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Mich JK, Ryu J, Wei AD, Gore BB, Guo R, Bard AM, Martinez RA, Bishaw Y, Luber E, Oliveira Santos LM, Miranda N, Ramirez JM, Ting JT, Lein ES, Levi BP, Kalume FK. AAV-mediated interneuron-specific gene replacement for Dravet syndrome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571820. [PMID: 38168178 PMCID: PMC10760176 DOI: 10.1101/2023.12.15.571820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Dravet syndrome (DS) is a devastating developmental epileptic encephalopathy marked by treatment-resistant seizures, developmental delay, intellectual disability, motor deficits, and a 10-20% rate of premature death. Most DS patients harbor loss-of-function mutations in one copy of SCN1A , which has been associated with inhibitory neuron dysfunction. Here we developed an interneuron-targeting AAV human SCN1A gene replacement therapy using cell class-specific enhancers. We generated a split-intein fusion form of SCN1A to circumvent AAV packaging limitations and deliver SCN1A via a dual vector approach using cell class-specific enhancers. These constructs produced full-length Na V 1.1 protein and functional sodium channels in HEK293 cells and in brain cells in vivo . After packaging these vectors into enhancer-AAVs and administering to mice, immunohistochemical analyses showed telencephalic GABAergic interneuron-specific and dose-dependent transgene biodistribution. These vectors conferred strong dose-dependent protection against postnatal mortality and seizures in two DS mouse models carrying independent loss-of-function alleles of Scn1a, at two independent research sites, supporting the robustness of this approach. No mortality or toxicity was observed in wild-type mice injected with single vectors expressing either the N-terminal or C-terminal halves of SCN1A , or the dual vector system targeting interneurons. In contrast, nonselective neuronal targeting of SCN1A conferred less rescue against mortality and presented substantial preweaning lethality. These findings demonstrate proof-of-concept that interneuron-specific AAV-mediated SCN1A gene replacement is sufficient for significant rescue in DS mouse models and suggest it could be an effective therapeutic approach for patients with DS.
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2
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Kuo CWS, Dobi S, Gök C, Da Silva Costa A, Main A, Robertson-Gray O, Baptista-Hon D, Wypijewski KJ, Costello H, Hales TG, MacQuaide N, Smith GL, Fuller W. Palmitoylation of the pore-forming subunit of Ca(v)1.2 controls channel voltage sensitivity and calcium transients in cardiac myocytes. Proc Natl Acad Sci U S A 2023; 120:e2207887120. [PMID: 36745790 PMCID: PMC9963536 DOI: 10.1073/pnas.2207887120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 12/07/2022] [Indexed: 02/08/2023] Open
Abstract
Mammalian voltage-activated L-type Ca2+ channels, such as Ca(v)1.2, control transmembrane Ca2+ fluxes in numerous excitable tissues. Here, we report that the pore-forming α1C subunit of Ca(v)1.2 is reversibly palmitoylated in rat, rabbit, and human ventricular myocytes. We map the palmitoylation sites to two regions of the channel: The N terminus and the linker between domains I and II. Whole-cell voltage clamping revealed a rightward shift of the Ca(v)1.2 current-voltage relationship when α1C was not palmitoylated. To examine function, we expressed dihydropyridine-resistant α1C in human induced pluripotent stem cell-derived cardiomyocytes and measured Ca2+ transients in the presence of nifedipine to block the endogenous channels. The transients generated by unpalmitoylatable channels displayed a similar activation time course but significantly reduced amplitude compared to those generated by wild-type channels. We thus conclude that palmitoylation controls the voltage sensitivity of Ca(v)1.2. Given that the identified Ca(v)1.2 palmitoylation sites are also conserved in most Ca(v)1 isoforms, we propose that palmitoylation of the pore-forming α1C subunit provides a means to regulate the voltage sensitivity of voltage-activated Ca2+ channels in excitable cells.
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Affiliation(s)
- Chien-Wen S. Kuo
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Sara Dobi
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Caglar Gök
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Ana Da Silva Costa
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Alice Main
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Olivia Robertson-Gray
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Daniel Baptista-Hon
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
- Center for Biomedicine and Innovations, Faculty of Medicine, Macau University of Science and Technology, Macau SAR, 999078China
| | | | - Hannah Costello
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Tim G. Hales
- Division of Systems Medicine, Institute of Academic Anaesthesia, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Niall MacQuaide
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - Godfrey L. Smith
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
| | - William Fuller
- School of Cardiovascular and Metabolic Health, University of Glasgow, GlasgowG12 8QQ, UK
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3
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Abstract
KCNQ2 and KCNQ3 channels are associated with multiple neurodevelopmental disorders and are also therapeutic targets for neurological and neuropsychiatric diseases. For more than two decades, it has been thought that most KCNQ channels in the brain are either KCNQ2/3 or KCNQ3/5 heteromers. Here, we investigated the potential heteromeric compositions of KCNQ2-containing channels. We applied split-intein protein trans-splicing to form KCNQ2/5 tandems and coexpressed these with and without KCNQ3. Unexpectedly, we found that KCNQ2/5 tandems form functional channels independent of KCNQ3 in heterologous cells. Using mass spectrometry, we went on to demonstrate that KCNQ2 associates with KCNQ5 in native channels in the brain, even in the absence of KCNQ3. Additionally, our functional heterologous expression data are consistent with the formation of KCNQ2/3/5 heteromers. Thus, the composition of KCNQ channels is more diverse than has been previously recognized, necessitating a re-examination of the genotype/phenotype relationship of KCNQ2 pathogenic variants.
