1
|
Oppenheimer KG, Hager NA, McAtee CK, Filiztekin E, Shang C, Warnick JA, Bruchez MP, Brodsky JL, Prosser DC, Kwiatkowski AV, O'Donnell AF. Optimization of the fluorogen-activating protein tag for quantitative protein trafficking and colocalization studies in S. cerevisiae. Mol Biol Cell 2024; 35:mr5. [PMID: 38809589 DOI: 10.1091/mbc.e24-04-0174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024] Open
Abstract
Spatial and temporal tracking of fluorescent proteins (FPs) in live cells permits visualization of proteome remodeling in response to extracellular cues. Historically, protein dynamics during trafficking have been visualized using constitutively active FPs fused to proteins of interest. While powerful, such FPs label all cellular pools of a protein, potentially masking the dynamics of select subpopulations. To help study protein subpopulations, bioconjugate tags, including the fluorogen activation proteins (FAPs), were developed. FAPs are comprised of two components: a single-chain antibody (SCA) fused to the protein of interest and a malachite-green (MG) derivative, which fluoresces only when bound to the SCA. Importantly, the MG derivatives can be either cell-permeant or -impermeant, thus permitting isolated detection of SCA-tagged proteins at the cell surface and facilitating quantitative endocytic measures. To expand FAP use in yeast, we optimized the SCA for yeast expression, created FAP-tagging plasmids, and generated FAP-tagged organelle markers. To demonstrate FAP efficacy, we coupled the SCA to the yeast G-protein coupled receptor Ste3. We measured Ste3 endocytic dynamics in response to pheromone and characterized cis- and trans-acting regulators of Ste3. Our work significantly expands FAP technology for varied applications in S. cerevisiae.
Collapse
Affiliation(s)
| | - Natalie A Hager
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Ceara K McAtee
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Elif Filiztekin
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Chaowei Shang
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Justina A Warnick
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Marcel P Bruchez
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, PA 15260
| | - Derek C Prosser
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284
| | - Adam V Kwiatkowski
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261
| | | |
Collapse
|
2
|
Machine learning/molecular dynamic protein structure prediction approach to investigate the protein conformational ensemble. Sci Rep 2022; 12:10018. [PMID: 35705565 PMCID: PMC9200820 DOI: 10.1038/s41598-022-13714-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/11/2022] [Indexed: 11/25/2022] Open
Abstract
Proteins exist in several different conformations. These structural changes are often associated with fluctuations at the residue level. Recent findings show that co-evolutionary analysis coupled with machine-learning techniques improves the precision by providing quantitative distance predictions between pairs of residues. The predicted statistical distance distribution from Multi Sequence Analysis reveals the presence of different local maxima suggesting the flexibility of key residue pairs. Here we investigate the ability of the residue-residue distance prediction to provide insights into the protein conformational ensemble. We combine deep learning approaches with mechanistic modeling to a set of proteins that experimentally showed conformational changes. The predicted protein models were filtered based on energy scores, RMSD clustering, and the centroids selected as the lowest energy structure per cluster. These models were compared to the experimental-Molecular Dynamics (MD) relaxed structure by analyzing the backbone residue torsional distribution and the sidechain orientations. Our pipeline allows to retrieve the experimental structural dynamics experimentally represented by different X-ray conformations for the same sequence as well the conformational space observed with the MD simulations. We show the potential correlation between the experimental structure dynamics and the predicted model ensemble demonstrating the susceptibility of the current state-of-the-art methods in protein folding and dynamics prediction and pointing out the areas of improvement.
