1
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Kantaputra P, Butali A, Eliason S, Chalkley C, Nakornchai S, Bongkochwilawan C, Kawasaki K, Kumchiang A, Ngamphiw C, Tongsima S, Ketudat Cairns JR, Olsen B, Intachai W, Ohazama A, Tucker AS, Amendt BA. CACNA1S mutation-associated dental anomalies: A calcium channelopathy. Oral Dis 2024; 30:1350-1359. [PMID: 36825457 PMCID: PMC11229413 DOI: 10.1111/odi.14551] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 02/11/2023] [Accepted: 02/22/2023] [Indexed: 02/25/2023]
Abstract
OBJECTIVES To identify the molecular etiology of distinct dental anomalies found in eight Thai patients and explore the mutational effects on cellular functions. MATERIALS AND METHODS Clinical and radiographic examinations were performed for eight patients. Whole exome sequencing, mutant protein modelling, qPCR, western blot analysis, scratch assays, immunofluorescence, confocal analysis, in situ hybridization, and scanning electron micrography of teeth were done. RESULTS All patients had molars with multiple supernumerary cusps, single-cusped premolars, and a reduction in root number. Mutation analysis highlighted a heterozygous c.865A>G; p.Ile289Val mutation in CACNA1S in the patients. CACNA1S is a component of the slowly inactivating L-type voltage-dependent calcium channel. Mutant protein modeling suggested that the mutation might allow leakage of Ca2+ or other cations, or a tightening, to restrict calcium flow. Immunohistochemistry analysis showed expression of Cacna1s in the developing murine tooth epithelium during stages of crown and root morphogenesis. In cell culture, the mutation resulted in abnormal cell migration of transfected CHO cells compared to wildtype CACNA1S, with changes to the cytoskeleton and markers of focal adhesion. CONCLUSIONS The malformations observed in our patients suggest a role for calcium signaling in organization of both cusps and roots, affecting cell dynamics within the dental epithelium.
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Affiliation(s)
- P Kantaputra
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - A Butali
- Iowa Institute of Oral Health Research, University of Iowa, Iowa City, Iowa, USA
- Department of Oral Pathology, Radiology and Medicine, College of Dentistry, University of Iowa, Iowa City, Iowa, USA
| | - S Eliason
- Department of Anatomy and Cell Biology, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, Iowa, USA
| | - C Chalkley
- Department of Anatomy and Cell Biology, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, Iowa, USA
| | - S Nakornchai
- Department of Pediatric Dentistry, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
| | - C Bongkochwilawan
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - K Kawasaki
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - A Kumchiang
- Na-Chauk Hospital, Na-Chauk, Maha Sarakham, Thailand
| | - C Ngamphiw
- National Biobank of Thailand, National Science and Technology Development Agency (NSTDA), Thailand Science Park, Khlong Luang, Pathum Thani, Thailand
| | - S Tongsima
- National Biobank of Thailand, National Science and Technology Development Agency (NSTDA), Thailand Science Park, Khlong Luang, Pathum Thani, Thailand
| | - J R Ketudat Cairns
- Center for Biomolecular Structure, Function and Application, School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
- Laboratory of Biochemistry, Chulabhorn Research Institute, Bangkok, Thailand
| | - B Olsen
- Department of Developmental Biology, Harvard School of Dental Medicine, Boston, Massachusetts, USA
| | - W Intachai
- Center of Excellence in Medical Genetics Research, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
- Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand
| | - A Ohazama
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - A S Tucker
- Centre for Craniofacial and Regenerative Biology, King's College London, London, UK
| | - B A Amendt
- Iowa Institute of Oral Health Research, University of Iowa, Iowa City, Iowa, USA
- Department of Anatomy and Cell Biology, Craniofacial Anomalies Research Center, University of Iowa, Iowa City, Iowa, USA
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2
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Cingolani LA, Thalhammer A, Jaudon F, Muià J, Baj G. Nanoscale organization of Ca V2.1 splice isoforms at presynaptic terminals: implications for synaptic vesicle release and synaptic facilitation. Biol Chem 2023; 404:931-937. [PMID: 37658578 PMCID: PMC10695435 DOI: 10.1515/hsz-2023-0235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/01/2023] [Indexed: 09/03/2023]
Abstract
The distance between CaV2.1 voltage-gated Ca2+ channels and the Ca2+ sensor responsible for vesicle release at presynaptic terminals is critical for determining synaptic strength. Yet, the molecular mechanisms responsible for a loose coupling configuration of CaV2.1 in certain synapses or developmental periods and a tight one in others remain unknown. Here, we examine the nanoscale organization of two CaV2.1 splice isoforms (CaV2.1[EFa] and CaV2.1[EFb]) at presynaptic terminals by superresolution structured illumination microscopy. We find that CaV2.1[EFa] is more tightly co-localized with presynaptic markers than CaV2.1[EFb], suggesting that alternative splicing plays a crucial role in the synaptic organization of CaV2.1 channels.