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4
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Macrophage-Dependent Interleukin-6-Production and Inhibition of IK Contributes to Acquired QT Prolongation in Lipotoxic Guinea Pig Heart. Int J Mol Sci 2021; 22:ijms222011249. [PMID: 34681909 PMCID: PMC8537919 DOI: 10.3390/ijms222011249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/08/2021] [Accepted: 10/16/2021] [Indexed: 11/17/2022] Open
Abstract
In the heart, the delayed rectifier K current, IK, composed of the rapid (IKr) and slow (IKs) components contributes prominently to normal cardiac repolarization. In lipotoxicity, chronic elevation of pro-inflammatory cytokines may remodel IK, elevating the risk for ventricular arrythmias and sudden cardiac death. We investigated whether and how the pro-inflammatory interleukin-6 altered IK in the heart, using electrophysiology to evaluate changes in IK in adult guinea pig ventricular myocytes. We found that palmitic acid (a potent inducer of lipotoxicity), induced a rapid (~24 h) and significant increase in IL-6 in RAW264.7 cells. PA-diet fed guinea pigs displayed a severely prolonged QT interval when compared to low-fat diet fed controls. Exposure to isoproterenol induced torsade de pointes, and ventricular fibrillation in lipotoxic guinea pigs. Pre-exposure to IL-6 with the soluble IL-6 receptor produced a profound depression of IKr and IKs densities, prolonged action potential duration, and impaired mitochondrial ATP production. Only with the inhibition of IKr did a proarrhythmic phenotype of IKs depression emerge, manifested as a further prolongation of action potential duration and QT interval. Our data offer unique mechanistic insights with implications for pathological QT interval in patients and vulnerability to fatal arrhythmias.
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5
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Koschak A, Fernandez-Quintero ML, Heigl T, Ruzza M, Seitter H, Zanetti L. Cav1.4 dysfunction and congenital stationary night blindness type 2. Pflugers Arch 2021; 473:1437-1454. [PMID: 34212239 PMCID: PMC8370969 DOI: 10.1007/s00424-021-02570-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/14/2021] [Accepted: 04/18/2021] [Indexed: 12/04/2022]
Abstract
Cav1.4 L-type Ca2+ channels are predominantly expressed in retinal neurons, particularly at the photoreceptor terminals where they mediate sustained Ca2+ entry needed for continuous neurotransmitter release at their ribbon synapses. Cav1.4 channel gating properties are controlled by accessory subunits, associated regulatory proteins, and also alternative splicing. In humans, mutations in the CACNA1F gene encoding for Cav1.4 channels are associated with X-linked retinal disorders such as congenital stationary night blindness type 2. Mutations in the Cav1.4 protein result in a spectrum of altered functional channel activity. Several mouse models broadened our understanding of the role of Cav1.4 channels not only as Ca2+ source at retinal synapses but also as synaptic organizers. In this review, we highlight different structural and functional phenotypes of Cav1.4 mutations that might also occur in patients with congenital stationary night blindness type 2. A further important yet mostly neglected aspect that we discuss is the influence of alternative splicing on channel dysfunction. We conclude that currently available functional phenotyping strategies should be refined and summarize potential specific therapeutic options for patients carrying Cav1.4 mutations. Importantly, the development of new therapeutic approaches will permit a deeper understanding of not only the disease pathophysiology but also the physiological function of Cav1.4 channels in the retina.
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MESH Headings
- 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology
- Animals
- Calcium Channel Agonists/pharmacology
- Calcium Channels, L-Type/genetics
- Calcium Channels, L-Type/metabolism
- Eye Diseases, Hereditary/genetics
- Eye Diseases, Hereditary/metabolism
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- Humans
- Mutation/physiology
- Myopia/genetics
- Myopia/metabolism
- Night Blindness/genetics
- Night Blindness/metabolism
- Retina/drug effects
- Retina/metabolism
- Synapses/drug effects
- Synapses/genetics
- Synapses/metabolism
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Affiliation(s)
- Alexandra Koschak
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria.
| | - Monica L Fernandez-Quintero
- Institute of General, Inorganic and Theoretical Chemistry, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Thomas Heigl
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Marco Ruzza
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Hartwig Seitter
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
| | - Lucia Zanetti
- Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, University of Innsbruck, Innrain 80-82/III, 6020, Innsbruck, Austria
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6
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Sarkar D, Harms H, Galleano I, Sheikh ZP, Pless SA. Ion channel engineering using protein trans-splicing. Methods Enzymol 2021; 654:19-48. [PMID: 34120713 DOI: 10.1016/bs.mie.2021.01.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Conventional site-directed mutagenesis and genetic code expansion approaches have been instrumental in providing detailed functional and pharmacological insight into membrane proteins such as ion channels. Recently, this has increasingly been complemented by semi-synthetic strategies, in which part of the protein is generated synthetically. This means a vast range of chemical modifications, including non-canonical amino acids (ncAA), backbone modifications, chemical handles, fluorescent or spectroscopic labels and any combination of these can be incorporated. Among these approaches, protein trans-splicing (PTS) is particularly promising for protein reconstitution in live cells. It relies on one or more split inteins, which can spontaneously and covalently link flanking peptide or protein sequences. Here, we describe the use of PTS and its variant tandem PTS (tPTS) in semi-synthesis of ion channels in Xenopus laevis oocytes to incorporate ncAAs, post-translational modifications or metabolically stable mimics thereof. This strategy has the potential to expand the type and number of modifications in ion channel research.
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Affiliation(s)
- Debayan Sarkar
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hendrik Harms
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Iacopo Galleano
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Zeshan Pervez Sheikh
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
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7
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Inteins in Science: Evolution to Application. Microorganisms 2020; 8:microorganisms8122004. [PMID: 33339089 PMCID: PMC7765530 DOI: 10.3390/microorganisms8122004] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022] Open
Abstract
Inteins are mobile genetic elements that apply standard enzymatic strategies to excise themselves post-translationally from the precursor protein via protein splicing. Since their discovery in the 1990s, recent advances in intein technology allow for them to be implemented as a modern biotechnological contrivance. Radical improvement in the structure and catalytic framework of cis- and trans-splicing inteins devised the development of engineered inteins that contribute to various efficient downstream techniques. Previous literature indicates that implementation of intein-mediated splicing has been extended to in vivo systems. Besides, the homing endonuclease domain also acts as a versatile biotechnological tool involving genetic manipulation and control of monogenic diseases. This review orients the understanding of inteins by sequentially studying the distribution and evolution pattern of intein, thereby highlighting a role in genetic mobility. Further, we include an in-depth summary of specific applications branching from protein purification using self-cleaving tags to protein modification, post-translational processing and labelling, followed by the development of intein-based biosensors. These engineered inteins offer a disruptive approach towards research avenues like biomaterial construction, metabolic engineering and synthetic biology. Therefore, this linear perspective allows for a more comprehensive understanding of intein function and its diverse applications.
