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Moss ND, Wells KL, Theis A, Kim YK, Spigelman AF, Liu X, MacDonald PE, Sussel L. Modulation of insulin secretion by RBFOX2-mediated alternative splicing. Nat Commun 2023; 14:7732. [PMID: 38007492 PMCID: PMC10676425 DOI: 10.1038/s41467-023-43605-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 11/15/2023] [Indexed: 11/27/2023] Open
Abstract
Insulin secretion is a tightly regulated process that is vital for maintaining blood glucose homeostasis. Although the molecular components of insulin granule trafficking and secretion are well established, how they are regulated to rapidly fine-tune secretion in response to changing environmental conditions is not well characterized. Recent studies have determined that dysregulation of RNA-binding proteins (RBPs) and aberrant mRNA splicing occurs at the onset of diabetes. We demonstrate that the RBP, RBFOX2, is a critical regulator of insulin secretion through the alternative splicing of genes required for insulin granule docking and exocytosis. Conditional mutation of Rbfox2 in the mouse pancreas results in decreased insulin secretion and impaired blood glucose homeostasis. Consistent with defects in secretion, we observe reduced insulin granule docking and corresponding splicing defects in the SNARE complex components. These findings identify an additional mechanism for modulating insulin secretion in both healthy and dysfunctional pancreatic β cells.
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Affiliation(s)
- Nicole D Moss
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kristen L Wells
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Alexandra Theis
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Yong-Kyung Kim
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Aliya F Spigelman
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Xiong Liu
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Lori Sussel
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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Zhong Y, Zhang N, Zhao F, Chang S, Chen W, Cao Q, Sun L, Wang Y, Gong Z, Lu L, Liu D, Yang L. RBFOX1 and Working Memory: From Genome to Transcriptome Revealed Posttranscriptional Mechanism Separate From Attention-Deficit/Hyperactivity Disorder. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2023; 3:1042-1052. [PMID: 37881587 PMCID: PMC10593897 DOI: 10.1016/j.bpsgos.2022.08.006] [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: 05/27/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/22/2022] Open
Abstract
Background Many psychiatric disorders share a working memory (WM) impairment phenotype, yet the genetic causes remain unclear. Here, we generated genetic profiles of WM deficits using attention-deficit/hyperactivity disorder samples and validated the results in zebrafish models. Methods We used 2 relatively large attention-deficit/hyperactivity disorder cohorts, 799 and 776 cases, respectively. WM impairment was assessed using the Rey Complex Figure Test. First, association analyses were conducted at single-variant, gene-based, and gene-set levels. Deeper insights into the biological mechanism were gained from further functional exploration by bioinformatic analyses and zebrafish models. Results Genomic analyses identified and replicated a locus with rs75885813 as the index single nucleotide polymorphism showing significant association with WM defects but not with attention-deficit/hyperactivity disorder. Functional feature exploration found that these single nucleotide polymorphisms may regulate the expression level of RBFOX1 through chromatin interaction. Further pathway enrichment analysis of potential associated single nucleotide polymorphisms revealed the involvement of posttranscription regulation that affects messenger RNA stability and/or alternative splicing. Zebrafish with functionally knocked down or genome-edited rbfox1 exhibited WM impairment but no hyperactivity. Transcriptome profiling of rbfox1-defective zebrafish indicated that alternative exon usages of snap25a might partially lead to reduced WM learning of larval zebrafish. Conclusions The locus with rs75885813 in RBFOX1 was identified as associated with WM. Rbfox1 regulates synaptic and long-term potentiation-related gene snap25a to adjust WM at the posttranscriptional level.
