1
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Katiyar AK, Hoang AT, Xu D, Hong J, Kim BJ, Ji S, Ahn JH. 2D Materials in Flexible Electronics: Recent Advances and Future Prospectives. Chem Rev 2024; 124:318-419. [PMID: 38055207 DOI: 10.1021/acs.chemrev.3c00302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.
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Affiliation(s)
- Ajit Kumar Katiyar
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Duo Xu
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Juyeong Hong
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Beom Jin Kim
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Seunghyeon Ji
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, Republic of Korea
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2
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Chen Z, Mondal A, Abderemane-Ali F, Jang S, Niranjan S, Montaño JL, Zaro BW, Minor DL. EMC chaperone-Ca V structure reveals an ion channel assembly intermediate. Nature 2023; 619:410-419. [PMID: 37196677 PMCID: PMC10896479 DOI: 10.1038/s41586-023-06175-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 05/05/2023] [Indexed: 05/19/2023]
Abstract
Voltage-gated ion channels (VGICs) comprise multiple structural units, the assembly of which is required for function1,2. Structural understanding of how VGIC subunits assemble and whether chaperone proteins are required is lacking. High-voltage-activated calcium channels (CaVs)3,4 are paradigmatic multisubunit VGICs whose function and trafficking are powerfully shaped by interactions between pore-forming CaV1 or CaV2 CaVα1 (ref. 3), and the auxiliary CaVβ5 and CaVα2δ subunits6,7. Here we present cryo-electron microscopy structures of human brain and cardiac CaV1.2 bound with CaVβ3 to a chaperone-the endoplasmic reticulum membrane protein complex (EMC)8,9-and of the assembled CaV1.2-CaVβ3-CaVα2δ-1 channel. These structures provide a view of an EMC-client complex and define EMC sites-the transmembrane (TM) and cytoplasmic (Cyto) docks; interaction between these sites and the client channel causes partial extraction of a pore subunit and splays open the CaVα2δ-interaction site. The structures identify the CaVα2δ-binding site for gabapentinoid anti-pain and anti-anxiety drugs6, show that EMC and CaVα2δ interactions with the channel are mutually exclusive, and indicate that EMC-to-CaVα2δ hand-off involves a divalent ion-dependent step and CaV1.2 element ordering. Disruption of the EMC-CaV complex compromises CaV function, suggesting that the EMC functions as a channel holdase that facilitates channel assembly. Together, the structures reveal a CaV assembly intermediate and EMC client-binding sites that could have wide-ranging implications for the biogenesis of VGICs and other membrane proteins.
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Affiliation(s)
- Zhou Chen
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Abhisek Mondal
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Fayal Abderemane-Ali
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Seil Jang
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - Sangeeta Niranjan
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
| | - José L Montaño
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Balyn W Zaro
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California, San Francisco, CA, USA.
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA.
- California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA, USA.
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA.
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.
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3
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Hernández-Plata E, Cruz AA, Becerril C. Na V1.7 channels are expressed in the lower airways of the human respiratory tract. Respir Physiol Neurobiol 2023; 311:104034. [PMID: 36792043 DOI: 10.1016/j.resp.2023.104034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 02/01/2023] [Accepted: 02/12/2023] [Indexed: 02/17/2023]
Abstract
NaV channels expression have been reported in upper airways and tracheal smooth muscle cells controlling the generation and propagation of action potentials in the respiratory tract sensory neurons, but information about the presence of these proteins in the bronchioalveolar structures in human lungs was missing. The main objective covered in this work was to determine whether the NaV1.7 channels are expressed in lower airways, and to identify the cellular identities expressing these proteins. We detected high levels of the mRNA coding for NaV1.7 channels in isolated lung fibroblasts obtained from both normal lungs, and fibrotic lungs of patients with respiratory diseases. The protein was detected with two different antibodies in the bronchioalveolar tissue, alveolar endothelium, and capillary endothelium, in normal and pathologic lungs. These evidences are useful in the dissection of molecular mechanisms of pulmonary pathologies, and lead to consider the NaV1.7 channels as potential therapeutic targets for the treatment of pulmonary diseases.
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Affiliation(s)
- Everardo Hernández-Plata
- Investigador por México, Consejo Nacional de Ciencia y Tecnología, and Instituto Nacional de Medicina Genómica, Mexico City, Mexico.
| | - Ana Alfaro Cruz
- Departamento de Patología, Hospital General de México, "Dr. Eduardo Liceaga", Mexico City, Mexico
| | - Carina Becerril
- Instituto Nacional de Enfermedades Respiratorias "Ismael Cosío Villegas", Mexico City, Mexico
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4
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Boyle Y, Johns TG, Fletcher EV. Potassium Ion Channels in Malignant Central Nervous System Cancers. Cancers (Basel) 2022; 14:cancers14194767. [PMID: 36230692 PMCID: PMC9563970 DOI: 10.3390/cancers14194767] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/19/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
Malignant central nervous system (CNS) cancers are among the most difficult to treat, with low rates of survival and a high likelihood of recurrence. This is primarily due to their location within the CNS, hindering adequate drug delivery and tumour access via surgery. Furthermore, CNS cancer cells are highly plastic, an adaptive property that enables them to bypass targeted treatment strategies and develop drug resistance. Potassium ion channels have long been implicated in the progression of many cancers due to their integral role in several hallmarks of the disease. Here, we will explore this relationship further, with a focus on malignant CNS cancers, including high-grade glioma (HGG). HGG is the most lethal form of primary brain tumour in adults, with the majority of patient mortality attributed to drug-resistant secondary tumours. Hence, targeting proteins that are integral to cellular plasticity could reduce tumour recurrence, improving survival. This review summarises the role of potassium ion channels in malignant CNS cancers, specifically how they contribute to proliferation, invasion, metastasis, angiogenesis, and plasticity. We will also explore how specific modulation of these proteins may provide a novel way to overcome drug resistance and improve patient outcomes.