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Affiliation(s)
- Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, via Giorgieri 5, I-34127Trieste, Italy
- Center for Synaptic Neuroscience and Technology (NSYN), Fondazione Istituto Italiano di Tecnologia (IIT), Largo Rosanna Benzi 10, I-16132Genoa, Italy
| | - Agnes Thalhammer
- Department of Life Sciences, University of Trieste, via Giorgieri 5, I-34127Trieste, Italy
- Centro Interdipartimentale di Microscopia Avanzata (CIMA), University of Trieste, via Fleming 31, I-34127Trieste, Italy
| | - Fanny Jaudon
- Department of Life Sciences, University of Trieste, via Giorgieri 5, I-34127Trieste, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, I-16132Genoa, Italy
| | - Jessica Muià
- Department of Life Sciences, University of Trieste, via Giorgieri 5, I-34127Trieste, Italy
| | - Gabriele Baj
- Department of Life Sciences, University of Trieste, via Giorgieri 5, I-34127Trieste, Italy
- Centro Interdipartimentale di Microscopia Avanzata (CIMA), University of Trieste, via Fleming 31, I-34127Trieste, Italy
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3
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Gando I, Becerra Flores M, Chen IS, Yang HQ, Nakamura TY, Cardozo TJ, Coetzee WA. CL-705G: a novel chemical Kir6.2-specific K ATP channel opener. Front Pharmacol 2023; 14:1197257. [PMID: 37408765 PMCID: PMC10319115 DOI: 10.3389/fphar.2023.1197257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 06/01/2023] [Indexed: 07/07/2023] Open
Abstract
Background: KATP channels have diverse roles, including regulation of insulin secretion and blood flow, and protection against biological stress responses and are excellent therapeutic targets. Different subclasses of KATP channels exist in various tissue types due to the unique assemblies of specific pore-forming (Kir6.x) and accessory (SURx) subunits. The majority of pharmacological openers and blockers act by binding to SURx and are poorly selective against the various KATP channel subclasses. Methods and Results: We used 3D models of the Kir6.2/SUR homotetramers based on existing cryo-EM structures of channels in both the open and closed states to identify a potential agonist binding pocket in a functionally critical area of the channel. Computational docking screens of this pocket with the Chembridge Core chemical library of 492,000 drug-like compounds yielded 15 top-ranked "hits", which were tested for activity against KATP channels using patch clamping and thallium (Tl+) flux assays with a Kir6.2/SUR2A HEK-293 stable cell line. Several of the compounds increased Tl+ fluxes. One of them (CL-705G) opened Kir6.2/SUR2A channels with a similar potency as pinacidil (EC50 of 9 µM and 11 μM, respectively). Remarkably, compound CL-705G had no or minimal effects on other Kir channels, including Kir6.1/SUR2B, Kir2.1, or Kir3.1/Kir3.4 channels, or Na+ currents of TE671 medulloblastoma cells. CL-705G activated Kir6.2Δ36 in the presence of SUR2A, but not when expressed by itself. CL-705G activated Kir6.2/SUR2A channels even after PIP2 depletion. The compound has cardioprotective effects in a cellular model of pharmacological preconditioning. It also partially rescued activity of the gating-defective Kir6.2-R301C mutant that is associated with congenital hyperinsulinism. Conclusion: CL-705G is a new Kir6.2 opener with little cross-reactivity with other channels tested, including the structurally similar Kir6.1. This, to our knowledge, is the first Kir-specific channel opener.