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8
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Braun N, Sheikh ZP, Pless SA. The current chemical biology tool box for studying ion channels. J Physiol 2020; 598:4455-4471. [DOI: 10.1113/jp276695] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 07/06/2020] [Indexed: 12/13/2022] Open
Affiliation(s)
- N. Braun
- Department of Drug Design and Pharmacology University of Copenhagen Jagtvej 160 Copenhagen 2100 Denmark
| | - Z. P. Sheikh
- Department of Drug Design and Pharmacology University of Copenhagen Jagtvej 160 Copenhagen 2100 Denmark
| | - S. A. Pless
- Department of Drug Design and Pharmacology University of Copenhagen Jagtvej 160 Copenhagen 2100 Denmark
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9
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Tornabene P, Trapani I, Minopoli R, Centrulo M, Lupo M, de Simone S, Tiberi P, Dell'Aquila F, Marrocco E, Iodice C, Iuliano A, Gesualdo C, Rossi S, Giaquinto L, Albert S, Hoyng CB, Polishchuk E, Cremers FPM, Surace EM, Simonelli F, De Matteis MA, Polishchuk R, Auricchio A. Intein-mediated protein trans-splicing expands adeno-associated virus transfer capacity in the retina. Sci Transl Med 2020; 11:11/492/eaav4523. [PMID: 31092694 DOI: 10.1126/scitranslmed.aav4523] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/21/2018] [Accepted: 04/04/2019] [Indexed: 12/26/2022]
Abstract
Retinal gene therapy with adeno-associated viral (AAV) vectors holds promises for treating inherited and noninherited diseases of the eye. Although clinical data suggest that retinal gene therapy is safe and effective, delivery of large genes is hindered by the limited AAV cargo capacity. Protein trans-splicing mediated by split inteins is used by single-cell organisms to reconstitute proteins. Here, we show that delivery of multiple AAV vectors each encoding one of the fragments of target proteins flanked by short split inteins results in protein trans-splicing and full-length protein reconstitution in the retina of mice and pigs and in human retinal organoids. The reconstitution of large therapeutic proteins using this approach improved the phenotype of two mouse models of inherited retinal diseases. Our data support the use of split intein-mediated protein trans-splicing in combination with AAV subretinal delivery for gene therapy of inherited blindness due to mutations in large genes.
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Affiliation(s)
- Patrizia Tornabene
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Ivana Trapani
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Medical Genetics, Department of Translational Medicine, Federico II University, 80131 Naples, Italy
| | - Renato Minopoli
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Miriam Centrulo
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Mariangela Lupo
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Sonia de Simone
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Paola Tiberi
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Fabio Dell'Aquila
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Elena Marrocco
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Carolina Iodice
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Antonella Iuliano
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Carlo Gesualdo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania L. Vanvitelli, 80131 Naples, Italy
| | - Settimio Rossi
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania L. Vanvitelli, 80131 Naples, Italy
| | - Laura Giaquinto
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Silvia Albert
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Frans P M Cremers
- Department of Ophthalmology and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 Nijmegen, Netherlands
| | - Enrico M Surace
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Medical Genetics, Department of Translational Medicine, Federico II University, 80131 Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania L. Vanvitelli, 80131 Naples, Italy
| | - Maria A De Matteis
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy.,Department of Molecular Medicine and Medical Biotechnology, Federico II University, 80131 Naples, Italy
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Alberto Auricchio
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy. .,Department of Advanced Biomedicine, Federico II University, 80131 Naples, Italy
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10
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Khoo KK, Galleano I, Gasparri F, Wieneke R, Harms H, Poulsen MH, Chua HC, Wulf M, Tampé R, Pless SA. Chemical modification of proteins by insertion of synthetic peptides using tandem protein trans-splicing. Nat Commun 2020; 11:2284. [PMID: 32385250 PMCID: PMC7210297 DOI: 10.1038/s41467-020-16208-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/20/2020] [Indexed: 12/20/2022] Open
Abstract
Manipulation of proteins by chemical modification is a powerful way to decipher their function. However, most ribosome-dependent and semi-synthetic methods have limitations in the number and type of modifications that can be introduced, especially in live cells. Here, we present an approach to incorporate single or multiple post-translational modifications or non-canonical amino acids into proteins expressed in eukaryotic cells. We insert synthetic peptides into GFP, NaV1.5 and P2X2 receptors via tandem protein trans-splicing using two orthogonal split intein pairs and validate our approach by investigating protein function. We anticipate the approach will overcome some drawbacks of existing protein enigineering methods.
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Affiliation(s)
- K K Khoo
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - I Galleano
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - F Gasparri
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - R Wieneke
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Strasse 9, 60438, Frankfurt/Main, Germany
| | - H Harms
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - M H Poulsen
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - H C Chua
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - M Wulf
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark
| | - R Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Strasse 9, 60438, Frankfurt/Main, Germany
| | - S A Pless
- Department of Drug Design and Pharmacology, University of Copenhagen, Jagtvej 160, 2100, Copenhagen, Denmark.
