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Liu W, Xiu L, Zhou M, Li T, Jiang N, Wan Y, Qiu C, Li J, Hu W, Zhang W, Wu J. The Critical Role of the Shroom Family Proteins in Morphogenesis, Organogenesis and Disease. PHENOMICS (CHAM, SWITZERLAND) 2024; 4:187-202. [PMID: 38884059 PMCID: PMC11169129 DOI: 10.1007/s43657-023-00119-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 06/18/2024]
Abstract
The Shroom (Shrm) family of actin-binding proteins has a unique and highly conserved Apx/Shrm Domain 2 (ASD2) motif. Shroom protein directs the subcellular localization of Rho-associated kinase (ROCK), which remodels the actomyosin cytoskeleton and changes cellular morphology via its ability to phosphorylate and activate non-muscle myosin II. Therefore, the Shrm-ROCK complex is critical for the cellular shape and the development of many tissues, including the neural tube, eye, intestines, heart, and vasculature system. Importantly, the structure and expression of Shrm proteins are also associated with neural tube defects, chronic kidney disease, metastasis of carcinoma, and X-link mental retardation. Therefore, a better understanding of Shrm-mediated signaling transduction pathways is essential for the development of new therapeutic strategies to minimize damage resulting in abnormal Shrm proteins. This paper provides a comprehensive overview of the various Shrm proteins and their roles in morphogenesis and disease.
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Affiliation(s)
- Wanling Liu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Lei Xiu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Mingzhe Zhou
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Tao Li
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Ning Jiang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Yanmin Wan
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Chao Qiu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032 China
| | - Jian Li
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Wei Hu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Monglia University, Hohhot, 010030 China
| | - Wenhong Zhang
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438 China
- Shanghai Huashen Institute of Microbes and Infections, Shanghai, 200052 China
| | - Jing Wu
- Department of Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, National Medical Center for Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, 200438 China
- Shanghai Huashen Institute of Microbes and Infections, Shanghai, 200052 China
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2
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Filamin A organizes γ‑aminobutyric acid type B receptors at the plasma membrane. Nat Commun 2023; 14:34. [PMID: 36596803 PMCID: PMC9810740 DOI: 10.1038/s41467-022-35708-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/21/2022] [Indexed: 01/05/2023] Open
Abstract
The γ-aminobutyric acid type B (GABAB) receptor is a prototypical family C G protein-coupled receptor (GPCR) that plays a key role in the regulation of synaptic transmission. Although growing evidence suggests that GPCR signaling in neurons might be highly organized in time and space, limited information is available about the mechanisms controlling the nanoscale organization of GABAB receptors and other GPCRs on the neuronal plasma membrane. Using a combination of biochemical assays in vitro, single-particle tracking, and super-resolution microscopy, we provide evidence that the spatial organization and diffusion of GABAB receptors on the plasma membrane are governed by dynamic interactions with filamin A, which tethers the receptors to sub-cortical actin filaments. We further show that GABAB receptors are located together with filamin A in small nanodomains in hippocampal neurons. These interactions are mediated by the first intracellular loop of the GABAB1 subunit and modulate the kinetics of Gαi protein activation in response to GABA stimulation.
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3
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Hobson BD, Choi SJ, Mosharov EV, Soni RK, Sulzer D, Sims P. Subcellular proteomics of dopamine neurons in the mouse brain. eLife 2022; 11:70921. [PMID: 35098924 PMCID: PMC8860448 DOI: 10.7554/elife.70921] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 01/30/2022] [Indexed: 11/13/2022] Open
Abstract
Dopaminergic neurons modulate neural circuits and behaviors via dopamine (DA) release from expansive, long range axonal projections. The elaborate cytoarchitecture of these neurons is embedded within complex brain tissue, making it difficult to access the neuronal proteome using conventional methods. Here, we demonstrate APEX2 proximity labeling within genetically targeted neurons in the mouse brain, enabling subcellular proteomics with cell-type specificity. By combining APEX2 biotinylation with mass spectrometry, we mapped the somatodendritic and axonal proteomes of midbrain dopaminergic neurons. Our dataset reveals the proteomic architecture underlying proteostasis, axonal metabolism, and neurotransmission in these neurons. We find that most proteins encoded by DA neuron-enriched genes are localized within striatal dopaminergic axons, including ion channels with previously undescribed axonal localization. These proteomic datasets provide a resource for neuronal cell biology, and this approach can be readily adapted for study of other neural cell types.
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Affiliation(s)
- Benjamin D Hobson
- Depart of Systems Biology, Columbia University Medical Center, New York, United States
| | - Se Joon Choi
- New York State Psychiatric Institute, Columbia University Medical Center, New York, United States
| | - Eugene V Mosharov
- New York State Psychiatric Institute, Columbia University Medical Center, New York, United States
| | - Rajesh K Soni
- Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, United States
| | - David Sulzer
- Department of Psychiatry, Columbia University Medical Center, New York, United States
| | - Peter Sims
- Department of Systems Biology, Columbia University Medical Center, New York, United States
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4
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GABA B Receptor Chemistry and Pharmacology: Agonists, Antagonists, and Allosteric Modulators. Curr Top Behav Neurosci 2021; 52:81-118. [PMID: 34036555 DOI: 10.1007/7854_2021_232] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The GABAB receptors are metabotropic G protein-coupled receptors (GPCRs) that mediate the actions of the primary inhibitory neurotransmitter, γ-aminobutyric acid (GABA). In the CNS, GABA plays an important role in behavior, learning and memory, cognition, and stress. GABA is also located throughout the gastrointestinal (GI) tract and is involved in the autonomic control of the intestine and esophageal reflex. Consequently, dysregulated GABAB receptor signaling is associated with neurological, mental health, and gastrointestinal disorders; hence, these receptors have been identified as key therapeutic targets and are the focus of multiple drug discovery efforts for indications such as muscle spasticity disorders, schizophrenia, pain, addiction, and gastroesophageal reflex disease (GERD). Numerous agonists, antagonists, and allosteric modulators of the GABAB receptor have been described; however, Lioresal® (Baclofen; β-(4-chlorophenyl)-γ-aminobutyric acid) is the only FDA-approved drug that selectively targets GABAB receptors in clinical use; undesirable side effects, such as sedation, muscle weakness, fatigue, cognitive deficits, seizures, tolerance and potential for abuse, limit their therapeutic use. Here, we review GABAB receptor chemistry and pharmacology, presenting orthosteric agonists, antagonists, and positive and negative allosteric modulators, and highlight the therapeutic potential of targeting GABAB receptor modulation for the treatment of various CNS and peripheral disorders.
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5
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Neurexins regulate presynaptic GABA B-receptors at central synapses. Nat Commun 2021; 12:2380. [PMID: 33888718 PMCID: PMC8062527 DOI: 10.1038/s41467-021-22753-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 03/20/2021] [Indexed: 11/28/2022] Open
Abstract
Diverse signaling complexes are precisely assembled at the presynaptic active zone for dynamic modulation of synaptic transmission and synaptic plasticity. Presynaptic GABAB-receptors nucleate critical signaling complexes regulating neurotransmitter release at most synapses. However, the molecular mechanisms underlying assembly of GABAB-receptor signaling complexes remain unclear. Here we show that neurexins are required for the localization and function of presynaptic GABAB-receptor signaling complexes. At four model synapses, excitatory calyx of Held synapses in the brainstem, excitatory and inhibitory synapses on hippocampal CA1-region pyramidal neurons, and inhibitory basket cell synapses in the cerebellum, deletion of neurexins rendered neurotransmitter release significantly less sensitive to GABAB-receptor activation. Moreover, deletion of neurexins caused a loss of GABAB-receptors from the presynaptic active zone of the calyx synapse. These findings extend the role of neurexins at the presynaptic active zone to enabling GABAB-receptor signaling, supporting the notion that neurexins function as central organizers of active zone signaling complexes. Neurexins are evolutionarily conserved cell adhesion molecules that tune synapse formation and specification. Here the authors show that neurexins play similar roles in regulating presynaptic GABAB receptors at multiple CNS synapses.
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Mechanisms and Regulation of Neuronal GABA B Receptor-Dependent Signaling. Curr Top Behav Neurosci 2020; 52:39-79. [PMID: 32808092 DOI: 10.1007/7854_2020_129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
γ-Aminobutyric acid B receptors (GABABRs) are broadly expressed throughout the central nervous system where they play an important role in regulating neuronal excitability and synaptic transmission. GABABRs are G protein-coupled receptors that mediate slow and sustained inhibitory actions via modulation of several downstream effector enzymes and ion channels. GABABRs are obligate heterodimers that associate with diverse arrays of proteins to form modular complexes that carry out distinct physiological functions. GABABR-dependent signaling is fine-tuned and regulated through a multitude of mechanisms that are relevant to physiological and pathophysiological states. This review summarizes the current knowledge on GABABR signal transduction and discusses key factors that influence the strength and sensitivity of GABABR-dependent signaling in neurons.
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7
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Papon MA, Le Feuvre Y, Barreda-Gómez G, Favereaux A, Farrugia F, Bouali-Benazzouz R, Nagy F, Rodríguez-Puertas R, Landry M. Spinal Inhibition of GABAB Receptors by the Extracellular Matrix Protein Fibulin-2 in Neuropathic Rats. Front Cell Neurosci 2020; 14:214. [PMID: 32765223 PMCID: PMC7378325 DOI: 10.3389/fncel.2020.00214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/17/2020] [Indexed: 12/23/2022] Open
Abstract
In the central nervous system, the inhibitory GABAB receptor is the archetype of heterodimeric G protein-coupled receptors (GPCRs). Receptor interaction with partner proteins has emerged as a novel mechanism to alter GPCR signaling in pathophysiological conditions. We propose here that GABAB activity is inhibited through the specific binding of fibulin-2, an extracellular matrix protein, to the B1a subunit in a rat model of neuropathic pain. We demonstrate that fibulin-2 hampers GABAB activation, presumably through decreasing agonist-induced conformational changes. Fibulin-2 regulates the GABAB-mediated presynaptic inhibition of neurotransmitter release and weakens the GABAB-mediated inhibitory effect in neuronal cell culture. In the dorsal spinal cord of neuropathic rats, fibulin-2 is overexpressed and colocalized with B1a. Fibulin-2 may thus interact with presynaptic GABAB receptors, including those on nociceptive afferents. By applying anti-fibulin-2 siRNA in vivo, we enhanced the antinociceptive effect of intrathecal baclofen in neuropathic rats, thus demonstrating that fibulin-2 limits the action of GABAB agonists in vivo. Taken together, our data provide an example of an endogenous regulation of GABAB receptor by extracellular matrix proteins and demonstrate its functional impact on pathophysiological processes of pain sensitization.
