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Aizawa K. The multiple realization of human color vision revisited. Front Psychol 2022; 13:985267. [PMID: 36204742 PMCID: PMC9531652 DOI: 10.3389/fpsyg.2022.985267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 08/30/2022] [Indexed: 11/27/2022] Open
Abstract
Over the last 25 years, there has been a concerted effort to settle questions about multiple realization by bringing detailed scientific evidence to bear. Ken Aizawa and Carl Gillett have pursued this scientific approach to multiple realization with a precise theory and applications. This paper reviews the application of the Dimensioned approach to human color vision, addressing objections that have appeared in the literature.
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Historical perspective and progress on protein ubiquitination at glutamatergic synapses. Neuropharmacology 2021; 196:108690. [PMID: 34197891 DOI: 10.1016/j.neuropharm.2021.108690] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 06/07/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022]
Abstract
Transcription-translation coupling leads to the production of proteins that are key for controlling essential neuronal processes that include neuronal development and changes in synaptic strength. Although these events have been a prevailing theme in neuroscience, the regulation of proteins via posttranslational signaling pathways are equally relevant for these neuronal processes. Ubiquitin is one type of posttranslational modification that covalently attaches to its targets/substrates. Ubiquitination of proteins play a key role in multiple signaling pathways, the predominant being removal of its substrates by a large molecular machine called the proteasome. Here, I review 40 years of progress on ubiquitination in the nervous system at glutamatergic synapses focusing on axon pathfinding, synapse formation, presynaptic release, dendritic spine formation, and regulation of postsynaptic glutamate receptors. Finally, I elucidate emerging themes in ubiquitin biology that may challenge our current understanding of ubiquitin signaling in the nervous system.
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Walters ET. Nociceptive Biology of Molluscs and Arthropods: Evolutionary Clues About Functions and Mechanisms Potentially Related to Pain. Front Physiol 2018; 9:1049. [PMID: 30123137 PMCID: PMC6085516 DOI: 10.3389/fphys.2018.01049] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/16/2018] [Indexed: 01/15/2023] Open
Abstract
Important insights into the selection pressures and core molecular modules contributing to the evolution of pain-related processes have come from studies of nociceptive systems in several molluscan and arthropod species. These phyla, and the chordates that include humans, last shared a common ancestor approximately 550 million years ago. Since then, animals in these phyla have continued to be subject to traumatic injury, often from predators, which has led to similar adaptive behaviors (e.g., withdrawal, escape, recuperative behavior) and physiological responses to injury in each group. Comparisons across these taxa provide clues about the contributions of convergent evolution and of conservation of ancient adaptive mechanisms to general nociceptive and pain-related functions. Primary nociceptors have been investigated extensively in a few molluscan and arthropod species, with studies of long-lasting nociceptive sensitization in the gastropod, Aplysia, and the insect, Drosophila, being especially fruitful. In Aplysia, nociceptive sensitization has been investigated as a model for aversive memory and for hyperalgesia. Neuromodulator-induced, activity-dependent, and axotomy-induced plasticity mechanisms have been defined in synapses, cell bodies, and axons of Aplysia primary nociceptors. Studies of nociceptive sensitization in Drosophila larvae have revealed numerous molecular contributors in primary nociceptors and interacting cells. Interestingly, molecular contributors examined thus far in Aplysia and Drosophila are largely different, but both sets overlap extensively with those in mammalian pain-related pathways. In contrast to results from Aplysia and Drosophila, nociceptive sensitization examined in moth larvae (Manduca) disclosed central hyperactivity but no obvious peripheral sensitization of nociceptive responses. Squid (Doryteuthis) show injury-induced sensitization manifested as behavioral hypersensitivity to tactile and especially visual stimuli, and as hypersensitivity and spontaneous activity in nociceptor terminals. Temporary blockade of nociceptor activity during injury subsequently increased mortality when injured squid were exposed to fish predators, providing the first demonstration in any animal of the adaptiveness of nociceptive sensitization. Immediate responses to noxious stimulation and nociceptive sensitization have also been examined behaviorally and physiologically in a snail (Helix), octopus (Adopus), crayfish (Astacus), hermit crab (Pagurus), and shore crab (Hemigrapsus). Molluscs and arthropods have systems that suppress nociceptive responses, but whether opioid systems play antinociceptive roles in these phyla is uncertain.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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Fischbach S, Kopec AM, Carew TJ. Activity-dependent inhibitory gating in molecular signaling cascades induces a novel form of intermediate-term synaptic facilitation in Aplysia californica. Learn Mem 2014; 21:199-204. [PMID: 24639486 PMCID: PMC3966539 DOI: 10.1101/lm.033894.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/31/2014] [Indexed: 11/24/2022]
Abstract
Mechanistically distinct forms of long-lasting plasticity and memory can be induced by a variety of different training patterns. Although several studies have identified distinct molecular pathways that are engaged during these different training patterns, relatively little work has explored potential interactions between pathways when they are simultaneously engaged in the same neurons and circuits during memory formation. Aplysia californica exhibits two forms of intermediate-term synaptic facilitation (ITF) in response to two different training patterns: (1) repeated trial (RT) ITF (induced by repeated tail nerve shocks [TNSs] or repeated serotonin [5HT] application) and (2) activity-dependent (AD) ITF (induced by sensory neuron activation paired with a single TNS or 5HT pulse). RT-ITF requires PKA activation and de novo protein synthesis, while AD-ITF requires PKC activation and has no requirement for protein synthesis. Here, we explored how these distinct molecular pathways underlying ITF interact when both training patterns occur in temporal register (an "Interactive" training pattern). We found that (1) RT, AD, and Interactive training all induce ITF; (2) Interactive ITF requires PKC activity but not de novo protein synthesis; and (3), surprisingly, Interactive training blocks persistent PKA activity 1 h after training, and this block is PKC-independent. These data support the hypothesis that sensory neuron activity coincident with the last RT training trial is sufficient to convert the molecular signaling already established by RT training into an AD-like molecular phenotype.
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Affiliation(s)
- Soren Fischbach
- Department of Neurobiology & Behavior, University of California–Irvine, Irvine, California 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, USA
| | - Ashley M. Kopec
- Department of Neurobiology & Behavior, University of California–Irvine, Irvine, California 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, USA
- Center for Neural Science, New York University, New York 10003, USA
| | - Thomas J. Carew
- Department of Neurobiology & Behavior, University of California–Irvine, Irvine, California 92697, USA
- Center for the Neurobiology of Learning and Memory, University of California–Irvine, Irvine, California 92697, USA
- Center for Neural Science, New York University, New York 10003, USA
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Day ME, Gaietta GM, Sastri M, Koller A, Mackey MR, Scott JD, Perkins GA, Ellisman MH, Taylor SS. Isoform-specific targeting of PKA to multivesicular bodies. ACTA ACUST UNITED AC 2011; 193:347-63. [PMID: 21502359 PMCID: PMC3080257 DOI: 10.1083/jcb.201010034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PKA RIα subunit is localized to MVBs by the A-kinase–anchoring protein AKAP11 when disassociated from the PKA catalytic subunit. Although RII protein kinase A (PKA) regulatory subunits are constitutively localized to discrete cellular compartments through binding to A-kinase–anchoring proteins (AKAPs), RI subunits are primarily diffuse in the cytoplasm. In this paper, we report a novel AKAP-dependent localization of RIα to distinct organelles, specifically, multivesicular bodies (MVBs). This localization depends on binding to AKAP11, which binds tightly to free RIα or RIα in complex with catalytic subunit (holoenzyme). However, recruitment to MVBs occurs only with the release of PKA catalytic subunit (PKAc). This recruitment is reversed by reassociation with PKAc, and it is disrupted by the presence of AKAP peptides, mutations in the RIα AKAP-binding site, or knockdown of AKAP11. Cyclic adenosine monophosphate binding not only unleashes active PKAc but also leads to the targeting of AKAP11:RIα to MVBs. Therefore, we show that the RIα holoenzyme is part of a signaling complex with AKAP11, in which AKAP11 may direct RIα functionality after disassociation from PKAc. This model defines a new paradigm for PKA signaling.
