA1 phosphorylation contributes to postsynaptic amplification of neuropathic pain in the insular cortex. J Neurosci 2015; 34:13505-15. [PMID: 25274827 DOI: 10.1523/jneurosci.1431-14.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Long-term potentiation of glutamatergic transmission has been observed after physiological learning or pathological injuries in different brain regions, including the spinal cord, hippocampus, amygdala, and cortices. The insular cortex is a key cortical region that plays important roles in aversive learning and neuropathic pain. However, little is known about whether excitatory transmission in the insular cortex undergoes plastic changes after peripheral nerve injury. Here, we found that peripheral nerve ligation triggered the enhancement of AMPA receptor (AMPAR)-mediated excitatory synaptic transmission in the insular cortex. The synaptic GluA1 subunit of AMPAR, but not the GluA2/3 subunit, was increased after nerve ligation. Genetic knock-in mice lacking phosphorylation of the Ser845 site, but not that of the Ser831 site, blocked the enhancement of the synaptic GluA1 subunit, indicating that GluA1 phosphorylation at the Ser845 site by protein kinase A (PKA) was critical for this upregulation after nerve injury. Furthermore, A-kinase anchoring protein 79/150 (AKAP79/150) and PKA were translocated to the synapses after nerve injury. Genetic deletion of adenylyl cyclase subtype 1 (AC1) prevented the translocation of AKAP79/150 and PKA, as well as the upregulation of synaptic GluA1-containing AMPARs. Pharmacological inhibition of calcium-permeable AMPAR function in the insular cortex reduced behavioral sensitization caused by nerve injury. Our results suggest that the expression of AMPARs is enhanced in the insular cortex after nerve injury by a pathway involving AC1, AKAP79/150, and PKA, and such enhancement may at least in part contribute to behavioral sensitization together with other cortical regions, such as the anterior cingulate and the prefrontal cortices.
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88
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Han J, Wu P, Wang F, Chen J. S-palmitoylation regulates AMPA receptors trafficking and function: a novel insight into synaptic regulation and therapeutics. Acta Pharm Sin B 2015; 5:1-7. [PMID: 26579419 PMCID: PMC4629138 DOI: 10.1016/j.apsb.2014.12.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 01/11/2023] Open
Abstract
Glutamate acting on AMPA-type ionotropic glutamate receptor (AMPAR) mediates the majority of fast excitatory synaptic transmission in the mammalian central nervous system. Dynamic regulation of AMPAR by post-translational modifications is one of the key elements that allow the nervous system to adapt to environment stimulations. S-palmitoylation, an important lipid modification by post-translational addition of a long-chain fatty acid to a cysteine residue, regulates AMPA receptor trafficking, which dynamically affects multiple fundamental brain functions, such as learning and memory. In vivo, S-palmitoylation is controlled by palmitoyl acyl transferases and palmitoyl thioesterases. In this review, we highlight advances in the mechanisms for dynamic AMPA receptors palmitoylation, and discuss how palmitoylation affects AMPA receptors function at synapses in recent years. Pharmacological regulation of S-palmitoylation may serve as a novel therapeutic strategy for neurobiological diseases.