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Affiliation(s)
- Marie-Amélie Papon
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | - Yves Le Feuvre
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | | | - Alexandre Favereaux
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | - Fanny Farrugia
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | - Rabia Bouali-Benazzouz
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | - Frédéric Nagy
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
| | | | - Marc Landry
- Institut Interdisciplinaire de Neurosciences, University of Bordeaux, Bordeaux, France.,CNRS UMR 5297, Institut Interdisciplinaire de Neurosciences, Bordeaux, France
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8
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Fonin AV, Darling AL, Kuznetsova IM, Turoverov KK, Uversky VN. Multi-functionality of proteins involved in GPCR and G protein signaling: making sense of structure-function continuum with intrinsic disorder-based proteoforms. Cell Mol Life Sci 2019; 76:4461-4492. [PMID: 31428838 PMCID: PMC11105632 DOI: 10.1007/s00018-019-03276-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/05/2019] [Accepted: 08/12/2019] [Indexed: 12/21/2022]
Abstract
GPCR-G protein signaling system recognizes a multitude of extracellular ligands and triggers a variety of intracellular signaling cascades in response. In humans, this system includes more than 800 various GPCRs and a large set of heterotrimeric G proteins. Complexity of this system goes far beyond a multitude of pair-wise ligand-GPCR and GPCR-G protein interactions. In fact, one GPCR can recognize more than one extracellular signal and interact with more than one G protein. Furthermore, one ligand can activate more than one GPCR, and multiple GPCRs can couple to the same G protein. This defines an intricate multifunctionality of this important signaling system. Here, we show that the multifunctionality of GPCR-G protein system represents an illustrative example of the protein structure-function continuum, where structures of the involved proteins represent a complex mosaic of differently folded regions (foldons, non-foldons, unfoldons, semi-foldons, and inducible foldons). The functionality of resulting highly dynamic conformational ensembles is fine-tuned by various post-translational modifications and alternative splicing, and such ensembles can undergo dramatic changes at interaction with their specific partners. In other words, GPCRs and G proteins exist as sets of conformational/basic, inducible/modified, and functioning proteoforms characterized by a broad spectrum of structural features and possessing various functional potentials.
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Affiliation(s)
- Alexander V Fonin
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - April L Darling
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Irina M Kuznetsova
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
| | - Konstantin K Turoverov
- Laboratory of structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russian Federation
- Department of Biophysics, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya av. 29, St. Petersburg, 195251, Russian Federation
| | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, Moscow, Russian Federation.
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9
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TERUNUMA M. Diversity of structure and function of GABA B receptors: a complexity of GABA B-mediated signaling. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2018; 94:390-411. [PMID: 30541966 PMCID: PMC6374141 DOI: 10.2183/pjab.94.026] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 10/09/2018] [Indexed: 05/24/2023]
Abstract
γ-aminobutyric acid type B (GABAB) receptors are broadly expressed in the nervous system and play an important role in neuronal excitability. GABAB receptors are G protein-coupled receptors that mediate slow and prolonged inhibitory action, via activation of Gαi/o-type proteins. GABAB receptors mediate their inhibitory action through activating inwardly rectifying K+ channels, inactivating voltage-gated Ca2+ channels, and inhibiting adenylate cyclase. Functional GABAB receptors are obligate heterodimers formed by the co-assembly of R1 and R2 subunits. It is well established that GABAB receptors interact not only with G proteins and effectors but also with various proteins. This review summarizes the structure, subunit isoforms, and function of GABAB receptors, and discusses the complexity of GABAB receptors, including how receptors are localized in specific subcellular compartments, the mechanism regulating cell surface expression and mobility of the receptors, and the diversity of receptor signaling through receptor crosstalk and interacting proteins.
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Affiliation(s)
- Miho TERUNUMA
- Division of Oral Biochemistry, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
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10
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Forghany Z, Robertson F, Lundby A, Olsen JV, Baker DA. Control of endothelial cell tube formation by Notch ligand intracellular domain interactions with activator protein 1 (AP-1). J Biol Chem 2017; 293:1229-1242. [PMID: 29196606 DOI: 10.1074/jbc.m117.819045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/30/2017] [Indexed: 01/08/2023] Open
Abstract
Notch signaling is a ubiquitous signal transduction pathway found in most if not all metazoan cell types characterized to date. It is indispensable for cell differentiation as well as tissue growth, tissue remodeling, and apoptosis. Although the canonical Notch signaling pathway is well characterized, accumulating evidence points to the existence of multiple, less well-defined layers of regulation. In this study, we investigated the function of the intracellular domain (ICD) of the Notch ligand Delta-like 4 (DLL4). We provide evidence that the DLL4 ICD is required for normal DLL4 subcellular localization. We further show that it is cleaved and interacts with the JUN proto-oncogene, which forms part of the activator protein 1 (AP-1) transcription factor complex. Mechanistically, the DLL4 ICD inhibited JUN binding to DNA and thereby controlled the expression of JUN target genes, including DLL4 Our work further demonstrated that JUN strongly stimulates endothelial cell tube formation and that DLL4 constrains this process. These results raise the possibility that Notch/DLL4 signaling is bidirectional and suggest that the DLL4 ICD could represent a point of cross-talk between Notch and receptor tyrosine kinase (RTK) signaling.
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Affiliation(s)
- Zary Forghany
- From the Department of Molecular Cell Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands and
| | - Francesca Robertson
- From the Department of Molecular Cell Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands and
| | - Alicia Lundby
- Novo Nordisk Foundation Center for Protein Research and.,the Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | | | - David A Baker
- From the Department of Molecular Cell Biology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands and
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11
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Towards a Better Understanding of GABAergic Remodeling in Alzheimer's Disease. Int J Mol Sci 2017; 18:ijms18081813. [PMID: 28825683 PMCID: PMC5578199 DOI: 10.3390/ijms18081813] [Citation(s) in RCA: 111] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/16/2017] [Accepted: 08/17/2017] [Indexed: 12/18/2022] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the vertebrate brain. In the past, there has been a major research drive focused on the dysfunction of the glutamatergic and cholinergic neurotransmitter systems in Alzheimer’s disease (AD). However, there is now growing evidence in support of a GABAergic contribution to the pathogenesis of this neurodegenerative disease. Previous studies paint a complex, convoluted and often inconsistent picture of AD-associated GABAergic remodeling. Given the importance of the GABAergic system in neuronal function and homeostasis, in the maintenance of the excitatory/inhibitory balance, and in the processes of learning and memory, such changes in GABAergic function could be an important factor in both early and later stages of AD pathogenesis. Given the limited scope of currently available therapies in modifying the course of the disease, a better understanding of GABAergic remodeling in AD could open up innovative and novel therapeutic opportunities.
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12
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Copy number variations and expression of MPDZ are prognostic biomarkers for clear cell renal cell carcinoma. Oncotarget 2017; 8:78713-78725. [PMID: 29108259 PMCID: PMC5667992 DOI: 10.18632/oncotarget.20220] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 07/12/2017] [Indexed: 11/25/2022] Open
Abstract
The vital copy number variation (CNV) plays a crucial role in clear cell renal cell carcinoma (ccRCC). MPDZ inhibit cell polarity associate with osmotic pressure response and cancer-related biological processes. In order to clarify the role of the CNV of MPDZ in the progression of ccRCC, we analyzed the CNV and expression of MPDZ and prognosis in ccRCC patients from The Cancer Genome Atlas data portal. Notably, we found that the deletion of MPDZ was the common CNV, which was present in 28.65% of ccRCC patients. With the development of tumors, the percentage of MPDZ deletion increased significantly (19.38% in stage I; 20.00% in stage II; 40.94% in stage III; and 45.00% in stage IV). The deletion of MPDZ significantly increased ccRCC risk (P=0.0025). Low MPDZ expression associated with its deletion was significantly associated with adverse outcomes in ccRCC patients (P=0.0342). Furthermore, immunohistochemical analysis by tissue microarray showed that MPDZ was expressed at lower levels in tumor tissues compared with adjacent tissues (P<0.01). Kaplan–Meier survival curves showed that ccRCC patients with low MPDZ expression had significantly shorter survival than those with high MPDZ expression (P=0.002). These results indicated that low MPDZ expression associated with CNV is a potential biomarker for the prognosis of ccRCC patients.
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13
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Li M, Milligan CJ, Wang H, Walker A, Churilov L, Lawrence AJ, Reid CA, Hopkins SC, Petrou S. KCTD12 modulation of GABA(B) receptor function. Pharmacol Res Perspect 2017; 5:e00319. [PMID: 28713569 PMCID: PMC5508304 DOI: 10.1002/prp2.319] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/21/2017] [Accepted: 03/31/2017] [Indexed: 12/20/2022] Open
Abstract
The molecular composition and functional diversity of native GABAB receptors (GABABR) are still poorly understood, thus hindering development of selective GABABR ligands. Potassium channel tetramerization domain‐containing protein (KCTD) 12 is a GABABR auxiliary subunit and mouse KCTD12 can alter GABABR function. In this study, we sought to characterize the effects of human KCTD12 on GABABR kinetics and pharmacology, using an automated electrophysiological assay. Seizure susceptibility and ethanol consumption were also investigated in a KCTD12 knockout mouse model. Human KCTD12 co‐expression altered the kinetics of GABABR‐mediated GIRK channels, speeding rates of both activation and desensitization. Analysis of concentration‐response curves showed that KCTD12 coexpression did not alter effects of the agonists GABA or baclofen on GABABR. KCTD12 coexpression enhanced the potentiating effects of the positive allosteric modulator CGP7930, and its effects on GABABR activation and desensitization. The function of KCTD12 in vivo was examined, using the KCTD12 knockout mouse model. The knockout mice were more resistant to a pentylenetetrazole proconvulsant challenge suggesting reduced seizure susceptibility. In the two bottle preference test, KCTD12 knockout mice demonstrated a reduced consumption at high ethanol concentrations. In summary, human KCTD12 accelerated the kinetics of GABABR in vitro, in a manner possibly sensitive to allosteric pharmacological modulation. This study also provides novel in vivo evidence that the interaction between KCTD12 and GABABR is of physiological significance, and may be a mechanism to more selectively modulate GABABR.
