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Anjum R, Clarke VRJ, Nagasawa Y, Murakoshi H, Paradis S. Rem2 interacts with CaMKII at synapses and restricts long-term potentiation in hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584540. [PMID: 38558974 PMCID: PMC10979978 DOI: 10.1101/2024.03.11.584540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Synaptic plasticity, the process whereby neuronal connections are either strengthened or weakened in response to stereotyped forms of stimulation, is widely believed to represent the molecular mechanism that underlies learning and memory. The holoenzyme CaMKII plays a well-established and critical role in the induction of a variety of forms of synaptic plasticity such as long-term potentiation (LTP), long-term depression (LTD) and depotentiation. Previously, we identified the GTPase Rem2 as a potent, endogenous inhibitor of CaMKII. Here, we report that knock out of Rem2 enhances LTP at the Schaffer collateral to CA1 synapse in hippocampus, consistent with an inhibitory action of Rem2 on CaMKII in vivo. Further, re-expression of WT Rem2 rescues the enhanced LTP observed in slices obtained from Rem2 conditional knock out (cKO) mice, while expression of a mutant Rem2 construct that is unable to inhibit CaMKII in vitro fails to rescue increased LTP. In addition, we demonstrate that CaMKII and Rem2 interact in dendritic spines using a 2pFLIM-FRET approach. Taken together, our data lead us to propose that Rem2 serves as a brake on runaway synaptic potentiation via inhibition of CaMKII activity. Further, the enhanced LTP phenotype we observe in Rem2 cKO slices reveals a previously unknown role for Rem2 in the negative regulation of CaMKII function.
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Affiliation(s)
- Rabia Anjum
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, United States of America
| | - Vernon R J Clarke
- Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611
| | - Yutaro Nagasawa
- Department of Physiological Sciences, The Graduate University for Advanced Studies; Hayama, Kanagawa 240-0193, Japan
- Supportive Center for Brain Research, National Institute for Physiological Sciences; Okazaki, Aichi 444-8585, Japan
| | - Hideji Murakoshi
- Department of Physiological Sciences, The Graduate University for Advanced Studies; Hayama, Kanagawa 240-0193, Japan
- Supportive Center for Brain Research, National Institute for Physiological Sciences; Okazaki, Aichi 444-8585, Japan
| | - Suzanne Paradis
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, Massachusetts 02454, United States of America
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Santiago C, Sharma N, Africawala N, Siegrist J, Handler A, Tasnim A, Anjum R, Turecek J, Lehnert BP, Renauld S, Nolan-Tamariz M, Iskols M, Magee AR, Paradis S, Ginty DD. Activity-dependent development of the body's touch receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.23.559109. [PMID: 37790437 PMCID: PMC10542488 DOI: 10.1101/2023.09.23.559109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We report a role for activity in the development of the primary sensory neurons that detect touch. Genetic deletion of Piezo2, the principal mechanosensitive ion channel in somatosensory neurons, caused profound changes in the formation of mechanosensory end organ structures and altered somatosensory neuron central targeting. Single cell RNA sequencing of Piezo2 conditional mutants revealed changes in gene expression in the sensory neurons activated by light mechanical forces, whereas other neuronal classes were less affected. To further test the role of activity in mechanosensory end organ development, we genetically deleted the voltage-gated sodium channel Nav1.6 (Scn8a) in somatosensory neurons throughout development and found that Scn8a mutants also have disrupted somatosensory neuron morphologies and altered electrophysiological responses to mechanical stimuli. Together, these findings indicate that mechanically evoked neuronal activity acts early in life to shape the maturation of the mechanosensory end organs that underlie our sense of gentle touch.