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Affiliation(s)
- Ivan Gando
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - Manuel Becerra Flores
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - I.-Shan Chen
- Phamacology, Wakayama Medical University, Wakayama, Japan
| | - Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, China
| | | | - Timothy J. Cardozo
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - William A. Coetzee
- Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
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4
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Cardoso FC, Schmit M, Kuiper MJ, Lewis RJ, Tuck KL, Duggan PJ. Inhibition of N-type calcium ion channels by tricyclic antidepressants - experimental and theoretical justification for their use for neuropathic pain. RSC Med Chem 2022; 13:183-195. [PMID: 35308021 PMCID: PMC8864487 DOI: 10.1039/d1md00331c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/20/2021] [Indexed: 11/21/2022] Open
Abstract
A number of tricyclic antidepressants (TCAs) are commonly prescribed off-label for the treatment of neuropathic pain. The blockade of neuronal calcium ion channels is often invoked to partially explain the analgesic activity of TCAs, but there has been very limited experimental or theoretical evidence reported to support this assertion. The N-type calcium ion channel (CaV2.2) is a well-established target for the treatment of neuropathic pain and in this study a series of eleven TCAs and two closely related drugs were shown to be moderately effective inhibitors of this channel when endogenously expressed in the SH-SY5Y neuroblastoma cell line. A homology model of the channel, which matches closely a recently reported Cryo-EM structure, was used to investigate via docking and molecular dynamics experiments the possible mode of inhibition of CaV2.2 channels by TCAs. Two closely related binding modes, that occur in the channel cavity that exists between the selectivity filter and the internal gate, were identified. The TCAs are predicted to position themselves such that their ammonium side chains interfere with the selectivity filter, with some, such as amitriptyline, also appearing to hinder the channel's ability to open. This study provides the most comprehensive evidence to date that supports the notion that the blockade of neuronal calcium ion channels by TCAs is at least partially responsible for their analgesic effect.
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Affiliation(s)
- Fernanda C Cardoso
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Matthieu Schmit
- School of Chemistry, Monash University Victoria 3800 Australia
- CSIRO Manufacturing Research Way Clayton Victoria 3168 Australia
| | | | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland St Lucia QLD 4072 Australia
| | - Kellie L Tuck
- School of Chemistry, Monash University Victoria 3800 Australia
| | - Peter J Duggan
- CSIRO Manufacturing Research Way Clayton Victoria 3168 Australia
- College of Science and Engineering, Flinders University Adelaide South Australia 5042 Australia
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5
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Computational Analysis of the Crystal and Cryo-EM Structures of P-Loop Channels with Drugs. Int J Mol Sci 2021; 22:ijms22158143. [PMID: 34360907 PMCID: PMC8348670 DOI: 10.3390/ijms22158143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 12/01/2022] Open
Abstract
The superfamily of P-loop channels includes various potassium channels, voltage-gated sodium and calcium channels, transient receptor potential channels, and ionotropic glutamate receptors. Despite huge structural and functional diversity of the channels, their pore-forming domain has a conserved folding. In the past two decades, scores of atomic-scale structures of P-loop channels with medically important drugs in the inner pore have been published. High structural diversity of these complexes complicates the comparative analysis of these structures. Here we 3D-aligned structures of drug-bound P-loop channels, compared their geometric characteristics, and analyzed the energetics of ligand-channel interactions. In the superimposed structures drugs occupy most of the sterically available space in the inner pore and subunit/repeat interfaces. Cationic groups of some drugs occupy vacant binding sites of permeant ions in the inner pore and selectivity-filter region. Various electroneutral drugs, lipids, and detergent molecules are seen in the interfaces between subunits/repeats. In many structures the drugs strongly interact with lipid and detergent molecules, but physiological relevance of such interactions is unclear. Some eukaryotic sodium and calcium channels have state-dependent or drug-induced π-bulges in the inner helices, which would be difficult to predict. The drug-induced π-bulges may represent a novel mechanism of gating modulation.