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Affiliation(s)
- Yasmin Boyle
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
- Correspondence:
| | - Terrance G. Johns
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
| | - Emily V. Fletcher
- Telethon Kids Institute, Perth Children’s Hospital, 15 Hospital Ave, Nedlands, Perth, WA 6009, Australia
- School of Biomedicine, The University of Western Australia, 35 Stirling Hwy, Crawley, Perth, WA 6009, Australia
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5
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Quaternary structure independent folding of voltage-gated ion channel pore domain subunits. Nat Struct Mol Biol 2022; 29:537-548. [PMID: 35655098 PMCID: PMC9809158 DOI: 10.1038/s41594-022-00775-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 04/08/2022] [Indexed: 01/07/2023]
Abstract
Every voltage-gated ion channel (VGIC) has a pore domain (PD) made from four subunits, each comprising an antiparallel transmembrane helix pair bridged by a loop. The extent to which PD subunit structure requires quaternary interactions is unclear. Here, we present crystal structures of a set of bacterial voltage-gated sodium channel (BacNaV) 'pore only' proteins that reveal a surprising collection of non-canonical quaternary arrangements in which the PD tertiary structure is maintained. This context-independent structural robustness, supported by molecular dynamics simulations, indicates that VGIC-PD tertiary structure is independent of quaternary interactions. This fold occurs throughout the VGIC superfamily and in diverse transmembrane and soluble proteins. Strikingly, characterization of PD subunit-binding Fabs indicates that non-canonical quaternary PD conformations can occur in full-length VGICs. Together, our data demonstrate that the VGIC-PD is an autonomously folded unit. This property has implications for VGIC biogenesis, understanding functional states, de novo channel design, and VGIC structural origins.
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6
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Jäger M, Koslowski T, Wolf S. Predicting Ion Channel Conductance via Dissipation-Corrected Targeted Molecular Dynamics and Langevin Equation Simulations. J Chem Theory Comput 2021; 18:494-502. [PMID: 34928150 DOI: 10.1021/acs.jctc.1c00426] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ion channels are important proteins for physiological information transfer and functional control. To predict the microscopic origins of their voltage-conductance characteristics, here we applied dissipation-corrected targeted molecular dynamics in combination with Langevin equation simulations to potassium diffusion through the gramicidin A channel as a test system. Performing a nonequilibrium principal component analysis on backbone dihedral angles, we find coupled protein-ion dynamics to occur during ion transfer. The dissipation-corrected free energy profiles correspond well to predictions from other biased simulation methods. The incorporation of an external electric field in Langevin simulations enables the prediction of macroscopic observables in the form of I-V characteristics.
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Affiliation(s)
- Miriam Jäger
- Biomolecular Dynamics, Institute of Physics, University of Freiburg, 79104 Freiburg, Germany
| | - Thorsten Koslowski
- Institute of Physical Chemistry, University of Freiburg, 79104 Freiburg, Germany
| | - Steffen Wolf
- Biomolecular Dynamics, Institute of Physics, University of Freiburg, 79104 Freiburg, Germany
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7
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Kwon JW, Jeon YK, Kim J, Kim SJ, Kim SJ. Intramolecular Disulfide Bonds for Biogenesis of CALHM1 Ion Channel Are Dispensable for Voltage-Dependent Activation. Mol Cells 2021; 44:758-769. [PMID: 34711692 PMCID: PMC8560582 DOI: 10.14348/molcells.2021.0131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/19/2021] [Accepted: 09/06/2021] [Indexed: 11/27/2022] Open
Abstract
Calcium homeostasis modulator 1 (CALHM1) is a membrane protein with four transmembrane helices that form an octameric ion channel with voltage-dependent activation. There are four conserved cysteine (Cys) residues in the extracellular domain that form two intramolecular disulfide bonds. We investigated the roles of C42-C127 and C44-C161 in human CALHM1 channel biogenesis and the ionic current (ICALHM1). Replacing Cys with Ser or Ala abolished the membrane trafficking as well as ICALHM1. Immunoblotting analysis revealed dithiothreitol-sensitive multimeric CALHM1, which was markedly reduced in C44S and C161S, but preserved in C42S and C127S. The mixed expression of C42S and wild-type did not show a dominant-negative effect. While the heteromeric assembly of CALHM1 and CALHM3 formed active ion channels, the co-expression of C42S and CALHM3 did not produce functional channels. Despite the critical structural role of the extracellular cysteine residues, a treatment with the membrane-impermeable reducing agent tris(2-carboxyethyl) phosphine (TCEP, 2 mM) did not affect ICALHM1 for up to 30 min. Interestingly, incubation with TCEP (2 mM) for 2-6 h reduced both ICALHM1 and the surface expression of CALHM1 in a time-dependent manner. We propose that the intramolecular disulfide bonds are essential for folding, oligomerization, trafficking and maintenance of CALHM1 in the plasma membrane, but dispensable for the voltage-dependent activation once expressed on the plasma membrane.
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Affiliation(s)
- Jae Won Kwon
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Young Keul Jeon
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Jinsung Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 03080, Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 03080, Korea
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8
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Şterbuleac D. Molecular dynamics: a powerful tool for studying the medicinal chemistry of ion channel modulators. RSC Med Chem 2021; 12:1503-1518. [PMID: 34671734 PMCID: PMC8459385 DOI: 10.1039/d1md00140j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Accepted: 07/21/2021] [Indexed: 01/10/2023] Open
Abstract
Molecular dynamics (MD) simulations allow researchers to investigate the behavior of desired biological targets at ever-decreasing costs with ever-increasing precision. Among the biological macromolecules, ion channels are remarkable transmembrane proteins, capable of performing special biological processes and revealing a complex regulatory matrix, including modulation by small molecules, either endogenous or exogenous. Recently, given the developments in ion channel structure determination and accessibility of bio-computational techniques, MD and related tools are becoming increasingly popular in the intense research area regarding ligand-channel interactions. This review synthesizes and presents the most important fields of MD involvement in investigating channel-molecule interactions, including, but not limited to, deciphering the binding modes of ligands to their ion channel targets and the mechanisms through which chemical compounds exert their effect on channel function. Special attention is devoted to the importance of more elaborate methods, such as free energy calculations, while principles regarding drug design and discovery are highlighted. Several technical aspects involving the creation and simulation of channel-molecule MD systems (ligand parameterization, proper membrane setup, system building, etc.) are also presented.