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Affiliation(s)
- Celine Santiago
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Nikhil Sharma
- Department of Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Nusrat Africawala
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Julianna Siegrist
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Annie Handler
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Aniqa Tasnim
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Rabia Anjum
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA, 02453, USA
| | - Josef Turecek
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Brendan P. Lehnert
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Sophia Renauld
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael Nolan-Tamariz
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael Iskols
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Alexandra R. Magee
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Suzanne Paradis
- Department of Biology and Volen Center for Complex Systems, Brandeis University, Waltham, MA, 02453, USA
| | - David D. Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA
- Lead Contact
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Laighneach A, Desbonnet L, Kelly JP, Donohoe G, Morris DW. Meta-Analysis of Brain Gene Expression Data from Mouse Model Studies of Maternal Immune Activation Using Poly(I:C). Genes (Basel) 2021; 12:genes12091363. [PMID: 34573345 PMCID: PMC8471627 DOI: 10.3390/genes12091363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/20/2021] [Accepted: 08/30/2021] [Indexed: 02/07/2023] Open
Abstract
Maternal immune activation (MIA) is a known risk factor for schizophrenia (SCZ) and autism spectrum disorder (ASD) and is often modelled in animal studies in order to study the effect of prenatal infection on brain function including behaviour and gene expression. Although the effect of MIA on gene expression are highly heterogeneous, combining data from multiple gene expression studies in a robust method may shed light on the true underlying biological effects caused by MIA and this could inform studies of SCZ and ASD. This study combined four RNA-seq and microarray datasets in an overlap analysis and ranked meta-analysis in order to investigate genes, pathways and cell types dysregulated in the MIA mouse models. Genes linked to SCZ and ASD and crucial in neurodevelopmental processes including neural tube folding, regulation of cellular stress and neuronal/glial cell differentiation were among the most consistently dysregulated in these ranked analyses. Gene ontologies including K+ ion channel function, neuron and glial cell differentiation, synaptic structure, axonal outgrowth, cilia function and lipid metabolism were also strongly implicated. Single-cell analysis identified excitatory and inhibitory cell types in the cortex, hippocampus and striatum that may be affected by MIA and are also enriched for genes associated with SCZ, ASD and cognitive phenotypes. This points to the cellular location of molecular mechanisms that may be consistent between the MIA model and neurodevelopmental disease, improving our understanding of its utility to study prenatal infection as an environmental stressor.
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Affiliation(s)
- Aodán Laighneach
- Centre for Neuroimaging, Cognition and Genomics, Discipline of Biochemistry and School of Psychology, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.L.); (G.D.)
| | - Lieve Desbonnet
- Discipline of Pharmacology and Therapeutics, National University of Ireland Galway, H91 TK33 Galway, Ireland; (L.D.); (J.P.K.)
| | - John P. Kelly
- Discipline of Pharmacology and Therapeutics, National University of Ireland Galway, H91 TK33 Galway, Ireland; (L.D.); (J.P.K.)
| | - Gary Donohoe
- Centre for Neuroimaging, Cognition and Genomics, Discipline of Biochemistry and School of Psychology, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.L.); (G.D.)
| | - Derek W. Morris
- Centre for Neuroimaging, Cognition and Genomics, Discipline of Biochemistry and School of Psychology, National University of Ireland Galway, H91 TK33 Galway, Ireland; (A.L.); (G.D.)
- Correspondence:
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Experience-Dependent Development of Dendritic Arbors in Mouse Visual Cortex. J Neurosci 2020; 40:6536-6556. [PMID: 32669356 DOI: 10.1523/jneurosci.2910-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/27/2022] Open
Abstract
The dendritic arbor of neurons constrains the pool of available synaptic partners and influences the electrical integration of synaptic currents. Despite these critical functions, our knowledge of the dendritic structure of cortical neurons during early postnatal development and how these dendritic structures are modified by visual experience is incomplete. Here, we present a large-scale dataset of 849 3D reconstructions of the basal arbor of pyramidal neurons collected across early postnatal development in visual cortex of mice of either sex. We found that the basal arbor grew substantially between postnatal day 7 (P7) and P30, undergoing a 45% increase in total length. However, the gross number of primary neurites and dendritic segments was largely determined by P7. Growth from P7 to P30 occurred primarily through extension of dendritic segments. Surprisingly, comparisons of dark-reared and typically reared mice revealed that a net gain of only 15% arbor length could be attributed to visual experience; most growth was independent of experience. To examine molecular contributions, we characterized the role of the activity-regulated small GTPase Rem2 in both arbor development and the maintenance of established basal arbors. We showed that Rem2 is an experience-dependent negative regulator of dendritic segment number during the visual critical period. Acute deletion of Rem2 reduced directionality of dendritic arbors. The data presented here establish a highly detailed, quantitative analysis of basal arbor development that we believe has high utility both in understanding circuit development as well as providing a framework for computationalists wishing to generate anatomically accurate neuronal models.SIGNIFICANCE STATEMENT Dendrites are the sites of the synaptic connections among neurons. Despite their importance for neural circuit function, only a little is known about the postnatal development of dendritic arbors of cortical pyramidal neurons and the influence of experience. Here we show that the number of primary basal dendritic arbors is already established before eye opening, and that these arbors primarily grow through lengthening of dendritic segments and not through addition of dendritic segments. Surprisingly, visual experience has a modest net impact on overall arbor length (15%). Experiments in KO animals revealed that the gene Rem2 is positive regulator of dendritic length and a negative regulator of dendritic segments.