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Affiliation(s)
- Yuanxin Zhong
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Na Zhang
- School of Life Science, Southern University of Science and Technology, Shenzhen, China
- Department of Biological Science, National University of Singapore, Singapore
| | - Feng Zhao
- School of Life Science, Southern University of Science and Technology, Shenzhen, China
| | - Suhua Chang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Wei Chen
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Qingjiu Cao
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Li Sun
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Yufeng Wang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
| | - Zhiyuan Gong
- Department of Biological Science, National University of Singapore, Singapore
| | - Lin Lu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
- Peking-Tsinghua Center for Life Sciences, International Data Group, McGovern Institute for Brain Research at Peking University, Peking University, Beijing, China
| | - Dong Liu
- School of Life Science, Southern University of Science and Technology, Shenzhen, China
| | - Li Yang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health, National Clinical Research Center for Mental Disorders, Beijing, China
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3
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Yoo DY, Jung HY, Kim W, Hahn KR, Kwon HJ, Nam SM, Chung JY, Yoon YS, Kim DW, Hwang IK. Entacapone Treatment Modulates Hippocampal Proteins Related to Synaptic Vehicle Trafficking. Cells 2020; 9:cells9122712. [PMID: 33352833 PMCID: PMC7765944 DOI: 10.3390/cells9122712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 11/29/2022] Open
Abstract
Entacapone, a reversible inhibitor of catechol-O-methyl transferase, is used for patients in Parkinson’s disease because it increases the bioavailability and effectiveness of levodopa. In the present study, we observed that entacapone increases novel object recognition and neuroblasts in the hippocampus. In the present study, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were performed to compare the abundance profiles of proteins expressed in the hippocampus after entacapone treatment in mice. Results of 2-DE, MALDI-TOF mass spectrometry, and subsequent proteomic analysis revealed an altered protein expression profile in the hippocampus after entacapone treatment. Based on proteomic analysis, 556 spots were paired during the image analysis of 2-DE gels and 76 proteins were significantly changed more than two-fold among identified proteins. Proteomic analysis indicated that treatment with entacapone induced expressional changes in proteins involved in synaptic transmission, cellular processes, cellular signaling, the regulation of cytoskeletal structure, energy metabolism, and various subcellular enzymatic reactions. In particular, entacapone significantly increased proteins related to synaptic trafficking and plasticity, such as dynamin 1, synapsin I, and Munc18-1. Immunohistochemical staining showed the localization of the proteins, and western blot confirmed the significant increases in dynamin I (203.5% of control) in the hippocampus as well as synapsin I (254.0% of control) and Munc18-1 (167.1% of control) in the synaptic vesicle fraction of hippocampus after entacapone treatment. These results suggest that entacapone can enhance hippocampal synaptic trafficking and plasticity against various neurological diseases related to hippocampal dysfunction.
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Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan 31151, Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Woosuk Kim
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Department of Biomedical Sciences, Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Korea
| | - Kyu Ri Hahn
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Korea;
| | - Sung Min Nam
- Department of Anatomy, School of Medicine and Institute for Environmental Science, Wonkwang University, Iksan 54538, Korea;
| | - Jin Young Chung
- Department of Veterinary Internal Medicine and Geriatrics, College of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Korea;
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Korea;
- Correspondence: (D.W.K.); (I.K.H.)
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Correspondence: (D.W.K.); (I.K.H.)
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4
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Disabling Gβγ-SNAP-25 interaction in gene-targeted mice results in enhancement of long-term potentiation at Schaffer collateral-CA1 synapses in the hippocampus. Neuroreport 2020; 30:695-699. [PMID: 31095110 DOI: 10.1097/wnr.0000000000001258] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Three SNARE proteins, SNAP-25, syntaxin 1A, and VAMP2 or synaptobrevin 2, constitute the minimal functional machinery needed for the regulated secretion of neurotransmitters. Dynamic changes in the regulated release of neurotransmitters are associated with the induction of long-term plasticity at central synapses. In-vitro studies have validated the C-terminus of SNAP-25 as a target for inhibitory Gi/o-coupled G-protein coupled receptors at a number of synapses. The physiological consequences of the interaction between Gi/o proteins and SNAP-25 in the context of activity-dependent long-term synaptic plasticity are not well understood. Here, we report direct ex-vivo evidence of the involvement of the C-terminus of SNAP-25 in inducing long-term potentiation of synaptic strength at Schaffer collateral-CA1 synapses using a gene-targeted mouse model with truncated C-terminus (carboxyl terminus) of SNAP-25. It has been shown previously that truncation of the three extreme C-terminal residues in SNAP-25[INCREMENT]3 homozygote mice reduces its interaction with the inhibitory Gβγ subunits two-fold. In in-vitro hippocampal slices, we show that these SNAP-25[INCREMENT]3 mice express significantly larger magnitude of long-term potentiation at hippocampal Schaffer collateral-CA1 synapses.