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Affiliation(s)
- Michele E Day
- Bioinformatics Program, University of California at San Diego, La Jolla, CA 92093, USA
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Sun Y, Monje FJ, Pollak DD, Lubec G. A first partial Aplysia californica proteome. Amino Acids 2010; 41:955-68. [PMID: 21069399 DOI: 10.1007/s00726-010-0795-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 10/20/2010] [Indexed: 11/28/2022]
Abstract
Aplysia proteins have not been studied systematically and it was therefore the aim of the study to carry out protein profiling in ganglia from Aplysia californica (AC). AC ganglia were extirpated, proteins extracted and run on 2DE with subsequent in-gel digestion, followed by identification of proteins by nano-LC-ESI-MS/MS on an ion trap. Proteins were identified based upon a public Aplysia EST database. Out of 408 picked spots, 276 spots were identified corresponding to 172 ESTs and 118 individual proteins. The range of sequence coverage was between 14 and 80% and the average amount of peptides used for the identification of proteins was 9 (from 3 to 24). Mean score for protein identification was 516. Comparison of protein levels between cerebral, pleural, pedal and abdominal ganglia revealed a series of significant differences including: signaling, metabolism, cytoskeleton and structural, redox, chaperone, replication/transcription and electron/proton transport proteins. The generation of a protein map complements transcriptional studies carried out in AC ganglia. The findings provide the basis for investigation into post-translational modifications, splice variants and assist in the generation of antibodies against AC proteins. Moreover, differences in protein expression between ganglia may be valuable for the design of future studies in neurobiology of AC.
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Affiliation(s)
- Yanwei Sun
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
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Reyes FD, Walters ET. Long-lasting synaptic potentiation induced by depolarization under conditions that eliminate detectable Ca2+ signals. J Neurophysiol 2009; 103:1283-94. [PMID: 20042699 DOI: 10.1152/jn.00704.2009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activity-dependent alterations of synaptic transmission important for learning and memory are often induced by Ca(2+) signals generated by depolarization. While it is widely assumed that Ca(2+) is the essential transducer of depolarization into cellular plasticity, little effort has been made to test whether Ca(2+)-independent responses to depolarization might also induce memory-like alterations. It was recently discovered that peripheral axons of nociceptive sensory neurons in Aplysia display long-lasting hyperexcitability triggered by conditioning depolarization in the absence of Ca(2+) entry (using nominally Ca(2+)-free solutions containing EGTA, "0Ca/EGTA") or the absence of detectable Ca(2+) transients (adding BAPTA-AM, "0Ca/EGTA/BAPTA-AM"). The current study reports that depolarization of central ganglia to approximately 0 mV for 2 min in these same solutions induced hyperexcitability lasting >1 h in sensory neuron processes near their synapses onto motor neurons. Furthermore, conditioning depolarization in these solutions produced a 2.5-fold increase in excitatory postsynaptic potential (EPSP) amplitude 1-3 h afterward despite a drop in motor neuron input resistance. Depolarization in 0 Ca/EGTA produced long-term potentiation (LTP) of the EPSP lasting > or = 1 days without changing postsynaptic input resistance. When re-exposed to extracellular Ca(2+) during synaptic tests, prior exposure to 0Ca/EGTA or to 0Ca/EGTA/BAPTA-AM decreased sensory neuron survival. However, differential effects on neuronal health are unlikely to explain the observed potentiation because conditioning depolarization in these solutions did not alter survival rates. These findings suggest that unrecognized Ca(2+)-independent signals can transduce depolarization into long-lasting synaptic potentiation, perhaps contributing to persistent synaptic alterations following large, sustained depolarizations that occur during learning, neural injury, or seizures.
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Affiliation(s)
- Fredy D Reyes
- Dept. of Integrative Biology and Pharmacology, University of Texas Medical School, Houston, TX 77030, USA
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Sossin WS, Abrams TW. Evolutionary conservation of the signaling proteins upstream of cyclic AMP-dependent kinase and protein kinase C in gastropod mollusks. BRAIN, BEHAVIOR AND EVOLUTION 2009; 74:191-205. [PMID: 20029183 DOI: 10.1159/000258666] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The protein kinase C (PKC) and the cAMP-dependent kinase (protein kinase A; PKA) pathways are known to play important roles in behavioral plasticity and learning in the nervous systems of a wide variety of species across phyla. We briefly review the members of the PKC and PKA family and focus on the evolution of the immediate upstream activators of PKC and PKA i.e., phospholipase C (PLC) and adenylyl cyclase (AC), and their conservation in gastropod mollusks, taking advantage of the recent assembly of the Aplysiacalifornica and Lottia gigantea genomes. The diversity of PLC and AC family members present in mollusks suggests a multitude of possible mechanisms to activate PKA and PKC; we briefly discuss the relevance of these pathways to the known physiological activation of these kinases in Aplysia neurons during plasticity and learning. These multiple mechanisms of activation provide the gastropod nervous system with tremendous flexibility for implementing neuromodulatory responses to both neuronal activity and extracellular signals.
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Affiliation(s)
- Wayne S Sossin
- Department of Neurology and Neurosurgery, McGill University, Montreal Neurological Institute, Montreal, Que., Canada.
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Abstract
Activity-dependent long-term synaptic plasticity requires gene expression and protein synthesis. Identifying essential genes and studying their transcriptional and translational regulation are key steps to understanding how synaptic changes become long lasting. Recently, the enzyme poly-(ADP-ribose) polymerase 1 (PARP-1) was shown to be necessary for long-term memory (LTM) in Aplysia. Since PARP-1 decondenses chromatin, we hypothesize that this enzyme regulates the expression of specific genes essential for long-term synaptic plasticity that underlies LTM. We cloned Aplysia PARP-1 (ApPARP-1) and determined that its expression in sensory neurons is necessary for serotonin (5-HT)-mediated long-term facilitation (LTF) of sensorimotor neuron synapses. PARP enzymatic activity is also required, since transient application of PARP inhibitors blocked LTF. Differential display and RNA analysis of ganglia dissected from intact animals exposed to 5-HT identified the ribosomal RNA genes as PARP-dependent effector genes. The increase in the expression of rRNAs is long lasting and dynamic. Pulse-labeling RNA studies showed a PARP-dependent increase in rRNAs but not in the total RNA 24 h after 5-HT treatment. Moreover, the expression of both the AprpL27a (Aplysia ribosomal protein L27a) and the ApE2N (Aplysia ubiquitin-conjugating enzyme E2N) mRNAs also increased after 5-HT. Thus, our results suggest that 5-HT, in part by regulating PARP-1 activity, alters the expression of transcripts required for the synthesis of new ribosomes necessary for LTF.
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Kurosu T, Hernández AI, Wolk J, Liu J, Schwartz JH. α/β-tubulin are A kinase anchor proteins for type I PKA in neurons. Brain Res 2009; 1251:53-64. [DOI: 10.1016/j.brainres.2008.11.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 10/30/2008] [Accepted: 11/01/2008] [Indexed: 12/15/2022]
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12
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Kurosu T, Hernández AI, Schwartz JH. Serotonin induces selective cleavage of the PKA RI subunit but not RII subunit in Aplysia neurons. Biochem Biophys Res Commun 2007; 359:563-7. [PMID: 17548057 DOI: 10.1016/j.bbrc.2007.05.146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 05/18/2007] [Indexed: 11/15/2022]
Abstract
PKA type I and type II are activated in Aplysia neurons by stimulation with serotonin (5-HT), which causes long-term facilitation (LTF). The proteolysis of the regulatory subunit (R) is thought important for the persistent activation of PKA, which is necessary to produce LTF. In this study, we report that the type I regulatory subunit (RI) and type II regulatory subunit (RII) are differentially regulated by proteolytic cleavage. RI, but not RII, was selectively cleaved after 5-HT treatment for 2h in Aplysia neurons. Interestingly, the proteasome inhibitor MG132 inhibited the cleavage of RI caused by 5-HT treatment in Aplysia neuron. Besides extracts from Aplysia ganglia treated with 5-HT cleaved (35)S-labeled RI synthesized in vitro, but not (35)S-labeled RII. This suggests that 5-HT induces the activation state of RI-specific proteolytic cleavage.
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Affiliation(s)
- Takeshi Kurosu
- Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, New York, NY 10032, USA.
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13
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Bardales JR, Hellman U, Villamarín JA. CK2-mediated phosphorylation of a type II regulatory subunit of cAMP-dependent protein kinase from the mollusk Mytilus galloprovincialis. Arch Biochem Biophys 2007; 461:130-7. [PMID: 17379180 DOI: 10.1016/j.abb.2007.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/15/2007] [Accepted: 02/04/2007] [Indexed: 11/17/2022]
Abstract
Two isoforms of regulatory (R) subunit of cAMP-dependent protein kinase (PKA), named R(myt1) and R(myt2), were identified so far in the sea mussel Mytilus galloprovincialis. Out of them, only R(myt2) was phosphorylated in vitro by casein kinase 2 (CK2) using GTP as phosphate donor. CK2 catalytic subunit (CK2alpha) itself was sufficient to phosphorylate R(myt2), but phosphorylation was enhanced by the presence of the regulatory subunit CK2beta. Even in the absence of CK2, R(myt2) was phosphorylated to a certain extent when it was incubated with GTP. This basal phosphorylation was partially abolished by the known inhibitors apigenin and emodin, which suggests the presence of a residual amount of endogenous CK2 in the preparation of purified R subunit. CK2-mediated phosphorylation significantly decreases the ability of R(myt2) to inhibit PKA catalytic (C) subunit activity in the absence of cAMP. On the other hand, the sequence of several peptides obtained from the tryptic digestion of R(myt2) showed that mussel protein contains the signature sequence common to all PKA family members, within the "phosphate binding cassette" (PBC) A and B. Moreover, the degree of identity between the sequences of peptides from R(myt2), as a whole, and those from type II R subunits was 68-75%, but the global identity percentage with type I R subunits was only about 30%, so that R(myt2) can be classified as a type II R subunit.
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Affiliation(s)
- José R Bardales
- Departamento de Bioquímica e Bioloxía Molecular, Facultade de Veterinaria, Universidade de Santiago de Compostela, Lugo, Spain
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Lockyer AE, Spinks JN, Walker AJ, Kane RA, Noble LR, Rollinson D, Dias-Neto E, Jones CS. Biomphalaria glabrata transcriptome: identification of cell-signalling, transcriptional control and immune-related genes from open reading frame expressed sequence tags (ORESTES). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2007; 31:763-82. [PMID: 17208299 PMCID: PMC1871615 DOI: 10.1016/j.dci.2006.11.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 11/06/2006] [Accepted: 11/08/2006] [Indexed: 05/13/2023]
Abstract
Biomphalaria glabrata is the major intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. Much remains to be discovered concerning specific molecules mediating the defence events in these intermediate hosts, triggered by invading schistosomes. An expressed sequence tag (EST) gene discovery strategy known as ORESTES has been employed to identify transcripts that might be involved in snail-schistosome interactions in order to examine gene expression patterns in infected B. glabrata. Over 3930 ESTs were sequenced from cDNA libraries made from both schistosome-exposed and unexposed snails using different tissue types, producing a database of 1843 non-redundant clones. The non-redundant set has been assessed for gene ontology and KEGG pathway assignments. This approach has revealed a number of signalling, antioxidant and immune-related gene homologues that, based on current understanding of molluscan and other comparative systems, might play an important role in the molluscan defence response towards infection.
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Affiliation(s)
- Anne E Lockyer
- Wolfson Wellcome Biomedical Laboratory, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
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Pettigrew DB, Smolen P, Baxter DA, Byrne JH. Dynamic properties of regulatory motifs associated with induction of three temporal domains of memory in aplysia. J Comput Neurosci 2005; 18:163-81. [PMID: 15714268 DOI: 10.1007/s10827-005-6557-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A model was developed to examine dynamical properties of regulatory motifs correlated with different temporal domains of memory. The model represents short-, intermediate-, and long-term phases of protein kinase A (PKA) activation, which appear related to corresponding phases of facilitation of the Aplysia sensorimotor synapse. The model also represents phosphorylation of the transcription factor CREB1 by PKA and consequent induction of the immediate-early gene Aplysia ubiquitin hydrolase (Ap-uch), which is essential for long-term synaptic facilitation (LTF). Simulations suggest mechanisms responsible for differing profiles of synaptic facilitation following massed vs. spaced exposures to 5-HT, and suggest a novel regulatory motif (gated positive feedback) is important for LTF. Simulations suggest zero-order ultrasensitivity may underlie a requirement of a threshold number of exposures to 5-HT for LTF induction. The model makes predictions for the dynamics of PKA activation and Ap-uch induction when MAP kinase is activated, or when repression of Ap-uch is relieved by inhibiting the transcription factor CREB2. This model may therefore be useful for understanding processes underlying memory formation in Aplysia and other systems.
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Affiliation(s)
- David B Pettigrew
- W.M. Keck Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, P.O. Box 20708, Houston, Texas 77030, USA.
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Hu JY, Glickman L, Wu F, Schacher S. Serotonin regulates the secretion and autocrine action of a neuropeptide to activate MAPK required for long-term facilitation in Aplysia. Neuron 2004; 43:373-85. [PMID: 15294145 DOI: 10.1016/j.neuron.2004.07.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 06/03/2004] [Accepted: 06/08/2004] [Indexed: 11/17/2022]
Abstract
In Aplysia, long-term facilitation (LTF) of sensory neuron synapses requires activation of both protein kinase A (PKA) and mitogen-activated protein kinase (MAPK). We find that 5-HT through activation of PKA regulates secretion of the sensory neuron-specific neuropeptide sensorin, which binds autoreceptors to activate MAPK. Anti-sensorin antibody blocked LTF and MAPK activation produced by 5-HT and LTF produced by medium containing sensorin that was secreted from sensory neurons after 5-HT treatment. A single application of 5-HT followed by a 2 hr incubation with sensorin produced protein synthesis-dependent LTF, growth of new presynaptic varicosities, and activation of MAPK and its translocation into sensory neuron nuclei. Inhibiting PKA during 5-HT applications and inhibiting receptor tyrosine kinase or MAPK during sensorin application blocked both LTF and MAPK activation and translocation. Thus, long-term synaptic plasticity is produced when stimuli activate kinases in a specific sequence by regulating the secretion and autocrine action of a neuropeptide.
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Affiliation(s)
- Jiang-Yuan Hu
- Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA
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Liu J, Hu JY, Schacher S, Schwartz JH. The two regulatory subunits of aplysia cAMP-dependent protein kinase mediate distinct functions in producing synaptic plasticity. J Neurosci 2004; 24:2465-74. [PMID: 15014122 PMCID: PMC6729487 DOI: 10.1523/jneurosci.4331-03.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Activation of the cAMP-dependent protein kinase (PKA) is critical for both short- and long-term facilitation in Aplysia sensory neurons. There are two types of the kinase, I and II, differing in their regulatory (R) subunits. We cloned Aplysia RII; RI was cloned previously. Type I PKA is mostly soluble in the cell body whereas type II is enriched at nerve endings where it is bound to two prominent A kinase-anchoring-proteins (AKAPs). Disruption of the binding of RII to AKAPs by Ht31, an inhibitory peptide derived from a human thyroid AKAP, prevents both the short- and the long-term facilitation produced by serotonin (5-HT). During long-term facilitation, RII is transcriptionally upregulated; in contrast, the amount of RI subunits decreases, and previous studies have indicated that the decrease is through ubiquitin-proteosome-mediated proteolysis. Experiments with antisense oligonucleotides injected into the sensory neuron cell body show that the increase in RII protein is essential for the production of long-term facilitation. Using synaptosomes, we found that 5-HT treatment causes RII protein to increase at nerve endings. In addition, using reverse transcription-PCR, we found that RII mRNA is transported from the cell body to nerve terminals. Our results suggest that type I operates in the nucleus to maintain cAMP response element-binding protein-dependent gene expression, and type II PKA acts at sensory neuron synapses phosphorylating proteins to enhance release of neurotransmitter. Thus, the two types of the kinase have distinct but complementary functions in the production of facilitation at synapses of an identified neuron.
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Affiliation(s)
- Jinming Liu
- Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, New York, New York 10032, USA
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Abstract
One of the most significant challenges in neuroscience is to identify the cellular and molecular processes that underlie learning and memory formation. The past decade has seen remarkable progress in understanding changes that accompany certain forms of acquisition and recall, particularly those forms which require activation of afferent pathways in the hippocampus. This progress can be attributed to a number of factors including well-characterized animal models, well-defined probes for analysis of cell signaling events and changes in gene transcription, and technology which has allowed gene knockout and overexpression in cells and animals. Of the several animal models used in identifying the changes which accompany plasticity in synaptic connections, long-term potentiation (LTP) has received most attention, and although it is not yet clear whether the changes that underlie maintenance of LTP also underlie memory consolidation, significant advances have been made in understanding cell signaling events that contribute to this form of synaptic plasticity. In this review, emphasis is focused on analysis of changes that occur after learning, especially spatial learning, and LTP and the value of assessing these changes in parallel is discussed. The effect of different stressors on spatial learning/memory and LTP is emphasized, and the review concludes with a brief analysis of the contribution of studies, in which transgenic animals were used, to the literature on memory/learning and LTP.
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Affiliation(s)
- M A Lynch
- Trinity College Institute of Neuroscience, Department of Physiology, Trinity College, Dublin, Ireland.
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Liu K, Hu JY, Wang D, Schacher S. Protein synthesis at synapse versus cell body: enhanced but transient expression of long-term facilitation at isolated synapses. JOURNAL OF NEUROBIOLOGY 2003; 56:275-86. [PMID: 12884266 DOI: 10.1002/neu.10242] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Protein synthesis at synaptic terminals contributes to LTP in hippocampus and to the formation of new synaptic connections by sensory neurons (SNs) of Aplysia. Here we report that after removal of the SN cell body, isolated SN synapses of Aplysia in culture express protein-synthesis dependent long-term facilitation (LTF) produced by 5-HT that decays rapidly. Changes in expression of a SN-specific neuropeptide sensorin in isolated SN varicosities parallel the changes in synaptic efficacy. At 24 h after 5-HT the magnitude of LTF produced at isolated SN synapses was significantly greater than that produced when SN cell bodies were present. LTF was maintained at 48 h at connections with SN cell bodies, but not at isolated SN synapses. The increase in synaptic efficacy at isolated SN synapses at 24 h was blocked by the protein synthesis inhibitor anisomycin. LTF was accompanied by changes in expression of sensorin. The increase in sensorin level at isolated SN varicosities with 5-HT was blocked by anisomycin or was reversed 48 h after 5-HT treatment alone. The results suggest that, as is the case for initial synapse formation between SNs and L7, changes in protein synthesis at synaptic terminals may contribute directly to LTF of stable synapses. Changes in expression within the cell body provide additional contributions for long-term maintenance of the new level of synaptic efficacy that was initiated directly by local changes in protein synthesis at or near synaptic terminals.
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Affiliation(s)
- Ke Liu
- Center for Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, 1051 Riverside Drive, New York, New York 10032, USA
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20
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Díaz-Enrich MJ, Ibarguren I, Hellman U, Villamarín JA. Characterization of a type I regulatory subunit of cAMP-dependent protein kinase from the bivalve mollusk Mytilus galloprovincialis. Arch Biochem Biophys 2003; 416:119-27. [PMID: 12859988 DOI: 10.1016/s0003-9861(03)00259-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two isoforms of the regulatory subunit (R) of cAMP-dependent protein kinase (PKA), named R(myt1) and R(myt2), had been purified in our laboratory from two different tissues of the sea mussel Mytilus galloprovincialis. In this paper, we report the sequences of several peptides obtained from tryptic digestion of R(myt1). As a whole, these sequences showed high homology with regions of type I R subunits from invertebrate and also from mammalian sources, but homology with those of fungal and type II R subunits was much lower, which indicates that R(myt1) can be considered as a type I R isoform. This conclusion is also supported by the following biochemical properties: (1) R(myt1) was proved to have interchain disulfide bonds stabilizing its dimeric structure; (2) it failed to be phosphorylated by the catalytic (C) subunit purified from mussel; (3) it has a higher pI value than that of the R(myt2) isoform; and (4) it showed cross-reactivity with mammalian anti-RIbeta antibody.
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Affiliation(s)
- María J Díaz-Enrich
- Departamento de Bioqui;mica e Bioloxi;a Molecular, Facultade de Veterinaria, Universidade de Santiago de Compostela, Campus de Lugo, 27002, Lugo, Spain
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21
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Abstract
Memory loss occurs by diverse mechanisms, as different time constants of performance decrement and sensitivities to experimental manipulations suggest. While the phenomena of memory decay, interference, and extinction are well established behaviorally, little is known about them at the circuit or molecular level. In Drosophila, odorant memories lasting up to 3 hr can be localized to mushroom body Kenyon cells, a single neuronal level in the olfactory pathway. The plasticity underlying this memory trace can be induced without Kenyon cell synaptic output. Experimental extinction, i.e., presentation of the conditioned stimulus without the reinforcer, reduces memory performance and does so at the same circuit level as memory formation. Thus, unreinforced presentation of learned odorants antagonizes intracellularly the signaling cascade underlying memory formation.
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Affiliation(s)
- Martin Schwaerzel
- Theodor Boveri Institut für Biowissenschaften, Lehrstuhl für Genetik und Neurobiologie, Biozentrum, Am Hubland, Würzburg, Germany
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22
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Abstract
Sensitization of defensive reflexes in Aplysia is a simple behavioral paradigm for studying both short- and long-term memory. In the marine mollusk, as in other animals, memory has at least two phases: a short-term phase lasting minutes and a long-term phase lasting several days or longer. Short-term memory is produced by covalent modification of pre-existing proteins. In contrast, long-term memory needs gene induction, synthesis of new protein, and the growth of new synapses. The switch from short-term (STF) to long-term facilitation (LTF) in Aplysia sensory neurons requires not only positive regulation through gene induction, but also the specific removal of several inhibitory proteins. One important inhibitory protein is the regulatory (R) subunit of the cAMP-dependent protein kinase (PKA). Degradation of R subunits, which is essential for initiating long-term stable memory, occurs through the ubiquitin-proteasome pathway.
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Affiliation(s)
- D G Chain
- Center for Neurobiology and Behavior, Columbia University, College of Physicians and Surgeons, New York, NY 10032, USA
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23
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Morimoto K, Hooper DC, Spitsin S, Koprowski H, Dietzschold B. Pathogenicity of different rabies virus variants inversely correlates with apoptosis and rabies virus glycoprotein expression in infected primary neuron cultures. J Virol 1999; 73:510-8. [PMID: 9847357 PMCID: PMC103858 DOI: 10.1128/jvi.73.1.510-518.1999] [Citation(s) in RCA: 216] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/1998] [Accepted: 09/23/1998] [Indexed: 11/20/2022] Open
Abstract
The mouse-adapted rabies virus strain CVS-24 has stable variants, CVS-B2c and CVS-N2c, which differ greatly in their pathogenicity for normal adult mice and in their ability to infect nonneuronal cells. The glycoprotein (G protein), which has previously been implicated in rabies virus pathogenicity, shows substantial structural differences between these variants. Although prior studies have identified antigenic site III of the G protein as the major pathogenicity determinant, CVS-B2c and CVS-N2c do not vary at this site. The possibility that pathogenicity is inversely related to G protein expression levels is suggested by the finding that CVS-B2c, the less pathogenic variant, expresses at least fourfold-higher levels of G protein than CVS-N2c in infected neurons. Although there is some difference between CVS-B2c- and CVS-N2c-infected neurons in G protein mRNA expression levels, the differential expression of G protein appears to be largely determined by posttranslational mechanisms that affect G protein stability. Pulse-chase experiments indicated that the G protein of CVS-B2c is degraded more slowly than that of CVS-N2c. The accumulation of G protein correlated with the induction of programmed cell death in CVS-B2c-infected neurons. The extent of apoptosis was considerably lower in CVS-N2c-infected neurons, where G protein expression was minimal. While nucleoprotein (N protein) expression levels were similar in neurons infected with either variant, the transport of N protein into neuronal processes was strongly inhibited in CVS-B2c-infected cells. Thus, downregulation of G protein expression in neuronal cells evidently contributes to rabies virus pathogenesis by preventing apoptosis and the apparently associated failure of the axonal transport of N protein.
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Affiliation(s)
- K Morimoto
- Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-6799, USA
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24
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Chain DG, Casadio A, Schacher S, Hegde AN, Valbrun M, Yamamoto N, Goldberg AL, Bartsch D, Kandel ER, Schwartz JH. Mechanisms for generating the autonomous cAMP-dependent protein kinase required for long-term facilitation in Aplysia. Neuron 1999; 22:147-56. [PMID: 10027297 DOI: 10.1016/s0896-6273(00)80686-8] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The formation of a persistently active cAMP-dependent protein kinase (PKA) is critical for establishing long-term synaptic facilitation (LTF) in Aplysia. The injection of bovine catalytic (C) subunits into sensory neurons is sufficient to produce protein synthesis-dependent LTF. Early in the LTF induced by serotonin (5-HT), an autonomous PKA is generated through the ubiquitin-proteasome-mediated proteolysis of regulatory (R) subunits. The degradation of R occurs during an early time window and appears to be a key function of proteasomes in LTF. Lactacystin, a specific proteasome inhibitor, blocks the facilitation induced by 5-HT, and this block is rescued by injecting C subunits. R is degraded through an allosteric mechanism requiring an elevation of cAMP coincident with the induction of a ubiquitin carboxy-terminal hydrolase.
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Affiliation(s)
- D G Chain
- Center for Neurobiology and Behavior, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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25
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Jiang YH, Armstrong D, Albrecht U, Atkins CM, Noebels JL, Eichele G, Sweatt JD, Beaudet AL. Mutation of the Angelman ubiquitin ligase in mice causes increased cytoplasmic p53 and deficits of contextual learning and long-term potentiation. Neuron 1998; 21:799-811. [PMID: 9808466 DOI: 10.1016/s0896-6273(00)80596-6] [Citation(s) in RCA: 634] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The E6-AP ubiquitin ligase (human/mouse gene UBE3A/Ube3a) promotes the degradation of p53 in association with papilloma E6 protein, and maternal deficiency causes human Angelman syndrome (AS). Ube3a is imprinted with silencing of the paternal allele in hippocampus and cerebellum in mice. We found that the phenotype of mice with maternal deficiency (m-/p+) for Ube3a resembles human AS with motor dysfunction, inducible seizures, and a context-dependent learning deficit. Long-term potentiation (LTP) was severely impaired in m-/p+ mice despite normal baseline synaptic transmission and neuroanatomy, indicating that ubiquitination may play a role in mammalian LTP and that LTP may be abnormal in AS. The cytoplasmic abundance of p53 was increased in postmitotic neurons in m-/p+ mice and in AS, providing a potential biochemical basis for the phenotype through failure to ubiquitinate and degrade various effectors.
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Affiliation(s)
- Y H Jiang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
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26
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Mykles DL. Intracellular proteinases of invertebrates: calcium-dependent and proteasome/ubiquitin-dependent systems. INTERNATIONAL REVIEW OF CYTOLOGY 1998; 184:157-289. [PMID: 9697313 DOI: 10.1016/s0074-7696(08)62181-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cytosolic proteinases carry out a variety of regulatory functions by controlling protein levels and/or activities within cells. Calcium-dependent and ubiquitin/proteasome-dependent pathways are common to all eukaryotes. The former pathway consists of a diverse group of Ca(2+)-dependent cysteine proteinases (CDPs; calpains in vertebrate tissues). The latter pathway is highly conserved and consists of ubiquitin, ubiquitin-conjugating enzymes, deubiquitinases, and the proteasome. This review summarizes the biochemical properties and genetics of invertebrate CDPs and proteasomes and their roles in programmed cell death, stress responses (heat shock and anoxia), skeletal muscle atrophy, gametogenesis and fertilization, development and pattern formation, cell-cell recognition, signal transduction and learning, and photoreceptor light adaptation. These pathways carry out bulk protein degradation in the programmed death of the intersegmental and flight muscles of insects and of individuals in a colonial ascidian; molt-induced atrophy of crustacean claw muscle; and responses of brine shrimp, mussels, and insects to environmental stress. Selective proteolysis occurs in response to specific signals, such as in modulating protein kinase A activity in sea hare and fruit fly associated with learning; gametogenesis, differentiation, and development in sponge, echinoderms, nematode, ascidian, and insects; and in light adaptation of photoreceptors in the eyes of squid, insects, and crustaceans. Proteolytic activities and specificities are regulated through proteinase gene expression (CDP isozymes and proteasomal subunits), allosteric regulators, and posttranslational modifications, as well as through specific targeting of protein substrates by a diverse assemblage of ubiquitin-conjugases and deubiquitinases. Thus, the regulation of intracellular proteolysis approaches the complexity and versatility of transcriptional and translational mechanisms.
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Affiliation(s)
- D L Mykles
- Department of Biology, Colorado State University, Fort Collins 80523, USA
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27
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Abel T, Kandel E. Positive and negative regulatory mechanisms that mediate long-term memory storage. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1998; 26:360-78. [PMID: 9651552 DOI: 10.1016/s0165-0173(97)00050-7] [Citation(s) in RCA: 209] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The protein kinase A pathway and the cyclic AMP-response element binding protein (CREB) appear to play a critical role in the consolidation of short-term changes in neuronal activity into long-term memory storage in a variety of systems ranging from the gill and siphon withdrawal reflex in Aplysia to olfactory conditioning in Drosophila to spatial and contextual learning in mice. In this review we describe the molecular machinery that mediates memory consolidation in each of these systems. One of the surprising findings to emerge, particularly from studies of long-term facilitation in Aplysia, is that memory storage is mediated by not only positive but also negative regulatory mechanisms, in much the same way as cell division is controlled by the proteins encoded by oncogenes and tumor suppressor genes. This suggests the interesting possibility that there are memory suppressor genes whose protein products impede memory storage.
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Affiliation(s)
- T Abel
- Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University, 722 West 168th Street, New York, NY 10032, USA
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28
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Zwartjes RE, West H, Hattar S, Ren X, Noel F, Nuñez-Regueiro M, MacPhee K, Homayouni R, Crow MT, Byrne JH, Eskin A. Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia. Learn Mem 1998; 4:478-95. [PMID: 10701873 DOI: 10.1101/lm.4.6.478] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Neural correlates of long-term sensitization of defensive withdrawal reflexes in Aplysia occur in sensory neurons in the pleural ganglia and can be mimicked by exposure of these neurons to serotonin (5-HT). Studies using inhibitors indicate that transcription is necessary for production of long-term facilitation by 5-HT. Several mRNAs that change in response to 5-HT have been identified, but the molecular events responsible for long-term facilitation have not yet been fully described. To detect additional changes in mRNAs, we investigated the effects of 5-HT (1.5 hr) on levels of mRNA in pleural-pedal ganglia using in vitro translation. Four mRNAs were affected by 5-HT, three of which were identified as calmodulin (CaM), phosphoglycerate kinase (PGK), and a novel gene product (protein 3). Using RNase protection assays, we found that 5-HT increased all three mRNAs in the pleural sensory neurons. CaM and protein 3 mRNAs were also increased in the sensory neurons by sensitization training. Furthermore, stimulation of peripheral nerves of pleural-pedal ganglia, an in vitro analog of sensitization training, increased the incorporation of labeled amino acids into CaM, PGK, and protein 3. These results indicate that increases in CaM, PGK, and protein 3 are part of the early response of sensory neurons to stimuli that produce long-term facilitation, and that CaM and protein 3 could have a role in the generation of long-term sensitization.
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Affiliation(s)
- R E Zwartjes
- Department of Biochemical and Biophysical Sciences, University of Houston, Texas 77204-5934, USA
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29
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Pittenger C, Kandel E. A genetic switch for long-term memory. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 1998; 321:91-6. [PMID: 9759326 DOI: 10.1016/s0764-4469(97)89807-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Current models of brain function hold that learning corresponds to changes in the efficacy of single synapses. The study of learning and of a variety of forms of synaptic plasticity has revealed that both have at least two phases: an early phase that is not dependent on protein synthesis and a late phase that depends on new transcription and translation. Our laboratory has examined synaptic plasticity in Aplysia and in mice to better understand the regulatory events that lead to the induction of the late, protein synthesis-dependent phase of synaptic plasticity. Our recent studies of Aplysia have revealed that the genes that control the late phase of synaptic facilitation are controlled by both an activator, ApCREB1, and a repressor, ApCREB2. This leads to a model in which the late phase of synaptic facilitation is initiated by a perturbation of the balance between activators and repressors of transcription; this perturbation can be accomplished by regulating the activator, the repressor, or both. We, and others, have shown that this transcriptional switch is conserved, at least in part, in the regulation of synaptic plasticity in mice: CREB is implicated in activation of genes required for LTP, a model for synaptic plasticity in the mammalian hippocampus. We speculate that a similar balance between activators and repressors may regulate the genes required for long-term memory in mammals.
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Affiliation(s)
- C Pittenger
- Howard Hughes Medical Institute, Center for Neurobiology and Behavior, Columbia University College, New York, NY 10032, USA
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30
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Coulson RL, Klein M. Rapid development of synaptic connections and plasticity between sensory neurons and motor neurons of Aplysia in cell culture: implications for learning and regulation of synaptic strength. J Neurophysiol 1997; 77:2316-27. [PMID: 9163360 DOI: 10.1152/jn.1997.77.5.2316] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We describe here the time course of functional synapse formation and of the development of short-term synaptic plasticity at Aplysia sensorimotor synapses in cell culture, as well as the effects of blocking protein synthesis or postsynaptic receptors on the development of synaptic transmission and plasticity. We find that synaptic responses can be elicited in 50% of sensory neuron-motor neuron pairs by 1 h after cell contact and that short-term homosynaptic depression and synaptic augmentation and restoration by the endogenous facilitatory transmitter serotonin are present at the earliest stages of synapse formation. Neither block of protein synthesis with anisomycin nor block of two types of postsynaptic glutamate receptor has any effect on the development of synaptic transmission or synaptic plasticity. The rapidity of synapse formation and maturation and their independence of protein synthesis suggest that changes in the number of functional synapses could contribute to short- and intermediate-term forms of synaptic plasticity and learning.
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Affiliation(s)
- R L Coulson
- University of Montreal, Centre de Recherche en Sciences Neurologiques, Quebec, Canada
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31
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Grzeszik C, Lübbers M, Reh M, Schlegel HG. Genes encoding the NAD-reducing hydrogenase of Rhodococcus opacus MR11. MICROBIOLOGY (READING, ENGLAND) 1997; 143 ( Pt 4):1271-1286. [PMID: 9141690 DOI: 10.1099/00221287-143-4-1271] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The dissociation of the soluble NAD-reducing hydrogenase of Rhodococcus opacus MR11 into two dimeric proteins with different catalytic activities and cofactor composition is unique among the NAD-reducing hydrogenases studied so far. The genes of the soluble hydrogenase were localized on a 7.4 kbp Asnl fragment of the linear plasmid pHG201 via heterologous hybridization. Analysis of the nucleotide sequence of this fragment revealed the seven open reading frames ORF1, hoxF, -U, -Y, -H, -W and ORF7. The six latter ORFs belong to the gene cluster of the soluble hydrogenase. Their gene products are highly homologous to those of the NAD-reducing enzyme of Alcaligenes eutrophus H16. The genes hoxF, -U, -Y and -H encode the subunits alpha, gamma, delta and beta, respectively. The gene hoxW encodes a putative protease, which may be essential for C-terminal processing of the beta subunit. Finally, ORF7 encodes a protein which has similarities to cAMP- and cGMP-binding protein kinases, but its function is not known. ORF1, which lies upstream of the hydrogenase gene cluster, encodes a putative transposase found in IS elements of other bacteria. Northern hybridizations and primer extensions using total RNA of autotrophically and heterotrophically grown cells of R. opacus MR11 indicated that the hydrogenase genes are under control of a delta 70-like promoter located at the right end of ORF1 and are even transcribed under heterotrophic conditions at a low level. Furthermore, this promoter was shown to be active in the recombinant Escherichia coli strain LHY1 harbouring the 7.4 kbp Asnl fragment, resulting in overexpression of the hydrogenase genes. Although all four subunits of the soluble hydrogenase were shown via Western immunoblots to be synthesized in E. coli, no active enzyme was detectable.
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Affiliation(s)
- Claudia Grzeszik
- institut für Mikrobiologie, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077 Göttingen, Germany
| | - Meike Lübbers
- institut für Mikrobiologie, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077 Göttingen, Germany
| | - Michael Reh
- institut für Mikrobiologie, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077 Göttingen, Germany
| | - Hans G Schlegel
- institut für Mikrobiologie, Georg-August-Universität Göttingen, Grisebachstraße 8, D-37077 Göttingen, Germany
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32
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Dohrman DP, Diamond I, Gordon AS. Ethanol causes translocation of cAMP-dependent protein kinase catalytic subunit to the nucleus. Proc Natl Acad Sci U S A 1996; 93:10217-21. [PMID: 8816779 PMCID: PMC38364 DOI: 10.1073/pnas.93.19.10217] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Short- and long-term ethanol exposures have been shown to alter cellular levels of cAMP, but little is known about the effects of ethanol on cAMP-dependent protein kinase (PKA). When cAMP levels increase, the catalytic subunit of PKA (C alpha) is released from the regulatory subunit, phosphorylates nearby proteins, and then translocates to the nucleus, where it regulates gene expression. Altered localization of C alpha would have profound effects on multiple cellular functions. Therefore, we investigated whether ethanol alters intracellular localization of C alpha. NG108-15 cells were incubated in the presence or absence of ethanol for as long as 48 h, and localization of PKA subunits was determined by immunocytochemistry. We found that ethanol exposure produced a significant translocation of C alpha from the Golgi area to the nucleus. C alpha remained in the nucleus as long as ethanol was present. There was no effect of ethanol on localization of the type I regulatory subunit of PKA. Ethanol also caused a 43% decrease in the amount of type I regulatory subunit but had no effect on the amount of C alpha as determined by Western blot. These data suggest that ethanol-induced translocation of C alpha to the nucleus may account, in part, for diverse changes in cellular function and gene expression produced by alcohol.
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Affiliation(s)
- D P Dohrman
- Department of Neurology, Ernest Gallo Clinic and Research Center, University of California, San Francisco General Hospital 94110, USA
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33
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Suzuki T. Messengers from the synapses to the nucleus (MSNs) that establish late phase of long-term potentiation (LTP) and long-term memory. Neurosci Res 1996; 25:1-6. [PMID: 8808794 DOI: 10.1016/0168-0102(96)01023-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The late stage of long-term potentiation (LTP) and long-term memory is believed to be largely governed by altered gene expression for its generation and maintenance, while the early stages of LTP and memory are controlled mainly by the phosphorylation-dephosphorylation of the synaptic proteins. For the altered gene expression, synaptic information must be transmitted from the synaptic sites to the nucleus. This article describes the presence of specific messenger molecules that transmit synaptic information to the nucleus; these molecules are referred to as MSNs (Messengers from Synapse to the Nucleus). In addition, recent studies have indicated that certain transcription factors localize at postsynaptic sites as well as the nucleus, and may function as MSNs.
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Affiliation(s)
- T Suzuki
- Department of Neuroplasticity, Shinshu University School of Medicine, Nagano, Japan
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34
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Jodar L, Kaneto H. Synaptic plasticity: stairway to memory. JAPANESE JOURNAL OF PHARMACOLOGY 1995; 68:359-87. [PMID: 8531412 DOI: 10.1254/jjp.68.359] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Since the idea that memory is associated with alterations in synaptic strength was accepted, studies on the cellular and molecular mechanisms responsible for the plastic changes in neurons have attracted wide interest in the scientific community. Recent studies on memory processes have also pointed out some unifying themes emerging from a wide range of nervous systems, suggesting that regardless of the species or brain regions, a common denominator for memory may exist. Thus, the present review attempted to create a hypothetical and universal synaptic model valid for a variety of nervous systems, ranging from molluscs to mammals. The cellular and molecular events leading to short- and long-term modifications of memory have been described in a sequential order, from the triggering signals to the gene expression, synthesis of new proteins and neuronal growth. These events are thought to represent the late phases of memory consolidation leading to persistent modifications in synaptic plasticity, thereby facilitating the permanent storage of acquired information throughout the individual's life.
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Affiliation(s)
- L Jodar
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Nagasaki University, Japan
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35
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Abstract
Protein kinase A activity is required for signalling by the extracellular molecule Hedgehog in developing Drosophila imaginal discs, but does the kinase actually respond to the Hedgehog signal?
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Affiliation(s)
- D Kalderon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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36
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Hildebrandt H, Müller U. PKA activity in the antennal lobe of honeybees is regulated by chemosensory stimulation in vivo. Brain Res 1995; 679:281-8. [PMID: 7633889 DOI: 10.1016/0006-8993(95)00246-m] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The involvement of cyclic nucleotide cascades has been suggested for chemosensory signal processing as well as synaptic plasticity. Cyclic AMP-dependent protein kinase (PKA) is a major mediator for transient changes in these second messengers. The objective of this study was to examine the role of PKA in the central processing of chemosensory information by the honeybee. Effects of chemosensory stimulation in vivo were detected in the first chemosensory neuropil of the honeybee brain, the antennal lobe (AL), by using a combination of shock freezing and specific determination of PKA activity. Mechanosensory or odor stimulation of the antennae had no effect on PKA activity. Brief application of aqueous solutions (pure water or sucrose solution) to an antenna caused a rapid and transient elevation of PKA activity in the ipsilateral AL. A series of such stimuli led to a graded increase in PKA activity followed by a rapid decrease during the first 10 s after the end of stimulation, but elevated levels of PKA activity were observed for as long as 1 min. These results suggest that PKA activity and its regulation contribute to central processing of chemosensory signals.
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Affiliation(s)
- H Hildebrandt
- Institut für Neurobiologie, Freien Universität Berlin, Germany
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37
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Spatz HC. Posttranslational modification of protein kinase A. The link between short-term and long-term memory. Behav Brain Res 1995; 66:79-84. [PMID: 7755904 DOI: 10.1016/0166-4328(94)00128-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Both for Aplysia and Drosophila a key role in the molecular mechanism of learning and memory processes has been assigned to the cAMP cascade. In any learning process a short-time stimulus has to be translated into long-lasting changes. The molecular correlate must be a cascade of biochemical reactions with different kinetics, functionally interlinked and operating in overlapping time ranges. Biochemical studies in Drosophila have led to the suggestion that one of these steps is a proteolytic modification of the regulatory subunits of protein kinase A. A quantitative analysis of the relaxation kinetics of a system of protein kinase A, phosphatases and a calcium-dependent protease can give an image of essential characteristics of learning behaviour in Drosophila.
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Affiliation(s)
- H C Spatz
- Institut für Biologie III, Freiburg i.Br., Germany
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38
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Condron BG, Zinn K. Activation of cAMP-dependent protein kinase triggers a glial-to-neuronal cell-fate switch in an insect neuroblast lineage. Curr Biol 1995; 5:51-61. [PMID: 7535171 DOI: 10.1016/s0960-9822(95)00016-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND The grasshopper median neuroblast (MNB) is a multipotent progenitor cell that produces neurons and midline glia in distinct temporal phases. The MNB generates pioneer neurons during its first few divisions, and then switches to production of midline glial precursors. After the glia have been produced, the MNB reverts to generating neurons. We have investigated the molecular mechanism underlying the transition from glia production back to neuron production in the MNB lineage. RESULTS We report evidence that this second transition in the MNB lineage is triggered by the activation of cAMP-dependent protein kinase (PKA). PKA is a heterodimer of a catalytic (PKA-C) and a cAMP-binding regulatory (R) subunit. The R subunit dissociates from PKA-C on binding cAMP, and free PKA-C than translocates into the nucleus. Nuclear localization of PKA-C can thus be used as an indicator of PKA activation within a cell. We have found that PKA-C is translocated into the nucleus at the time of the second switch in the MNB lineage. When PKA is prematurely activated in the MNB by microinjection of purified PKA-C, or by pharmacological agents that elevate intracellular cAMP levels, the glial-to-neuronal cell-fate switch takes place prematurely. Inhibition of PKA activity by microinjection of a peptide inhibitor, or by a non-hydrolyzable cAMP analog, blocks the glial-to-neuronal switch. CONCLUSIONS Our results imply that elevation of cAMP in the MNB, and the resultant activation of PKA, is likely to be a trigger for the glial-to-neuronal cell-fate transition within the MNB lineage.
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Affiliation(s)
- B G Condron
- Division of Biology, Institute of Technology, Pasadena, California 91125
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39
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Bennett MR. Nitric oxide release and long term potentiation at synapses in autonomic ganglia. GENERAL PHARMACOLOGY 1994; 25:1541-51. [PMID: 7721027 DOI: 10.1016/0306-3623(94)90353-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. Long-term potentiation (LTP) of synaptic transmission in autonomic ganglia is reviewed, together with the possible role of nitric oxide (NO) in this process. 2. Calcium levels in preganglionic nerve terminals are elevated during at least the induction phase of LTP following a tetanus as well as during LTP induced by transmitter substances acting on the nerve terminals. Of the large number of calcium-dependent processes in the nerve terminal that might affect transmitter release, only calcium-calmodulin has been shown to be important in both the induction and maintenance of LTP. 3. The possibility that there is a decrease in the open time of nerve-terminal potassium channels following a tetanus, leading to an increase in duration of the terminal action potential and hence an increase in calcium influx and transmitter release is considered. There is little evidence for such an effect as yet for preganglionic nerve terminals. 4. Phosphorylation of potassium channels by cAMP-dependent protein kinase can lead to their inactivation with consequent action potential broadening in some systems. Exogenous cAMP enhances synaptic efficacy at preganglionic nerve terminals. Whether this occurs through an inactivation of potassium channels is not known. 5. Nitric oxide (NO) synthase is present in both sympathetic ganglia and the ciliary ganglia. NO increases synaptic efficacy in both ganglia. In at least the case of ciliary ganglion this is due to elevation of quantal secretion. 6. NO can in some conditions increase the terminal action potential duration in ciliary ganglia, probably through decrease in the Ic potassium current. There is evidence that this happens through cGMP modulating cAMP phosphodiesterases, thereby affecting cAMP phosphorylation of the Ic channel. 7. Blocking NO synthase markedly decreases LTP following a tetanus in the ciliary ganglion. The possibility is considered that NO is released from the terminal during a tetanus and through altering cAMP phosphorylation of Ic enhances transmitter release.
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Affiliation(s)
- M R Bennett
- Department of Physiology, University of Sydney, NSW, Australia
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40
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Abstract
Behavioral and pharmacological experiments in many animal species have suggested that memory is consolidated from an initial, disruptable form into a long-lasting, stable form within a few hours after training. We combined these traditional approaches with genetic analyses in Drosophila to show that consolidated memory of conditioned (learned) odor avoidance 1 day after extended training consisted of two genetically distinct, functionally independent memory components: anesthesia-resistant memory (ARM) and long-term memory (LTM). ARM decayed away within 4 days, was resistant to hypothermic disruption, was insensitive to the protein synthesis inhibitor cycloheximide (CXM), and was disrupted by the radish single-gene mutation. LTM showed no appreciable decay over 7 days, was sensitive to CXM, and was not disrupted by the radish mutation.
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Affiliation(s)
- T Tully
- Cold Spring Harbor Laboratory, New York 11724
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41
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Panchal R, Cheley S, Bayley H. Differential phosphorylation of neuronal substrates by catalytic subunits of Aplysia cAMP-dependent protein kinase with alternative N termini. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)31575-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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42
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Suzuki T. Protein kinases involved in the expression of long-term potentiation. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1994; 26:735-44. [PMID: 8063002 DOI: 10.1016/0020-711x(94)90102-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review describes the protein kinases that are involved in long-term potentiation (LTP). The following items are described. 1. Ca2+/calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC) may play pivotal roles in the different phases of the expression of LTP. This involvement has been indicated mainly by using specific inhibitor of these kinases. The involvement of the CaMKII alpha-subunit was confirmed in mutant mice which are deficient in the gene for the subunit. 2. Involvement of persistently active protein kinases in the maintenance of LTP has been proposed and, since then, several studies have focused upon the persistent kinase. Both PKC and CaMKII are possible sources of the persistent kinase activities. 3. Protein kinases other than CaMKII or PKC (ex. protein kinase A, tyrosine kinases, mitogen-activated kinase) also play roles in the expression of LTP. 4. Finally, the importance of postsynaptic density as a device where complex chemical reactions related to neuronal signal transduction occur is discussed.
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Affiliation(s)
- T Suzuki
- Department of Biochemistry, Nagoya City University Medical School, Japan
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43
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Walters ET. Injury-related behavior and neuronal plasticity: an evolutionary perspective on sensitization, hyperalgesia, and analgesia. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1994; 36:325-427. [PMID: 7822120 DOI: 10.1016/s0074-7742(08)60307-4] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- E T Walters
- Department of Physiology and Cell Biology, University of Texas Medical School at Houston 77030
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44
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Type II regulatory subunits of cAMP-dependent protein kinase and their binding proteins in the nervous system of Aplysia californica. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)42028-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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45
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Clark GA, Kandel ER. Induction of long-term facilitation in Aplysia sensory neurons by local application of serotonin to remote synapses. Proc Natl Acad Sci U S A 1993; 90:11411-5. [PMID: 8248263 PMCID: PMC47992 DOI: 10.1073/pnas.90.23.11411] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Long-term synaptic facilitation at the connections of Aplysia sensory neurons onto their target cells involves alterations in gene expression. How then are the relevant cellular signals for the induction and expression of long-term synaptic changes conveyed between the nucleus and remote synaptic terminals? We have explored this question using a set of remote, peripheral terminals of siphon sensory cells, which are approximately 3 cm from the sensory cell body in the abdominal ganglion. We found that these remote synapses, like the proximal synapses previously studied in dissociated cell culture, can exhibit long-term facilitation 24 hr after cell-wide serotonin application. Furthermore, serotonin applications restricted to the remote synaptic terminals nevertheless produced long-term facilitation, indicating that signals generated in synaptic regions can trigger the long-term process, perhaps via retrograde signals to the nucleus to modify gene expression, followed by anterograde signals back to the terminal. Serotonin applications restricted to the cell body and proximal synapses of the sensory neuron also produced long-term facilitation at remote synapses, although to a lesser extent, suggesting that long-term facilitation is expressed cell-wide, but that superimposed on this cell-wide facilitation there appears to be a component that is synapse-specific.
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Affiliation(s)
- G A Clark
- Psychology Department, Princeton University, NJ 08544
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46
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Beushausen S, Kladakis A, Jaffe H. Kinesin light chains: identification and characterization of a family of proteins from the optic lobe of the squid Loligo pealii. DNA Cell Biol 1993; 12:901-9. [PMID: 8274223 DOI: 10.1089/dna.1993.12.901] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Multiple transcripts coding for kinesin light chain isoforms are present in the tissues of the squid Loligo pealii. Isoform diversity arises through alternative RNA splicing in the amino and carboxyl termini of the putative proteins. Comparison to rat and Drosophila proteins demonstrates a remarkable conservation of structural domains and regulatory motifs. We have identified a PEST domain that may be the site of degradative uncoupling of kinesin functions. Selective transcript distribution occurs in disparate tissues, suggesting an adaptation toward specialized functions. Expression is highest in the nervous system and some evidence for neural-specific transcripts is provided. In neurons, this may relate to the differential targeting of specific membrane-bound organelles such as synaptic vesicles.
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Affiliation(s)
- S Beushausen
- Laboratory of Neurobiology, National Institutes for Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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47
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Hegde AN, Goldberg AL, Schwartz JH. Regulatory subunits of cAMP-dependent protein kinases are degraded after conjugation to ubiquitin: a molecular mechanism underlying long-term synaptic plasticity. Proc Natl Acad Sci U S A 1993; 90:7436-40. [PMID: 8395048 PMCID: PMC47156 DOI: 10.1073/pnas.90.16.7436] [Citation(s) in RCA: 173] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In Aplysia, behavioral sensitization of defensive reflexes and the underlying presynaptic facilitation of sensory-to-motor neuron synapses lasts for several minutes (short term) or days to weeks (long term). Short-term sensitization has been explained by modulation of ion-channel function through cAMP-dependent protein phosphorylation. Long-term facilitation requires additional molecular changes including protein synthesis. A key event is the persistent activation of the cAMP-dependent protein kinase at baseline concentrations of cAMP. This activation is due to selective loss of regulatory (R) subunits of PKA without any change in catalytic (C) subunits. To understand the molecular mechanisms that produce the loss of R subunits in long-term facilitation, we investigated how R subunits are degraded in extracts of Aplysia nervous tissue and in rabbit reticulocyte lysates. Degradation of Aplysia R subunits requires ATP, ubiquitin, and a particulate component that appears to be the proteasome complex. Degradation is blocked by hemin, which causes the accumulation of high molecular weight derivatives of R subunits that are likely to be ubiquitin conjugates of R subunits and intermediates in the degradative pathway. We also show that vertebrate RI and RII subunits can be degraded through the ubiquitin pathway. We suggest that degradation is initiated by cAMP, which causes the holoenzyme to dissociate and, further, that the altered R-to-C ratio in Aplysia sensory neurons is maintained in long-term facilitation by newly synthesized proteins that help target R subunits for accelerated degradation.
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Affiliation(s)
- A N Hegde
- Center for Neurobiology and Behavior, College of Physicians and Surgeons of Columbia University, New York, NY 10032
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48
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Noel F, Nuñez-Regueiro M, Cook R, Byrne JH, Eskin A. Long-term changes in synthesis of intermediate filament protein, actin and other proteins in pleural sensory neurons of Aplysia produced by an in vitro analogue of sensitization training. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1993; 19:203-10. [PMID: 8412561 DOI: 10.1016/0169-328x(93)90027-m] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Electrical stimulation of peripheral nerves of isolated pleural-pedal ganglia, an in vitro analogue of long-term behavioral training in Aplysia, produced changes in the synthesis of specific proteins in pleural sensory neurons. The changes in incorporation of [35S]methionine into proteins occurring 24 h after electrical stimulation (late) were determined and compared with changes occurring immediately after stimulation (early). Eight proteins were affected 24 h after electrical stimulation. Three of these proteins were also affected immediately after electrical stimulation. Two of the proteins affected late are components of the cytoskeleton. One protein was identified as actin. The other protein was purified from preparative 2D-gels and partial amino acid sequences of 3 peptides derived from this protein were determined. The peptide sequences were found to be identical to those of an Aplysia intermediate filament protein.
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Affiliation(s)
- F Noel
- Department of Biochemical and Biophysical Sciences, University of Houston, TX 77204-5934
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49
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Bergold PJ, Casaccia-Bonnefil P, Zeng XL, Federoff HJ. Transsynaptic neuronal loss induced in hippocampal slice cultures by a herpes simplex virus vector expressing the GluR6 subunit of the kainate receptor. Proc Natl Acad Sci U S A 1993; 90:6165-9. [PMID: 8392189 PMCID: PMC46888 DOI: 10.1073/pnas.90.13.6165] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Patients with severe temporal lobe epilepsy lose neurons within the CA3 and hilar regions of the hippocampus. Loss of CA3 and hilar neurons was also induced by transducing organotypic hippocampal slice cultures with a replication-defective herpes simplex virus (HSV) vector expressing the GluR6 kainate subtype of the glutamate receptor (HSVGluR6). In transduced fibroblasts, HSVGluR6 expressed a M(r) 115,000 protein that reacted with anti-GluR6 serum. After exposure of fibroblast to HSVGluR6, a kainate-dependent toxicity appeared in cells that were previously resistant to kainate. Microapplication of nanoliter amounts of recombinant HSV stocks into organotypic hippocampal slice cultures resulted in localized transduction and gene transfer at the site of microapplication. Microapplication of 100 HSVGluR6 virions into CA3 stratum pyramidale induced a large loss of CA3 pyramidal cells and hilar neurons, despite the small number of transduced neurons. This effect was not seen when 100 virions of HSVGluR6 were microapplied to CA1 stratum pyramidale. Tetrodotoxin or N-methyl-D-aspartate receptor antagonists inhibited the large loss of CA3 and hilar neurons, suggesting that the small cluster of HSVGluR6-transduced cells induced an N-methyl-D-aspartate-dependent transsynaptic loss of non-transduced neurons.
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Affiliation(s)
- P J Bergold
- Department of Pharmacology, State University of New York-Health Science Center, Brooklyn 11203
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50
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Schacher S, Kandel ER, Montarolo P. cAMP and arachidonic acid simulate long-term structural and functional changes produced by neurotransmitters in Aplysia sensory neurons. Neuron 1993; 10:1079-88. [PMID: 7686379 DOI: 10.1016/0896-6273(93)90056-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The efficacy of the synapses between the sensory and motor cells of Aplysia, as well as the number of presynaptic sensory cell varicosities in vitro, can undergo long-term increases and decreases, respectively, following application of the facilitatory modulator serotonin or the inhibitory modulator FMRFamide. We here report that cAMP and arachidonic acid, two second messenger systems mediating some of the short-term actions of serotonin and FMRFamide on sensory cells, reproduce some of the long-term changes in the structure of the sensory cells, and these structural changes in turn parallel the long-term changes in the functional effectiveness of the synapses. cAMP enhances the strength of the connections between the sensory and motor cells and increases the number of sensory varicosities. Conversely, arachidonic acid decreases the strength of the connections and decreases the number of sensory varicosities. Thus, each of the modulatory neurotransmitters may activate the same intracellular second messenger system to establish both short and long lasting functional changes in synaptic efficacy, as well as to produce enduring structural changes in neuron connectivity.
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Affiliation(s)
- S Schacher
- Center for Neurobiology and Behavior, College of Physicians and Surgeons, Columbia University, New York, New York
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