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Royer L, Herzog JJ, Kenny K, Tzvetkova B, Cochrane JC, Marr MT, Paradis S. The Ras-like GTPase Rem2 is a potent inhibitor of calcium/calmodulin-dependent kinase II activity. J Biol Chem 2018; 293:14798-14811. [PMID: 30072381 DOI: 10.1074/jbc.ra118.003560] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/20/2018] [Indexed: 02/05/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a well-characterized, abundant protein kinase that regulates a diverse set of functions in a tissue-specific manner. For example, in heart muscle, CaMKII regulates Ca2+ homeostasis, whereas in neurons, CaMKII regulates activity-dependent dendritic remodeling and long-term potentiation (LTP), a neurobiological correlate of learning and memory. Previously, we identified the GTPase Rem2 as a critical regulator of dendrite branching and homeostatic plasticity in the vertebrate nervous system. Here, we report that Rem2 directly interacts with CaMKII and potently inhibits the activity of the intact holoenzyme, a previously unknown Rem2 function. Our results suggest that Rem2 inhibition involves interaction with both the CaMKII hub domain and substrate recognition domain. Moreover, we found that Rem2-mediated inhibition of CaMKII regulates dendritic branching in cultured hippocampal neurons. Lastly, we report that substitution of two key amino acid residues in the Rem2 N terminus (Arg-79 and Arg-80) completely abolishes its ability to inhibit CaMKII. We propose that our biochemical findings will enable further studies unraveling the functional significance of Rem2 inhibition of CaMKII in cells.
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Affiliation(s)
| | | | | | | | - Jesse C Cochrane
- Department of Molecular Biology and Genetics, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
| | - Michael T Marr
- From the Department of Biology, .,Rosenstiel Basic Medical Sciences Research Center
| | - Suzanne Paradis
- From the Department of Biology, .,Volen Center for Complex Systems, and.,National Center for Behavioral Genomics, Brandeis University, Waltham, Massachusetts 02454 and
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Moore AR, Richards SE, Kenny K, Royer L, Chan U, Flavahan K, Van Hooser SD, Paradis S. Rem2 stabilizes intrinsic excitability and spontaneous firing in visual circuits. eLife 2018; 7:e33092. [PMID: 29809135 PMCID: PMC6010341 DOI: 10.7554/elife.33092] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/28/2018] [Indexed: 12/20/2022] Open
Abstract
Sensory experience plays an important role in shaping neural circuitry by affecting the synaptic connectivity and intrinsic properties of individual neurons. Identifying the molecular players responsible for converting external stimuli into altered neuronal output remains a crucial step in understanding experience-dependent plasticity and circuit function. Here, we investigate the role of the activity-regulated, non-canonical Ras-like GTPase Rem2 in visual circuit plasticity. We demonstrate that Rem2-/- mice fail to exhibit normal ocular dominance plasticity during the critical period. At the cellular level, our data establish a cell-autonomous role for Rem2 in regulating intrinsic excitability of layer 2/3 pyramidal neurons, prior to changes in synaptic function. Consistent with these findings, both in vitro and in vivo recordings reveal increased spontaneous firing rates in the absence of Rem2. Taken together, our data demonstrate that Rem2 is a key molecule that regulates neuronal excitability and circuit function in the context of changing sensory experience.
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Affiliation(s)
- Anna R Moore
- Department of BiologyBrandeis UniversityWalthamUnited States
| | - Sarah E Richards
- Department of BiologyBrandeis UniversityWalthamUnited States
- Volen Center for Complex SystemsBrandeis UniversityWalthamUnited States
| | - Katelyn Kenny
- National Center for Behavioral GenomicsBrandeis UniversityWalthamUnited States
| | - Leandro Royer
- Department of BiologyBrandeis UniversityWalthamUnited States
| | - Urann Chan
- Department of BiologyBrandeis UniversityWalthamUnited States
| | - Kelly Flavahan
- Department of BiologyBrandeis UniversityWalthamUnited States
| | - Stephen D Van Hooser
- Department of BiologyBrandeis UniversityWalthamUnited States
- Volen Center for Complex SystemsBrandeis UniversityWalthamUnited States
| | - Suzanne Paradis
- Department of BiologyBrandeis UniversityWalthamUnited States
- Volen Center for Complex SystemsBrandeis UniversityWalthamUnited States
- National Center for Behavioral GenomicsBrandeis UniversityWalthamUnited States
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7
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Abstract
Circuit operations are determined jointly by the properties of the circuit elements and the properties of the connections among these elements. In the nervous system, neurons exhibit diverse morphologies and branching patterns, allowing rich compartmentalization within individual cells and complex synaptic interactions among groups of cells. In this review, we summarize work detailing how neuronal morphology impacts neural circuit function. In particular, we consider example neurons in the retina, cerebral cortex, and the stomatogastric ganglion of crustaceans. We also explore molecular coregulators of morphology and circuit function to begin bridging the gap between molecular and systems approaches. By identifying motifs in different systems, we move closer to understanding the structure-function relationships that are present in neural circuits.