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Key Words
- 17-ODYA, 17-octadecynoic acid
- ABE, acyl-biotinyl exchange
- ABP, AMPA receptor binding protein
- AD, Alzheimer׳s disease
- AKAP79/150, A-kinase anchoring protein 79/150
- AMPA receptors
- AMPAR, α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor
- APT1, acyl-protein thioesterase-1
- APT2, acyl-protein thioesterase-2
- CP-AMPARs, Ca2+-permeable AMPARs
- DHHC
- DHHC, aspartate-histidine-histidine-cysteine
- FMRP, fragile X mental retardation protein
- FXS, Fragile X syndrome
- GAP-43, growth associated protein-43
- GRIP, glutamate receptor interacting protein
- LTD, long-term depression
- LTP, long-term potentiation
- PATs, palmitoyl acyl transferases
- PDZ, postsynaptic density-95/discs large/zona occludens-1
- PICK1, protein interacting with C-kinase 1
- PKA, protein kinase A
- PKC, protein kinase C
- PPT1, palmitoyl-protein thioesterase-1
- PSD-95, postsynaptic density-95
- Palmitoylation
- Ras, rat sarcoma
- SNAP-23, soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor protein-23
- Trafficking
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Nakamura Y, Darnieder LM, Deeb TZ, Moss SJ. Regulation of GABAARs by phosphorylation. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 72:97-146. [PMID: 25600368 PMCID: PMC5337123 DOI: 10.1016/bs.apha.2014.11.008] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
γ-Aminobutyric acid type A receptors (GABAARs) are the principal mediators of fast synaptic inhibition in the brain as well as the low persistent extrasynaptic inhibition, both of which are fundamental to proper brain function. Thus unsurprisingly, deficits in GABAARs are implicated in a number of neurological disorders and diseases. The complexity of GABAAR regulation is determined not only by the heterogeneity of these receptors but also by its posttranslational modifications, the foremost, and best characterized of which is phosphorylation. This review will explore the details of this dynamic process, our understanding of which has barely scratched the surface. GABAARs are regulated by a number of kinases and phosphatases, and its phosphorylation plays an important role in governing its trafficking, expression, and interaction partners. Here, we summarize the progress in understanding the role phosphorylation plays in the regulation of GABAARs. This includes how phosphorylation can affect the allosteric modulation of GABAARs, as well as signaling pathways that affect GABAAR phosphorylation. Finally, we discuss the dysregulation of GABAAR phosphorylation and its implication in disease processes.
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90
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Down-regulation of Stargazin inhibits the enhanced surface delivery of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor GluR1 subunit in rat dorsal horn and ameliorates postoperative pain. Anesthesiology 2014; 121:609-19. [PMID: 25093662 DOI: 10.1097/aln.0000000000000291] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Stargazin is the first transmembrane protein known to regulate synaptic targeting of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors. However, it is unclear whether regulation of the surface delivery of spinal AMPA receptor subunits by stargazin contributes to postoperative pain development. METHODS Western blot analysis was used to examine changes in the surface delivery of AMPA receptor subunits, GluR1 and GluR2, in rat dorsal horn. The interaction between stargazin and GluR1 and GluR2 was examined by coimmunoprecipitation. Expression of stargazin was suppressed by intrathecal administration of small interfering RNA311. RESULTS Membrane-bound GluR1, but not GluR2, in ipsilateral dorsal horn was increased at 3 h (1.49 ± 0.15-fold of β-tubulin, mean ± SEM) and 1 day (1.03 ± 0.25) after incision, as compared with that in control rats (naive, 0.63 ± 0.23, P < 0.05, n = 6 per group). The amount of GluR1 coimmunoprecipitated with stargazin was greater at 3 h after incision (1.48 ± 0.31-fold of input) than that in control animals (0.45 ± 0.24, P < 0.05, n = 6 per group). Importantly, the increase in membrane GluR1 at 3 h after incision was normalized to near control level (0.72 ± 0.20-fold of β-tubulin) by pretreatment with intrathecal stargazin small interfering RNA311 (0.87 ± 0.09), but not scrambled small interfering RNA (1.48 ± 0.24) or vehicle (1.25 ± 0.13, P < 0.05, n = 6 per group). Stargazin small interfering RNA311 pretreatment prevented the increase in stargazin-GluR1 interaction and decreased postoperative pain after incision. CONCLUSIONS This study suggests a critical role of stargazin-mediated surface delivery of GluR1 subunit in the development of postoperative pain. A better therapeutic strategy for postoperative pain may involve selectively down-regulating spinal stargazin to inhibit synaptic targeting of GluR1 subunit.
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91
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Diering GH, Gustina AS, Huganir RL. PKA-GluA1 coupling via AKAP5 controls AMPA receptor phosphorylation and cell-surface targeting during bidirectional homeostatic plasticity. Neuron 2014; 84:790-805. [PMID: 25451194 PMCID: PMC4254581 DOI: 10.1016/j.neuron.2014.09.024] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2014] [Indexed: 11/29/2022]
Abstract
Bidirectional synaptic plasticity occurs locally at individual synapses during long-term potentiation (LTP) or long-term depression (LTD), or globally during homeostatic scaling. LTP, LTD, and homeostatic scaling alter synaptic strength through changes in postsynaptic AMPA-type glutamate receptors (AMPARs), suggesting the existence of overlapping molecular mechanisms. Phosphorylation controls AMPAR trafficking during LTP/LTD. We addressed the role of AMPAR phosphorylation during homeostatic scaling. We observed bidirectional changes of the levels of phosphorylated GluA1 S845 during scaling, resulting from a loss of protein kinase A (PKA) from synapses during scaling down and enhanced activity of PKA in synapses during scaling up. Increased phosphorylation of S845 drove scaling up, while a knockin mutation of S845, or knockdown of the scaffold AKAP5, blocked scaling up. Finally, we show that AMPARs scale differentially based on their phosphorylation status at S845. These results show that rearrangement in PKA signaling controls AMPAR phosphorylation and surface targeting during homeostatic plasticity.