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6
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Lavinda O, Manga P, Orlow SJ, Cardozo T. Biophysical Compatibility of a Heterotrimeric Tyrosinase-TYRP1-TYRP2 Metalloenzyme Complex. Front Pharmacol 2021; 12:602206. [PMID: 33995009 PMCID: PMC8114058 DOI: 10.3389/fphar.2021.602206] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/08/2021] [Indexed: 11/20/2022] Open
Abstract
Tyrosinase (TYR) is a copper-containing monooxygenase central to the function of melanocytes. Alterations in its expression or activity contribute to variations in skin, hair and eye color, and underlie a variety of pathogenic pigmentary phenotypes, including several forms of oculocutaneous albinism (OCA). Many of these phenotypes are linked to individual missense mutations causing single nucleotide variants and polymorphisms (SNVs) in TYR. We previously showed that two TYR homologues, TYRP1 and TYRP2, modulate TYR activity and stabilize the TYR protein. Accordingly, to investigate whether TYR, TYRP1, and TYRP2 are biophysically compatible with various heterocomplexes, we computationally docked a high-quality 3D model of TYR to the crystal structure of TYRP1 and to a high-quality 3D model of TYRP2. Remarkably, the resulting TYR-TYRP1 heterodimer was complementary in structure and energy with the TYR-TYRP2 heterodimer, with TYRP1 and TYRP2 docking to different adjacent surfaces on TYR that apposed a third realistic protein interface between TYRP1-TYRP2. Hence, the 3D models are compatible with a heterotrimeric TYR-TYRP1-TYRP2 complex. In addition, this heterotrimeric TYR-TYRP1-TYRP2 positioned the C-terminus of each folded enzymatic domain in an ideal position to allow their C-terminal transmembrane helices to form a putative membrane embedded three-helix bundle. Finally, pathogenic TYR mutations causing OCA1A, which also destabilize TYR biochemically, cluster on an unoccupied protein interface at the periphery of the heterotrimeric complex, suggesting that this may be a docking site for OCA2, an anion channel. Pathogenic OCA2 mutations result in similar phenotypes to those produced by OCA1A TYR mutations. While this complex may be difficult to detect in vitro, due to the complex environment of the vertebrate cellular membranous system, our results support the existence of a heterotrimeric complex in melanogenesis.
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Affiliation(s)
- Olga Lavinda
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
| | - Prashiela Manga
- The Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, NY, United States
| | - Seth J Orlow
- The Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, NY, United States
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, United States
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7
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Rangel-Galván M, Rangel A, Romero-Méndez C, Dávila EM, Castro ME, Caballero NA, Meléndez Bustamante FJ, Sanchez-Gaytan BL, Meza U, Perez-Aguilar JM. Inhibitory Mechanism of the Isoflavone Derivative Genistein in the Human Ca V3.3 Channel. ACS Chem Neurosci 2021; 12:651-659. [PMID: 33507062 DOI: 10.1021/acschemneuro.0c00684] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Regulation of cellular excitability and oscillatory behavior of resting membrane potential in nerve cells are largely mediated by the low-voltage activated T-type calcium channels. This calcium channel family is constituted by three isoforms, namely, CaV3.1, CaV3.2, and CaV3.3, that are largely distributed in the nervous system and other parts of the body. Dysfunction of T-type calcium channels is associated with a wide range of pathophysiologies including epilepsy, neuropathic pain, cardiac problems, and major depressive disorders. Due to their pharmacological relevance, finding molecular agents able to modulate the channel's function may provide therapeutic means to ameliorate their related disorders. Here we used electrophysiological experiments to show that genistein, a canonical tyrosine kinase inhibitor, reduces the activity of the human CaV3.3 channel in a concentration-dependent manner. The inhibitory effect of genistein is independent of tyrosine kinase modulation and does not affect the voltage-dependent gating of the channel. Subsequently, we used computational methods to identify plausible molecular poses for the interaction of genistein and the CaV3.3 channel. Starting from different molecular poses, we carried out all-atom molecular dynamics (MD) simulations to identify the interacting determinants for the CaV3.3/genistein complex formation. Our extensive (microsecond-length) simulations suggest specific binding interactions that seem to stabilize the protein/inhibitor complex. Furthermore, our results from the unbiased MD simulations are in good agreement with the recently solved cryoelectron microscopy structure of the CaV3.1/Z944 complex in terms of both the location of the ligand binding site and the role of several equivalent amino acid residues. Proposed interacting complex loci were subsequently tested and corroborated by electrophysiological experiments using another naturally occurring isoflavone derivative, daidzein. Thus, by using a combination of in vitro and in silico techniques, we have identified interacting determinants relevant to the CaV3.3/genistein complex formation and propose that genistein directly blocks the function of the human CaV3.3 channel as a result of such interaction. Specifically, we proposed that a combination of polar interactions involving the three hydroxyl groups of genistein and an aromatic interaction with the fused rings are the main binding interactions in the complex formation. Our results pave the way for the rational development of improved and novel low-voltage activated T-type calcium channel inhibitors.