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Affiliation(s)
- Melody Li
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Carol J Milligan
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Haiyan Wang
- Sunovion Pharmaceuticals Inc Marlborough Massachusetts
| | - Andrew Walker
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Leonid Churilov
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia
| | | | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health Parkville Victoria Australia.,Department of Anatomy and Neuroscience University of Melbourne Parkville Victoria Australia.,Centre for Neural Engineering University of Melbourne Parkville Victoria Australia
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14
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Epilepsy and intellectual disability linked protein Shrm4 interaction with GABA BRs shapes inhibitory neurotransmission. Nat Commun 2017; 8:14536. [PMID: 28262662 PMCID: PMC5343488 DOI: 10.1038/ncomms14536] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 01/09/2017] [Indexed: 02/07/2023] Open
Abstract
Shrm4, a protein expressed only in polarized tissues, is encoded by the KIAA1202 gene, whose mutations have been linked to epilepsy and intellectual disability. However, a physiological role for Shrm4 in the brain is yet to be established. Here, we report that Shrm4 is localized to synapses where it regulates dendritic spine morphology and interacts with the C terminus of GABAB receptors (GABABRs) to control their cell surface expression and intracellular trafficking via a dynein-dependent mechanism. Knockdown of Shrm4 in rat severely impairs GABABR activity causing increased anxiety-like behaviour and susceptibility to seizures. Moreover, Shrm4 influences hippocampal excitability by modulating tonic inhibition in dentate gyrus granule cells, in a process involving crosstalk between GABABRs and extrasynaptic δ-subunit-containing GABAARs. Our data highlights a role for Shrm4 in synaptogenesis and in maintaining GABABR-mediated inhibition, perturbation of which may be responsible for the involvement of Shrm4 in cognitive disorders and epilepsy. Mutations in the gene encoding Shrm4 are associated with epilepsy and intellectual disability. The authors show that Shrm4 interacts with GABAB receptors and regulates tonic inhibition in the hippocampus, and knockdown of Shrm4 in rats leads to anxiety-like behaviour and seizures.
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Harper DE, Schrepf A, Clauw DJ. Pain Mechanisms and Centralized Pain in Temporomandibular Disorders. J Dent Res 2016; 95:1102-8. [PMID: 27422858 DOI: 10.1177/0022034516657070] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Until recently, most clinicians and scientists believed that the experience of pain is perceptually proportional to the amount of incoming peripheral nociceptive drive due to injury or inflammation in the area perceived to be painful. However, many cases of chronic pain have defied this logic, leaving clinicians perplexed as to how patients are experiencing pain with no obvious signs of injury in the periphery. Conversely, there are patients who have a peripheral injury and/or inflammation but little or no pain. What makes some individuals experience intense pain with minimal peripheral nociceptive stimulation and others experience minimal pain with serious injury? It is increasingly well accepted in the scientific community that pain can be generated and maintained or, through other mechanisms, suppressed by changes in the central nervous system, creating a complete mismatch between peripheral nociceptive drive and perceived pain. In fact, there is no known chronic pain condition where the observed extent of peripheral damage reproducibly engenders the same level of pain across individuals. Temporomandibular disorders (TMDs) are no exception. This review focuses on the idea that TMD patients range on a continuum-from those whose pain is generated peripherally to those whose pain is centralized (i.e., generated, exacerbated, and/or maintained by central nervous system mechanisms). This article uses other centralized chronic pain conditions as a guide, and it suggests that the mechanistic variability in TMD pain etiology has prevented us from adequately treating many individuals who are diagnosed with the condition. As the field moves forward, it will be imperative to understand each person's pain from its own mechanistic standpoint, which will enable clinicians to deliver personalized medicine to TMD patients and eventually provide relief in even the most recalcitrant cases.
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Affiliation(s)
- D E Harper
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - A Schrepf
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - D J Clauw
- Chronic Pain and Fatigue Research Center, Department of Anesthesiology, School of Medicine, University of Michigan, Ann Arbor, MI, USA
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Donaldson R, Sun Y, Liang DY, Zheng M, Sahbaie P, Dill DL, Peltz G, Buck KJ, Clark JD. The multiple PDZ domain protein Mpdz/MUPP1 regulates opioid tolerance and opioid-induced hyperalgesia. BMC Genomics 2016; 17:313. [PMID: 27129385 PMCID: PMC4850636 DOI: 10.1186/s12864-016-2634-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 04/22/2016] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Opioids are a mainstay for the treatment of chronic pain. Unfortunately, therapy-limiting maladaptations such as loss of treatment effect (tolerance), and paradoxical opioid-induced hyperalgesia (OIH) can occur. The objective of this study was to identify genes responsible for opioid tolerance and OIH. RESULTS These studies used a well-established model of ascending morphine administration to induce tolerance, OIH and other opioid maladaptations in 23 strains of inbred mice. Genome-wide computational genetic mapping was then applied to the data in combination with a false discovery rate filter. Transgenic mice, gene expression experiments and immunoprecipitation assays were used to confirm the functional roles of the most strongly linked gene. The behavioral data processed using computational genetic mapping and false discovery rate filtering provided several strongly linked biologically plausible gene associations. The strongest of these was the highly polymorphic Mpdz gene coding for the post-synaptic scaffolding protein Mpdz/MUPP1. Heterozygous Mpdz +/- mice displayed reduced opioid tolerance and OIH. Mpdz gene expression and Mpdz/MUPP1 protein levels were lower in the spinal cords of low-adapting 129S1/Svlm mice than in high-adapting C57BL/6 mice. Morphine did not alter Mpdz expression levels. In addition, association of Mpdz/MUPP1 with its known binding partner CaMKII did not differ between these high- and low-adapting strains. CONCLUSIONS The degrees of maladaptive changes in response to repeated administration of morphine vary greatly across inbred strains of mice. Variants of the multiple PDZ domain gene Mpdz may contribute to the observed inter-strain variability in tolerance and OIH by virtue of changes in the level of their expression.
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Affiliation(s)
- Robin Donaldson
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Yuan Sun
- Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Anesthesiology, 112A, Palo Alto, CA, 94304, USA.,Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - De-Yong Liang
- Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Anesthesiology, 112A, Palo Alto, CA, 94304, USA.,Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Ming Zheng
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Peyman Sahbaie
- Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Anesthesiology, 112A, Palo Alto, CA, 94304, USA.,Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - David L Dill
- Department of Computer Science, Stanford University, Stanford, CA, USA
| | - Gary Peltz
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Kari J Buck
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA
| | - J David Clark
- Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Anesthesiology, 112A, Palo Alto, CA, 94304, USA. .,Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, USA.
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Hammad MM, Dunn HA, Walther C, Ferguson SSG. Role of cystic fibrosis transmembrane conductance regulator-associated ligand (CAL) in regulating the trafficking and signaling of corticotropin-releasing factor receptor 1. Cell Signal 2015; 27:2120-30. [PMID: 26115868 DOI: 10.1016/j.cellsig.2015.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 06/18/2015] [Accepted: 06/21/2015] [Indexed: 10/23/2022]
Abstract
Corticotropin releasing factor (CRF) receptor1 (CRFR1) is associated with psychiatric illness and is a proposed target for the treatment of anxiety and depression. Like many G protein-coupled receptors (GPCRs), CRFR1 harbors a PDZ (PSD95/Disc Large/Zona Occludens 1)-binding motif at the end of its carboxyl terminal tail. The interactions of PDZ proteins with GPCRs are crucial for the regulation of their receptor function. In the present study, we characterize the interaction of the cystic fibrosis transmembrane conductance regulator-associated ligand (CAL) with CRFR1. We show using co-immunoprecipitation that the two proteins interact in human embryonic kidney (HEK293) cells in a PDZ motif-dependent manner. We find that the interaction occurs at the Golgi apparatus and that overexpression of CAL retains a proportion of CRFR1 in the intracellular compartment and prevents trafficking to the cell surface. We also demonstrate a significant reduction in the levels of receptor at the plasma membrane upon CAL overexpression, as well as a reduction in internalization. We find that the overexpression of CAL in HEK293 cells resulted in a significant decrease in CRF-stimulated extracellular-regulated protein kinase 1/2 (ERK1/2) phosphorylation, but has no effect on cAMP signaling mediated by the receptor. This effect was dependent on an intact PDZ motif and knockdown of CAL expression using CAL siRNA results in a significant enhancement in ERK1/2 signaling. We show that CAL contributes to the regulation of CRFR1 glycosylation and utilize glycosylation-deficient CRFR1 mutants to further examine the role of glycosylation in the cell surface trafficking of CRFR1. We find that the mutation of Asn residues 90 and 98 results in a reduction in cell surface CRFR1 that is comparable to the effect of CAL overexpression and that these mutants are retained in the Golgi apparatus. Mutation of Asn residues 90 and 98 also results in a decrease in the efficacy for CRF-stimulated cAMP formation mediated by CRFR1. Taken together, our data suggest that CAL can regulate the anterograde trafficking, the internalization as well as the signaling of CRFR1 via modulating the post-translational modifications that the receptor undergoes at the Golgi apparatus.
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Affiliation(s)
- Maha M Hammad
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Henry A Dunn
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Dr. Ottawa, Ontario K1H 8M5, Canada
| | - Cornelia Walther
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Stephen S G Ferguson
- Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Dr. Ottawa, Ontario K1H 8M5, Canada.