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Affiliation(s)
- Graham H Diering
- Department of Neuroscience and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Hunterian 1001, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Ahleah S Gustina
- Department of Neuroscience and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Hunterian 1001, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Richard L Huganir
- Department of Neuroscience and Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Hunterian 1001, 725 North Wolfe Street, Baltimore, MD 21205, USA.
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92
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Kobori N, Moore AN, Dash PK. Altered regulation of protein kinase a activity in the medial prefrontal cortex of normal and brain-injured animals actively engaged in a working memory task. J Neurotrauma 2014; 32:139-48. [PMID: 25027811 DOI: 10.1089/neu.2014.3487] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) signaling is required for short- and long-term memory. In contrast, enhanced PKA activity has been shown to impair working memory, a prefrontal cortex (PFC)-dependent, transient form of memory critical for cognition and goal-directed behaviors. Working memory can be impaired after traumatic brain injury (TBI) in the absence of overt damage to the PFC. The cellular and molecular mechanisms that contribute to this deficit are largely unknown. In the present study, we examined whether altered PKA signaling in the PFC as a result of TBI is a contributing mechanism. We measured PKA activity in medial PFC (mPFC) tissue homogenates prepared from sham and 14-day postinjury rats. PKA activity was measured both when animals were inactive and when actively engaged in a spatial working memory task. Our results demonstrate, for the first time, that PKA activity in the mPFC is actively suppressed in uninjured animals performing a working memory task. By comparison, both basal and working memory-related PKA activity was elevated in TBI animals. Inhibition of PKA activity by intra-mPFC administration of Rp-cAMPS into TBI animals had no influence on working memory performance 30 min postinfusion, but significantly improved working memory when tested 24 h later. This improvement was associated with reduced glutamic acid decarboxylase 67 messenger RNA levels. Taken together, these results suggest that TBI-associated working memory dysfunction may result, in part, from enhanced PKA activity, possibly leading to altered expression of plasticity-related genes in the mPFC.
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Affiliation(s)
- Nobuhide Kobori
- 1 Vivian L. Smith Department of Neurosurgery, The University of Texas Medical School at Houston , Houston, Texas
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93
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Novel insights into the neurobiology underlying LRRK2-linked Parkinson's disease. Neuropharmacology 2014; 85:45-56. [DOI: 10.1016/j.neuropharm.2014.05.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2014] [Revised: 04/16/2014] [Accepted: 05/10/2014] [Indexed: 01/08/2023]
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94
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Jayakar SS, Pugh PC, Dale Z, Starr ER, Cole S, Margiotta JF. PACAP induces plasticity at autonomic synapses by nAChR-dependent NOS1 activation and AKAP-mediated PKA targeting. Mol Cell Neurosci 2014; 63:1-12. [PMID: 25168001 DOI: 10.1016/j.mcn.2014.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/06/2014] [Accepted: 08/23/2014] [Indexed: 12/12/2022] Open
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a pleiotropic neuropeptide found at synapses throughout the central and autonomic nervous system. We previously found that PACAP engages a selective G-protein coupled receptor (PAC1R) on ciliary ganglion neurons to rapidly enhance quantal acetylcholine (ACh) release from presynaptic terminals via neuronal nitric oxide synthase (NOS1) and cyclic AMP/protein kinase A (PKA) dependent processes. Here, we examined how PACAP stimulates NO production and targets resultant outcomes to synapses. Scavenging extracellular NO blocked PACAP-induced plasticity supporting a retrograde (post- to presynaptic) NO action on ACh release. Live-cell imaging revealed that PACAP stimulates NO production by mechanisms requiring NOS1, PKA and Ca(2+) influx. Ca(2+)-permeable nicotinic ACh receptors composed of α7 subunits (α7-nAChRs) are potentiated by PKA-dependent PACAP/PAC1R signaling and were required for PACAP-induced NO production and synaptic plasticity since both outcomes were drastically reduced following their selective inhibition. Co-precipitation experiments showed that NOS1 associates with α7-nAChRs, many of which are perisynaptic, as well as with heteromeric α3*-nAChRs that generate the bulk of synaptic activity. NOS1-nAChR physical association could facilitate NO production at perisynaptic and adjacent postsynaptic sites to enhance focal ACh release from juxtaposed presynaptic terminals. The synaptic outcomes of PACAP/PAC1R signaling are localized by PKA anchoring proteins (AKAPs). PKA regulatory-subunit overlay assays identified five AKAPs in ganglion lysates, including a prominent neuronal subtype. Moreover, PACAP-induced synaptic plasticity was selectively blocked when PKA regulatory-subunit binding to AKAPs was inhibited. Taken together, our findings indicate that PACAP/PAC1R signaling coordinates nAChR, NOS1 and AKAP activities to induce targeted, retrograde plasticity at autonomic synapses. Such coordination has broad relevance for understanding the control of autonomic synapses and consequent visceral functions.