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Affiliation(s)
- Daniel Şterbuleac
- Department of Health and Human Development, "Ştefan cel Mare" University of Suceava Str. Universităţii 13, 720229, E Building Suceava Romania
- Department of Forestry and Environmental Protection, "Ştefan cel Mare" University of Suceava Str. Universităţii 13, 720229, E Building Suceava Romania
- Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies and Distributed Systems for Fabrication and Control (MANSiD), "Ştefan cel Mare" University of Suceava Str. Universităţii 13 720229 Suceava Romania
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9
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Zhou H, Yamada T, Kimizuka N. Supramolecular Thermocells based on Thermo-Responsiveness of Host–Guest Chemistry. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210061] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Hongyao Zhou
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Teppei Yamada
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan
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10
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Rivas S, Hanif K, Chakouri N, Ben-Johny M. Probing ion channel macromolecular interactions using fluorescence resonance energy transfer. Methods Enzymol 2021; 653:319-347. [PMID: 34099178 DOI: 10.1016/bs.mie.2021.01.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ion channels are macromolecular complexes whose functions are exquisitely tuned by interacting proteins. Fluorescence resonance energy transfer (FRET) is a powerful methodology that is adept at quantifying ion channel protein-protein interactions in living cells. For FRET experiments, the interacting partners are tagged with appropriate donor and acceptor fluorescent proteins. If the fluorescently-labeled molecules are in close proximity, then photoexcitation of the donor results in non-radiative energy transfer to the acceptor, and subsequent fluorescence emission of the acceptor. The stoichiometry of ion channel interactions and their relative binding affinities can be deduced by quantifying both the FRET efficiency and the total number of donors and acceptors in a given cell. In this chapter, we discuss general considerations for FRET analysis of biological interactions, various strategies for estimating FRET efficiencies, and detailed protocols for construction of binding curves and determination of stoichiometry. We focus on implementation of FRET assays using a flow cytometer given its amenability for high-throughput data acquisition, enhanced accessibility, and robust analysis. This versatile methodology permits mechanistic dissection of dynamic changes in ion channel interactions.
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Affiliation(s)
- Sharen Rivas
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, United States
| | | | - Nourdine Chakouri
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, United States
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, United States.
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11
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Schwenk J, Fakler B. Building of AMPA‐type glutamate receptors in the endoplasmic reticulum and its implication for excitatory neurotransmission. J Physiol 2020; 599:2639-2653. [DOI: 10.1113/jp279025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/21/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Jochen Schwenk
- Institute of Physiology, Faculty of Medicine University of Freiburg Hermann‐Herder‐Str. 7 Freiburg 79104 Germany
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine University of Freiburg Hermann‐Herder‐Str. 7 Freiburg 79104 Germany
- Signalling Research Centres BIOSS and CIBSS Schänzlestr. 18 Freiburg 79104 Germany
- Center for Basics in NeuroModulation Breisacherstr. 4 Freiburg 79106 Germany
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12
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Barros F, Pardo LA, Domínguez P, Sierra LM, de la Peña P. New Structures and Gating of Voltage-Dependent Potassium (Kv) Channels and Their Relatives: A Multi-Domain and Dynamic Question. Int J Mol Sci 2019; 20:ijms20020248. [PMID: 30634573 PMCID: PMC6359393 DOI: 10.3390/ijms20020248] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/30/2018] [Accepted: 01/07/2019] [Indexed: 12/15/2022] Open
Abstract
Voltage-dependent potassium channels (Kv channels) are crucial regulators of cell excitability that participate in a range of physiological and pathophysiological processes. These channels are molecular machines that display a mechanism (known as gating) for opening and closing a gate located in a pore domain (PD). In Kv channels, this mechanism is triggered and controlled by changes in the magnitude of the transmembrane voltage sensed by a voltage-sensing domain (VSD). In this review, we consider several aspects of the VSD–PD coupling in Kv channels, and in some relatives, that share a common general structure characterized by a single square-shaped ion conduction pore in the center, surrounded by four VSDs located at the periphery. We compile some recent advances in the knowledge of their architecture, based in cryo-electron microscopy (cryo-EM) data for high-resolution determination of their structure, plus some new functional data obtained with channel variants in which the covalent continuity between the VSD and PD modules has been interrupted. These advances and new data bring about some reconsiderations about the use of exclusively a classical electromechanical lever model of VSD–PD coupling by some Kv channels, and open a view of the Kv-type channels as allosteric machines in which gating may be dynamically influenced by some long-range interactional/allosteric mechanisms.
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Affiliation(s)
- Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
| | - Luis A Pardo
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen, Germany.
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
| | - Luisa Maria Sierra
- Departamento de Biología Funcional (Area de Genética), Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, 33006 Oviedo, Asturias, Spain.
| | - Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006 Oviedo, Asturias, Spain.
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13
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Osei-Owusu J, Yang J, Vitery MDC, Qiu Z. Molecular Biology and Physiology of Volume-Regulated Anion Channel (VRAC). CURRENT TOPICS IN MEMBRANES 2018; 81:177-203. [PMID: 30243432 DOI: 10.1016/bs.ctm.2018.07.005] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The Volume-Regulated Anion Channel (VRAC) is activated by cell swelling and plays a key role in cell volume regulation. VRAC is ubiquitously expressed in vertebrate cells and also implicated in many other physiological and cellular processes including fluid secretion, glutamate release, membrane potential regulation, cell proliferation, migration, and apoptosis. Although its biophysical properties have been well characterized, the molecular identity of VRAC remained a mystery for almost three decades. The field was transformed by recent discoveries showing that the leucine-rich repeat-containing protein 8A (LRRC8A, also named SWELL1) and its four other homologs form heteromeric VRAC channels. The composition of LRRC8 subunits determines channel properties and substrate selectivity of a large variety of different VRACs. Incorporating purified SWELL1-containing protein complexes into lipid bilayers is sufficient to reconstitute channel activities, a finding that supports the decrease in intracellular ionic strength as the mechanism of VRAC activation during cell swelling. Characterization of Swell1 knockout mice uncovers the important role of VRAC in T cell development, pancreatic β-cell glucose-stimulated insulin secretion, and adipocyte metabolic function. The ability to permeate organic osmolytes and metabolites is a major feature of VRAC. The list of VRAC substrates is expected to grow, now also including some cancer drugs and antibiotics even under non-cell swelling conditions. Therefore, a critical role of VRAC in drug resistance and cell-cell communication is emerging. This review summarizes the exciting recent progress on the structure-function relationship and physiology of VRAC and discusses key future questions to be solved.