Collapse
|
3
|
Lombardi JP, Kinzlmaier DA, Jacob TC. Visualizing GABA A Receptor Trafficking Dynamics with Fluorogenic Protein Labeling. ACTA ACUST UNITED AC 2021; 92:e97. [PMID: 32364672 DOI: 10.1002/cpns.97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is increasingly evident that neurotransmitter receptors, including ionotropic GABA A receptors (GABAARs), exhibit highly dynamic trafficking and cell surface mobility. Regulated trafficking to and from the surface is a critical determinant of GABAAR neurotransmission. Receptors delivered by exocytosis diffuse laterally in the plasma membrane, with tethering and reduced movement at synapses occurring through receptor interactions with the subsynaptic scaffold. After diffusion away from synapses, receptors are internalized by clathrin-dependent endocytosis at extrasynaptic sites and can be either recycled back to the cell membrane or degraded in lysosomes. To study the dynamics of these key trafficking events in neurons, we have developed novel optical methods based around receptors containing a dual-tagged γ2 subunit (γ2pHFAP) in combination with fluorogen dyes. Specifically, the GABAAR γ2 subunit is tagged with a pH-sensitive green fluorescent protein and a fluorogen-activating peptide (FAP). The FAP allows receptor labeling with fluorogen dyes that are optically silent until bound to the FAP. Combining FAP and fluorescent imaging with organelle labeling allows novel and accurate measurement of receptor turnover and accumulation into intracellular compartments under basal conditions in scenarios ranging from in vitro seizure models to drug exposure paradigms. Here we provide a protocol to track and quantify receptors in transit from the neuronal surface to endosomes and lysosomes. This protocol is readily applicable to cell lines and primary cells, allowing rapid quantitative measurements of receptor surface levels and postendocytic trafficking decisions. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Preparation of cortical neuronal cultures for imaging assays Basic Protocol 2: Surface receptor internalization and trafficking to early endosomes Basic Protocol 3: Measurement of receptor steady state surface level, synaptic level, and lysosomal targeting.
Collapse
Affiliation(s)
- Jacob P Lombardi
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - David A Kinzlmaier
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| |
Collapse
|
4
|
A novel fluorescence probe based on specific recognition of GABA A receptor for imaging cell membrane. Talanta 2020; 219:121317. [PMID: 32887057 DOI: 10.1016/j.talanta.2020.121317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/15/2020] [Accepted: 06/20/2020] [Indexed: 01/19/2023]
Abstract
Long and real time imaging of cell membrane is very important for better understanding of cell performances in physiological and pathological processes. Nowadays, fluorescence probe analysis has become an indispensable tool for monitoring cell membrane. Herein, a novel fluorescent probe based on specific recognition of GABAA receptor was developed for imaging cell membrane. The probe synthesized in this work has been successfully applied to image different kinds of cell membrane with some advantages over the reported probes. Moreover, the probe also showed good superiority in the preliminary screening GABAA drugs.
Collapse
|
5
|
Broch F, Gautier A. Illuminating Cellular Biochemistry: Fluorogenic Chemogenetic Biosensors for Biological Imaging. Chempluschem 2020; 85:1487-1497. [PMID: 32644262 DOI: 10.1002/cplu.202000413] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 06/18/2020] [Indexed: 12/19/2022]
Abstract
Cellular activity is defined by the precise spatiotemporal regulation of various components, such as ions, small molecules, or proteins. Studying cell physiology consequently requires the optical recording of these processes, notably by using fluorescent biosensors. The recent development of various fluorogenic systems greatly expanded the palette of reporters to be included in these sensors design. Fluorogenic reporters consist of a protein or RNA tag that can complex either an endogenous or a synthetic fluorogenic dye (so-called fluorogen). The intrinsic nature of these tags, along with the high tunability of their cognate chromophore provide interesting features such as far-red to near-infrared emission, oxygen independence, or unprecedented color versatility. These engineered photoreceptors, self-labelling proteins, or noncovalent aptamers and protein tags were rapidly identified as promising reporters to observe biological events. This Minireview focuses on the new perspectives they offer to design unique and innovative biosensors, thus pushing the boundaries of cellular imaging.