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Affiliation(s)
- Selwyn S Jayakar
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
| | - Phyllis C Pugh
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
| | - Zack Dale
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
| | - Eric R Starr
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
| | - Samantha Cole
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
| | - Joseph F Margiotta
- Department of Neurosciences, University of Toledo, College of Medicine and Life Sciences, United States.
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95
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Kim S, Ziff EB. Calcineurin mediates synaptic scaling via synaptic trafficking of Ca2+-permeable AMPA receptors. PLoS Biol 2014; 12:e1001900. [PMID: 24983627 PMCID: PMC4077568 DOI: 10.1371/journal.pbio.1001900] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 05/22/2014] [Indexed: 11/19/2022] Open
Abstract
Kim and Ziff examine the molecular mechanism of synaptic scaling, showing that inhibition of neuronal excitability reduces calcium influx into neurons, resulting in decreased calcineurin activity. This leads to increased surface expression of calcium-permeable AMPA receptors as a homeostatic response. Homeostatic synaptic plasticity is a negative-feedback mechanism for compensating excessive excitation or inhibition of neuronal activity. When neuronal activity is chronically suppressed, neurons increase synaptic strength across all affected synapses via synaptic scaling. One mechanism for this change is alteration of synaptic AMPA receptor (AMPAR) accumulation. Although decreased intracellular Ca2+ levels caused by chronic inhibition of neuronal activity are believed to be an important trigger of synaptic scaling, the mechanism of Ca2+-mediated AMPAR-dependent synaptic scaling is not yet understood. Here, we use dissociated mouse cortical neurons and employ Ca2+ imaging, electrophysiological, cell biological, and biochemical approaches to describe a novel mechanism in which homeostasis of Ca2+ signaling modulates activity deprivation-induced synaptic scaling by three steps: (1) suppression of neuronal activity decreases somatic Ca2+ signals; (2) reduced activity of calcineurin, a Ca2+-dependent serine/threonine phosphatase, increases synaptic expression of Ca2+-permeable AMPARs (CPARs) by stabilizing GluA1 phosphorylation; and (3) Ca2+ influx via CPARs restores CREB phosphorylation as a homeostatic response by Ca2+-induced Ca2+ release from the ER. Therefore, we suggest that synaptic scaling not only maintains neuronal stability by increasing postsynaptic strength but also maintains nuclear Ca2+ signaling by synaptic expression of CPARs and ER Ca2+ propagation. Synaptic scaling is a form of homeostatic plasticity that normalizes the strength of synapses (the structure that allows nerve cells to communicate) and is triggered by chronic inhibition of neuronal activity. Although extensive studies have been conducted, the molecular mechanism of this synaptic adaptation is not understood. Using cultured cortical neurons, we show that chronic inhibition of neuronal activity reduces calcium influx into neurons, which, in turn, decreases the activity of the calcium-dependent phosphatase calcineurin. These changes lead to an increase in GluA1-containing, calcium-permeable AMPA receptors, which mediate communication at the synapse. Newly inserted calcium-permeable AMPA receptors restore calcium currents, which enhance synaptic strength and recover calcium signaling. We also show that inhibition or activation of calcineurin activity is sufficient to induce or block synaptic scaling, respectively, suggesting that calcineurin is an important mediator of homeostatic synaptic plasticity. Taken together, our findings show that synaptic scaling is a homeostatic process that not only enhances synaptic transmission but also maintains calcium signaling in neurons under activity deprivation.