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Affiliation(s)
- James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Junhua Yang
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Maria Del Carmen Vitery
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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14
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Mackie TD, Brodsky JL. Investigating Potassium Channels in Budding Yeast: A Genetic Sandbox. Genetics 2018; 209:637-650. [PMID: 29967058 PMCID: PMC6028241 DOI: 10.1534/genetics.118.301026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 05/15/2018] [Indexed: 12/26/2022] Open
Abstract
Like all species, the model eukaryote Saccharomyces cerevisiae, or Bakers' yeast, concentrates potassium in the cytosol as an electrogenic osmolyte and enzyme cofactor. Yeast are capable of robust growth on a wide variety of potassium concentrations, ranging from 10 µM to 2.5 M, due to the presence of a high-affinity potassium uptake system and a battery of cation exchange transporters. Genetic perturbation of either of these systems retards yeast growth on low or high potassium, respectively. However, these potassium-sensitized yeast are a powerful genetic tool, which has been leveraged for diverse studies. Notably, the potassium-sensitive cells can be transformed with plasmids encoding potassium channels from bacteria, plants, or mammals, and subsequent changes in growth rate have been found to correlate with the activity of the introduced potassium channel. Discoveries arising from the use of this assay over the past three decades have increased our understanding of the structure-function relationships of various potassium channels, the mechanisms underlying the regulation of potassium channel function and trafficking, and the chemical basis of potassium channel modulation. In this article, we provide an overview of the major genetic tools used to study potassium channels in S. cerevisiae, a survey of seminal studies utilizing these tools, and a prospective for the future use of this elegant genetic approach.
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Affiliation(s)
- Timothy D Mackie
- Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260
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15
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Bai X, Li K, Yao L, Kang XL, Cai SQ. A forward genetic screen identifies chaperone CNX-1 as a conserved biogenesis regulator of ERG K + channels. J Gen Physiol 2018; 150:1189-1201. [PMID: 29941431 PMCID: PMC6080891 DOI: 10.1085/jgp.201812025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/15/2018] [Indexed: 12/15/2022] Open
Abstract
The human ether-a-go-go-related gene (hERG) encodes a voltage-gated potassium channel that controls repolarization of cardiac action potentials. Accumulating evidence suggests that most disease-related hERG mutations reduce the function of the channel by disrupting protein biogenesis of the channel in the endoplasmic reticulum (ER). However, the molecular mechanism underlying the biogenesis of ERG K+ channels is largely unknown. By forward genetic screening, we identified an ER-located chaperone CNX-1, the worm homologue of mammalian chaperone Calnexin, as a critical regulator for the protein biogenesis of UNC-103, the ERG-type K+ channel in Caenorhabditis elegans Loss-of-function mutations of cnx-1 decreased the protein level and current density of the UNC-103 K+ channel and suppressed the behavioral defects caused by a gain-of-function mutation in unc-103 Moreover, CNX-1 facilitated tetrameric assembly of UNC-103 channel subunits in a liposome-assisted cell-free translation system. Further studies showed that CNX-1 act in parallel to DNJ-1, another ER-located chaperone known to regulate maturation of UNC-103 channels, on controlling the protein biogenesis of UNC-103. Importantly, Calnexin interacted with hERG proteins in the ER in HEK293T cells. Deletion of calnexin reduced the expression and current densities of endogenous hERG K+ channels in SH-SY5Y cells. Collectively, we reveal an evolutionarily conserved chaperone CNX-1/Calnexin controlling the biogenesis of ERG-type K+ channels.
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Affiliation(s)
- Xue Bai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Kai Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Li Yao
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xin-Lei Kang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Shi-Qing Cai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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16
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Yang Y, Liu N, He Y, Liu Y, Ge L, Zou L, Song S, Xiong W, Liu X. Improved calcium sensor GCaMP-X overcomes the calcium channel perturbations induced by the calmodulin in GCaMP. Nat Commun 2018; 9:1504. [PMID: 29666364 PMCID: PMC5904127 DOI: 10.1038/s41467-018-03719-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 03/09/2018] [Indexed: 01/09/2023] Open
Abstract
GCaMP, one popular type of genetically-encoded Ca2+ indicator, has been associated with various side-effects. Here we unveil the intrinsic problem prevailing over different versions and applications, showing that GCaMP containing CaM (calmodulin) interferes with both gating and signaling of L-type calcium channels (CaV1). GCaMP acts as an impaired apoCaM and Ca2+/CaM, both critical to CaV1, which disrupts Ca2+ dynamics and gene expression. We then design and implement GCaMP-X, by incorporating an extra apoCaM-binding motif, effectively protecting CaV1-dependent excitation–transcription coupling from perturbations. GCaMP-X resolves the problems of detrimental nuclear accumulation, acute and chronic Ca2+ dysregulation, and aberrant transcription signaling and cell morphogenesis, while still demonstrating excellent Ca2+-sensing characteristics partly inherited from GCaMP. In summary, CaM/CaV1 gating and signaling mechanisms are elucidated for GCaMP side-effects, while allowing the development of GCaMP-X to appropriately monitor cytosolic, submembrane or nuclear Ca2+, which is also expected to guide the future design of CaM-based molecular tools. The popular genetically-encoded Ca2+ indicator, GCaMP, has several side-effects. Here the authors show that GCaMP containing CaM interferes with gating and signaling of L-type calcium channels, which disrupts Ca2+ dynamics and gene expression, and develop GCaMP-X to overcome these limitations.