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18
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Tanabe Y, Fujita-Jimbo E, Momoi MY, Momoi T. CASPR2 forms a complex with GPR37 via MUPP1 but not with GPR37(R558Q), an autism spectrum disorder-related mutation. J Neurochem 2015; 134:783-93. [DOI: 10.1111/jnc.13168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/25/2015] [Accepted: 05/06/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Yuko Tanabe
- International University of Health and Welfare; Otawara Tochigi Japan
| | - Eriko Fujita-Jimbo
- International University of Health and Welfare; Otawara Tochigi Japan
- Department of Pediatrics; Jichi Medical University School of Medicine; Shimotsuke Tochigi Japan
| | - Mariko Y. Momoi
- International University of Health and Welfare; Otawara Tochigi Japan
| | - Takashi Momoi
- International University of Health and Welfare; Otawara Tochigi Japan
- Department of Pathophysiology; Tokyo Medical University Shinjuku Tokyo, Japan
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19
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Jansen F, Kalbe B, Scholz P, Fränzel B, Osterloh M, Wolters D, Hatt H, Neuhaus EM, Osterloh S. Biochemical Large-Scale Interaction Analysis of Murine Olfactory Receptors and Associated Signaling Proteins with Post-Synaptic Density 95, Drosophila Discs Large, Zona-Occludens 1 (PDZ) Domains. Mol Cell Proteomics 2015; 14:2072-84. [PMID: 25979994 DOI: 10.1074/mcp.m114.045997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family among mammalian membrane proteins and are capable of initiating numerous essential signaling cascades. Various GPCR-mediated pathways are organized into protein microdomains that can be orchestrated and regulated through scaffolding proteins, such as PSD-95/discs-large/ZO1 (PDZ) domain proteins. However, detailed binding characteristics of PDZ-GPCR interactions remain elusive because these interactions seem to be more complex than previously thought. To address this issue, we analyzed binding modalities using our established model system. This system includes the 13 individual PDZ domains of the multiple PDZ domain protein 1 (MUPP1; the largest PDZ protein), a broad range of murine olfactory receptors (a multifaceted gene cluster within the family of GPCRs), and associated olfactory signaling proteins. These proteins were analyzed in a large-scale peptide microarray approach and continuative interaction studies. As a result, we demonstrate that canonical binding motifs were not overrepresented among the interaction partners of MUPP1. Furthermore, C-terminal phosphorylation and distinct amino acid replacements abolished PDZ binding promiscuity. In addition to the described in vitro experiments, we identified new interaction partners within the murine olfactory epithelium using pull-down-based interactomics and could verify the partners through co-immunoprecipitation. In summary, the present study provides important insight into the complexity of the binding characteristics of PDZ-GPCR interactions based on olfactory signaling proteins, which could identify novel clinical targets for GPCR-associated diseases in the future.
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Affiliation(s)
- Fabian Jansen
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Benjamin Kalbe
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Paul Scholz
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Benjamin Fränzel
- §Department of Analytical Chemistry, Faculty for Chemistry and Biochemistry, Ruhr-University Bochum, Germany
| | - Markus Osterloh
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Dirk Wolters
- §Department of Analytical Chemistry, Faculty for Chemistry and Biochemistry, Ruhr-University Bochum, Germany
| | - Hanns Hatt
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | | | - Sabrina Osterloh
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology,
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20
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Dunn HA, Ferguson SSG. PDZ Protein Regulation of G Protein–Coupled Receptor Trafficking and Signaling Pathways. Mol Pharmacol 2015; 88:624-39. [DOI: 10.1124/mol.115.098509] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 03/25/2015] [Indexed: 01/03/2023] Open
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21
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Isovaline does not activate GABA(B) receptor-coupled potassium currents in GABA(B) expressing AtT-20 cells and cultured rat hippocampal neurons. PLoS One 2015; 10:e0118497. [PMID: 25706125 PMCID: PMC4337901 DOI: 10.1371/journal.pone.0118497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/19/2015] [Indexed: 01/13/2023] Open
Abstract
Isovaline is a non-proteinogenic amino acid that has analgesic properties. R-isovaline is a proposed agonist of the γ-aminobutyric acid type B (GABAB) receptor in the thalamus and peripheral tissue. Interestingly, the responses to R-isovaline differ from those of the canonical GABAB receptor agonist R-baclofen, warranting further investigation. Using whole cell recording techniques we explored isovaline actions on GABAB receptors coupled to rectifying K+ channels in cells of recombinant and native receptor preparations. In AtT-20 cells transfected with GABAB receptor subunits, bath application of the GABAB receptor agonists, GABA (1 μM) and R-baclofen (5 μM) produced inwardly rectifying currents that reversed approximately at the calculated reversal potential for K+ R- isovaline (50 μM to 1 mM) and S-isovaline (500 μM) did not evoke a current. R-isovaline applied either extracellularly (250 μM) or intracellularly (10 μM) did not alter responses to GABA at 1 μM. Co-administration of R-isovaline (250 μM) with a low concentration (10 nM) of GABA did not result in a response. In cultured rat hippocampal neurons that natively express GABAB receptors, R-baclofen (5 μM) induced GABAB receptor-dependent inward currents. Under the same conditions R-isovaline (1 or 50 μM) did not evoke a current or significantly alter R-baclofen-induced effects. Therefore, R-isovaline does not interact with recombinant or native GABAB receptors to open K+ channels in these preparations.
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22
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Walther C, Caetano FA, Dunn HA, Ferguson SSG. PDZK1/NHERF3 differentially regulates corticotropin-releasing factor receptor 1 and serotonin 2A receptor signaling and endocytosis. Cell Signal 2015; 27:519-31. [PMID: 25562428 DOI: 10.1016/j.cellsig.2014.12.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 12/18/2014] [Accepted: 12/28/2014] [Indexed: 10/24/2022]
Abstract
The corticotropin-releasing factor receptor 1 (CRFR1) and serotonin 2A receptor (5-HT2AR) are linked to cellular mechanisms underlying stress anxiety and depression. Both receptors are members of the G protein-coupled receptor (GPCR) superfamily and encode class I PSD-95/DiscsLarge/Zona Occludens 1 (PDZ) binding motifs (-S/T-x-V/I/L) at the end of their carboxyl-terminal tails. We have identified PDZK1, also referred to as Na(+)/H(+) exchange regulatory cofactor 3 (NHERF3) as both a CRFR1- and 5-HT2AR-interacting protein. We have examined whether PDZK1 plays a role in regulating both CRFR1 and 5-HT2AR activity. We find that while PDZK1 interactions with CRFR1 are PDZ binding motif-dependent, PDZK1 associates with 5-HT2AR in a PDZ binding motif-independent manner and CRFR1 expression, but not 5-HT2AR expression, redistributes PDZK1 to the plasma membrane in PDZ binding motif-dependent manner. PDZK1, negatively regulates 5-HT2AR endocytosis and has no effect upon 5-HT2AR-mediated ERK1/2 phosphorylation. In contrast, PDZK1 overexpression does not affect CRFR1 endocytosis, but selectively increases CRFR1-stimulated ERK1/2 phosphorylation. Similar to what has been previously reported for PSD-95 and SAP97, PDZK1 positively influences 5-HT2AR-stimulated inositol phosphate formation, but does not contribute to the regulation of CRFR1-mediated cAMP signaling. Taken together, these results indicate that PDZK1 differentially regulates the signaling and trafficking of CRFR1 and 5-HT2AR via PDZ-dependent and -independent mechanisms, respectively.
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Affiliation(s)
- Cornelia Walther
- J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute
| | | | - Henry A Dunn
- J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute; Department of Physiology and Pharmacology, University of Western Ontario, 100 Perth Dr., London, Ontario, Canada, N6A5K8
| | - Stephen S G Ferguson
- J. Allyn Taylor Centre for Cell Biology, Robarts Research Institute; Department of Physiology and Pharmacology, University of Western Ontario, 100 Perth Dr., London, Ontario, Canada, N6A5K8.
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23
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Milner LC, Shirley RL, Kozell LB, Walter NA, Kruse LC, Komiyama NH, Grant SG, Buck KJ. Novel MPDZ/MUPP1 transgenic and knockdown models confirm Mpdz's role in ethanol withdrawal and support its role in voluntary ethanol consumption. Addict Biol 2015; 20:143-7. [PMID: 24118405 PMCID: PMC3997615 DOI: 10.1111/adb.12087] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Association studies implicate multiple PDZ domain protein (MPDZ/MUPP1) sequence and/or expression in risk for alcoholism in humans and ethanol withdrawal (EW) in mice, but confirmation has been hindered by the dearth of targeted genetic models. We report the creation of transgenic (MPDZ-TG) and knockout heterozygote (Mpdz(+/-) ) mice, with increased (2.9-fold) and decreased (53%) target expression, respectively. Both models differ in EW compared with wild-type littermates (P ≤ 0.03), providing compelling evidence for an inverse relationship between Mpdz expression and EW severity. Additionally, ethanol consumption is reduced up to 18% (P = 0.006) in Mpdz(+/-) , providing the first evidence implicating Mpdz in ethanol self-administration.