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Affiliation(s)
- Seonil Kim
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, New York, United States of America
| | - Edward B. Ziff
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, New York, United States of America
- * E-mail:
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96
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He Y, Kulasiri D, Samarasinghe S. Systems biology of synaptic plasticity: a review on N-methyl-D-aspartate receptor mediated biochemical pathways and related mathematical models. Biosystems 2014; 122:7-18. [PMID: 24929130 DOI: 10.1016/j.biosystems.2014.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Revised: 06/05/2014] [Accepted: 06/06/2014] [Indexed: 10/25/2022]
Abstract
Synaptic plasticity, an emergent property of synaptic networks, has shown strong correlation to one of the essential functions of the brain, memory formation. Through understanding synaptic plasticity, we hope to discover the modulators and mechanisms that trigger memory formation. In this paper, we first review the well understood modulators and mechanisms underlying N-methyl-D-aspartate receptor dependent synaptic plasticity, a major form of synaptic plasticity in hippocampus, and then comment on the key mathematical modelling approaches available in the literature to understand synaptic plasticity as the integration of the established functionalities of synaptic components.
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Affiliation(s)
- Y He
- Centre for Advanced Computational Solutions (C-fACS), Molecular Biosciences Department, Lincoln University, Christchurch, New Zealand
| | - D Kulasiri
- Centre for Advanced Computational Solutions (C-fACS), Molecular Biosciences Department, Lincoln University, Christchurch, New Zealand.
| | - S Samarasinghe
- Centre for Advanced Computational Solutions (C-fACS), Molecular Biosciences Department, Lincoln University, Christchurch, New Zealand
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97
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Park AJ, Havekes R, Choi JH, Luczak V, Nie T, Huang T, Abel T. A presynaptic role for PKA in synaptic tagging and memory. Neurobiol Learn Mem 2014; 114:101-112. [PMID: 24882624 DOI: 10.1016/j.nlm.2014.05.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/01/2014] [Accepted: 05/04/2014] [Indexed: 12/14/2022]
Abstract
Protein kinase A (PKA) and other signaling molecules are spatially restricted within neurons by A-kinase anchoring proteins (AKAPs). Although studies on compartmentalized PKA signaling have focused on postsynaptic mechanisms, presynaptically anchored PKA may contribute to synaptic plasticity and memory because PKA also regulates presynaptic transmitter release. Here, we examine this issue using genetic and pharmacological application of Ht31, a PKA anchoring disrupting peptide. At the hippocampal Schaffer collateral CA3-CA1 synapse, Ht31 treatment elicits a rapid decay of synaptic responses to repetitive stimuli, indicating a fast depletion of the readily releasable pool of synaptic vesicles. The interaction between PKA and proteins involved in producing this pool of synaptic vesicles is supported by biochemical assays showing that synaptic vesicle protein 2 (SV2), Rim1, and SNAP25 are components of a complex that interacts with cAMP. Moreover, acute treatment with Ht31 reduces the levels of SV2. Finally, experiments with transgenic mouse lines, which express Ht31 in excitatory neurons at the Schaffer collateral CA3-CA1 synapse, highlight a requirement for presynaptically anchored PKA in pathway-specific synaptic tagging and long-term contextual fear memory. These results suggest that a presynaptically compartmentalized PKA is critical for synaptic plasticity and memory by regulating the readily releasable pool of synaptic vesicles.