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Affiliation(s)
| | - Stephen D Van Hooser
- Department of Biology, Brandeis University , Waltham, Massachusetts.,Volen Center for Complex Systems, Brandeis University , Waltham, Massachusetts.,Sloan-Swartz Center for Theoretical Neurobiology, Brandeis University , Waltham, Massachusetts
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8
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Kenny K, Royer L, Moore AR, Chen X, Marr MT, Paradis S. Rem2 signaling affects neuronal structure and function in part by regulation of gene expression. Mol Cell Neurosci 2017; 85:190-201. [PMID: 29066292 DOI: 10.1016/j.mcn.2017.10.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/27/2017] [Accepted: 10/11/2017] [Indexed: 12/12/2022] Open
Abstract
The central nervous system has the remarkable ability to convert changes in the environment in the form of sensory experience into long-term alterations in synaptic connections and dendritic arborization, in part through changes in gene expression. Surprisingly, the molecular mechanisms that translate neuronal activity into changes in neuronal connectivity and morphology remain elusive. Rem2, a member of the Rad/Rem/Rem2/Gem/Kir (RGK) subfamily of small Ras-like GTPases, is a positive regulator of synapse formation and negative regulator of dendritic arborization. Here we identify that one output of Rem2 signaling is the regulation of gene expression. Specifically, we demonstrate that Rem2 signaling modulates the expression of genes required for a variety of cellular processes from neurite extension to synapse formation and synaptic function. Our results highlight Rem2 as a unique molecule that transduces changes in neuronal activity detected at the cell membrane to morphologically relevant changes in gene expression in the nucleus.
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Affiliation(s)
- Katelyn Kenny
- Department of Biology, Brandeis University, Waltham, MA 02454, United States
| | - Leandro Royer
- Department of Biology, Brandeis University, Waltham, MA 02454, United States
| | - Anna R Moore
- Department of Biology, Brandeis University, Waltham, MA 02454, United States; Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, United States; National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, United States
| | - Xiao Chen
- Department of Biology, Brandeis University, Waltham, MA 02454, United States; National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, United States
| | - Michael T Marr
- Department of Biology, Brandeis University, Waltham, MA 02454, United States; Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, United States
| | - Suzanne Paradis
- Department of Biology, Brandeis University, Waltham, MA 02454, United States; Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, United States; National Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, United States.
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Two Components of Aversive Memory in Drosophila, Anesthesia-Sensitive and Anesthesia-Resistant Memory, Require Distinct Domains Within the Rgk1 Small GTPase. J Neurosci 2017; 37:5496-5510. [PMID: 28416593 DOI: 10.1523/jneurosci.3648-16.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 03/12/2017] [Accepted: 04/12/2017] [Indexed: 12/17/2022] Open
Abstract
Multiple components have been identified that exhibit different stabilities for aversive olfactory memory in Drosophila These components have been defined by behavioral and genetic studies and genes specifically required for a specific component have also been identified. Intermediate-term memory generated after single cycle conditioning is divided into anesthesia-sensitive memory (ASM) and anesthesia-resistant memory (ARM), with the latter being more stable. We determined that the ASM and ARM pathways converged on the Rgk1 small GTPase and that the N-terminal domain-deleted Rgk1 was sufficient for ASM formation, whereas the full-length form was required for ARM formation. Rgk1 is specifically accumulated at the synaptic site of the Kenyon cells (KCs), the intrinsic neurons of the mushroom bodies, which play a pivotal role in olfactory memory formation. A higher than normal Rgk1 level enhanced memory retention, which is consistent with the result that Rgk1 suppressed Rac-dependent memory decay; these findings suggest that rgk1 bolsters ASM via the suppression of forgetting. We propose that Rgk1 plays a pivotal role in the regulation of memory stabilization by serving as a molecular node that resides at KC synapses, where the ASM and ARM pathway may interact.SIGNIFICANCE STATEMENT Memory consists of multiple components. Drosophila olfactory memory serves as a fundamental model with which to investigate the mechanisms that underlie memory formation and has provided genetic and molecular means to identify the components of memory, namely short-term, intermediate-term, and long-term memory, depending on how long the memory lasts. Intermediate memory is further divided into anesthesia-sensitive memory (ASM) and anesthesia-resistant memory (ARM), with the latter being more stable. We have identified a small GTPase in Drosophila, Rgk1, which plays a pivotal role in the regulation of olfactory memory stability. Rgk1 is required for both ASM and ARM. Moreover, N-terminal domain-deleted Rgk1 was sufficient for ASM formation, whereas the full-length form was required for ARM formation.