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11
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Pathophysiology of Calcium Mediated Ventricular Arrhythmias and Novel Therapeutic Options with Focus on Gene Therapy. Int J Mol Sci 2019; 20:ijms20215304. [PMID: 31653119 PMCID: PMC6862059 DOI: 10.3390/ijms20215304] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/16/2019] [Accepted: 10/21/2019] [Indexed: 12/19/2022] Open
Abstract
Cardiac arrhythmias constitute a major health problem with a huge impact on mortality rates and health care costs. Despite ongoing research efforts, the understanding of the molecular mechanisms and processes responsible for arrhythmogenesis remains incomplete. Given the crucial role of Ca2+-handling in action potential generation and cardiac contraction, Ca2+ channels and Ca2+ handling proteins represent promising targets for suppression of ventricular arrhythmias. Accordingly, we report the different roles of Ca2+-handling in the development of congenital as well as acquired ventricular arrhythmia syndromes. We highlight the therapeutic potential of gene therapy as a novel and innovative approach for future arrhythmia therapy. Furthermore, we discuss various promising cellular and mitochondrial targets for therapeutic gene transfer currently under investigation.
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12
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Kushner J, Ferrer X, Marx SO. Roles and Regulation of Voltage-gated Calcium Channels in Arrhythmias. J Innov Card Rhythm Manag 2019; 10:3874-3880. [PMID: 32494407 PMCID: PMC7252866 DOI: 10.19102/icrm.2019.101006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 03/04/2019] [Indexed: 12/25/2022] Open
Abstract
Calcium flowing through voltage-dependent calcium channels into cardiomyocytes mediates excitation–contraction coupling, controls action-potential duration and automaticity in nodal cells, and regulates gene expression. Proper surface targeting and basal and hormonal regulation of calcium channels are vital for normal cardiac physiology. In this review, we discuss the roles of voltage-gated calcium channels in the heart and the mechanisms by which these channels are regulated by physiological signaling pathways in health and disease.
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Affiliation(s)
- Jared Kushner
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Xavier Ferrer
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
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13
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Morgenstern TJ, Park J, Fan QR, Colecraft HM. A potent voltage-gated calcium channel inhibitor engineered from a nanobody targeted to auxiliary Ca Vβ subunits. eLife 2019; 8:49253. [PMID: 31403402 PMCID: PMC6701945 DOI: 10.7554/elife.49253] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 08/10/2019] [Indexed: 12/15/2022] Open
Abstract
Inhibiting high-voltage-activated calcium channels (HVACCs; CaV1/CaV2) is therapeutic for myriad cardiovascular and neurological diseases. For particular applications, genetically-encoded HVACC blockers may enable channel inhibition with greater tissue-specificity and versatility than is achievable with small molecules. Here, we engineered a genetically-encoded HVACC inhibitor by first isolating an immunized llama nanobody (nb.F3) that binds auxiliary HVACC CaVβ subunits. Nb.F3 by itself is functionally inert, providing a convenient vehicle to target active moieties to CaVβ-associated channels. Nb.F3 fused to the catalytic HECT domain of Nedd4L (CaV-aβlator), an E3 ubiquitin ligase, ablated currents from diverse HVACCs reconstituted in HEK293 cells, and from endogenous CaV1/CaV2 channels in mammalian cardiomyocytes, dorsal root ganglion neurons, and pancreatic β cells. In cardiomyocytes, CaV-aβlator redistributed CaV1.2 channels from dyads to Rab-7-positive late endosomes. This work introduces CaV-aβlator as a potent genetically-encoded HVACC inhibitor, and describes a general approach that can be broadly adapted to generate versatile modulators for macro-molecular membrane protein complexes.
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Affiliation(s)
- Travis J Morgenstern
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Jinseo Park
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Qing R Fan
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Henry M Colecraft
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States.,Department of Physiology and Cellular Biophysics, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
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14
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Sutherland AR, Alam MK, Geyer CR. Post‐translational Assembly of Protein Parts into Complex Devices by Using SpyTag/SpyCatcher Protein Ligase. Chembiochem 2018; 20:319-328. [DOI: 10.1002/cbic.201800538] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Ashley R. Sutherland
- Department of BiochemistryUniversity of Saskatchewan Saskatoon SK S7N 5E5 Canada
| | - Md. Kausar Alam
- Donnelly Centre for Cellular and Biomolecular ResearchUniversity of Toronto Toronto ON M5S3E1 Canada
| | - C. Ronald Geyer
- Department of Pathology and Laboratory MedicineUniversity of Saskatchewan Saskatoon SK S7N 5E5 Canada
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15
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Engineering selectivity into RGK GTPase inhibition of voltage-dependent calcium channels. Proc Natl Acad Sci U S A 2018; 115:12051-12056. [PMID: 30397133 PMCID: PMC6255209 DOI: 10.1073/pnas.1811024115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetically encoded inhibitors for voltage-dependent Ca2+ (CaV) channels (GECCIs) are useful research tools and potential therapeutics. Rad/Rem/Rem2/Gem (RGK) proteins are Ras-like G proteins that potently inhibit high voltage-activated (HVA) Ca2+ (CaV1/CaV2 family) channels, but their nonselectivity limits their potential applications. We hypothesized that nonselectivity of RGK inhibition derives from their binding to auxiliary CaVβ-subunits. To investigate latent CaVβ-independent components of inhibition, we coexpressed each RGK individually with CaV1 (CaV1.2/CaV1.3) or CaV2 (CaV2.1/CaV2.2) channels reconstituted in HEK293 cells with either wild-type (WT) β2a or a mutant version (β2a,TM) that does not bind RGKs. All four RGKs strongly inhibited CaV1/CaV2 channels reconstituted with WT β2a By contrast, when channels were reconstituted with β2a,TM, Rem inhibited only CaV1.2, Rad selectively inhibited CaV1.2 and CaV2.2, while Gem and Rem2 were ineffective. We generated mutant RGKs (Rem[R200A/L227A] and Rad[R208A/L235A]) unable to bind WT CaVβ, as confirmed by fluorescence resonance energy transfer. Rem[R200A/L227A] selectively blocked reconstituted CaV1.2 while Rad[R208A/L235A] inhibited CaV1.2/CaV2.2 but not CaV1.3/CaV2.1. Rem[R200A/L227A] and Rad[R208A/L235A] both suppressed endogenous CaV1.2 channels in ventricular cardiomyocytes and selectively blocked 25 and 62%, respectively, of HVA currents in somatosensory neurons of the dorsal root ganglion, corresponding to their distinctive selectivity for CaV1.2 and CaV1.2/CaV2.2 channels. Thus, we have exploited latent β-binding-independent Rem and Rad inhibition of specific CaV1/CaV2 channels to develop selective GECCIs with properties unmatched by current small-molecule CaV channel blockers.