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Affiliation(s)
- Alan Jung Park
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
| | - Robbert Havekes
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
| | - Jennifer Hk Choi
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
| | - Vince Luczak
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
| | - Ting Nie
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA.,Department of Pediatrics, Emory University, VAMC, 1670 Clairmont Rd Atlanta, GA 30033, USA
| | - Ted Huang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
| | - Ted Abel
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104-6018, USA
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98
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AKAP-anchored PKA maintains neuronal L-type calcium channel activity and NFAT transcriptional signaling. Cell Rep 2014; 7:1577-1588. [PMID: 24835999 DOI: 10.1016/j.celrep.2014.04.027] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 03/18/2014] [Accepted: 04/15/2014] [Indexed: 11/23/2022] Open
Abstract
L-type voltage-gated Ca2+ channels (LTCC) couple neuronal excitation to gene transcription. LTCC activity is elevated by the cyclic AMP (cAMP)-dependent protein kinase (PKA) and depressed by the Ca2+-dependent phosphatase calcineurin (CaN), and both enzymes are localized to the channel by A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 anchoring of CaN also promotes LTCC activation of transcription through dephosphorylation of the nuclear factor of activated T cells (NFAT). We report here that the basal activity of AKAP79/150-anchored PKA maintains neuronal LTCC coupling to CaN-NFAT signaling by preserving LTCC phosphorylation in opposition to anchored CaN. Genetic disruption of AKAP-PKA anchoring promoted redistribution of the kinase out of postsynaptic dendritic spines, profound decreases in LTCC phosphorylation and Ca2+ influx, and impaired NFAT movement to the nucleus and activation of transcription. Thus, LTCC-NFAT transcriptional signaling in neurons requires precise organization and balancing of PKA and CaN activities in the channel nanoenvironment, which is only made possible by AKAP79/150 scaffolding.
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99
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Fischer MJM, McNaughton PA. How anchoring proteins shape pain. Pharmacol Ther 2014; 143:316-22. [PMID: 24727631 DOI: 10.1016/j.pharmthera.2014.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 03/28/2014] [Indexed: 11/29/2022]
Abstract
Cellular responsiveness to external stimuli can be altered by extracellular mediators which activate membrane receptors, in turn signalling to the intracellular space via calcium, cyclic nucleotides, membrane lipids or enzyme activity. These signalling events trigger a cascade leading to an effector which can be a channel, an enzyme or a transcription factor. The effectiveness of these intracellular events is enhanced when they are maintained in close proximity by anchoring proteins, which assemble complexes of signalling molecules such as kinases together with their targets, and in this way enhance both the speed and the precision of intracellular signalling. The A kinase anchoring protein (AKAP) family are adaptor proteins originally named for their ability to associate Protein Kinase A and its targets, but several other enzymes bound by AKAPs have now been found and a wide variety of target structures has been described. This review provides an overview of anchoring proteins involved in pain signalling. The key anchoring proteins and their ion channel targets in primary sensory neurons responding to painful stimuli (nociceptors) are discussed.
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Affiliation(s)
- Michael J M Fischer
- Institute of Physiology and Pathophysiology, FAU Erlangen-Nürnberg, Germany.
| | - Peter A McNaughton
- Wolfson Centre for Age-Related Research, Hodgkin Building, King's College London, London SE1 1UH, UK
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100
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Wang Y, Ho TG, Bertinetti D, Neddermann M, Franz E, Mo GCH, Schendowich LP, Sukhu A, Spelts RC, Zhang J, Herberg FW, Kennedy EJ. Isoform-selective disruption of AKAP-localized PKA using hydrocarbon stapled peptides. ACS Chem Biol 2014; 9:635-42. [PMID: 24422448 PMCID: PMC3985448 DOI: 10.1021/cb400900r] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
![]()
A-kinase
anchoring proteins (AKAPs) play an important role in the
spatial and temporal regulation of protein kinase A (PKA) by scaffolding
critical intracellular signaling complexes. Here we report the design
of conformationally constrained peptides that disrupt interactions
between PKA and AKAPs in an isoform-selective manner. Peptides derived
from the A Kinase Binding (AKB) domain of several AKAPs were chemically
modified to contain an all-hydrocarbon staple and target the docking/dimerization
domain of PKA-R, thereby occluding AKAP interactions. The peptides
are cell-permeable against diverse human cell lines, are highly isoform-selective
for PKA-RII, and can effectively inhibit interactions between AKAPs
and PKA-RII in intact cells. These peptides can be applied as useful
reagents in cell-based studies to selectively disrupt AKAP-localized
PKA-RII activity and block AKAP signaling complexes. In summary, the
novel hydrocarbon-stapled peptides developed in this study represent
a new class of AKAP disruptors to study compartmentalized RII-regulated
PKA signaling in cells.
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Affiliation(s)
- Yuxiao Wang
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Tienhuei G. Ho
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | | | | | - Eugen Franz
- Department
of Biochemistry, University of Kassel, 34132 Kassel, Germany
| | - Gary C. H. Mo
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Lewis P. Schendowich
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Avinash Sukhu
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Raybun C. Spelts
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Jin Zhang
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | | | - Eileen J. Kennedy
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
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