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Affiliation(s)
- Maricruz Rangel-Galván
- School of Chemical Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - Azahel Rangel
- Coordinación Académica Región Altiplano, Universidad Autónoma de San Luis Potosí, San Luis Potosí 78700, México
| | - Catalina Romero-Méndez
- Departamento de Fisiología y Biofísica, Facultad de Medicina Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, México
| | - Eliud Morales Dávila
- School of Chemical Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - María Eugenia Castro
- Chemistry Center, Science Institute, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - Norma A. Caballero
- School of Biological Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | | | - Brenda L. Sanchez-Gaytan
- Chemistry Center, Science Institute, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - Ulises Meza
- Departamento de Fisiología y Biofísica, Facultad de Medicina Universidad Autónoma de San Luis Potosí, San Luis Potosí 78210, México
| | - Jose Manuel Perez-Aguilar
- School of Chemical Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
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8
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Neumaier F, Schneider T, Albanna W. Ca v2.3 channel function and Zn 2+-induced modulation: potential mechanisms and (patho)physiological relevance. Channels (Austin) 2020; 14:362-379. [PMID: 33079629 PMCID: PMC7583514 DOI: 10.1080/19336950.2020.1829842] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Voltage-gated calcium channels (VGCCs) are critical for Ca2+ influx into all types of excitable cells, but their exact function is still poorly understood. Recent reconstruction of homology models for all human VGCCs at atomic resolution provides the opportunity for a structure-based discussion of VGCC function and novel insights into the mechanisms underlying Ca2+ selective flux through these channels. In the present review, we use these data as a basis to examine the structure, function, and Zn2+-induced modulation of Cav2.3 VGCCs, which mediate native R-type currents and belong to the most enigmatic members of the family. Their unique sensitivity to Zn2+ and the existence of multiple mechanisms of Zn2+ action strongly argue for a role of these channels in the modulatory action of endogenous loosely bound Zn2+, pools of which have been detected in a number of neuronal, endocrine, and reproductive tissues. Following a description of the different mechanisms by which Zn2+ has been shown or is thought to alter the function of these channels, we discuss their potential (patho)physiological relevance, taking into account what is known about the magnitude and function of extracellular Zn2+ signals in different tissues. While still far from complete, the picture that emerges is one where Cav2.3 channel expression parallels the occurrence of loosely bound Zn2+ pools in different tissues and where these channels may serve to translate physiological Zn2+ signals into changes of electrical activity and/or intracellular Ca2+ levels.