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Affiliation(s)
- Lauren C. Milner
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
| | - Renee L. Shirley
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
| | - Laura B. Kozell
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
| | - Nicole A. Walter
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
| | - Lauren C. Kruse
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
| | | | - Seth G.N. Grant
- Edinburgh University, 49 Little France Crescent, Edinburgh EH16 4SB, UK
| | - Kari J. Buck
- Department of Behavioral Neuroscience, Department of Veterans Affairs Medical Center and Oregon Health & Science University, 3710 SW US Veterans Hospital Road, mail code RD40, Portland, OR 97239-3098, USA
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Kruse LC, Walter NAR, Buck KJ. Mpdz expression in the caudolateral substantia nigra pars reticulata is crucially involved in alcohol withdrawal. GENES, BRAIN, AND BEHAVIOR 2014; 13:769-76. [PMID: 25109596 PMCID: PMC4241148 DOI: 10.1111/gbb.12171] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/16/2014] [Accepted: 08/07/2014] [Indexed: 11/29/2022]
Abstract
Association studies implicate the multiple PDZ domain protein (MUPP1/MPDZ) gene in risk for alcoholism in humans and alcohol withdrawal in mice. Although manipulation of the Mpdz gene by homologous recombination and bacterial artificial chromosome transgenesis has suggested that its expression affects alcohol withdrawal risk, the potential confounding effects of linked genes and developmental compensation currently limit interpretation. Here, using RNA interference (RNAi), we directly test the impact of Mpdz expression on alcohol withdrawal severity and provide brain regional mechanistic information. Lentiviral-mediated delivery of Mpdz short hairpin RNA (shRNA) to the caudolateral substantia nigra pars reticulata (clSNr) significantly reduces Mpdz expression and exacerbates alcohol withdrawal convulsions compared with control mice that delivered a scrambled shRNA. Neither baseline nor pentylenetetrazol-enhanced convulsions differed between Mpdz shRNA and control animals, indicating Mpdz expression in the clSNr does not generally affect seizure susceptibility. To our knowledge, these represent the first in vivo Mpdz RNAi analyses, and provide the first direct evidence that Mpdz expression impacts behavior. Our results confirm that Mpdz is a quantitative trait gene for alcohol withdrawal and demonstrate that its expression in the clSNr is crucially involved in risk for alcohol withdrawal.
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Affiliation(s)
- L C Kruse
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA; Department of Veterans Affairs Medical Center, Oregon Health & Science University, Portland, OR, USA
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25
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Smith SB, Mir E, Bair E, Slade GD, Dubner R, Fillingim RB, Greenspan JD, Ohrbach R, Knott C, Weir B, Maixner W, Diatchenko L. Genetic variants associated with development of TMD and its intermediate phenotypes: the genetic architecture of TMD in the OPPERA prospective cohort study. THE JOURNAL OF PAIN 2014; 14:T91-101.e1-3. [PMID: 24275226 DOI: 10.1016/j.jpain.2013.09.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 08/29/2013] [Indexed: 02/06/2023]
Abstract
UNLABELLED Genetic risk factors are believed to combine with environmental exposures and contribute to the risk of developing temporomandibular disorder (TMD). In this prospective cohort study, 2,737 people without TMD were assessed for common genetic variation in 358 genes known to contribute to nociceptive pathways, inflammation, and affective distress. During a median follow-up period of 2.8 years, 260 people developed first-onset TMD. Hazard ratios were computed as measures of association between 2,924 single-nucleotide polymorphisms and TMD incidence. After correction for multiple testing, no single single-nucleotide polymorphism was significantly associated with risk of onset TMD. However, several single-nucleotide polymorphisms exceeded Bonferroni correction for multiple comparison or false discovery rate thresholds (.05, .1, or .2) for association with intermediate phenotypes shown to be predictive of TMD onset. Nonspecific orofacial symptoms were associated with voltage-gated sodium channel, type I, alpha subunit (SCN1A, rs6432860, P = 2.77 × 10(-5)) and angiotensin I-converting enzyme 2 (ACE2, rs1514280, P = 4.86 × 10(-5)); global psychological symptoms with prostaglandin-endoperoxide synthase 1 (PTGS1, rs3842803, P = 2.79 × 10(-6)); stress and negative affectivity with amyloid-β (A4) precursor protein (APP, rs466448, P = 4.29 × 10(-5)); and heat pain temporal summation with multiple PDZ domain protein (MPDZ, rs10809907, P = 3.05 × 10(-5)). The use of intermediate phenotypes for complex pain diseases revealed new genetic pathways influencing risk of TMD. PERSPECTIVE This article reports the findings of a large candidate gene association study of first-onset TMD and related intermediate phenotypes in the OPPERA Study. Although no genetic markers predicted TMD onset, several genetic risk factors for clinical, psychological, and sensory phenotypes associated with TMD onset were observed.
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Affiliation(s)
- Shad B Smith
- Regional Center for Neurosensory Disorders, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Endodontics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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26
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Jang WH, Choi SH, Jeong JY, Park JH, Kim SJ, Seog DH. Neuronal cell-surface protein neurexin 1 interaction with multi-PDZ domain protein MUPP1. Biosci Biotechnol Biochem 2014; 78:644-6. [DOI: 10.1080/09168451.2014.890031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract
Location of membrane proteins is often stabilized by PDZ domain-containing scaffolding proteins. Using the yeast two-hybrid screening, we found that neurexin 1 interacted with multi-PDZ domain protein 1 (MUPP1) through PDZ domain. Neurexin 2 and 3 also interacted with MUPP1. MUPP1 and neurexin 1 were co-localized in cultured cells. These results suggest a novel mechanism for localizing neurexin 1 to synaptic sites.
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Affiliation(s)
- Won Hee Jang
- Department of Biochemistry and u-HARC, College of Medicine, Inje University, Busan, Korea
| | - Sun Hee Choi
- Department of Biochemistry and u-HARC, College of Medicine, Inje University, Busan, Korea
| | - Joo Young Jeong
- Department of Biochemistry and u-HARC, College of Medicine, Inje University, Busan, Korea
| | - Jung-Hwa Park
- Department of Biochemistry and u-HARC, College of Medicine, Inje University, Busan, Korea
| | - Sang-Jin Kim
- Department of Neurology, College of Medicine, Inje University, Busan, Korea
| | - Dae-Hyun Seog
- Department of Biochemistry and u-HARC, College of Medicine, Inje University, Busan, Korea
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27
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Baumgart S, Jansen F, Bintig W, Kalbe B, Herrmann C, Klumpers F, Köster SD, Scholz P, Rasche S, Dooley R, Metzler-Nolte N, Spehr M, Hatt H, Neuhaus EM. The scaffold protein MUPP1 regulates odorant-mediated signaling in olfactory sensory neurons. J Cell Sci 2014; 127:2518-27. [PMID: 24652834 DOI: 10.1242/jcs.144220] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The olfactory signal transduction cascade transforms odor information into electrical signals by a cAMP-based amplification mechanism. The mechanisms underlying the very precise temporal and spatial organization of the relevant signaling components remains poorly understood. Here, we identify, using co-immunoprecipitation experiments, a macromolecular assembly of signal transduction components in mouse olfactory neurons, organized through MUPP1. Disruption of the PDZ signaling complex, through use of an inhibitory peptide, strongly impaired odor responses and changed the activation kinetics of olfactory sensory neurons. In addition, our experiments demonstrate that termination of the response is dependent on PDZ-based scaffolding. These findings provide new insights into the functional organization, and regulation, of olfactory signal transduction.
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Affiliation(s)
- Sabrina Baumgart
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Fabian Jansen
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Willem Bintig
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Benjamin Kalbe
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Christian Herrmann
- Physical Chemistry I, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Fabian Klumpers
- Physical Chemistry I, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - S David Köster
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Paul Scholz
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Sebastian Rasche
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Ruth Dooley
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Nils Metzler-Nolte
- Chair of Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Worringer Weg 1, 52074 Aachen, Germany
| | - Hanns Hatt
- Cell Physiology, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Eva M Neuhaus
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany Pharmacology and Toxicology, University Hospital Jena, Drakendorfer Weg 1, 07743 Jena, Germany
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Xu C, Zhang W, Rondard P, Pin JP, Liu J. Complex GABAB receptor complexes: how to generate multiple functionally distinct units from a single receptor. Front Pharmacol 2014; 5:12. [PMID: 24575041 PMCID: PMC3920572 DOI: 10.3389/fphar.2014.00012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/22/2014] [Indexed: 01/05/2023] Open
Abstract
The main inhibitory neurotransmitter, GABA, acts on both ligand-gated and G protein-coupled receptors, the GABAA/C and GABAB receptors, respectively. The later play important roles in modulating many synapses, both at the pre- and post-synaptic levels, and are then still considered as interesting targets to treat a number of brain diseases, including addiction. For many years, several subtypes of GABAB receptors were expected, but cloning revealed only two genes that work in concert to generate a single type of GABAB receptor composed of two subunits. Here we will show that the signaling complexity of this unit receptor type can be largely increased through various ways, including receptor stoichiometry, subunit isoforms, cell-surface expression and localization, crosstalk with other receptors, or interacting proteins. These recent data revealed how complexity of a receptor unit can be increased, observation that certainly are not unique to the GABAB receptor.
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Affiliation(s)
- Chanjuan Xu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
| | - Wenhua Zhang
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Universités de Montpellier I & II Montpellier, France
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Universités de Montpellier I & II Montpellier, France
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology Wuhan, China
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Abstract
Alcohol abuse and alcoholism incur a heavy socioeconomic cost in many countries. Both genetic and environmental factors contribute to variation in the inebriating effects of alcohol and alcohol addiction among individuals within and across populations. From a genetics perspective, alcohol sensitivity is a quantitative trait determined by the cumulative effects of multiple segregating genes and their interactions with the environment. This review summarizes insights from model organisms as well as human populations that represent our current understanding of the genetic and genomic underpinnings that govern alcohol metabolism and the sedative and addictive effects of alcohol on the nervous system.