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Parent C, Wen X, Dhir SK, Ryan R, Diorio J, Zhang TY. Maternal care associates with differences in morphological complexity in the medial preoptic area. Behav Brain Res 2017; 326:22-32. [PMID: 28259675 DOI: 10.1016/j.bbr.2017.02.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/10/2017] [Accepted: 02/28/2017] [Indexed: 10/20/2022]
Abstract
The medial preoptic area (MPOA) is implicated in the expression of maternal behavior including the frequency of pup licking/grooming (LG) in the rat. Cyclic adenosine monophosphate (cAMP) responsive element-binding protein (CREB) is a transcription factor that regulates the expression of many genes. We found that lactating rats that are more maternal towards their pups showing increased licking/grooming (i.e. high-LG mothers) had increased levels of phosphorylated CREB (pCREB) in the MPOA following a nursing bout and they displayed a reduced population of greater dendritic complexity index (DCI) neurons compared to less maternal rats showing decreased licking/grooming (i.e. low-LG mothers). CREB overexpression in MPOA neuronal cultures associated with a decrease in dendritic complexity and an increase in the expression of Rem2 and brain-derived neurotrophic factor (BDNF), genes implicated in dendritic pruning. While there were no differences in Rem2 expression in virgin high and low-LG female rats, Rem2 was significantly increased in the MPOA of high-LG compared to low-LG lactating rats. CREB activity in the MPOA associates with maternal behavior and reduced dendritic complexity possibly by increasing Rem2 expression.
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Affiliation(s)
- Carine Parent
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Xianglan Wen
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Sabine K Dhir
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Richard Ryan
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Josie Diorio
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada
| | - Tie-Yuan Zhang
- Sackler Program for Epigenetics and Developmental Psychobiology at McGill University, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec H4H 1R3, Canada; Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada.
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11
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Puhl HL, Lu VB, Won YJ, Sasson Y, Hirsch JA, Ono F, Ikeda SR. Ancient origins of RGK protein function: modulation of voltage-gated calcium channels preceded the protostome and deuterostome split. PLoS One 2014; 9:e100694. [PMID: 24992013 PMCID: PMC4081519 DOI: 10.1371/journal.pone.0100694] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/23/2014] [Indexed: 11/21/2022] Open
Abstract
RGK proteins, Gem, Rad, Rem1, and Rem2, are members of the Ras superfamily of small GTP-binding proteins that interact with Ca2+ channel β subunits to modify voltage-gated Ca2+ channel function. In addition, RGK proteins affect several cellular processes such as cytoskeletal rearrangement, neuronal dendritic complexity, and synapse formation. To probe the phylogenetic origins of RGK protein–Ca2+ channel interactions, we identified potential RGK-like protein homologs in genomes for genetically diverse organisms from both the deuterostome and protostome animal superphyla. RGK-like protein homologs cloned from Danio rerio (zebrafish) and Drosophila melanogaster (fruit flies) expressed in mammalian sympathetic neurons decreased Ca2+ current density as reported for expression of mammalian RGK proteins. Sequence alignments from evolutionarily diverse organisms spanning the protostome/deuterostome divide revealed conservation of residues within the RGK G-domain involved in RGK protein – Cavβ subunit interaction. In addition, the C-terminal eleven residues were highly conserved and constituted a signature sequence unique to RGK proteins but of unknown function. Taken together, these data suggest that RGK proteins, and the ability to modify Ca2+ channel function, arose from an ancestor predating the protostomes split from deuterostomes approximately 550 million years ago.