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Affiliation(s)
- Yaxiong Yang
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 102402, China.,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China
| | - Nan Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,School of Life Sciences, Yunan University, Kunming, 650091, China
| | - Yuanyuan He
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Yuxia Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Lin Ge
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Sen Song
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China
| | - Wei Xiong
- IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China.,School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaodong Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China. .,School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China. .,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 102402, China. .,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China. .,School of Life Sciences, Tsinghua University, Beijing, 100084, China. .,Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou, 310027, China.
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17
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de la Peña P, Domínguez P, Barros F. Functional characterization of Kv11.1 (hERG) potassium channels split in the voltage-sensing domain. Pflugers Arch 2018; 470:1069-1085. [PMID: 29572566 PMCID: PMC6013512 DOI: 10.1007/s00424-018-2135-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/26/2018] [Accepted: 02/28/2018] [Indexed: 12/20/2022]
Abstract
Voltage-dependent KCNH family potassium channel functionality can be reconstructed using non-covalently linked voltage-sensing domain (VSD) and pore modules (split channels). However, the necessity of a covalent continuity for channel function has not been evaluated at other points within the two functionally independent channel modules. We find here that by cutting Kv11.1 (hERG, KCNH2) channels at the different loops linking the transmembrane spans of the channel core, not only channels split at the S4–S5 linker level, but also those split at the intracellular S2–S3 and the extracellular S3–S4 loops, yield fully functional channel proteins. Our data indicate that albeit less markedly, channels split after residue 482 in the S2–S3 linker resemble the uncoupled gating phenotype of those split at the C-terminal end of the VSD S4 transmembrane segment. Channels split after residues 514 and 518 in the S3–S4 linker show gating characteristics similar to those of the continuous wild-type channel. However, breaking the covalent link at this level strongly accelerates the voltage-dependent accessibility of a membrane impermeable methanethiosulfonate reagent to an engineered cysteine at the N-terminal region of the S4 transmembrane helix. Thus, besides that of the S4–S5 linker, structural integrity of the intracellular S2–S3 linker seems to constitute an important factor for proper transduction of VSD rearrangements to opening and closing the cytoplasmic gate. Furthermore, our data suggest that the short and probably rigid characteristics of the extracellular S3–S4 linker are not an essential component of the Kv11.1 voltage sensing machinery.
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Affiliation(s)
- Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006, Oviedo, Asturias, Spain.
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006, Oviedo, Asturias, Spain
| | - Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Edificio Santiago Gascón, Campus de El Cristo, 33006, Oviedo, Asturias, Spain.
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18
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de la Peña P, Domínguez P, Barros F. Gating mechanism of Kv11.1 (hERG) K + channels without covalent connection between voltage sensor and pore domains. Pflugers Arch 2017; 470:517-536. [PMID: 29270671 PMCID: PMC5805800 DOI: 10.1007/s00424-017-2093-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/17/2017] [Accepted: 11/28/2017] [Indexed: 12/20/2022]
Abstract
Kv11.1 (hERG, KCNH2) is a voltage-gated potassium channel crucial in setting the cardiac rhythm and the electrical behaviour of several non-cardiac cell types. Voltage-dependent gating of Kv11.1 can be reconstructed from non-covalently linked voltage sensing and pore modules (split channels), challenging classical views of voltage-dependent channel activation based on a S4–S5 linker acting as a rigid mechanical lever to open the gate. Progressive displacement of the split position from the end to the beginning of the S4–S5 linker induces an increasing negative shift in activation voltage dependence, a reduced zg value and a more negative ΔG0 for current activation, an almost complete abolition of the activation time course sigmoid shape and a slowing of the voltage-dependent deactivation. Channels disconnected at the S4–S5 linker near the S4 helix show a destabilization of the closed state(s). Furthermore, the isochronal ion current mode shift magnitude is clearly reduced in the different splits. Interestingly, the progressive modifications of voltage dependence activation gating by changing the split position are accompanied by a shift in the voltage-dependent availability to a methanethiosulfonate reagent of a Cys introduced at the upper S4 helix. Our data demonstrate for the first time that alterations in the covalent connection between the voltage sensor and the pore domains impact on the structural reorganizations of the voltage sensor domain. Also, they support the hypothesis that the S4–S5 linker integrates signals coming from other cytoplasmic domains that constitute either an important component or a crucial regulator of the gating machinery in Kv11.1 and other KCNH channels.
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Affiliation(s)
- Pilar de la Peña
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006, Oviedo, Asturias, Spain.
| | - Pedro Domínguez
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006, Oviedo, Asturias, Spain
| | - Francisco Barros
- Departamento de Bioquímica y Biología Molecular, Edificio Santiago Gascón, Campus de El Cristo, Universidad de Oviedo, 33006, Oviedo, Asturias, Spain.