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Affiliation(s)
- Felix Neumaier
- Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine, Nuclear Chemistry (INM-5) , Jülich, Germany.,University of Cologne, Faculty of Medicine and University Hospital Cologne, Institute of Radiochemistry and Experimental Molecular Imaging , Cologne, Germany
| | - Toni Schneider
- Institute of Neurophysiology , Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Walid Albanna
- Department of Neurosurgery, RWTH Aachen University , Aachen, Germany
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9
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Vasudevan D, Neuman SD, Yang A, Lough L, Brown B, Bashirullah A, Cardozo T, Ryoo HD. Translational induction of ATF4 during integrated stress response requires noncanonical initiation factors eIF2D and DENR. Nat Commun 2020; 11:4677. [PMID: 32938929 PMCID: PMC7495428 DOI: 10.1038/s41467-020-18453-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 08/17/2020] [Indexed: 01/25/2023] Open
Abstract
The Integrated Stress Response (ISR) helps metazoan cells adapt to cellular stress by limiting the availability of initiator methionyl-tRNA for translation. Such limiting conditions paradoxically stimulate the translation of ATF4 mRNA through a regulatory 5' leader sequence with multiple upstream Open Reading Frames (uORFs), thereby activating stress-responsive gene expression. Here, we report the identification of two critical regulators of such ATF4 induction, the noncanonical initiation factors eIF2D and DENR. Loss of eIF2D and DENR in Drosophila results in increased vulnerability to amino acid deprivation, susceptibility to retinal degeneration caused by endoplasmic reticulum (ER) stress, and developmental defects similar to ATF4 mutants. eIF2D requires its RNA-binding motif for regulation of 5' leader-mediated ATF4 translation. Consistently, eIF2D and DENR deficient human cells show impaired ATF4 protein induction in response to ER stress. Altogether, our findings indicate that eIF2D and DENR are critical mediators of ATF4 translational induction and stress responses in vivo.
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Affiliation(s)
- Deepika Vasudevan
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Sarah D Neuman
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Amy Yang
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Lea Lough
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Brian Brown
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Arash Bashirullah
- Department of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY, 10016, USA.
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10
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Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
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Palmitoylation of the K ATP channel Kir6.2 subunit promotes channel opening by regulating PIP 2 sensitivity. Proc Natl Acad Sci U S A 2020; 117:10593-10602. [PMID: 32332165 DOI: 10.1073/pnas.1918088117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A physiological role for long-chain acyl-CoA esters to activate ATP-sensitive K+ (KATP) channels is well established. Circulating palmitate is transported into cells and converted to palmitoyl-CoA, which is a substrate for palmitoylation. We found that palmitoyl-CoA, but not palmitic acid, activated the channel when applied acutely. We have altered the palmitoylation state by preincubating cells with micromolar concentrations of palmitic acid or by inhibiting protein thioesterases. With acyl-biotin exchange assays we found that Kir6.2, but not sulfonylurea receptor (SUR)1 or SUR2, was palmitoylated. These interventions increased the KATP channel mean patch current, increased the open time, and decreased the apparent sensitivity to ATP without affecting surface expression. Similar data were obtained in transfected cells, rat insulin-secreting INS-1 cells, and isolated cardiac myocytes. Kir6.2ΔC36, expressed without SUR, was also positively regulated by palmitoylation. Mutagenesis of Kir6.2 Cys166 prevented these effects. Clinical variants in KCNJ11 that affect Cys166 had a similar gain-of-function phenotype, but was more pronounced. Molecular modeling studies suggested that palmitoyl-C166 and selected large hydrophobic mutations make direct hydrophobic contact with Kir6.2-bound PIP2 Patch-clamp studies confirmed that palmitoylation of Kir6.2 at Cys166 enhanced the PIP2 sensitivity of the channel. Physiological relevance is suggested since palmitoylation blunted the regulation of KATP channels by α1-adrenoreceptor stimulation. The Cys166 residue is conserved in some other Kir family members (Kir6.1 and Kir3, but not Kir2), which are also subject to regulated palmitoylation, suggesting a general mechanism to control the open state of certain Kir channels.