Collapse
Affiliation(s)
- Fanny Broch
- Sorbonne Université, École normale supérieure, PSL University, CNRS Laboratoire des biomolécules, LBM, 75005, Paris, France
| | - Arnaud Gautier
- Sorbonne Université, École normale supérieure, PSL University, CNRS Laboratoire des biomolécules, LBM, 75005, Paris, France.,Institut Universitaire de France, France
| |
Collapse
|
6
|
Perkins LA, Bruchez MP. Fluorogen activating protein toolset for protein trafficking measurements. Traffic 2020; 21:333-348. [PMID: 32080949 PMCID: PMC7462100 DOI: 10.1111/tra.12722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/17/2020] [Accepted: 02/18/2020] [Indexed: 12/11/2022]
Abstract
Throughout the past decade the use of fluorogen activating proteins (FAPs) has expanded with several unique reporter dyes that support a variety of methods to specifically quantify protein trafficking events. The platform's capabilities have been demonstrated in several systems and shared for widespread use. This review will highlight the current FAP labeling techniques for protein traffic measurements and focus on the use of the different designed fluorogenic dyes for selective and specific labeling applications.
Collapse
Affiliation(s)
- Lydia A. Perkins
- School of MedicineUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Marcel P. Bruchez
- The Department of Biological SciencesCarnegie MellonPittsburghPennsylvaniaUSA
- Department of ChemistryCarnegie MellonPittsburghPennsylvaniaUSA
- Molecular and Biosensor Imaging CenterCarnegie MellonPittsburghPennsylvaniaUSA
| |
Collapse
|
7
|
Péresse T, Gautier A. Next-Generation Fluorogen-Based Reporters and Biosensors for Advanced Bioimaging. Int J Mol Sci 2019; 20:E6142. [PMID: 31817528 PMCID: PMC6940837 DOI: 10.3390/ijms20246142] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 12/17/2022] Open
Abstract
Our ability to observe biochemical events with high spatial and temporal resolution is essential for understanding the functioning of living systems. Intrinsically fluorescent proteins such as the green fluorescent protein (GFP) have revolutionized the way biologists study cells and organisms. The fluorescence toolbox has been recently extended with new fluorescent reporters composed of a genetically encoded tag that binds endogenously present or exogenously applied fluorogenic chromophores (so-called fluorogens) and activates their fluorescence. This review presents the toolbox of fluorogen-based reporters and biosensors available to biologists. Various applications are detailed to illustrate the possible uses and opportunities offered by this new generation of fluorescent probes and sensors for advanced bioimaging.
Collapse
Affiliation(s)
- Tiphaine Péresse
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France;
| | - Arnaud Gautier
- Sorbonne Université, École Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules, LBM, 75005 Paris, France;
- Institut Universitaire de France (IUF), 1 rue Descartes, 75005 Paris, France
| |
Collapse
|
8
|
Gallo E. Fluorogen-Activating Proteins: Next-Generation Fluorescence Probes for Biological Research. Bioconjug Chem 2019; 31:16-27. [DOI: 10.1021/acs.bioconjchem.9b00710] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Eugenio Gallo
- Department of Molecular Genetics, University of Toronto, Charles Best Institute, 112 College Street, Toronto, Ontario M5G 1L6, Canada
| |
Collapse
|
9
|
Mortensen M, Krall J, Kongstad KT, Brygger BM, Lenzi O, Francotte P, Sørensen TE, Nielsen B, Jensen AA, Smart TG, Frølund B. Developing New 4-PIOL and 4-PHP Analogues for Photoinactivation of γ-Aminobutyric Acid Type A Receptors. ACS Chem Neurosci 2019; 10:4669-4684. [PMID: 31589403 DOI: 10.1021/acschemneuro.9b00478] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The critical roles played by GABAA receptors as inhibitory regulators of excitation in the central nervous system has been known for many years. Aberrant GABAA receptor function and trafficking deficits have also been associated with several diseases including anxiety, depression, epilepsy, and insomnia. As a consequence, important drug groups such as the benzodiazepines, barbiturates, and many general anesthetics have become established as modulators of GABAA receptor activity. Nevertheless, there is much we do not understand about the roles and mechanisms of GABAA receptors at neural network and systems levels. It is therefore crucial to develop novel technologies and especially chemical entities that can interrogate GABAA receptor function in the nervous system. Here, we describe the chemistry and characterization of a novel set of 4-PIOL and 4-PHP analogues synthesized with the aim of developing a toolkit of drugs that can photoinactivate GABAA receptors. Most of these new analogues show higher affinities/potencies compared with the respective lead compounds. This is indicative of cavernous areas being present near their binding sites that can be potentially associated with novel receptor interactions. The 4-PHP azide-analogue, 2d, possesses particularly impressive nanomolar affinity/potency and is an effective UV-inducible photoinhibitor of GABAA receptors with considerable potential for photocontrol of GABAA receptor function in situ.