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Fuxe K, Borroto-Escuela DO, Ciruela F, Guidolin D, Agnati LF. Receptor-receptor interactions in heteroreceptor complexes: a new principle in biology. Focus on their role in learning and memory. ACTA ACUST UNITED AC 2014. [DOI: 10.7243/2052-6946-2-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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31
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Tanabe Y, Fujita E, Hayashi YK, Zhu X, Lubbert H, Mezaki Y, Senoo H, Momoi T. Synaptic adhesion molecules in Cadm family at the neuromuscular junction. Cell Biol Int 2013; 37:731-6. [DOI: 10.1002/cbin.10092] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 02/19/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Yuko Tanabe
- Center for Medical Science; International University of Health and Welfare; Kitakanamaru, Otawara, Tochigi; Japan
| | | | - Yukiko K. Hayashi
- Department of Neuromuscular Research; National Institute of Neuroscience, National Center of Neurology and Psychiatry; Ogawa-Higashi, Kodaira, Tokyo; Japan
| | - Xinran Zhu
- Department of Animal Physiology; Ruhr-University Bochum; Bochum; Germany
| | - Hermann Lubbert
- Department of Animal Physiology; Ruhr-University Bochum; Bochum; Germany
| | - Yoshihiro Mezaki
- Department of Cell Biology and Morphology; Akita University Graduate School of Medicine; Hondo, Akita; Japan
| | - Haruki Senoo
- Department of Cell Biology and Morphology; Akita University Graduate School of Medicine; Hondo, Akita; Japan
| | - Takashi Momoi
- Center for Medical Science; International University of Health and Welfare; Kitakanamaru, Otawara, Tochigi; Japan
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Dunn HA, Walther C, Godin CM, Hall RA, Ferguson SSG. Role of SAP97 protein in the regulation of corticotropin-releasing factor receptor 1 endocytosis and extracellular signal-regulated kinase 1/2 signaling. J Biol Chem 2013; 288:15023-34. [PMID: 23576434 DOI: 10.1074/jbc.m113.473660] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The corticotropin-releasing factor (CRF) receptor 1 (CRFR1) is a target for the treatment of psychiatric diseases such as depression, schizophrenia, anxiety disorder, and bipolar disorder. The carboxyl-terminal tail of the CRFR1 terminates in a PDZ-binding motif that provides a potential site for the interaction of PSD-95/Discs Large/Zona Occludens 1 (PDZ) domain-containing proteins. In this study, we found that CRFR1 interacts with synapse-associated protein 97 (SAP97; also known as DLG1) by co-immunoprecipitation in human embryonic 293 (HEK 293) cells and cortical brain lysates and that this interaction is dependent upon an intact PDZ-binding motif at the end of the CRFR1 carboxyl-terminal tail. Similarly, we demonstrated that SAP97 is recruited to the plasma membrane in HEK 293 cells expressing CRFR1 and that mutation of the CRFR1 PDZ-binding motif results in the redistribution of SAP97 into the cytoplasm. Overexpression of SAP97 antagonized agonist-stimulated CRFR1 internalization, whereas single hairpin (shRNA) knockdown of endogenous SAP97 in HEK 293 cells resulted in increased agonist-stimulated CRFR1 endocytosis. CRFR1 was internalized as a complex with SAP97 resulting in the redistribution of SAP97 to endocytic vesicles. Overexpression or shRNA knockdown of SAP97 did not significantly affect CRFR1-mediated cAMP formation, but SAP97 knockdown did significantly attenuate CRFR1-stimulated ERK1/2 phosphorylation in a PDZ interaction-independent manner. Taken together, our studies show that SAP97 interactions with CRFR1 attenuate CRFR1 endocytosis and that SAP97 is involved in coupling G protein-coupled receptors to the activation of the ERK1/2 signaling pathway.
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Affiliation(s)
- Henry A Dunn
- J Allyn Taylor Centre for Cell Biology, Robarts Research Institute, University of Western Ontario, London, Ontario N6A 5K8, Canada
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33
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Fujita E, Tanabe Y, Imhof BA, Momoi MY, Momoi T. A complex of synaptic adhesion molecule CADM1, a molecule related to autism spectrum disorder, with MUPP1 in the cerebellum. J Neurochem 2012; 123:886-94. [PMID: 22994563 DOI: 10.1111/jnc.12022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 06/27/2012] [Accepted: 09/10/2012] [Indexed: 01/14/2023]
Abstract
Mutations in the synaptic adhesion protein CADM1 (RA175/SynCAM1) are associated with autism spectrum disorder (ASD), a neurodevelopmental disorder of uncertain molecular origin. Cadm1-knock out (KO) mice exhibit smaller cerebella with decreased number of synapse of Purkinje cells and some ASD-like symptoms, including impaired ultrasonic vocalization. In this study, we examined the alteration of the Cadm1 synaptic complex in the mouse cerebellum at post-natal stages. The C-terminal peptide of Cadm1 associated with Mupp1 at PSD-95/Dlg/ZO-1 (PDZ)(1-5), a scaffold protein containing 13 PDZ domains, which interacted with gamma-aminobutyric acid type B receptor (GABBR)2 at PDZ13, but not with PSD-95. The GABBR2 was detected in a set of proteins interacting with Cadm1 C-terminal. Cadm1 colocalized with Mupp1 and GABBR2 on the dendrites of Purkinje cells in the molecular layers of the developing cerebellum and on the dendrites of hippocampal neurons cultured in vitro. These observations suggest that the Cadm1 synaptic receptor complex, including Mupp1-GABBR2, is located on the dendrites of Purkinje cells. The amount of GABBR2 protein, but not mRNA, was increased in the cerebella of Cadm1 KO mice, suggesting that lack of Cadm1 does not affect transcription of GABBR2, but may stabilize the Mupp1-GABBR2 complex; the Mupp1-GABBR2 interaction may be stabilized by conformational change in Mupp1 or association with other adhesion molecules and by anchorage to the post-synaptic membrane. Up-regulation of GABBR2 in the cerebellum in the absence of CADM1 may be associated with ASD pathogenesis.
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Affiliation(s)
- Eriko Fujita
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
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34
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Magalhaes AC, Dunn H, Ferguson SS. Regulation of GPCR activity, trafficking and localization by GPCR-interacting proteins. Br J Pharmacol 2012; 165:1717-1736. [PMID: 21699508 DOI: 10.1111/j.1476-5381.2011.01552.x] [Citation(s) in RCA: 252] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
GPCRs represent the largest family of integral membrane proteins and were first identified as receptor proteins that couple via heterotrimeric G-proteins to regulate a vast variety of effector proteins to modulate cellular function. It is now recognized that GPCRs interact with a myriad of proteins that not only function to attenuate their signalling but also function to couple these receptors to heterotrimeric G-protein-independent signalling pathways. In addition, intracellular and transmembrane proteins associate with GPCRs and regulate their processing in the endoplasmic reticulum, trafficking to the cell surface, compartmentalization to plasma membrane microdomains, endocytosis and trafficking between intracellular membrane compartments. The present review will overview the functional consequence of β-arrestin, receptor activity-modifying proteins (RAMPS), regulators of G-protein signalling (RGS), GPCR-associated sorting proteins (GASPs), Homer, small GTPases, PSD95/Disc Large/Zona Occludens (PDZ), spinophilin, protein phosphatases, calmodulin, optineurin and Src homology 3 (SH3) containing protein interactions with GPCRs.
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Affiliation(s)
- Ana C Magalhaes
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, London, ON, CanadaThe Department of Physiology & Pharmacology, the University of Western Ontario, London, ON, Canada
| | - Henry Dunn
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, London, ON, CanadaThe Department of Physiology & Pharmacology, the University of Western Ontario, London, ON, Canada
| | - Stephen Sg Ferguson
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research Institute, London, ON, CanadaThe Department of Physiology & Pharmacology, the University of Western Ontario, London, ON, Canada
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35
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Karpyak VM, Geske JR, Colby CL, Mrazek DA, Biernacka JM. Genetic variability in the NMDA-dependent AMPA trafficking cascade is associated with alcohol dependence. Addict Biol 2012; 17:798-806. [PMID: 21762291 PMCID: PMC3197973 DOI: 10.1111/j.1369-1600.2011.00338.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Model studies in mice indicate that the severity of alcohol withdrawal is associated with polymorphic variation and expression of the MPDZ gene. Current knowledge about variation in the human MPDZ gene is limited; however, our data indicate its potential association with alcohol dependence. The multi-PDZ protein is an important part of the N-methyl-D-aspartate (NMDA)-dependent α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor trafficking cascade that controls glutamate-related excitatory neurotransmission. To investigate association of variation in the NMDA-dependent AMPA trafficking cascade with alcohol dependence, we performed a gene-set (pathway) analysis using single nucleotide polymorphism (SNP) data from the Study of Addiction: Genetic and Environment. Rather than testing for association with each SNP individually, which typically has low power to detect small effects of multiple SNPs, gene-set analysis applies a single statistical test to evaluate whether variation in a set of genes is associated with the phenotype of interest. Gene-set analysis of 988 SNPs in 13 genes in the pathway demonstrated a significant association with alcohol dependence, with P < 0.01 for the global effect of variation in this pathway. The statistically significant association of alcohol dependence with genetic variation in the NMDA-dependent AMPA receptor trafficking cascade indicates a need for further investigation of the role of this pathway in alcohol dependence.
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Affiliation(s)
- Victor M Karpyak
- Department of Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.
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36
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Liu Z, Fenech C, Cadiou H, Grall S, Tili E, Laugerette F, Wiencis A, Grosmaitre X, Montmayeur JP. Identification of new binding partners of the chemosensory signaling protein Gγ13 expressed in taste and olfactory sensory cells. Front Cell Neurosci 2012; 6:26. [PMID: 22737109 PMCID: PMC3380295 DOI: 10.3389/fncel.2012.00026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/31/2012] [Indexed: 01/19/2023] Open
Abstract
Tastant detection in the oral cavity involves selective receptors localized at the apical extremity of a subset of specialized taste bud cells called taste receptor cells (TRCs). The identification of the genes coding for the taste receptors involved in this process have greatly improved our understanding of the molecular mechanisms underlying detection. However, how these receptors signal in TRCs, and whether the components of the signaling cascades interact with each other or are organized in complexes is mostly unexplored. Here we report on the identification of three new binding partners for the mouse G protein gamma 13 subunit (Gγ13), a component of the bitter taste receptors signaling cascade. For two of these Gγ13 associated proteins, namely GOPC and MPDZ, we describe the expression in taste bud cells for the first time. Furthermore, we demonstrate by means of a yeast two-hybrid interaction assay that the C terminal PDZ binding motif of Gγ13 interacts with selected PDZ domains in these proteins. In the case of the PDZ domain-containing protein zona occludens-1 (ZO-1), a major component of the tight junction defining the boundary between the apical and baso-lateral region of TRCs, we identified the first PDZ domain as the site of strong interaction with Gγ13. This association was further confirmed by co-immunoprecipitation experiments in HEK 293 cells. In addition, we present immunohistological data supporting partial co-localization of GOPC, MPDZ, or ZO-1, and Gγ13 in taste buds cells. Finally, we extend this observation to olfactory sensory neurons (OSNs), another type of chemosensory cells known to express both ZO-1 and Gγ13. Taken together our results implicate these new interaction partners in the sub-cellular distribution of Gγ13 in olfactory and gustatory primary sensory cells.
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Affiliation(s)
- Zhenhui Liu
- Chemosensory Perception, Centre des Sciences du Goût et de l'Alimentation, UMR-6265 CNRS, UMR-1324 INRA Dijon, France
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37
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Lynn BD, Li X, Nagy JI. Under construction: building the macromolecular superstructure and signaling components of an electrical synapse. J Membr Biol 2012; 245:303-17. [PMID: 22722764 PMCID: PMC3506381 DOI: 10.1007/s00232-012-9451-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/01/2012] [Indexed: 10/28/2022]
Abstract
A great deal is now known about the protein components of tight junctions and adherens junctions, as well as how these are assembled. Less is known about the molecular framework of gap junctions, but these also have membrane specializations and are subject to regulation of their assembly and turnover. Thus, it is reasonable to consider that these three types of junctions may share macromolecular commonalities. Indeed, the tight junction scaffolding protein zonula occluden-1 (ZO-1) is also present at adherens and gap junctions, including neuronal gap junctions. On the basis of these earlier observations, we more recently found that two additional proteins, AF6 and MUPP1, known to be associated with ZO-1 at tight and adherens junctions, are also components of neuronal gap junctions in rodent brain and directly interact with connexin36 (Cx36) that forms these junctions. Here, we show by immunofluorescence labeling that the cytoskeletal-associated protein cingulin, commonly found at tight junctions, is also localized at neuronal gap junctions throughout the central nervous system. In consideration of known functions related to ZO-1, AF6, MUPP1, and cingulin, our results provide a context in which to examine functional relationships between these proteins at Cx36-containing electrical synapses in brain--specifically, how they may contribute to regulation of transmission at these synapses, and how they may govern gap junction channel assembly and/or disassembly.
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Affiliation(s)
- B. D. Lynn
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Xinbo Li
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - J. I. Nagy
- Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
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38
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Lin L, Tran T, Hu S, Cramer T, Komuniecki R, Steven RM. RHGF-2 is an essential Rho-1 specific RhoGEF that binds to the multi-PDZ domain scaffold protein MPZ-1 in Caenorhabditis elegans. PLoS One 2012; 7:e31499. [PMID: 22363657 PMCID: PMC3282746 DOI: 10.1371/journal.pone.0031499] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 01/12/2012] [Indexed: 11/18/2022] Open
Abstract
RhoGEF proteins activate the Rho family of small GTPases and thus play a key role in regulating fundamental cellular processes such as cell morphology and polarity, cell cycle progression and gene transcription. We identified a Caenorhabditis elegans RhoGEF protein, RHGF-2, as a binding partner of the C. elegans multi-PDZ domain scaffold protein MPZ-1 (MUPP1 in mammals). RHGF-2 exhibits significant identity to the mammalian RhoGEFs PLEKHG5/Tech/Syx and contains a class I C-terminal PDZ binding motif (SDV) that interacts most strongly to MPZ-1 PDZ domain eight. RHGF-2 RhoGEF activity is specific to the C. elegans RhoA homolog RHO-1 as determined by direct binding, GDP/GTP exchange and serum response element-driven reporter activity. rhgf-2 is an essential gene since rhgf-2 deletion mutants do not elongate during embryogenesis and hatch as short immobile animals that arrest development. Interestingly, the expression of a functional rhgf-2::gfp transgene appears to be exclusively neuronal and rhgf-2 overexpression results in loopy movement with exaggerated body bends. Transient expression of RHGF-2 in N1E-115 neuroblastoma cells prevents neurite outgrowth similar to constitutive RhoA activation in these cells. Together, these observations indicate neuronally expressed RHGF-2 is an essential RHO-1 specific RhoGEF that binds most strongly to MPZ-1 PDZ domain eight and is required for wild-type C. elegans morphology and growth.
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Affiliation(s)
- Li Lin
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Thuy Tran
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Shuang Hu
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Todd Cramer
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Richard Komuniecki
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Robert M. Steven
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
- * E-mail:
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Li X, Lynn BD, Nagy JI. The effector and scaffolding proteins AF6 and MUPP1 interact with connexin36 and localize at gap junctions that form electrical synapses in rodent brain. Eur J Neurosci 2012; 35:166-81. [PMID: 22211808 DOI: 10.1111/j.1460-9568.2011.07947.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Electrical synapses formed by neuronal gap junctions composed of connexin36 (Cx36) occur in most major structures in the mammalian central nervous system. These synapses link ensembles of neurons and influence their network properties. Little is known about the macromolecular constituents of neuronal gap junctions or how transmission through electrical synapses is regulated at the level of channel conductance or gap junction assembly/disassembly. Such knowledge is a prerequisite to understanding the roles of gap junctions in neuronal circuitry. Gap junctions share similarities with tight and adhesion junctions in that all three reside at close plasma membrane appositions, and therefore may associate with similar structural and regulatory proteins. Previously, we reported that the tight junction-associated protein zonula occludens-1 (ZO-1) interacts with Cx36 and is localized at gap junctions. Here, we demonstrate that two proteins known to be associated with tight and adherens junctions, namely AF6 and MUPP1, are components of neuronal gap junctions in rodent brain. By immunofluorescence, AF6 and MUPP1 were co-localized with Cx36 in many brain areas. Co-immunoprecipitation and pull-down approaches revealed an association of Cx36 with AF6 and MUPP1, which required the C-terminus PDZ domain interaction motif of Cx36 for interaction with the single PDZ domain of AF6 and with the 10th PDZ domain of MUPP1. As AF6 is a target of the cAMP/Epac/Rap1 signalling pathway and MUPP1 is a scaffolding protein that interacts with CaMKII, the present results suggest that AF6 may be a target for cAMP/Epac/Rap1 signalling at electrical synapses, and that MUPP1 may contribute to anchoring CaMKII at these synapses.
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Affiliation(s)
- X Li
- Department of Physiology, Faculty of Medicine, University of Manitoba, 745 Bannatyne Ave., Winnipeg, Manitoba, Canada
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40
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Kuzirian MS, Paradis S. Emerging themes in GABAergic synapse development. Prog Neurobiol 2011; 95:68-87. [PMID: 21798307 DOI: 10.1016/j.pneurobio.2011.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 06/30/2011] [Accepted: 07/03/2011] [Indexed: 12/25/2022]
Abstract
Glutamatergic synapse development has been rigorously investigated for the past two decades at both the molecular and cell biological level yet a comparable intensity of investigation into the cellular and molecular mechanisms of GABAergic synapse development has been lacking until relatively recently. This review will provide a detailed overview of the current understanding of GABAergic synapse development with a particular emphasis on assembly of synaptic components, molecular mechanisms of synaptic development, and a subset of human disorders which manifest when GABAergic synapse development is disrupted. An unexpected and emerging theme from these studies is that glutamatergic and GABAergic synapse development share a number of overlapping molecular and cell biological mechanisms that will be emphasized in this review.
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Affiliation(s)
- Marissa S Kuzirian
- Brandeis Univeristy, Department of Biology, National Center for Behavioral Genomics, Volen Center for Complex Systems, Waltham, MA 02453, USA
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41
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Saba LM, Bennett B, Hoffman PL, Barcomb K, Ishii T, Kechris K, Tabakoff B. A systems genetic analysis of alcohol drinking by mice, rats and men: influence of brain GABAergic transmission. Neuropharmacology 2011; 60:1269-80. [PMID: 21185315 PMCID: PMC3079014 DOI: 10.1016/j.neuropharm.2010.12.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 12/01/2010] [Accepted: 12/15/2010] [Indexed: 11/19/2022]
Abstract
Genetic influences on the predisposition to complex behavioral or physiological traits can reflect genetic polymorphisms that lead to altered gene product function, and/or variations in gene expression levels. We have explored quantitative variations in an animal's alcohol consumption, using a genetical genomic/phenomic approach. In our studies, gene expression is correlated with amount of alcohol consumed, and genomic regions that regulate the alcohol consumption behavior and the quantitative levels of gene expression (behavioral and expression quantitative trait loci [QTL]) are determined and used as a filter to identify candidate genes predisposing the behavior. We determined QTLs for alcohol consumption using the LXS panel of recombinant inbred mice. We then identified genes that were: 1) differentially expressed between five high and five low alcohol-consuming lines or strains of mice; and 2) were physically located in, or had an expression QTL (eQTL) within the alcohol consumption QTLs. Comparison of mRNA and protein levels in brains of high and low alcohol consuming mice led us to a bioinformatic examination of potential regulation by microRNAs of an identified candidate transcript, Gnb1 (G protein beta subunit 1). We combined our current analysis with our earlier work identifying candidate genes for the alcohol consumption trait in mice, rats and humans. Our overall analysis leads us to postulate that the activity of the GABAergic system, and in particular GABA release and GABA receptor trafficking and signaling, which involves G protein function, contributes significantly to genetic variation in the predisposition to varying levels of alcohol consumption. This article is part of a Special Issue entitled 'Trends in neuropharmacology: in memory of Erminio Costa'.
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Affiliation(s)
- Laura M. Saba
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
| | - Beth Bennett
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
| | - Paula L. Hoffman
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
| | - Kelsey Barcomb
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
| | - Takao Ishii
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
| | - Katerina Kechris
- Colorado School of Public Health, Campus Box B119, Aurora, CO 80045 USA,
| | - Boris Tabakoff
- University of Colorado Denver School of Medicine, PO Box 6511, MS 8303, Aurora, CO 80045 USA; , , , , ,
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Chalifoux JR, Carter AG. GABAB receptor modulation of synaptic function. Curr Opin Neurobiol 2011; 21:339-44. [PMID: 21376567 DOI: 10.1016/j.conb.2011.02.004] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 01/17/2023]
Abstract
Neuromodulators have complex effects on both the presynaptic release and postsynaptic detection of neurotransmitters. Here we describe recent advances in our understanding of synaptic modulation by metabotropic GABAB receptors. By inhibiting multivesicular release from the presynaptic terminal, these receptors decrease the synaptic glutamate signal. GABAB receptors also inhibit the Ca2+ permeability of NMDA receptors to decrease Ca2+ signals in postsynaptic spines. These new findings highlight the importance of GABAB receptors in regulating many aspects of synaptic transmission. They also point to novel questions about the spatiotemporal dynamics and sources of synaptic modulation in the brain.
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Affiliation(s)
- Jason R Chalifoux
- Center for Neural Science, New York University, 4 Washington Place, New York, NY 10003, United States
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Maurice P, Guillaume JL, Benleulmi-Chaachoua A, Daulat AM, Kamal M, Jockers R. GPCR-Interacting Proteins, Major Players of GPCR Function. PHARMACOLOGY OF G PROTEIN COUPLED RECEPTORS 2011; 62:349-80. [DOI: 10.1016/b978-0-12-385952-5.00001-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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44
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Romero G, von Zastrow M, Friedman PA. Role of PDZ proteins in regulating trafficking, signaling, and function of GPCRs: means, motif, and opportunity. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 62:279-314. [PMID: 21907913 DOI: 10.1016/b978-0-12-385952-5.00003-8] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PDZ proteins, named for the common structural domain shared by the postsynaptic density protein (PSD95), Drosophila disc large tumor suppressor (DlgA), and zonula occludens-1 protein (ZO-1), constitute a family of 200-300 recognized members. These cytoplasmic adapter proteins are capable of assembling a variety of membrane-associated proteins and signaling molecules in short-lived functional units. Here, we review PDZ proteins that participate in the regulation of signaling, trafficking, and function of G protein-coupled receptors. Salient structural features of PDZ proteins that allow them to recognize targeted GPCRs are considered. Scaffolding proteins harboring PDZ domains may contain single or multiple PDZ modules and may also include other protein-protein interaction modules. PDZ proteins may impact receptor signaling by diverse mechanisms that include retaining the receptor at the cell membrane, thereby increasing the duration of ligand binding, as well as importantly influencing GPCR internalization, trafficking, recycling, and intracellular sorting. PDZ proteins are also capable of modifying the assembled complex of accessory proteins such as β-arrestins that themselves regulate GPCR signaling. Additionally, PDZ proteins may modulate GPCR signaling by altering the G protein to which the receptor binds, or affect other regulatory proteins that impact GTPase activity, protein kinase A, phospholipase C, or modify downstream signaling events. Small molecules targeting the PDZ protein-GPCR interaction are being developed and may become important and selective drug candidates.
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Affiliation(s)
- Guillermo Romero
- Laboratory for G Protein-Coupled Receptor Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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45
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Fukui M, Ozawa S, Nakamichi N, Nakazato R, Takarada T, Yoneda Y. Gradual downregulation of protein expression of the partner GABA(B)R2 subunit during postnatal brain development in mice defective of GABA(B)R1 subunit. J Pharmacol Sci 2010; 115:45-55. [PMID: 21160134 DOI: 10.1254/jphs.10254fp] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
We have previously shown the functional expression of GABA(B) receptors (GABA(B)R) composed of GABA(B)R1 and GABA(B)R2 subunits with ability to promote proliferation and neuronal differentiation in cultured neural progenitor cells (NPC) isolated from embryonic mouse brains. In this study, we evaluated postnatal changes in the expression profiles of different markers for progenitor, neuronal, astroglial, and microglial cells in brains of GABA(B)R1-null mice. Consistent with undifferentiated murine NPC cultured with epidermal growth factor, a significant and selective decrease was seen in mRNA expression of the proneural gene Mash1 in brains of GABA(B)R1-null mice at 1 day after birth. The expression of several NPC marker proteins was similarly decreased in brains of both wild-type and GABA(B)R1-null mice from 1 to 7 days after birth, while slight changes were induced in both mRNA and proteins for neuronal, astroglial, and microglial markers between wild-type and GABA(B)R1-null mouse brains within this developmental stage. In particular discrete brain structures of adult GABA(B)R1-null mice at 56 days after birth, a significant decrease was seen in neuronal marker protein levels along with a significant increase in both astroglial and microglial marker protein expression. Although no significant difference was found in mRNA expression of the partner GABA(B)R2 subunit between wild-type and GABA(B)R1-null mouse brains, GABA(B)R2 subunit protein levels were gradually declined during postnatal development within 56 days after birth in GABA(B)R1-null mouse brains. These results suggest that GABA(B)R2 protein levels are closely correlated with the partner subunit GABA(B)R1 protein levels in mouse brains during postnatal development in vivo.
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Affiliation(s)
- Masaki Fukui
- Kanazawa University Graduate School of Natural Science and Technology, Kanazawa, Japan
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46
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Substantia nigra pars reticulata is crucially involved in barbiturate and ethanol withdrawal in mice. Behav Brain Res 2010; 218:152-7. [PMID: 20974184 DOI: 10.1016/j.bbr.2010.10.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 10/15/2010] [Accepted: 10/19/2010] [Indexed: 11/21/2022]
Abstract
Sedative-hypnotic CNS depressant drugs are widely prescribed to treat a variety of disorders, and are abused for their sedative and euphoric effects. Physiological dependence and associated withdrawal episodes are thought to constitute a motivational force that sustains their use/abuse and may contribute to relapse in dependent individuals. Although no animal model duplicates depressant dependence, models for specific factors, like withdrawal, are useful for identifying potential neural determinants of liability in humans. Recent analyses implicate the caudolateral substantia nigra pars reticulata (clSNr) in withdrawal following acute and repeated ethanol exposures in mice, but did not assess its impact on withdrawal from other sedative-hypnotics or whether intrinsic neurons or fibers of passage are involved. Here, we demonstrate that bilateral chemical (ibotenic acid) lesions of the clSNr attenuate barbiturate (pentobarbital) and ethanol withdrawal. Chemical lesions did not affect convulsions in response to pentylenetetrazole, which blocks GABA(A) receptor-mediated transmission. Our results demonstrate that the clSNr nucleus itself rather than fibers of passage is crucial to its effects on barbiturate and ethanol withdrawal. These findings support suggest that clSNr could be one of the shared neural substrates mediating withdrawal from sedative-hypnotic drugs.
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47
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Ishii H, Nakajo K, Yanagawa Y, Kubo Y. Identification and characterization of Cs+-permeable K+ channel current in mouse cerebellar Purkinje cells in lobules 9 and 10 evoked by molecular layer stimulation. Eur J Neurosci 2010; 32:736-48. [DOI: 10.1111/j.1460-9568.2010.07336.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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48
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GLAST stability and activity are enhanced by interaction with the PDZ scaffold NHERF-2. Neurosci Lett 2010; 487:3-7. [PMID: 20430067 DOI: 10.1016/j.neulet.2010.04.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 04/17/2010] [Accepted: 04/19/2010] [Indexed: 01/18/2023]
Abstract
The astrocytic glutamate transporter GLAST (also known as EAAT1) is a key regulator of extracellular glutamate levels in many regions of vertebrate brains. To identify novel interacting partners that might regulate the localization and function of GLAST in astrocytes, we screened the transporter's C-terminus (GLAST-CT) against a proteomic array of 96 different PDZ domains. The GLAST-CT robustly and specifically interacted with PDZ domains from two related scaffolding proteins, the Na(+)/H(+) exchanger regulatory factors 1 and 2 (NHERF-1 and NHERF-2). Studies on cultured rat cortical astrocytes revealed that these cells are highly enriched in NHERF-2 relative to NHERF-1. Endogenous GLAST and NHERF-2 from cultured astrocytes were found to robustly co-immunoprecipitate, and further co-immunoprecipitation studies on mutant versions of GLAST expressed in transfected cells revealed the GLAST/NHERF-2 interaction to be dependent on the last amino acid of the GLAST-CT. Knockdown of endogenous NHERF-2 in astrocytes via siRNA treatment resulted in a significant reduction in GLAST activity, which corresponded to significantly reduced total expression of GLAST protein and reduced half-life of GLAST, as assessed in pulse-chase metabolic labeling studies. These findings reveal that NHERF-2 can interact with GLAST in astrocytes to enhance GLAST stability and activity.
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Cheng S, Zhang J, Zhu P, Ma Y, Xiong Y, Sun L, Xu J, Zhang H, He J. The PDZ domain protein CAL interacts with mGluR5a and modulates receptor expression. J Neurochem 2010; 112:588-98. [DOI: 10.1111/j.1471-4159.2009.06454.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Dooley R, Baumgart S, Rasche S, Hatt H, Neuhaus EM. Olfactory receptor signaling is regulated by the post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) scaffold multi-PDZ domain protein 1. FEBS J 2010; 276:7279-90. [PMID: 19909339 DOI: 10.1111/j.1742-4658.2009.07435.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The unique ability of mammals to detect and discriminate between thousands of different odorant molecules is governed by the diverse array of olfactory receptors expressed by olfactory sensory neurons in the nasal epithelium. Olfactory receptors consist of seven transmembrane domain G protein-coupled receptors and comprise the largest gene superfamily in the mammalian genome. We found that approximately 30% of olfactory receptors possess a classical post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) domain binding motif in their C-termini. PDZ domains have been established as sites for protein-protein interaction and play a central role in organizing diverse cell signaling assemblies. In the present study, we show that multi-PDZ domain protein 1 (MUPP1) is expressed in the apical compartment of olfactory sensory neurons. Furthermore, on heterologous co-expression with olfactory sensory neurons, MUPP1 was shown to translocate to the plasma membrane. We found direct interaction of PDZ domains 1 + 2 of MUPP1 with the C-terminus of olfactory receptors in vitro. Moreover, the odorant-elicited calcium response of OR2AG1 showed a prolonged decay in MUPP1 small interfering RNA-treated cells. We have therefore elucidated the first building blocks of the putative 'olfactosome', brought together by the scaffolding protein MUPP1, a possible central nucleator of the olfactory response.
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Affiliation(s)
- Ruth Dooley
- Molecular Medicine Lab RCSI, Beaumont Hospital, Dublin, Republic of Ireland
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