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Chu Y, Qiu P, Yu R. Centipede Venom Peptides Acting on Ion Channels. Toxins (Basel) 2020; 12:toxins12040230. [PMID: 32260499 PMCID: PMC7232367 DOI: 10.3390/toxins12040230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/30/2020] [Accepted: 04/01/2020] [Indexed: 12/19/2022] Open
Abstract
Centipedes are among the oldest venomous arthropods that use their venom to subdue the prey. The major components of centipede venom are a variety of low-molecular-weight peptide toxins that have evolved to target voltage-gated ion channels to interfere with the central system of prey and produce pain or paralysis for efficient hunting. Peptide toxins usually contain several intramolecular disulfide bonds, which confer chemical, thermal and biological stability. In addition, centipede peptides generally have novel structures and high potency and specificity and therefore hold great promise both as diagnostic tools and in the treatment of human disease. Here, we review the centipede peptide toxins with reported effects on ion channels, including Nav, Kv, Cav and the nonselective cation channel polymodal transient receptor potential vanilloid 1 (TRPV1).
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Affiliation(s)
- YanYan Chu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Marine Biomedical Research Institute of Qingdao, Qingdao 266071, China
- Correspondence: (Y.C.); (R.Y.)
| | - PeiJu Qiu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Marine Biomedical Research Institute of Qingdao, Qingdao 266071, China
| | - RiLei Yu
- School of Medicine and Pharmacy, Ocean University of China, 5 Yushan Road, Qingdao 266003, China;
- Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Innovation Center for Marine Drug Screening & Evaluation, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266003, China
- Correspondence: (Y.C.); (R.Y.)
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Tarnovskaya SI, Korkosh VS, Zhorov BS, Frishman D. Predicting novel disease mutations in the cardiac sodium channel. Biochem Biophys Res Commun 2020; 521:603-611. [DOI: 10.1016/j.bbrc.2019.10.142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 10/20/2019] [Indexed: 12/22/2022]
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14
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Tikhonov DB, Zhorov BS. Intersegment contacts determine geometry of the open and closed states in P-loop channels. J Biomol Struct Dyn 2019; 38:1012-1027. [DOI: 10.1080/07391102.2019.1592026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Denis B. Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Boris S. Zhorov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russian Federation
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
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Atomistic modeling and molecular dynamics analysis of human Ca V1.2 channel using external electric field and ion pulling simulations. Biochim Biophys Acta Gen Subj 2019; 1863:1116-1126. [PMID: 30978379 DOI: 10.1016/j.bbagen.2019.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 03/19/2019] [Accepted: 04/08/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Human CaV1.2 (hCav1.2), a calcium selective voltage-gated channel, plays important roles in normal cardiac and neuronal functions. Calcium influx and gating mechanisms leading to the activation of hCaV1.2 are critical for its functionalities. Lack of an experimentally resolved structure of hCaV1.2 remains a significant impediment in molecular-level understanding of this channel. This work focuses on building atomistic hCaV1.2 model and studying calcium influx using computational approaches. METHODS We employed homology modeling and molecular dynamics (MD) to build the structure of hCaV1.2. Subsequently, we employed steered molecular dynamics (SMD) to understand calcium ion permeation in hCaV1.2. RESULTS We report a comprehensive three-dimensional model of a closed state hCaV1.2 refined under physiological membrane-bound conditions using MD simulations. Our SMD simulations on the model revealed four important barriers for ion permeation: this includes three calcium binding sites formed by the EEEE- and TTTT- rings within the selectivity filter region and a large barrier rendered by the hydrophobic internal gate. Our results also revealed that the first hydration shell of calcium remained intact throughout the simulations, thus playing an important role in ion permeation in hCaV1.2. CONCLUSIONS Our results have provided some important mechanistic insights into the structure, dynamics and ion permeation in hCaV1.2. The significant barriers for ion permeation formed by the four phenylalanine residues at the internal gate region suggest that this site is important for channel activation.
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Nastou KC, Batskinis MA, Litou ZI, Hamodrakas SJ, Iconomidou VA. Analysis of Single-Nucleotide Polymorphisms in Human Voltage-Gated Ion Channels. J Proteome Res 2019; 18:2310-2320. [DOI: 10.1021/acs.jproteome.9b00121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katerina C. Nastou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Michail A. Batskinis
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Zoi I. Litou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Stavros J. Hamodrakas
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
| | - Vassiliki A. Iconomidou
- Section of Cell Biology and Biophysics, Department of Biology, School of Sciences, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15701, Greece
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