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16
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Woon MT, Long PA, Reilly L, Evans JM, Keefe AM, Lea MR, Beglinger CJ, Balijepalli RC, Lee Y, Olson TM, Kamp TJ. Pediatric Dilated Cardiomyopathy-Associated LRRC10 (Leucine-Rich Repeat-Containing 10) Variant Reveals LRRC10 as an Auxiliary Subunit of Cardiac L-Type Ca 2+ Channels. J Am Heart Assoc 2018; 7:e006428. [PMID: 29431102 PMCID: PMC5850229 DOI: 10.1161/jaha.117.006428] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Accepted: 11/10/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Genetic causes of dilated cardiomyopathy (DCM) are incompletely understood. LRRC10 (leucine-rich repeat-containing 10) is a cardiac-specific protein of unknown function. Heterozygous mutations in LRRC10 have been suggested to cause DCM, and deletion of Lrrc10 in mice results in DCM. METHODS AND RESULTS Whole-exome sequencing was carried out on a patient who presented at 6 weeks of age with DCM and her unaffected parents, filtering for rare, deleterious, recessive, and de novo variants. Whole-exome sequencing followed by trio-based filtering identified a homozygous recessive variant in LRRC10, I195T. Coexpression of I195T LRRC10 with the L-type Ca2+ channel (Cav1.2, β2CN2, and α2δ subunits) in HEK293 cells resulted in a significant ≈0.5-fold decrease in ICa,L at 0 mV, in contrast to the ≈1.4-fold increase in ICa,L by coexpression of LRRC10 (n=9-12, P<0.05). Coexpression of LRRC10 or I195T LRRC10 did not alter the surface membrane expression of Cav1.2. LRRC10 coexpression with Cav1.2 in the absence of auxiliary β2CN2 and α2δ subunits revealed coassociation of Cav1.2 and LRRC10 and a hyperpolarizing shift in the voltage dependence of activation (n=6-9, P<0.05). Ventricular myocytes from Lrrc10-/- mice had significantly smaller ICa,L, and coimmunoprecipitation experiments confirmed association between LRRC10 and the Cav1.2 subunit in mouse hearts. CONCLUSIONS Examination of a patient with DCM revealed homozygosity for a previously unreported LRRC10 variant: I195T. Wild-type and I195T LRRC10 function as cardiac-specific subunits of L-type Ca2+ channels and exert dramatically different effects on channel gating, providing a potential link to DCM.
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Affiliation(s)
- Marites T Woon
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Pamela A Long
- Mayo Graduate School, Molecular Pharmacology and Experimental Therapeutics Track, Mayo Clinic, Rochester, MN
| | - Louise Reilly
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Jared M Evans
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | - Alexis M Keefe
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Martin R Lea
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Carl J Beglinger
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Ravi C Balijepalli
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
| | - Youngsook Lee
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
| | - Timothy M Olson
- Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN
| | - Timothy J Kamp
- Cellular and Molecular Arrhythmia Research Program, University of Wisconsin-Madison, Madison, WI
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI
- Department of Medicine, University of Wisconsin-Madison, Madison, WI
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17
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Kanner SA, Morgenstern T, Colecraft HM. Sculpting ion channel functional expression with engineered ubiquitin ligases. eLife 2017; 6:29744. [PMID: 29256394 PMCID: PMC5764571 DOI: 10.7554/elife.29744] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 12/13/2017] [Indexed: 12/18/2022] Open
Abstract
The functional repertoire of surface ion channels is sustained by dynamic processes of trafficking, sorting, and degradation. Dysregulation of these processes underlies diverse ion channelopathies including cardiac arrhythmias and cystic fibrosis. Ubiquitination powerfully regulates multiple steps in the channel lifecycle, yet basic mechanistic understanding is confounded by promiscuity among E3 ligase/substrate interactions and ubiquitin code complexity. Here we targeted the catalytic domain of E3 ligase, CHIP, to YFP-tagged KCNQ1 ± KCNE1 subunits with a GFP-nanobody to selectively manipulate this channel complex in heterologous cells and adult rat cardiomyocytes. Engineered CHIP enhanced KCNQ1 ubiquitination, eliminated KCNQ1 surface-density, and abolished reconstituted K+ currents without affecting protein expression. A chemo-genetic variation enabling chemical control of ubiquitination revealed KCNQ1 surface-density declined with a ~ 3.5 hr t1/2 by impaired forward trafficking. The results illustrate utility of engineered E3 ligases to elucidate mechanisms underlying ubiquitin regulation of membrane proteins, and to achieve effective post-translational functional knockdown of ion channels. Cells are surrounded by a membrane that separates the outside of the cell from its inside. Proteins called ion channels are embedded within this membrane and allow charged ions to move in and out of the cell. The movement of ions generates electrical currents that are essential for many processes that keep us alive, including our heartbeat and the activity within our brain. Like many other proteins, newly made ion channels undergo several steps before they mature and become active. Cells destroy any proteins that do not mature properly, as well as those that become damaged or are simply no longer needed. A small protein called ubiquitin helps to mark such unwanted proteins for destruction. Enzymes known as E3 ligases attach ubiquitin to target proteins in a process known as ubiquitination. This process regulates both the quality and amount of proteins within cells. To understand the role of a particular protein, it is often necessary to remove it from the cell and then examine the consequences. In the past, researchers have harnessed the ubiquitin system to remove many kinds of proteins, but this approach had not previously been used to target an ion channel. Now, Kanner et al. set out to selectively eliminate ion channels via targeted ubiquitination. The experiments showed that previous approaches that could destroy proteins within the cell were not effective against ion channels. Kanner et al. then engineered a particular E3 ligase so that it could selectively attach ubiquitin to the desired ion channels. This approach successfully prevented the channels from reaching the cell membrane, thereby silencing the electrical currents that they normally generate. Additionally, a new tool was developed to stop ion channels in their tracks, essentially with a flip of a chemical switch. Kanner et al. then used this approach to manipulate ion channels in a highly controlled manner, within their normal environment of heart muscle cells. These new approaches form a toolset that scientists can now exploit to study diverse ion channels. In the future, the toolkit could potentially be used to develop treatments for disorders such as epilepsy, chronic pain, and irregular heartbeats, where too many channels are active or present at the cell membrane.