Collapse
Affiliation(s)
- Martin Mortensen
- Department of Neuroscience, Physiology & Pharmacology , University College London , Gower Street , London WC1E 6BT , United Kingdom
| | - Jacob Krall
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Kenneth T Kongstad
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Benjamin M Brygger
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Ombretta Lenzi
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Pierre Francotte
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark.,Department of Medicinal Chemistry, Center for Interdisciplinary Research on Medicines (CIRM) , University of Liege , Avenue de l'Hôpital, 1, B36 , B-4000 Liège , Belgium
| | - Troels E Sørensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Birgitte Nielsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| | - Trevor G Smart
- Department of Neuroscience, Physiology & Pharmacology , University College London , Gower Street , London WC1E 6BT , United Kingdom
| | - Bente Frølund
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences , University of Copenhagen , Universitetsparken 2 , DK-2100 Copenhagen , Denmark
| |
Collapse
|
10
|
Lorenz-Guertin JM, Bambino MJ, Das S, Weintraub ST, Jacob TC. Diazepam Accelerates GABA AR Synaptic Exchange and Alters Intracellular Trafficking. Front Cell Neurosci 2019; 13:163. [PMID: 31080408 PMCID: PMC6497791 DOI: 10.3389/fncel.2019.00163] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/08/2019] [Indexed: 12/21/2022] Open
Abstract
Despite 50+ years of clinical use as anxiolytics, anti-convulsants, and sedative/hypnotic agents, the mechanisms underlying benzodiazepine (BZD) tolerance are poorly understood. BZDs potentiate the actions of gamma-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the adult brain, through positive allosteric modulation of γ2 subunit containing GABA type A receptors (GABAARs). Here we define key molecular events impacting γ2 GABAAR and the inhibitory synapse gephyrin scaffold following initial sustained BZD exposure in vitro and in vivo. Using immunofluorescence and biochemical experiments, we found that cultured cortical neurons treated with the classical BZD, diazepam (DZP), presented no substantial change in surface or synaptic levels of γ2-GABAARs. In contrast, both γ2 and the postsynaptic scaffolding protein gephyrin showed diminished total protein levels following a single DZP treatment in vitro and in mouse cortical tissue. We further identified DZP treatment enhanced phosphorylation of gephyrin Ser270 and increased generation of gephyrin cleavage products. Selective immunoprecipitation of γ2 from cultured neurons revealed enhanced ubiquitination of this subunit following DZP exposure. To assess novel trafficking responses induced by DZP, we employed a γ2 subunit containing an N terminal fluorogen-activating peptide (FAP) and pH-sensitive green fluorescent protein (γ2pHFAP). Live-imaging experiments using γ2pHFAP GABAAR expressing neurons identified enhanced lysosomal targeting of surface GABAARs and increased overall accumulation in vesicular compartments in response to DZP. Using fluorescence resonance energy transfer (FRET) measurements between α2 and γ2 subunits within a GABAAR in neurons, we identified reductions in synaptic clusters of this subpopulation of surface BZD sensitive receptor. Additional time-series experiments revealed the gephyrin regulating kinase ERK was inactivated by DZP at multiple time points. Moreover, we found DZP simultaneously enhanced synaptic exchange of both γ2-GABAARs and gephyrin using fluorescence recovery after photobleaching (FRAP) techniques. Finally we provide the first proteomic analysis of the BZD sensitive GABAAR interactome in DZP vs. vehicle treated mice. Collectively, our results indicate DZP exposure elicits down-regulation of gephyrin scaffolding and BZD sensitive GABAAR synaptic availability via multiple dynamic trafficking processes.
