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Cartier E, Hamilton PJ, Belovich AN, Shekar A, Campbell NG, Saunders C, Andreassen TF, Gether U, Veenstra-Vanderweele J, Sutcliffe JS, Ulery-Reynolds PG, Erreger K, Matthies HJG, Galli A. Rare autism-associated variants implicate syntaxin 1 (STX1 R26Q) phosphorylation and the dopamine transporter (hDAT R51W) in dopamine neurotransmission and behaviors. EBioMedicine 2015; 2:135-146. [PMID: 25774383 PMCID: PMC4353922 DOI: 10.1016/j.ebiom.2015.01.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Background Syntaxin 1 (STX1) is a presynaptic plasma membrane protein that coordinates synaptic vesicle fusion. STX1 also regulates the function of neurotransmitter transporters, including the dopamine (DA) transporter (DAT). The DAT is a membrane protein that controls DA homeostasis through the high-affinity re-uptake of synaptically released DA. Methods We adopt newly developed animal models and state-of-the-art biophysical techniques to determine the contribution of the identified gene variants to impairments in DA neurotransmission observed in autism spectrum disorder (ASD). Outcomes Here, we characterize two independent autism-associated variants in the genes that encode STX1 and the DAT. We demonstrate that each variant dramatically alters DAT function. We identify molecular mechanisms that converge to inhibit reverse transport of DA and DA-associated behaviors. These mechanisms involve decreased phosphorylation of STX1 at Ser14 mediated by casein kinase 2 as well as a reduction in STX1/DAT interaction. These findings point to STX1/DAT interactions and STX1 phosphorylation as key regulators of DA homeostasis. Interpretation We determine the molecular identity and the impact of these variants with the intent of defining DA dysfunction and associated behaviors as possible complications of ASD. We report two independent autism-associated variants in syntaxin and the dopamine transporter. The variants in syntaxin and dopamine transporter each impair reverse transport of dopamine. Dysregulation of dopamine neurotransmission may represent a complication of autism spectrum disorder.
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Affiliation(s)
- Etienne Cartier
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Peter J Hamilton
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Andrea N Belovich
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Aparna Shekar
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Nicholas G Campbell
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Christine Saunders
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Thorvald F Andreassen
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Jeremy Veenstra-Vanderweele
- Department of Psychiatry and New York State Psychiatric Institute, Columbia University, New York, NY, 10032 USA
| | - James S Sutcliffe
- Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Paula G Ulery-Reynolds
- Department of Psychiatry, UT Southwestern Medical Center, Dallas TX 75390-8813, United States
| | - Kevin Erreger
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Heinrich J G Matthies
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Aurelio Galli
- Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Neuroscience Program in Substance Abuse, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States ; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
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Castillo MA, Ghose S, Tamminga CA, Ulery-Reynolds PG. Deficits in syntaxin 1 phosphorylation in schizophrenia prefrontal cortex. Biol Psychiatry 2010; 67:208-16. [PMID: 19748077 DOI: 10.1016/j.biopsych.2009.07.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Schizophrenia has been described as a disease of the synapse. On the basis of previous studies reporting reductions in the levels and activity of CK2 (also know as casein kinase 2 or II) in the brain of subjects with schizophrenia, we hypothesized that CK2-mediated phosphorylation of the presynaptic protein syntaxin 1 (Stx 1) is deficient in schizophrenia. This in turn could affect the binding of Stx 1 to its protein partners and result in abnormal neurotransmitter release and synaptic transmission. METHODS We analyzed post mortem prefrontal cortex samples from 15 schizophrenia cases and matched controls by quantitative immunoblotting. RESULTS In addition to replicating previous findings of reduced CK2 levels, we show that as predicted, the deficit in CK2 correlates with a deficit in phospho-Stx 1. In contrast, we find that these deficits are not present in depression cases. Further, we show that the reduced levels of CK2 and phospho-Stx 1 are not due to treatment with antipsychotic drugs (APDs). In fact, APDs seem to increase both CK2 and phospho-Stx 1, suggesting that their therapeutic action may be associated with the reversal of these deficits. Finally, we show that lower phospho-Stx 1 levels are associated with reduced binding of Stx 1 to SNAP-25 and MUNC18 and decreased SNARE complex formation. CONCLUSIONS Our findings constitute the first report of altered phosphorylation of a key component for neurotransmitter release in humans and suggest that regulation of Stx 1 by CK2-mediated phosphorylation could play a role in the pathophysiology of schizophrenia.
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Affiliation(s)
- Max A Castillo
- Department of Neurology, The University of Texas, Southwestern Medical Center, Dallas, Texas, USA
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Ulery-Reynolds PG, Castillo MA, Vialou V, Russo SJ, Nestler EJ. Phosphorylation of DeltaFosB mediates its stability in vivo. Neuroscience 2008; 158:369-72. [PMID: 19041372 DOI: 10.1016/j.neuroscience.2008.10.059] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 10/25/2008] [Accepted: 10/29/2008] [Indexed: 10/21/2022]
Abstract
The transcription factor, DeltaFosB, accumulates in a region-specific manner in brain in response to many types of chronic stimulation due to the unusual stability of the protein. The phosphorylation of Ser27 in DeltaFosB has been shown to promote this stability in vitro. We show here that this phosphorylation reaction is also important for DeltaFosB's stability in the brain in vivo and for the unique behavioral plasticity mediated by this transcription factor.
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Affiliation(s)
- P G Ulery-Reynolds
- Department of Neurology, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9070, USA
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