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Affiliation(s)
- Scott A Kanner
- Doctoral Program in Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, United States
| | - Travis Morgenstern
- Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, United States
| | - Henry M Colecraft
- Doctoral Program in Neurobiology and Behavior, Columbia University College of Physicians and Surgeons, New York, United States.,Department of Pharmacology, Columbia University College of Physicians and Surgeons, New York, United States.,Department of Physiology and Cellular Biophysics, Columbia University College of Physicians and Surgeons, New York, United States
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18
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Moll JM, Wehmöller M, Frank NC, Homey L, Baran P, Garbers C, Lamertz L, Axelrod JH, Galun E, Mootz HD, Scheller J. Split 2 Protein-Ligation Generates Active IL-6-Type Hyper-Cytokines from Inactive Precursors. ACS Synth Biol 2017; 6:2260-2272. [PMID: 29136368 DOI: 10.1021/acssynbio.7b00208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Trans-signaling of the major pro- and anti-inflammatory cytokines Interleukin (IL)-6 and IL-11 has the unique feature to virtually activate all cells of the body and is critically involved in chronic inflammation and regeneration. Hyper-IL-6 and Hyper-IL-11 are single chain designer trans-signaling cytokines, in which the cytokine and soluble receptor units are trapped in one complex via a flexible peptide linker. Albeit, Hyper-cytokines are essential tools to study trans-signaling in vitro and in vivo, the superior potency of these designer cytokines are accompanied by undesirable stress responses. To enable tailor-made generation of Hyper-cytokines, we developed inactive split-cytokine-precursors adapted for posttranslational reassembly by split-intein mediated protein trans-splicing (PTS). We identified cutting sites within IL-6 (E134/S135) and IL-11 (G116/S117) and obtained inactive split-Hyper-IL-6 and split-Hyper-IL-11 cytokine precursors. After fusion with split-inteins, PTS resulted in reconstitution of active Hyper-cytokines, which were efficiently secreted from transfected cells. Our strategy comprises the development of a background-free cytokine signaling system from reversibly inactivated precursor cytokines.
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Affiliation(s)
- Jens M. Moll
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Melanie Wehmöller
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Nils C. Frank
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Lisa Homey
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Paul Baran
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | | | - Larissa Lamertz
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Jonathan H. Axelrod
- Goldyne
Savad Institute of Gene Therapy, Hadassah Medical Organization, 91120 Jerusalem, Israel
| | - Eithan Galun
- Goldyne
Savad Institute of Gene Therapy, Hadassah Medical Organization, 91120 Jerusalem, Israel
| | - Henning D. Mootz
- Department
Chemistry and Pharmacy, Institute of Biochemistry, University of Muenster, 48149 Münster, Germany
| | - Jürgen Scheller
- Institute
of Biochemistry and Molecular Biology II, Heinrich-Heine University, 40225 Düsseldorf, Germany
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19
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Efficient generation of bispecific IgG antibodies by split intein mediated protein trans-splicing system. Sci Rep 2017; 7:8360. [PMID: 28827777 PMCID: PMC5567192 DOI: 10.1038/s41598-017-08641-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/03/2017] [Indexed: 12/19/2022] Open
Abstract
Many methods have been developed to produce bispecific antibodies (BsAbs) for industrial application. However, huge challenges still remain in synthesizing whole length BsAbs, including their assembly, stability, immunogenicity, and pharmacodynamics. Here we present for first time a generic technology platform of generating bispecific IgG antibodies, “Bispecific Antibody by Protein Trans-splicing (BAPTS)”. Different from published methods, we assembled two parental antibody fragments in the hinge region by the protein trans-splicing reaction of a split intein to generate BsAbs without heavy/heavy and light/heavy chain mispairing. Utilizing this simple and efficient approach, there have been several BsAbs (CD3×HER2, CD3×EGFR, EGFR×HER2) synthesized to demonstrate its broad applicability. Correctly paired mAb arms were assembled to form BsAbs that were purified through protein A affinity chromatography to demonstrate industrial applicability at large scale. Further, the products were characterized through physical-biochemistry properties and biological activities to confirm expected quality of the products from “BAPTS”. More importantly, correct pairing was confirmed by mass spectrum. Proof-of-concept studies with CD3×HER2 BsAb (T-cell recruitment) demonstrated superior bioactivity compared with trastuzumab. The results of undetectable mispairing and high biological activity have indicated that this method has the potential to be utilized to manufacture BsAbs with high efficiency at industrial scale.