Collapse
Affiliation(s)
- Joshua M. Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew J. Bambino
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sabyasachi Das
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Susan T. Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Tija C. Jacob
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| |
Collapse
|
11
|
Ackerman DS, Altun B, Kolodieznyi D, Bruchez MP, Tsourkas A, Jarvik JW. Antibody-Linked Fluorogen-Activating Proteins for Antigen Detection and Cell Ablation. Bioconjug Chem 2018; 30:63-69. [PMID: 30543409 DOI: 10.1021/acs.bioconjchem.8b00720] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We demonstrate selective labeling of cell surface proteins using fluorogen-activating proteins (FAPs) conjugated to standard immunoglobulins (IgGs). Conjugation was achieved with a polypeptide reagent comprised of an N-terminal photoactivatable Fc-binding domain and a C-terminal FAP domain. The resulting FAP-antibody conjugates were effective agents for protein detection and cell ablation in cultured mammalian cells and for visualizing cell-cell contacts using a tethered fluorogen assay. Because our approach allows FAP-antibody conjugates to be generated for most currently available IgGs, it should have broad utility for experimental and therapeutic applications.
Collapse
Affiliation(s)
| | - Burcin Altun
- Department of Bioengineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | | | | | - Andrew Tsourkas
- Department of Bioengineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | | |
Collapse
|
12
|
Gautier A, Tebo AG. Fluorogenic Protein‐Based Strategies for Detection, Actuation, and Sensing. Bioessays 2018; 40:e1800118. [DOI: 10.1002/bies.201800118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/01/2018] [Indexed: 01/02/2023]
Affiliation(s)
- Arnaud Gautier
- PASTEUR, Département de Chimie, École Normale SupérieurePSL University, Sorbonne Université, CNRS75005 ParisFrance
| | - Alison G. Tebo
- PASTEUR, Département de Chimie, École Normale SupérieurePSL University, Sorbonne Université, CNRS75005 ParisFrance
| |
Collapse
|
13
|
Lorenz-Guertin JM, Bambino MJ, Jacob TC. γ2 GABA AR Trafficking and the Consequences of Human Genetic Variation. Front Cell Neurosci 2018; 12:265. [PMID: 30190672 PMCID: PMC6116786 DOI: 10.3389/fncel.2018.00265] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/02/2018] [Indexed: 11/13/2022] Open
Abstract
GABA type A receptors (GABAARs) mediate the majority of fast inhibitory neurotransmission in the central nervous system (CNS). Most prevalent as heteropentamers composed of two α, two β, and a γ2 subunit, these ligand-gated ionotropic chloride channels are capable of extensive genetic diversity (α1-6, β1-3, γ1-3, δ, 𝜀, 𝜃, π, ρ1-3). Part of this selective GABAAR assembly arises from the critical role for γ2 in maintaining synaptic receptor localization and function. Accordingly, mutations in this subunit account for over half of the known epilepsy-associated genetic anomalies identified in GABAARs. Fundamental structure-function studies and cellular pathology investigations have revealed dynamic GABAAR trafficking and synaptic scaffolding as critical regulators of GABAergic inhibition. Here, we introduce in vitro and in vivo findings regarding the specific role of the γ2 subunit in receptor trafficking. We then examine γ2 subunit human genetic variation and assess disease related phenotypes and the potential role of altered GABAAR trafficking. Finally, we discuss new-age imaging techniques and their potential to provide novel insight into critical regulatory mechanisms of GABAAR function.
Collapse
Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthew J Bambino
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| |
Collapse
|