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Affiliation(s)
- Henry L. Puhl
- Laboratory of Molecular Physiology, Section on Transmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Van B. Lu
- Laboratory of Molecular Physiology, Section on Transmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yu-Jin Won
- Laboratory of Molecular Physiology, Section on Transmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Yehezkel Sasson
- Department of Biochemistry & Molecular Biology, Faculty of Life Sciences, Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Joel A. Hirsch
- Department of Biochemistry & Molecular Biology, Faculty of Life Sciences, Institute for Structural Biology, Tel Aviv University, Ramat Aviv, Israel
| | - Fumihito Ono
- Laboratory of Molecular Physiology, Section on Model Synaptic Systems, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Stephen R. Ikeda
- Laboratory of Molecular Physiology, Section on Transmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
- * E-mail:
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12
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Ghiretti AE, Paradis S. Molecular mechanisms of activity-dependent changes in dendritic morphology: role of RGK proteins. Trends Neurosci 2014; 37:399-407. [PMID: 24910262 PMCID: PMC4113564 DOI: 10.1016/j.tins.2014.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 01/10/2023]
Abstract
The nervous system has the amazing capacity to transform sensory experience from the environment into changes in neuronal activity that, in turn, cause long-lasting alterations in neuronal morphology. Recent findings indicate that, surprisingly, sensory experience concurrently activates molecular signaling pathways that both promote and inhibit dendritic complexity. Historically, a number of positive regulators of activity-dependent dendritic complexity have been described, whereas the list of identified negative regulators of this process is much shorter. In recent years, there has been an emerging appreciation of the importance of the Rad/Rem/Rem2/Gem/Kir (RGK) GTPases as mediators of activity-dependent structural plasticity. In the following review, we discuss the traditional view of RGK proteins, as well as our evolving understanding of the role of these proteins in instructing structural plasticity.
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Affiliation(s)
- Amy E Ghiretti
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | - Suzanne Paradis
- Department of Biology, National Center for Behavioral Genomics, and Volen Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA.
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DeRocher MM, Armaly FH, Lepore CJ, Hollis DM. Rem2 in the bullfrog (Rana catesbeiana): Patterns of expression within the central nervous system and brain expression at different ontogenetic stages. Gene 2014; 540:37-45. [PMID: 24576576 DOI: 10.1016/j.gene.2014.02.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/13/2014] [Accepted: 02/18/2014] [Indexed: 12/12/2022]
Abstract
Rem2 is a member of the RGK (Rem, Rad, and Gem/Kir) subfamily of the Ras superfamily of GTP binding proteins. In mammals, Rem2 has been found to be unique in not only its structure, but also its tissue specificity, as it is the first member to be found at high levels in neuronal tissue. Because Rem2 has previously been implicated in neuronal cell proliferation, and amphibians maintain relatively high neuronal proliferative activity as adults, we sought to isolate and acquire the full-length sequence of the rem2 gene from the brain of the bullfrog (Rana catesbeiana). Furthermore, we used real time PCR (rtPCR) to characterize its tissue specificity, regional brain expression, and brain expression levels at different stages of development. Deduced amino acid sequence analysis showed that the bullfrog Rem2 protein possesses the unique 5' extension characteristic of mammalian Rem2 and the RGK subfamily to which it belongs. Tissue specificity of the bullfrog rem2 gene showed that the bullfrog is similar to both mammals and fish in that the levels of rem2 gene expression were significantly greater in the brain than all other tissues assayed. In the brain itself, differential rem2 expression patterns were observed between six major brain areas assayed and the spinal cord, with expression significantly high in the cerebrum and low in the cerebellum. Finally, examination of whole brain rem2 expression levels in bullfrogs at different stages of development revealed greater expression after metamorphic climax.
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Abstract
A key feature of the CNS is structural plasticity, the ability of neurons to alter their morphology and connectivity in response to sensory experience and other changes in the environment. How this structural plasticity is achieved at the molecular level is not well understood. We provide evidence that changes in sensory experience simultaneously trigger multiple signaling pathways that either promote or restrict growth of the dendritic arbor; structural plasticity is achieved through a balance of these opposing signals. Specifically, we have uncovered a novel, activity-dependent signaling pathway that restricts dendritic arborization. We demonstrate that the GTPase Rem2 is regulated at the transcriptional level by calcium influx through L-VGCCs and inhibits dendritic arborization in cultured rat cortical neurons and in the Xenopus laevis tadpole visual system. Thus, our results demonstrate that changes in neuronal activity initiate competing signaling pathways that positively and negatively regulate the growth of the dendritic arbor. It is the balance of these opposing signals that leads to proper dendritic morphology.
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