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20
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Seitter H, Koschak A. Relevance of tissue specific subunit expression in channelopathies. Neuropharmacology 2017; 132:58-70. [PMID: 28669898 DOI: 10.1016/j.neuropharm.2017.06.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 06/22/2017] [Accepted: 06/28/2017] [Indexed: 12/27/2022]
Abstract
Channelopathies are a diverse group of human disorders that are caused by mutations in genes coding for ion channels or channel-regulating proteins. Several dozen channelopathies have been identified that involve both non-excitable cells as well as electrically active tissues like brain, skeletal and smooth muscle or the heart. In this review, we start out from the general question which ion channel genes are expressed tissue-selectively. We mined the human gene expression database Human Protein Atlas (HPA) for tissue-enriched ion channel genes and found 85 genes belonging to the ion channel families. Most of these genes were enriched in brain, testis and muscle and a complete list of the enriched ion channel genes is provided. We further focused on the tissue distribution of voltage-gated calcium channel (VGCC) genes including different brain areas and the retina based on the human gene expression from the FANTOM5 dataset. The expression data is complemented by an overview of the tissue-dependent aspects of L-type calcium channel (LTCC) function, dysfunction and pharmacology, as well as of their splice variants. Finally, we focus on the pathology of tissue-restricted LTCC channelopathies and their treatment options. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Hartwig Seitter
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, Innrain 80-82/III, 6020 Innsbruck, Austria
| | - Alexandra Koschak
- University of Innsbruck, Institute of Pharmacy, Pharmacology and Toxicology, Center for Chemistry and Biomedicine, Innrain 80-82/III, 6020 Innsbruck, Austria.
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21
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Nguyen HX, Kirkton RD, Bursac N. Engineering prokaryotic channels for control of mammalian tissue excitability. Nat Commun 2016; 7:13132. [PMID: 27752065 PMCID: PMC5071848 DOI: 10.1038/ncomms13132] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 09/06/2016] [Indexed: 12/19/2022] Open
Abstract
The ability to directly enhance electrical excitability of human cells is hampered by the lack of methods to efficiently overexpress large mammalian voltage-gated sodium channels (VGSC). Here we describe the use of small prokaryotic sodium channels (BacNav) to create de novo excitable human tissues and augment impaired action potential conduction in vitro. Lentiviral co-expression of specific BacNav orthologues, an inward-rectifying potassium channel, and connexin-43 in primary human fibroblasts from the heart, skin or brain yields actively conducting cells with customizable electrophysiological phenotypes. Engineered fibroblasts ('E-Fibs') retain stable functional properties following extensive subculture or differentiation into myofibroblasts and rescue conduction slowing in an in vitro model of cardiac interstitial fibrosis. Co-expression of engineered BacNav with endogenous mammalian VGSCs enhances action potential conduction and prevents conduction failure during depolarization by elevated extracellular K+, decoupling or ischaemia. These studies establish the utility of engineered BacNav channels for induction, control and recovery of mammalian tissue excitability.
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Affiliation(s)
- Hung X Nguyen
- Department of Biomedical Engineering, Duke University, 101 Science Drive, Room 1427, Fitzpatrick CIEMAS, Durham, North Carolina 27708, USA
| | - Robert D Kirkton
- Department of Biomedical Engineering, Duke University, 101 Science Drive, Room 1427, Fitzpatrick CIEMAS, Durham, North Carolina 27708, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, 101 Science Drive, Room 1427, Fitzpatrick CIEMAS, Durham, North Carolina 27708, USA
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22
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Lueck JD, Mackey AL, Infield DT, Galpin JD, Li J, Roux B, Ahern CA. Atomic mutagenesis in ion channels with engineered stoichiometry. eLife 2016; 5. [PMID: 27710770 PMCID: PMC5092047 DOI: 10.7554/elife.18976] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 10/05/2016] [Indexed: 12/28/2022] Open
Abstract
C-type inactivation of potassium channels fine-tunes the electrical signaling in excitable cells through an internal timing mechanism that is mediated by a hydrogen bond network in the channels' selectively filter. Previously, we used nonsense suppression to highlight the role of the conserved Trp434-Asp447 indole hydrogen bond in Shaker potassium channels with a non-hydrogen bonding homologue of tryptophan, Ind (Pless et al., 2013). Here, molecular dynamics simulations indicate that the Trp434Ind hydrogen bonding partner, Asp447, unexpectedly 'flips out' towards the extracellular environment, allowing water to penetrate the space behind the selectivity filter while simultaneously reducing the local negative electrostatic charge. Additionally, a protein engineering approach is presented whereby split intein sequences are flanked by endoplasmic reticulum retention/retrieval motifs (ERret) are incorporated into the N- or C- termini of Shaker monomers or within sodium channels two-domain fragments. This system enabled stoichiometric control of Shaker monomers and the encoding of multiple amino acids within a channel tetramer. DOI:http://dx.doi.org/10.7554/eLife.18976.001
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Affiliation(s)
- John D Lueck
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, United States
| | - Adam L Mackey
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, United States
| | - Daniel T Infield
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, United States
| | - Jason D Galpin
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, United States
| | - Jing Li
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, United States
| | - Christopher A Ahern
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, United States
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23
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Localized force application reveals mechanically sensitive domains of Piezo1. Nat Commun 2016; 7:12939. [PMID: 27694883 PMCID: PMC5063965 DOI: 10.1038/ncomms12939] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 08/16/2016] [Indexed: 01/12/2023] Open
Abstract
Piezos are mechanically activated ion channels that function as sensors of touch and pressure in various cell types. However, the precise mechanism and structures mediating mechanical activation and subsequent inactivation have not yet been identified. Here we use magnetic nanoparticles as localized transducers of mechanical force in combination with pressure-clamp electrophysiology to identify mechanically sensitive domains important for activation and inactivation.