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19
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Findeisen F, Campiglio M, Jo H, Abderemane-Ali F, Rumpf CH, Pope L, Rossen ND, Flucher BE, DeGrado WF, Minor DL. Stapled Voltage-Gated Calcium Channel (Ca V) α-Interaction Domain (AID) Peptides Act As Selective Protein-Protein Interaction Inhibitors of Ca V Function. ACS Chem Neurosci 2017; 8:1313-1326. [PMID: 28278376 PMCID: PMC5481814 DOI: 10.1021/acschemneuro.6b00454] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
![]()
For many voltage-gated
ion channels (VGICs), creation of a properly functioning ion channel
requires the formation of specific protein–protein interactions
between the transmembrane pore-forming subunits and cystoplasmic accessory
subunits. Despite the importance of such protein–protein interactions
in VGIC function and assembly, their potential as sites for VGIC modulator
development has been largely overlooked. Here, we develop meta-xylyl (m-xylyl) stapled peptides that
target a prototypic VGIC high affinity protein–protein interaction,
the interaction between the voltage-gated calcium channel (CaV) pore-forming subunit α-interaction domain (AID) and
cytoplasmic β-subunit (CaVβ). We show using
circular dichroism spectroscopy, X-ray crystallography, and isothermal
titration calorimetry that the m-xylyl staples enhance
AID helix formation are structurally compatible with native-like AID:CaVβ interactions and reduce the entropic penalty associated
with AID binding to CaVβ. Importantly, electrophysiological
studies reveal that stapled AID peptides act as effective inhibitors
of the CaVα1:CaVβ interaction
that modulate CaV function in an CaVβ
isoform-selective manner. Together, our studies provide a proof-of-concept
demonstration of the use of protein–protein interaction inhibitors
to control VGIC function and point to strategies for improved AID-based
CaV modulator design.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Daniel L. Minor
- Molecular Biophysics & Integrated Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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20
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Tomczak AP, Fernández-Trillo J, Bharill S, Papp F, Panyi G, Stühmer W, Isacoff EY, Pardo LA. A new mechanism of voltage-dependent gating exposed by K V10.1 channels interrupted between voltage sensor and pore. J Gen Physiol 2017; 149:577-593. [PMID: 28360219 PMCID: PMC5412533 DOI: 10.1085/jgp.201611742] [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: 12/15/2016] [Revised: 02/09/2017] [Accepted: 02/16/2017] [Indexed: 12/03/2022] Open
Abstract
A linker that connects the voltage-sensing domain and pore domain in voltage-gated K+ channels is thought to provide coupling during gating, but this view has been challenged in KCNH channels. Tomczak et al. investigate gating in KV10.1 channels with disrupted linkers and reveal multiple mechanisms. Voltage-gated ion channels couple transmembrane potential changes to ion flow. Conformational changes in the voltage-sensing domain (VSD) of the channel are thought to be transmitted to the pore domain (PD) through an α-helical linker between them (S4–S5 linker). However, our recent work on channels disrupted in the S4–S5 linker has challenged this interpretation for the KCNH family. Furthermore, a recent single-particle cryo-electron microscopy structure of KV10.1 revealed that the S4–S5 linker is a short loop in this KCNH family member, confirming the need for an alternative gating model. Here we use “split” channels made by expression of VSD and PD as separate fragments to investigate the mechanism of gating in KV10.1. We find that disruption of the covalent connection within the S4 helix compromises the ability of channels to close at negative voltage, whereas disconnecting the S4–S5 linker from S5 slows down activation and deactivation kinetics. Surprisingly, voltage-clamp fluorometry and MTS accessibility assays show that the motion of the S4 voltage sensor is virtually unaffected when VSD and PD are not covalently bound. Finally, experiments using constitutively open PD mutants suggest that the presence of the VSD is structurally important for the conducting conformation of the pore. Collectively, our observations offer partial support to the gating model that assumes that an inward motion of the C-terminal S4 helix, rather than the S4–S5 linker, closes the channel gate, while also suggesting that control of the pore by the voltage sensor involves more than one mechanism.
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Affiliation(s)
- Adam P Tomczak
- Oncophysiology Group, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Jorge Fernández-Trillo
- Oncophysiology Group, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Shashank Bharill
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Ferenc Papp
- Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary.,MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, 4032 Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, University of Debrecen, 4032 Debrecen, Hungary.,MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, 4032 Debrecen, Hungary
| | - Walter Stühmer
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Ehud Y Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720.,Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Luis A Pardo
- Oncophysiology Group, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
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21
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Li K, Jiang Q, Bai X, Yang YF, Ruan MY, Cai SQ. Tetrameric Assembly of K + Channels Requires ER-Located Chaperone Proteins. Mol Cell 2017; 65:52-65. [DOI: 10.1016/j.molcel.2016.10.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/02/2016] [Accepted: 10/20/2016] [Indexed: 10/20/2022]
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22
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Schwartz AB, Kapur A, Wang W, Huang Z, Fardone E, Palui G, Mattoussi H, Fadool DA. Margatoxin-bound quantum dots as a novel inhibitor of the voltage-gated ion channel Kv1.3. J Neurochem 2016; 140:404-420. [PMID: 27861889 DOI: 10.1111/jnc.13891] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 10/24/2016] [Accepted: 10/31/2016] [Indexed: 01/01/2023]
Abstract
Venom-derived ion channel inhibitors have strong channel selectivity, potency, and stability; however, tracking delivery to their target can be challenging. Herein, we utilized luminescent quantum dots (QDs) conjugated to margatoxin (MgTx) as a traceable vehicle to target a voltage-dependent potassium channel, Kv1.3, which has a select distribution and well-characterized role in immunity, glucose metabolism, and sensory ability. We screened both unconjugated (MgTx) and conjugated MgTx (QD-MgTx) for their ability to inhibit Shaker channels Kv1.1 to Kv1.7 using patch-clamp electrophysiology in HEK293 cells. Our data indicate that MgTx inhibits 79% of the outward current in Kv1.3-transfected cells and that the QD-MgTx conjugate is able to achieve a similar level of block, albeit a slightly reduced efficacy (66%) and at a slower time course (50% block by 10.9 ± 1.1 min, MgTx; vs. 15.3 ± 1.2 min, QD-MgTx). Like the unbound peptide, the QD-MgTx conjugate inhibits both Kv1.3 and Kv1.2 at a 1 nM concentration, whereas it does not inhibit other screened Shaker channels. We tested the ability of QD-MgTx to inhibit native Kv1.3 expressed in the mouse olfactory bulb (OB). In brain slices of the OB, the conjugate acted similarly to MgTx to inhibit Kv1.3, causing an increased action potential firing frequency attributed to decreased intraburst duration rather than interspike interval. Our data demonstrate a retention of known biophysical properties associated with block of the vestibule of Kv1.3 by QD-MgTx conjugate compared to that of MgTx, inferring QDs could provide a useful tool to deliver ion channel inhibitors to targeted tissues in vivo.