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5
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Gopaul KR, Irfan M, Miry O, Vose LR, Moghadam A, Subah G, Hökfelt T, Bark C, Stanton PK. Developmental Time Course of SNAP-25 Isoforms Regulate Hippocampal Long-Term Synaptic Plasticity and Hippocampus-Dependent Learning. Int J Mol Sci 2020; 21:ijms21041448. [PMID: 32093363 PMCID: PMC7073020 DOI: 10.3390/ijms21041448] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 12/28/2022] Open
Abstract
SNAP-25 is essential to activity-dependent vesicle fusion and neurotransmitter release in the nervous system. During early development and adulthood, SNAP-25 appears to have differential influences on short- and long-term synaptic plasticity. The involvement of SNAP-25 in these processes may be different at hippocampal and neocortical synapses because of the presence of two different splice variants, which are developmentally regulated. We show here that the isoform SNAP-25a, which is expressed first developmentally in rodent brain, contributes to developmental regulation of the expression of both long-term depression (LTD) and long-term potentiation (LTP) at Schaffer collateral-CA1 synapses in the hippocampus. In one month old mice lacking the developmentally later expressed isoform SNAP-25b, Schaffer collateral-CA1 synapses showed faster release kinetics, decreased LTP and enhanced LTD. By four months of age, SNAP-25b-deficient mice appeared to have compensated for the lack of the adult SNAP-25b isoform, now exhibiting larger LTP and no differences in LTD compared to wild type mice. Interestingly, learning a hippocampus-dependent task reversed the reductions in LTP, but not LTD, seen at one month of age. In four month old adult mice, learning prevented the compensatory up-regulation of LTD that we observed prior to training. These findings support the hypothesis that SNAP-25b promotes stronger LTP and weakens LTD at Schaffer collateral-CA1 synapses in young mice, and suggest that compensatory mechanisms can reverse alterations in synaptic plasticity associated with a lack of SNAP-25b, once mice reach adulthood.
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Affiliation(s)
- Katisha R. Gopaul
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Muhammad Irfan
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Omid Miry
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Linnea R. Vose
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Alexander Moghadam
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Galadu Subah
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Christina Bark
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Correspondence: (C.B.); (P.K.S.); Tel. +46-085-248-6984 (C.B.); +1-914-594-4883 (P.K.S.)
| | - Patric K. Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
- Correspondence: (C.B.); (P.K.S.); Tel. +46-085-248-6984 (C.B.); +1-914-594-4883 (P.K.S.)
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6
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Interaction of Synaptosomal-Associated Protein 25 with Neutral Sphingomyelinase 2: Functional Impact on the Sphingomyelin Pathway. Neuroscience 2020; 427:1-15. [PMID: 31765623 DOI: 10.1016/j.neuroscience.2019.08.015] [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: 03/19/2019] [Revised: 08/06/2019] [Accepted: 08/07/2019] [Indexed: 11/22/2022]
Abstract
Neurotransmitter release is mediated by ceramide, which is generated by sphingomyelin hydrolysis. In the present study, we examined whether synaptosomal-associated protein 25 (SNAP-25) is involved in ceramide production and exocytosis. Neutral sphingomyelinase 2 (nSMase2) was partially purified from bovine brain and we found that SNAP-25 was enriched in the nSMase2-containing fractions. In rat synaptosomes and PC12 cells, the immunoprecipitation pellet of anti-SNAP-25 antibody showed higher nSMase activity than the immunoprecipitation pellet of anti-nSMase2 antibody. In PC12 cells, SNAP-25 was colocalized with nSMase2. Transfection of SNAP-25 small interfering RNA (siRNA) significantly inhibited nSMase2 translocation to the plasma membrane. A23187-induced ceramide production was concomitantly reduced in SNAP-25 siRNA-transfected PC12 cells compared with that in scrambled siRNA-transfected cells. Moreover, transfection of SNAP-25 siRNA inhibited dopamine release, whereas addition of C6-ceramide to the siRNA-treated cells moderately reversed this inhibition. Additionally, nSMase2 inhibition reduced dopamine release. Collectively, our results indicate that SNAP-25 interacts with nSMase2 during ceramide production, which mediates exocytosis and neurotransmitter release.
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7
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SNAP-25 Puts SNAREs at Center Stage in Metabolic Disease. Neuroscience 2019; 420:86-96. [DOI: 10.1016/j.neuroscience.2018.07.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/12/2018] [Accepted: 07/19/2018] [Indexed: 12/20/2022]
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8
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The SNAP-25 Protein Family. Neuroscience 2019; 420:50-71. [DOI: 10.1016/j.neuroscience.2018.09.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/31/2018] [Accepted: 09/14/2018] [Indexed: 01/04/2023]
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9
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SNAP-25 isoforms differentially regulate synaptic transmission and long-term synaptic plasticity at central synapses. Sci Rep 2019; 9:6403. [PMID: 31024034 PMCID: PMC6484009 DOI: 10.1038/s41598-019-42833-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/09/2019] [Indexed: 01/08/2023] Open
Abstract
SNAP-25 exists as two developmentally regulated alternatively spliced isoforms, SNAP-25a and SNAP-25b. We explored the function of SNAP-25a and SNAP-25b at Schaffer collateral-CA1 synapses in hippocampus using 4-week-old wild-type (WT) and SNAP-25b-deficient (MT) mice. Characterizing the protein expression of individual SNAP-25 isoforms revealed that WT females had higher levels of SNAP-25a than WT males, suggesting a sex-dependent delay of the alternative splicing switch from SNAP-25a to SNAP-25b. MT mice expressed normal levels of total SNAP-25, Syntaxin 1A and SNAP-47 in the hippocampus, but females expressed lower levels of VAMP2. Electrophysiological recordings in in vitro hippocampal slices revealed significantly reduced magnitude of LTP in MT mice. We also found reduction in paired-pulse facilitation after induction of LTP in WT males, but not in WT females, possibly related to the difference in SNAP-25a/SNAP-25b ratios, suggesting that the splicing switch may play a sex-specific role in LTP-associated increases in presynaptic release probability. Basal synaptic transmission measured in input-output relations revealed that the ability to discriminate between the intensity of presynaptic stimuli was affected in SNAP-25b-deficient mice. Learning in a behavioural paradigm of active-avoidance was impaired in MT mice, strengthening the conclusion that SNAP-25b is important for cognitive performance by altering activity-dependent synaptic plasticity.