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24
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Chang DD, Colecraft HM. Rad and Rem are non-canonical G-proteins with respect to the regulatory role of guanine nucleotide binding in Ca(V)1.2 channel regulation. J Physiol 2016; 593:5075-90. [PMID: 26426338 DOI: 10.1113/jp270889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/27/2015] [Indexed: 12/15/2022] Open
Abstract
Rad and Rem are Ras-like G-proteins linked to diverse cardiovascular functions and pathophysiology. Understanding how Rad and Rem are regulated is important for deepened insights into their pathophysiological roles. As in other Ras-like G-proteins, Rad and Rem contain a conserved guanine-nucleotide binding domain (G-domain). Canonically, G-domains are key control modules, functioning as nucleotide-regulated switches of G-protein activity. Whether Rad and Rem G-domains conform to this canonical paradigm is ambiguous. Here, we used multiple functional measurements in HEK293 cells and cardiomyocytes (Ca(V)1.2 currents, Ca(2+) transients, Ca(V)β binding) as biosensors to probe the role of the G-domain in regulation of Rad and Rem function. We utilized Rad(S105N) and Rem(T94N), which are the cognate mutants to Ras(S17N), a dominant-negative variant of Ras that displays decreased nucleotide binding affinity. In HEK293 cells, over-expression of either Rad(S105N) or Rem(T94N) strongly inhibited reconstituted Ca(V)1.2 currents to the same extent as their wild-type (wt) counterparts, contrasting with reports that Rad(S105N) is functionally inert in HEK293 cells. Adenovirus-mediated expression of either wt Rad or Rad(S105N) in cardiomyocytes dramatically blocked L-type calcium current (I(Ca,L)) and inhibited Ca(2+)-induced Ca(2+) release, contradicting reports that Rad(S105N) acts as a dominant negative in heart. By contrast, Rem(T94N) was significantly less effective than wt Rem at inhibiting I(Ca,L) and Ca(2+) transients in cardiomyocytes. FRET analyses in cardiomyocytes revealed that both Rad(S105N) and Rem(T94N) had moderately reduced binding affinity for Ca(V)βs relative to their wt counterparts. The results indicate Rad and Rem are non-canonical G-proteins with respect to the regulatory role of their G-domain in Ca(V)1.2 regulation.
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Affiliation(s)
- Donald D Chang
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
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25
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Puckerin AA, Chang DD, Subramanyam P, Colecraft HM. Similar molecular determinants on Rem mediate two distinct modes of inhibition of Ca V1.2 channels. Channels (Austin) 2016; 10:379-394. [PMID: 27115600 PMCID: PMC4988437 DOI: 10.1080/19336950.2016.1180489] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rad/Rem/Rem2/Gem (RGK) proteins are Ras-like GTPases that potently inhibit all high-voltage-gated calcium (CaV1/CaV2) channels and are, thus, well-positioned to tune diverse physiological processes. Understanding how RGK proteins inhibit CaV channels is important for perspectives on their (patho)physiological roles and could advance their development and use as genetically-encoded CaV channel blockers. We previously reported that Rem can block surface CaV1.2 channels in 2 independent ways that engage distinct components of the channel complex: (1) by binding auxiliary β subunits (β-binding-dependent inhibition, or BBD); and (2) by binding the pore-forming α1C subunit N-terminus (α1C-binding-dependent inhibition, or ABD). By contrast, Gem uses only the BBD mechanism to block CaV1.2. Rem molecular determinants required for BBD CaV1.2 inhibition are the distal C-terminus and the guanine nucleotide binding G-domain which interact with the plasma membrane and CaVβ, respectively. However, Rem determinants for ABD CaV1.2 inhibition are unknown. Here, combining fluorescence resonance energy transfer, electrophysiology, systematic truncations, and Rem/Gem chimeras we found that the same Rem distal C-terminus and G-domain also mediate ABD CaV1.2 inhibition, but with different interaction partners. Rem distal C-terminus interacts with α1C N-terminus to anchor the G-domain which likely interacts with an as-yet-unidentified site. In contrast to some previous studies, neither the C-terminus of Rem nor Gem was sufficient to inhibit CaV1/CaV2 channels. The results reveal that similar molecular determinants on Rem are repurposed to initiate 2 independent mechanisms of CaV1.2 inhibition.
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Affiliation(s)
- Akil A Puckerin
- a Department of Pharmacology & Molecular Signaling , Columbia University , New York , NY , USA
| | - Donald D Chang
- b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
| | - Prakash Subramanyam
- b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
| | - Henry M Colecraft
- a Department of Pharmacology & Molecular Signaling , Columbia University , New York , NY , USA.,b Department of Physiology & Cellular Biophysics , Columbia University , New York , NY , USA
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26
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Dick IE, Joshi-Mukherjee R, Yang W, Yue DT. Arrhythmogenesis in Timothy Syndrome is associated with defects in Ca(2+)-dependent inactivation. Nat Commun 2016; 7:10370. [PMID: 26822303 PMCID: PMC4740114 DOI: 10.1038/ncomms10370] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/03/2015] [Indexed: 12/18/2022] Open
Abstract
Timothy Syndrome (TS) is a multisystem disorder, prominently featuring cardiac action potential prolongation with paroxysms of life-threatening arrhythmias. The underlying defect is a single de novo missense mutation in CaV1.2 channels, either G406R or G402S. Notably, these mutations are often viewed as equivalent, as they produce comparable defects in voltage-dependent inactivation and cause similar manifestations in patients. Yet, their effects on calcium-dependent inactivation (CDI) have remained uncertain. Here, we find a significant defect in CDI in TS channels, and uncover a remarkable divergence in the underlying mechanism for G406R versus G402S variants. Moreover, expression of these TS channels in cultured adult guinea pig myocytes, combined with a quantitative ventricular myocyte model, reveals a threshold behaviour in the induction of arrhythmias due to TS channel expression, suggesting an important therapeutic principle: a small shift in the complement of mutant versus wild-type channels may confer significant clinical improvement. Timothy Syndrome (TS) is a multisystem disorder caused by two mutations leading to dysfunction of the CaV1.2 channel. Here, Dick et al. uncover a major and mechanistically divergent effect of both mutations on Ca2+/calmodulin-dependent inactivation of CaV1.2 channels, suggesting genetic variant-tailored therapy for TS treatment.
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Affiliation(s)
- Ivy E Dick
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Rosy Joshi-Mukherjee
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - Wanjun Yang
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
| | - David T Yue
- Calcium Signals Laboratory, Departments of Biomedical Engineering and Neuroscience, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, Maryland 21205, USA
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Odnoshivkina UG, Sytchev VI, Nurullin LF, Giniatullin AR, Zefirov AL, Petrov AM. β2-adrenoceptor agonist-evoked reactive oxygen species generation in mouse atria: implication in delayed inotropic effect. