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Novikov DA, Beletsky AP, Kolosov PM. The Putative Role of m6A-RNA Methylation in Memory Consolidation. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421020112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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2
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Serine/Threonine Phosphatases in LTP: Two B or Not to Be the Protein Synthesis Blocker-Induced Impairment of Early Phase. Int J Mol Sci 2021; 22:ijms22094857. [PMID: 34064311 PMCID: PMC8125358 DOI: 10.3390/ijms22094857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 11/25/2022] Open
Abstract
Dephosphorylation of target proteins at serine/threonine residues is one of the most crucial mechanisms regulating their activity and, consequently, the cellular functions. The role of phosphatases in synaptic plasticity, especially in long-term depression or depotentiation, has been reported. We studied serine/threonine phosphatase activity during the protein synthesis blocker (PSB)-induced impairment of long-term potentiation (LTP). Established protein phosphatase 2B (PP2B, calcineurin) inhibitor cyclosporin A prevented the LTP early phase (E-LTP) decline produced by pretreatment of hippocampal slices with cycloheximide or anisomycin. For the first time, we directly measured serine/threonine phosphatase activity during E-LTP, and its significant increase in PSB-treated slices was demonstrated. Nitric oxide (NO) donor SNAP also heightened phosphatase activity in the same manner as PSB, and simultaneous application of anisomycin + SNAP had no synergistic effect. Direct measurement of the NO production in hippocampal slices by the NO-specific fluorescent probe DAF-FM revealed that PSBs strongly stimulate the NO concentration in all studied brain areas: CA1, CA3, and dentate gyrus (DG). Cyclosporin A fully abolished the PSB-induced NO production in the hippocampus, suggesting a close relationship between nNOS and PP2B activity. Surprisingly, cyclosporin A alone impaired short-term plasticity in CA1 by decreasing paired-pulse facilitation, which suggests bi-directionality of the influences of PP2B in the hippocampus. In conclusion, we proposed a minimal model of signaling events that occur during LTP induction in normal conditions and the PSB-treated slices.
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Report on the First Symposium on Invertebrate Neuroscience held on 13-17th August 2019 at the Balaton Limnological Institute, MTA Centre for Ecological Research, Tihany, Hungary. INVERTEBRATE NEUROSCIENCE 2020; 20:13. [PMID: 32816072 DOI: 10.1007/s10158-020-00245-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/11/2020] [Indexed: 10/23/2022]
Abstract
This meeting report provides an overview of the oral and poster presentations at the first international symposium for invertebrate neuroscience. The contents reflect the contributions of invertebrate neuroscience in addressing fundamental and fascinating challenges in understanding the neural substrates of animal behaviour.
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Zuzina AB, Vinarskaya AK, Balaban PM. Histone deacetylase inhibitors rescue the impaired memory in terrestrial snails. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:639-649. [PMID: 32409855 DOI: 10.1007/s00359-020-01422-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/06/2020] [Accepted: 05/09/2020] [Indexed: 01/17/2023]
Abstract
It is becoming increasingly clear that the long-term plasticity can be regulated via histone modifications. Many studies demonstrated the role of histone acetylation in acquisition, maintenance, and extinction of long-term memory. Nonetheless, the role of histone acetylation in memory reinstatement following its disruption by antimnemonic treatments was not studied in details. In terrestrial snails, we examined effects of the histone deacetylases inhibitors (HDACi) sodium butyrate (NaB) and trichostatin A (TSA) on reinstatement of the context fear memory impaired by antimnemonic agents such as protein synthesis blocker anisomycin (ANI) + reminding or a specific inhibitor of protein-kinase Mζ, zeta inhibitory peptide (ZIP). It was observed that both NaB and TSA applications restored the ANI-impaired context memory regardless of memory reactivation, while a combination of NaB or TSA plus memory reactivation (or additional training) was necessary for the effective reinstatement of the ZIP-impaired memory. Additionally, NaB injections significantly facilitated development of long-term memory in animals with weak memory, while no effect was observed in animals with strong memory. The data obtained confirmed the assumption that histone acetylation is a critical regulatory component of memory development and reinstatement.
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Affiliation(s)
- Alena B Zuzina
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
| | - Alia Kh Vinarskaya
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
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5
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Nikitin VP, Solntseva SV, Kozyrev SA. Changes in Amnesia Parameters over Time after Long-Term Memory Disruption with Protein Kinase Mζ Inhibitor. Bull Exp Biol Med 2019; 167:711-715. [PMID: 31655990 DOI: 10.1007/s10517-019-04605-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 11/29/2022]
Abstract
We studied the involvement of protein kinase Mζ (PKMζ) in the mechanisms of amnesia development within 10 days after disruption of conditioned food aversion memory with ZIP (a PKMζ inhibitor). Repeated training performed in 3 days after amnesia induction with ZIP, led to the formation of conditioned food aversion memory, but the number of combined presentations of food and reinforcer stimuli was lower than during the initial training. Repeated training performed in 10 days after amnesia induction also led to memory formation, but the number of combined presentations of the stimuli was similar to that during the initial training. It was hypothesized that at the early stages of ZIP-induced amnesia, residual memory trace can be restored and amplified during repeated training, which led to memory expression at the behavioral level. At the late stages of amnesia, this memory trace was completely erased and repeated training led to the formation of a new memory. Thus, PKMζ inhibition results in the relatively fast impairment of memory retrieval and induces long-term process of memory erasing.
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Affiliation(s)
- V P Nikitin
- P. K. Anokhin Research Institute of Normal Physiology, Moscow, Russia.
| | - S V Solntseva
- P. K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
| | - S A Kozyrev
- P. K. Anokhin Research Institute of Normal Physiology, Moscow, Russia
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6
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Increase in serotonin precursor levels reinstates the context memory during reconsolidation. INVERTEBRATE NEUROSCIENCE 2019; 19:8. [PMID: 31363864 DOI: 10.1007/s10158-019-0227-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 07/22/2019] [Indexed: 12/20/2022]
Abstract
In the present study, we tested possible ways of modification of the context long-term memory using the reconsolidation as a tool. Recently, using a depletion of the serotonin content, it was shown that the reinforcing neurotransmitter serotonin is necessary for successful repeated reconsolidation of context memory in terrestrial snails Helix lucorum (Balaban et al. in Sci Rep 6:36933, 2016), and in the present study, we investigated effects of serotonin increase in memory maintenance by injection of the serotonin precursor 5-hydroxytryptophan (5-HTP). We studied reinstatement of the context memory after its impairment during reconsolidation with a protein synthesis blocker anisomycin (ANI) or with a specific inhibitor of protein-kinase Mζ (ZIP). It was observed that applications of 5-HTP alone, known to increase the release of serotonin, or reactivation of memory alone did not restore the ZIP- or ANI-impaired context memory, while combination of the 5-HTP + reactivation of memory effectively reinstated the context memory. The data obtained confirmed the assumption that serotonin/reinforcing transmitter is a part of successful reconsolidation necessary for memory maintenance, demonstrated possible ways of long-term memory regulation during the reconsolidation process.
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Farah CA, Dunn TW, Hastings MH, Ferguson L, Gao C, Gong K, Sossin WS. A role for Numb in Protein kinase M (PKM)-mediated increase in surface AMPA receptors during facilitation in Aplysia. J Neurochem 2019; 150:366-384. [PMID: 31254393 DOI: 10.1111/jnc.14807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 12/15/2022]
Abstract
There is considerable evidence from both vertebrates and invertebrates that persistently active protein kinases maintain changes in synaptic strength that underlie memory. In the hermaphrodite marine mollusk, Aplysia californica, truncated forms of protein kinase C (PKC) termed protein kinase Ms have been implicated in both intermediate- and long-term facilitation, an increase in synaptic strength between sensory neurons and motor neurons thought to underlie behavioural sensitization in the animal. However, few substrates have been identified as candidates that could mediate this increase in synaptic strength. PKMs have been proposed to maintain synaptic strength through preventing endocytosis of AMPA receptors. Numb is a conserved regulator of endocytosis that is modulated by phosphorylation. We have identified and cloned Aplysia Numb (ApNumb). ApNumb contains three conserved PKC phosphorylation sites and PKMs generated from classical and atypical Aplysia PKCs can phosphorylate ApNumb in vitro and in cells. Over-expression of ApNumb that lacks the conserved PKC phosphorylation sites blocks increases in surface levels of a pHluorin-tagged Aplysia glutamate receptor measured using live imaging after intermediate- or long-term facilitation. Over-expression of this form of ApNumb did not block increases in synaptic strength seen during intermediate-term facilitation, but did block increases in synaptic strength seen during long-term facilitation. There was no effect of over-expression of this form of ApNumb on other putative Numb targets as measured using increases in calcium downstream of neurotrophins or agonists of metabotropic glutamate receptors. These results suggest that in Aplysia neurons, Numb specifically regulates AMPA receptor trafficking and is an attractive candidate for a target of PKMs in long-term maintenance of synaptic strength. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/. Open Science: This manuscript was awarded with the Open Materials Badge For more information see: https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Carole A Farah
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Tyler W Dunn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Margaret H Hastings
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Larissa Ferguson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Cherry Gao
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Katrina Gong
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
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Xu C, Li Q, Efimova O, Jiang X, Petrova M, K Vinarskaya A, Kolosov P, Aseyev N, Koshkareva K, Ierusalimsky VN, Balaban PM, Khaitovich P. Identification of Immediate Early Genes in the Nervous System of Snail Helix lucorum. eNeuro 2019; 6:ENEURO.0416-18.2019. [PMID: 31053606 PMCID: PMC6584072 DOI: 10.1523/eneuro.0416-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/02/2019] [Accepted: 03/17/2019] [Indexed: 02/06/2023] Open
Abstract
Immediate early genes (IEGs) are useful markers of neuronal activation and essential components of neuronal response. While studies of gastropods have provided many insights into the basic learning and memory mechanisms, the genome-wide assessment of IEGs has been mainly restricted to vertebrates. In this study, we identified IEGs in the terrestrial snail Helix lucorum In the absence of the genome, we conducted de novo transcriptome assembly using reads with short and intermediate lengths cumulatively covering more than 98 billion nucleotides. Based on this assembly, we identified 37 proteins corresponding to contigs differentially expressed (DE) in either the parietal ganglia (PaG) or two giant interneurons located within the PaG of the snail in response to the neuronal stimulation. These proteins included homologues of well-known mammalian IEGs, such as c-jun/jund, C/EBP, c-fos/fosl2, and Egr1, as well as homologues of genes not yet implicated in the neuronal response.
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Affiliation(s)
- Chuan Xu
- CAS Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Gesellschaft Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qian Li
- CAS Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Gesellschaft Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Olga Efimova
- Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | - Xi Jiang
- CAS Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Gesellschaft Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Marina Petrova
- CAS Key Laboratory of Computational Biology, Chinese Academy of Sciences-Max Planck Gesellschaft Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Alia K Vinarskaya
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Peter Kolosov
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Nikolay Aseyev
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Kira Koshkareva
- Skolkovo Institute of Science and Technology, Moscow 143026, Russia
| | | | - Pavel M Balaban
- Institute of Higher Nervous Activity and Neurophysiology, Moscow 117485, Russia
| | - Philipp Khaitovich
- Skolkovo Institute of Science and Technology, Moscow 143026, Russia
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
- Comparative Biology Laboratory, Chinese Academy of Sciences-Max Planck Gesellschaft Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
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9
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Histone acetylation determines transcription of atypical protein kinases in rat neurons. Sci Rep 2019; 9:4332. [PMID: 30867503 PMCID: PMC6416243 DOI: 10.1038/s41598-019-40823-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 02/11/2019] [Indexed: 01/19/2023] Open
Abstract
It is widely accepted that memory consolidation requires de-novo transcription of memory-related genes. Epigenetic modifications, particularly histone acetylation, may facilitate gene transcription, but their potential molecular targets are poorly characterized. In the current study, we addressed the question of epigenetic control of atypical protein kinases (aPKC) that are critically involved in memory consolidation and maintenance. We examined the patterns of expression of two aPKC genes (Prkci and Prkcz) in rat cultured cortical neurons treated with histone deacetylase inhibitors. Histone hyperacetylation in the promoter region of Prkci gene elicited direct activation of transcriptional machinery, resulting in increased production of PKCλ mRNA. In parallel, histone hyperacetylation in the upstream promoter of Prkcz gene led to appearance of the corresponding PKCζ transcripts that are almost absent in the brain in resting conditions. In contrast, histone hyperacetylation in the downstream promoter of Prkcz gene was accompanied by a decreased expression of the brain-specific PKMζ products. We showed that epigenetically-triggered differential expression of PKMζ and PKCζ mRNA depended on protein synthesis. Summarizing, our results suggest that genes, encoding memory-related aPKC, may represent the molecular targets for epigenetic regulation through posttranslational histone modifications.
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10
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Kinases of eIF2a Switch Translation of mRNA Subset during Neuronal Plasticity. Int J Mol Sci 2017; 18:ijms18102213. [PMID: 29065505 PMCID: PMC5666893 DOI: 10.3390/ijms18102213] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 12/31/2022] Open
Abstract
Compared to other types of cells, neurons express the largest number of diverse mRNAs, including neuron-specific ones. This mRNA diversity is required for neuronal function, memory storage, maintenance and retrieval. Regulation of translation in neurons is very complicated and involves various proteins. Some proteins, implementing translational control in other cell types, are used by neurons for synaptic plasticity. In this review, we discuss the neuron-specific activity of four kinases: protein kinase R (PKR), PKR-like endoplasmic reticulum kinase (PERK), general control nonderepressible 2 kinase (GCN2), and heme-reguated eIF2α kinase (HRI), the substrate for which is α-subunit of eukaryotic initiation factor 2 (eIF2α). Phosphorylation of eIF2α is necessary for the cell during stress conditions, such as lack of amino acids, energy stress or viral infection. We propose that, during memory formation, neurons use some mechanisms similar to those involved in the cellular stress. The four eIF2α kinases regulate translation of certain mRNAs containing upstream open reading frames (uORFs). These mRNAs encode proteins involved in the processes of long-term potentiation (LTP) or long-term depression (LTD). The review examines some neuronal proteins for which translation regulation by eIF2 was suggested and checked experimentally. Of such proteins, we pay close attention to protein kinase Mζ, which is involved in memory storage and regulated at the translational level.
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11
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Borodinova AA, Zuzina AB, Balaban PM. Role of atypical protein kinases in maintenance of long-term memory and synaptic plasticity. BIOCHEMISTRY (MOSCOW) 2017; 82:243-256. [DOI: 10.1134/s0006297917030026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Bal NV, Susorov D, Chesnokova E, Kasianov A, Mikhailova T, Alkalaeva E, Balaban PM, Kolosov P. Upstream Open Reading Frames Located in the Leader of Protein Kinase Mζ mRNA Regulate Its Translation. Front Mol Neurosci 2016; 9:103. [PMID: 27790092 PMCID: PMC5061749 DOI: 10.3389/fnmol.2016.00103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/30/2016] [Indexed: 12/17/2022] Open
Abstract
For protein synthesis that occurs locally in dendrites, the translational control mechanisms are much more important for neuronal functioning than the transcription levels. Here, we show that uORFs (upstream open reading frames) in the 5′ untranslated region (5′UTR) play a critical role in regulation of the translation of protein kinase Mζ (PKMζ). Elimination of these uORFs activates translation of the reporter protein in vitro and in primary cultures of rat hippocampal neurons. Using cell-free translation systems, we demonstrate that translational initiation complexes are formed only on uORFs. Further, we address the mechanism of translational repression of PKMζ translation, by uORFs. We observed an increase in translation of the reporter protein under the control of PKMζ leader in neuronal culture during non-specific activation by picrotoxin. We also show that such a mechanism is similar to the mechanism seen in cell stress, as application of sodium arsenite to neuron cultures induced translation of mRNA carrying PKMζ 5′UTR similarly to picrotoxin activation. Therefore, we suppose that phosphorylation of eIF2a, like in cell stress, is a main regulator of PKMζ translation. Altogether, our findings considerably extend our understanding of the role of uORF in regulation of PKMζ translation in activated neurons, important at early stages of LTP.
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Affiliation(s)
- Natalia V Bal
- Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia
| | - Denis Susorov
- Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia; Faculty of Bioengineering and Bioinformatics, M. V. Lomonosov Moscow State UniversityMoscow, Russia
| | - Ekaterina Chesnokova
- Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia
| | - Artem Kasianov
- Laboratory of System Biology and Computational Genetics, Vavilov Institute of General Genetics, Russian Academy of Sciences Moscow, Russia
| | - Tatiana Mikhailova
- Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences Moscow, Russia
| | - Elena Alkalaeva
- Laboratory of Mechanisms and Control of Translation, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences Moscow, Russia
| | - Pavel M Balaban
- Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia
| | - Peter Kolosov
- Cellular Neurobiology of Learning Laboratory, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences Moscow, Russia
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Tsokas P, Hsieh C, Yao Y, Lesburguères E, Wallace EJC, Tcherepanov A, Jothianandan D, Hartley BR, Pan L, Rivard B, Farese RV, Sajan MP, Bergold PJ, Hernández AI, Cottrell JE, Shouval HZ, Fenton AA, Sacktor TC. Compensation for PKMζ in long-term potentiation and spatial long-term memory in mutant mice. eLife 2016; 5. [PMID: 27187150 PMCID: PMC4869915 DOI: 10.7554/elife.14846] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/23/2016] [Indexed: 02/07/2023] Open
Abstract
PKMζ is a persistently active PKC isoform proposed to maintain late-LTP and long-term memory. But late-LTP and memory are maintained without PKMζ in PKMζ-null mice. Two hypotheses can account for these findings. First, PKMζ is unimportant for LTP or memory. Second, PKMζ is essential for late-LTP and long-term memory in wild-type mice, and PKMζ-null mice recruit compensatory mechanisms. We find that whereas PKMζ persistently increases in LTP maintenance in wild-type mice, PKCι/λ, a gene-product closely related to PKMζ, persistently increases in LTP maintenance in PKMζ-null mice. Using a pharmacogenetic approach, we find PKMζ-antisense in hippocampus blocks late-LTP and spatial long-term memory in wild-type mice, but not in PKMζ-null mice without the target mRNA. Conversely, a PKCι/λ-antagonist disrupts late-LTP and spatial memory in PKMζ-null mice but not in wild-type mice. Thus, whereas PKMζ is essential for wild-type LTP and long-term memory, persistent PKCι/λ activation compensates for PKMζ loss in PKMζ-null mice. DOI:http://dx.doi.org/10.7554/eLife.14846.001 How are long-term memories stored in the brain? The formation of memories is believed to depend on the strengthening of connections between neurons. During learning, neurons produce an enzyme called PKMzeta (or PKMζ), which is thought to be responsible for maintaining the newly strengthened connections. Inhibitors of PKMzeta, such as a drug called ZIP, disrupt long-term memories. This suggests that the brain may be like a computer hard disc in that its stored information — its memories — could be erased. However, recent experiments on genetically engineered mice have thrown the role of PKMzeta into question. Knockout mice that lack the gene for PKMzeta can still strengthen connections between neurons and can still learn and remember. Moreover, ZIP still works to reverse the strengthening and to erase long-term memories. This indicates that ZIP can act on something other than the PKMzeta enzyme. These results have led many neuroscientists to doubt that PKMzeta has anything to do with memory. Yet there are two possible explanations for the normal memory in PKMzeta knockout mice. First, PKMzeta is not required for memory, so getting rid of it has no effect. Second, PKMzeta is essential for long-term memory in normal mice. However, knockout mice recruit a back-up mechanism for long-term memory storage, which is also sensitive to the effects of ZIP. To test these possibilities, Tsokas et al. used a modified piece of DNA that prevents neurons with the gene for PKMzeta from producing the enzyme. The DNA blocked memory formation in normal mice, consistent with a role for PKMzeta in memory. However, it had no effect in knockout mice — the DNA had nothing to work on. This suggests that another molecule does indeed act as a back-up for PKMzeta in these animals. Further experiments revealed that an enzyme closely related to PKMzeta, called PKCiota/lambda (PKCι/λ), substitutes for PKMzeta during memory storage in the knockout mice. These findings restore PKMzeta to its early promise. They show that PKMzeta is crucial for long-term memory in normal mice, but that something as important as memory storage has a back-up mechanism should PKMzeta fail. Future work may reveal when and how this back-up becomes engaged. DOI:http://dx.doi.org/10.7554/eLife.14846.002
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Affiliation(s)
- Panayiotis Tsokas
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Changchi Hsieh
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Yudong Yao
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | | | - Emma Jane Claire Wallace
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Andrew Tcherepanov
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Desingarao Jothianandan
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Benjamin Rush Hartley
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Ling Pan
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Bruno Rivard
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Robert V Farese
- Department of Internal Medicine, James A Haley Veterans Hospital, University of South Florida, Tampa, United States
| | - Mini P Sajan
- Department of Internal Medicine, James A Haley Veterans Hospital, University of South Florida, Tampa, United States
| | - Peter John Bergold
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Alejandro Iván Hernández
- Department of Pathology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - James E Cottrell
- Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States
| | - Harel Z Shouval
- Department of Neurobiology and Anatomy, University of Texas Medical School at Houston, Houston, United States
| | - André Antonio Fenton
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Center for Neural Science, New York University, New York, United States
| | - Todd Charlton Sacktor
- Department of Physiology and Pharmacology, The Robert F Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Anesthesiology, State University of New York Downstate Medical Center, Brooklyn, United States.,Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, United States
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Report on the 13th symposium on invertebrate neurobiology held 26-30 August 2015 at the Balaton Limnological Institute, MTA Centre for ecological research of the Hungarian Academy of Sciences, Tihany, Hungary. INVERTEBRATE NEUROSCIENCE 2016; 16:3. [PMID: 27149972 DOI: 10.1007/s10158-016-0186-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
This report summarizes the lectures and posters presented at the International Society for Invertebrate Neurobiology's 13th symposium held 26-30 August 2015, at the Balaton Limnological Institute, MTA Centre for Ecological Research, Tihany, Hungary. The symposium provided an opportunity for scientists working on a range of topics in invertebrate neurobiology to meet and present their research and discuss ways to advance the discipline.
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