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Affiliation(s)
- Austin B Schwartz
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Anshika Kapur
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Wentao Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Zhenbo Huang
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA
| | - Erminia Fardone
- Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Goutam Palui
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Hedi Mattoussi
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida, USA
| | - Debra Ann Fadool
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, USA.,Program in Neuroscience, Florida State University, Tallahassee, Florida, USA.,Department of Biological Science, Florida State University, Tallahassee, Florida, USA
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23
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Gan Q, Dai J, Zhou HX, Wollmuth LP. The Transmembrane Domain Mediates Tetramerization of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors. J Biol Chem 2016; 291:6595-606. [PMID: 26839312 DOI: 10.1074/jbc.m115.686246] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Indexed: 11/06/2022] Open
Abstract
AMPA receptors (AMPARs) mediate fast excitatory neurotransmission in the central nervous system. Functional AMPARs are tetrameric complexes with a highly modular structure, consisting of four evolutionarily distinct structural domains: an amino-terminal domain (ATD), a ligand-binding domain (LBD), a channel-forming transmembrane domain (TMD), and a carboxyl-terminal domain (CTD). Here we show that the isolated TMD of the GluA1 AMPAR is fully capable of tetramerization. Additionally, removal of the extracellular domains from the receptor did not affect membrane topology or surface delivery. Furthermore, whereas the ATD and CTD contribute positively to tetramerization, the LBD presents a barrier to the process by reducing the stability of the receptor complex. These experiments pinpoint the TMD as the "tetramerization domain" for AMPARs, with other domains playing modulatory roles. They also raise intriguing questions about the evolution of iGluRs as well as the mechanisms regulating the biogenesis of AMPAR complexes.
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Affiliation(s)
- Quan Gan
- Graduate Program in Neuroscience, From the Department of Neurobiology and Behavior
| | - Jian Dai
- the Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Huan-Xiang Zhou
- the Department of Physics and Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306
| | - Lonnie P Wollmuth
- From the Department of Neurobiology and Behavior, the Department of Biochemistry and Cell Biology, and the Center for Nervous System Disorders, Stony Brook University, Stony Brook, New York 11794-5230 and
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24
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Abstract
Ion channels and receptors are the fundamental basis for neuronal communication in the nervous system and are important targets of autoimmunity. The different neuronal domains contain a unique repertoire of voltage-gated Na(+) (Nav), Ca(2+) (Cav), and K(+) (Kv), as well as other K(+) channels and hyperpolarization-gated cyclic nucleotide-regulated channels. The distinct ion channel distribution defines the electrophysiologic properties of different subtypes of neurons. The different neuronal compartments also express neurotransmitter-gated ion channels, or ionotropic receptors, as well as G protein-coupled receptors. Of particular relevance in the central nervous system are excitatory glutamate receptors and inhibitory γ-aminobutyric acid and glycine receptors. The interactions among different ion channels and receptors regulate neuronal excitability; frequency and pattern of firing of action potentials (AP); propagation of the AP along the axon; neurotransmitter release at synaptic terminals; AP backpropagation from the axon initial segment to the somatodendritic domain; dendritic integration of synaptic signals; and use-dependent plasticity.
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25
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TRP and Rhodopsin Transport Depends on Dual XPORT ER Chaperones Encoded by an Operon. Cell Rep 2015; 13:573-584. [PMID: 26456832 DOI: 10.1016/j.celrep.2015.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/30/2015] [Accepted: 09/04/2015] [Indexed: 11/24/2022] Open
Abstract
TRP channels and G protein-coupled receptors (GPCRs) play critical roles in sensory reception. However, the identities of the chaperones that assist GPCRs in translocating from the endoplasmic reticulum (ER) are limited, and TRP ER chaperones are virtually unknown. The one exception for TRPs is Drosophila XPORT. Here, we show that the xport locus is bicistronic and encodes unrelated transmembrane proteins, which enable the signaling proteins that initiate and culminate phototransduction, rhodopsin 1 (Rh1) and TRP, to traffic to the plasma membrane. XPORT-A and XPORT-B are ER proteins, and loss of either has a profound impact on TRP and Rh1 targeting to the light-sensing compartment of photoreceptor cells. XPORT-B complexed in vivo with the Drosophila homolog of the mammalian HSP70 protein, GRP78/BiP, which, in turn, associated with Rh1. Our work highlights a coordinated network of chaperones required for the biosynthesis of the TRP channel and rhodopsin in Drosophila photoreceptor cells.
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26
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Li Y, Gong H. Theoretical and simulation studies on voltage-gated sodium channels. Protein Cell 2015; 6:413-22. [PMID: 25894089 PMCID: PMC4444806 DOI: 10.1007/s13238-015-0152-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/05/2015] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (Nav) channels are indispensable membrane elements for the generation and propagation of electric signals in excitable cells. The successes in the crystallographic studies on prokaryotic Nav channels in recent years greatly promote the mechanistic investigation of these proteins and their eukaryotic counterparts. In this paper, we mainly review the progress in computational studies, especially the simulation studies, on these proteins in the past years.
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Affiliation(s)
- Yang Li
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Haipeng Gong
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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27
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Insights into the molecular foundations of electrical excitation. J Mol Biol 2015; 427:1-2. [PMID: 25542854 DOI: 10.1016/j.jmb.2014.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/22/2014] [Accepted: 10/12/2014] [Indexed: 01/04/2023]
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28
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Abstract
Potassium channels are pore-forming transmembrane proteins that regulate a multitude of biological processes by controlling potassium flow across cell membranes. Aberrant potassium channel functions contribute to diseases such as epilepsy, cardiac arrhythmia, and neuromuscular symptoms collectively known as channelopathies. Increasing evidence suggests that cancer constitutes another category of channelopathies associated with dysregulated channel expression. Indeed, potassium channel–modulating agents have demonstrated antitumor efficacy. Potassium channels regulate cancer cell behaviors such as proliferation and migration through both canonical ion permeation–dependent and noncanonical ion permeation–independent functions. Given their cell surface localization and well-known pharmacology, pharmacological strategies to target potassium channel could prove to be promising cancer therapeutics.
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Affiliation(s)
- Xi Huang
- Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
| | - Lily Yeh Jan
- Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158Howard Hughes Medical Institute, Department of Physiology, and Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
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29
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Bagriantsev SN, Chatelain FC, Clark KA, Alagem N, Reuveny E, Minor DL. Tethered protein display identifies a novel Kir3.2 (GIRK2) regulator from protein scaffold libraries. ACS Chem Neurosci 2014; 5:812-22. [PMID: 25028803 PMCID: PMC4176385 DOI: 10.1021/cn5000698] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
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Use of randomized peptide libraries
to evolve molecules with new
functions provides a means for developing novel regulators of protein
activity. Despite the demonstrated power of such approaches for soluble
targets, application of this strategy to membrane systems, such as
ion channels, remains challenging. Here, we have combined libraries
of a tethered protein scaffold with functional selection in yeast
to develop a novel activator of the G-protein-coupled mammalian inwardly
rectifying potassium channel Kir3.2 (GIRK2). We show that the novel
regulator, denoted N5, increases Kir3.2 (GIRK2) basal activity by
inhibiting clearance of the channel from the cellular surface rather
than affecting the core biophysical properties of the channel. These
studies establish the tethered protein display strategy as a means
to create new channel modulators and highlight the power of approaches
that couple randomized libraries with direct selections for functional
effects. Our results further underscore the possibility for the development
of modulators that influence channel function by altering cell surface
expression densities rather than by direct action on channel biophysical
parameters. The use of tethered library selection strategies coupled
with functional selection bypasses the need for a purified target
and is likely to be applicable to a range of membrane protein systems.
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Affiliation(s)
| | | | | | - Noga Alagem
- Department
of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Reuveny
- Department
of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Daniel L. Minor
- Physical
Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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30
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Payandeh J, Minor DL. Bacterial voltage-gated sodium channels (BacNa(V)s) from the soil, sea, and salt lakes enlighten molecular mechanisms of electrical signaling and pharmacology in the brain and heart. J Mol Biol 2014; 427:3-30. [PMID: 25158094 DOI: 10.1016/j.jmb.2014.08.010] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 08/11/2014] [Accepted: 08/18/2014] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels (Na(V)s) provide the initial electrical signal that drives action potential generation in many excitable cells of the brain, heart, and nervous system. For more than 60years, functional studies of Na(V)s have occupied a central place in physiological and biophysical investigation of the molecular basis of excitability. Recently, structural studies of members of a large family of bacterial voltage-gated sodium channels (BacNa(V)s) prevalent in soil, marine, and salt lake environments that bear many of the core features of eukaryotic Na(V)s have reframed ideas for voltage-gated channel function, ion selectivity, and pharmacology. Here, we analyze the recent advances, unanswered questions, and potential of BacNa(V)s as templates for drug development efforts.
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Affiliation(s)
- Jian Payandeh
- Department of Structural Biology, Genentech, Inc., South San Francisco, CA 94080, USA.
| | - Daniel L Minor
- Cardiovascular Research Institute, Departments of Biochemistry and Biophysics and Cellular and Molecular Pharmacology, California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 93858-2330, USA; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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31
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Nakajo K, Kubo Y. Steric hindrance between S4 and S5 of the KCNQ1/KCNE1 channel hampers pore opening. Nat Commun 2014; 5:4100. [PMID: 24920132 DOI: 10.1038/ncomms5100] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 05/13/2014] [Indexed: 01/06/2023] Open
Abstract
In voltage-gated K(+) channels, membrane depolarization induces an upward movement of the voltage-sensing domains (VSD) that triggers pore opening. KCNQ1 is a voltage-gated K(+) channel and its gating behaviour is substantially modulated by auxiliary subunit KCNE proteins. KCNE1, for example, markedly shifts the voltage dependence of KCNQ1 towards the positive direction and slows down the activation kinetics. Here we identify two phenylalanine residues on KCNQ1, Phe232 on S4 (VSD) and Phe279 on S5 (pore domain) to be responsible for the gating modulation by KCNE1. Phe232 collides with Phe279 during the course of the VSD movement and hinders KCNQ1 channel from opening in the presence of KCNE1. This steric hindrance caused by the bulky amino-acid residues destabilizes the open state and thus shifts the voltage dependence of KCNQ1/KCNE1 channel.
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Affiliation(s)
- Koichi Nakajo
- 1] Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan [2] Department of Physiological Sciences, Hayama, Kanagawa 240-0193, Japan
| | - Yoshihiro Kubo
- 1] Division of Biophysics and Neurobiology, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan [2] Department of Physiological Sciences, Hayama, Kanagawa 240-0193, Japan
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32
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Dai G, Sherpa T, Varnum MD. Alternative splicing governs cone cyclic nucleotide-gated (CNG) channel sensitivity to regulation by phosphoinositides. J Biol Chem 2014; 289:13680-90. [PMID: 24675082 DOI: 10.1074/jbc.m114.562272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Precursor mRNA encoding CNGA3 subunits of cone photoreceptor cyclic nucleotide-gated (CNG) channels undergoes alternative splicing, generating isoforms differing in the N-terminal cytoplasmic region of the protein. In humans, four variants arise from alternative splicing, but the functional significance of these changes has been a persistent mystery. Heterologous expression of the four possible CNGA3 isoforms alone or with CNGB3 subunits did not reveal significant differences in basic channel properties. However, inclusion of optional exon 3, with or without optional exon 5, produced heteromeric CNGA3 + CNGB3 channels exhibiting an ∼2-fold greater shift in K1/2,cGMP after phosphatidylinositol 4,5-biphosphate or phosphatidylinositol 3,4,5-trisphosphate application compared with channels lacking the sequence encoded by exon 3. We have previously identified two structural features within CNGA3 that support phosphoinositides (PIPn) regulation of cone CNG channels: N- and C-terminal regulatory modules. Specific mutations within these regions eliminated PIPn sensitivity of CNGA3 + CNGB3 channels. The exon 3 variant enhanced the component of PIPn regulation that depends on the C-terminal region rather than the nearby N-terminal region, consistent with an allosteric effect on PIPn sensitivity because of altered N-C coupling. Alternative splicing of CNGA3 occurs in multiple species, although the exact variants are not conserved across CNGA3 orthologs. Optional exon 3 appears to be unique to humans, even compared with other primates. In parallel, we found that a specific splice variant of canine CNGA3 removes a region of the protein that is necessary for high sensitivity to PIPn. CNGA3 alternative splicing may have evolved, in part, to tune the interactions between cone CNG channels and membrane-bound phosphoinositides.
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Affiliation(s)
- Gucan Dai
- From the Department of Integrative Physiology and Neuroscience
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