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10
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Zurawski Z, Yim YY, Alford S, Hamm HE. The expanding roles and mechanisms of G protein-mediated presynaptic inhibition. J Biol Chem 2019; 294:1661-1670. [PMID: 30710014 PMCID: PMC6364771 DOI: 10.1074/jbc.tm118.004163] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Throughout the past five decades, tremendous advancements have been made in our understanding of G protein signaling and presynaptic inhibition, many of which were published in the Journal of Biological Chemistry under the tenure of Herb Tabor as Editor-in-Chief. Here, we identify these critical advances, including the formulation of the ternary complex model of G protein-coupled receptor signaling and the discovery of Gβγ as a critical signaling component of the heterotrimeric G protein, along with the nature of presynaptic inhibition and its physiological role. We provide an overview for the discovery and physiological relevance of the two known Gβγ-mediated mechanisms for presynaptic inhibition: first, the action of Gβγ on voltage-gated calcium channels to inhibit calcium influx to the presynaptic active zone and, second, the direct binding of Gβγ to the SNARE complex to displace synaptotagmin downstream of calcium entry, which has been demonstrated to be important in neurons and secretory cells. These two mechanisms act in tandem with each other in a synergistic manner to provide more complete spatiotemporal control over neurotransmitter release.
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Affiliation(s)
- Zack Zurawski
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600; Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois 60612-7308
| | - Yun Young Yim
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600
| | - Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois, Chicago, Illinois 60612-7308
| | - Heidi E Hamm
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600.
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11
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Abstract
Modulation of neurotransmitter exocytosis by activated Gi/o coupled G-protein coupled receptors (GPCRs) is a universal regulatory mechanism used both to avoid overstimulation and to influence circuitry. One of the known modulation mechanisms is the interaction between Gβγ and the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNAREs). There are 5 Gβ and 12 Gγ subunits, but specific Gβγs activated by a given GPCR and the specificity to effectors, such as SNARE, in vivo are not known. Although less studied, Gβγ binding to the exocytic fusion machinery (i.e. SNARE) provides a more direct regulatory mechanism for neurotransmitter release. Here, we review some recent insights in the architecture of the synaptic terminal, modulation of synaptic transmission, and implications of G protein modulation of synaptic transmission in diseases. Numerous presynaptic proteins are involved in the architecture of synaptic terminals, particularly the active zone, and their importance in the regulation of exocytosis is still not completely understood. Further understanding of the Gβγ-SNARE interaction and the architecture and mechanisms of exocytosis may lead to the discovery of novel therapeutic targets to help patients with various disorders such as hypertension, attention-deficit/hyperactivity disorder, post-traumatic stress disorder, and acute/chronic pain.
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Affiliation(s)
- Yun Young Yim
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Zack Zurawski
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University, Nashville 37232-6600, TN, United States.
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12
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Pozzi D, Corradini I, Matteoli M. The Control of Neuronal Calcium Homeostasis by SNAP-25 and its Impact on Neurotransmitter Release. Neuroscience 2018; 420:72-78. [PMID: 30476527 DOI: 10.1016/j.neuroscience.2018.11.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/05/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023]
Abstract
The process of neurotransmitter release is central to the control of cell-to-cell communication in brain. SNAP-25 is a component of the SNARE complex, which, together with syntaxin-1 and synaptobrevin, mediates synaptic vesicle fusion with the plasma membrane. The genetic ablation of the protein or its proteolytic cleavage by botulinum neurotoxins results in a complete block of synaptic transmission. In the last years, several evidences have indicated that SNAP-25 also plays additional modulatory roles in neurotransmission through the control of voltage-gated calcium channels and presynaptic calcium ion concentration. Consistently, reduced levels of the protein affect presynaptic calcium homeostasis and result in pathologically enhanced glutamate exocytosis. The SNAP-25-dependent alterations of synaptic calcium dynamics may have direct impact on the development of neuropsychiatric disorders where the Snap-25 gene has been found to be involved.
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Affiliation(s)
- Davide Pozzi
- Humanitas University, Via Rita Levi Montalcini, 4, 20090 Pieve Emanuele, Milano, Italy; IRCCS Humanitas, via Manzoni 56, 20089 Rozzano, Italy.
| | - Irene Corradini
- CNR Institute of Neuroscience, via Vanvitelli 32, 20129 Milano, Italy
| | - Michela Matteoli
- Humanitas University, Via Rita Levi Montalcini, 4, 20090 Pieve Emanuele, Milano, Italy; IRCCS Humanitas, via Manzoni 56, 20089 Rozzano, Italy.
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13
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Blue RE, Curry EG, Engels NM, Lee EY, Giudice J. How alternative splicing affects membrane-trafficking dynamics. J Cell Sci 2018; 131:jcs216465. [PMID: 29769303 PMCID: PMC6031328 DOI: 10.1242/jcs.216465] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The cell biology field has outstanding working knowledge of the fundamentals of membrane-trafficking pathways, which are of critical importance in health and disease. Current challenges include understanding how trafficking pathways are fine-tuned for specialized tissue functions in vivo and during development. In parallel, the ENCODE project and numerous genetic studies have revealed that alternative splicing regulates gene expression in tissues and throughout development at a post-transcriptional level. This Review summarizes recent discoveries demonstrating that alternative splicing affects tissue specialization and membrane-trafficking proteins during development, and examines how this regulation is altered in human disease. We first discuss how alternative splicing of clathrin, SNAREs and BAR-domain proteins influences endocytosis, secretion and membrane dynamics, respectively. We then focus on the role of RNA-binding proteins in the regulation of splicing of membrane-trafficking proteins in health and disease. Overall, our aim is to comprehensively summarize how trafficking is molecularly influenced by alternative splicing and identify future directions centered on its physiological relevance.
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Affiliation(s)
- R Eric Blue
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ennessa G Curry
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Nichlas M Engels
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Eunice Y Lee
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jimena Giudice
- Department of Cell Biology & Physiology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology (GMB), The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Alford S, Hamm H, Rodriguez S, Zurawski Z. Gβγ SNARE Interactions and Their Behavioral Effects. Neurochem Res 2018; 44:636-649. [PMID: 29752624 DOI: 10.1007/s11064-018-2531-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/09/2018] [Accepted: 04/16/2018] [Indexed: 11/25/2022]
Abstract
Presynaptic terminals possess interlocking molecular mechanisms that control exocytosis. An example of such complexity is the modulation of release by presynaptic G Protein Coupled Receptors (GPCRs). GPCR ubiquity at synapses-GPCRs are present at every studied presynaptic terminal-underlies their critical importance in synaptic function. GPCRs mediate presynaptic modulation by mechanisms including via classical Gα effectors, but membrane-delimited actions of Gβγ can also alter probability of release by altering presynaptic ionic conductances. This directly or indirectly modifies action potential-evoked presynaptic Ca2+ entry. In addition, Gβγ can interact directly with SNARE complexes responsible for synaptic vesicle fusion to reduce peak cleft neurotransmitter concentrations during evoked release. The interaction of Gβγ with SNARE is displaced via competitive interaction with C2AB-domain containing calcium sensors such as synaptotagmin I in a Ca2+-sensitive manner, restoring exocytosis. Synaptic modulation of this form allows selective inhibition of postsynaptic receptor-mediated responses, and this, in combination with Ca2+ sensitivity of Gβγ effects on SNARE complexes allows for specific behavioral outcomes. One such outcome mediated by 5-HT receptors in the spinal cord seen in all vertebrates shows remarkable synergy between presynaptic effects of Gβγ and postsynaptic 5-HT-mediated changes in activation of Ca2+-dependent K+ channels. While acting through entirely separate cellular compartments and signal transduction pathways, these effects converge on the same effect on locomotion and other critical functions of the central nervous system.
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Affiliation(s)
- Simon Alford
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA.
| | - Heidi Hamm
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, 37232-6600, USA
| | - Shelagh Rodriguez
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA
| | - Zack Zurawski
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, 60612-7308, USA
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, 37232-6600, USA
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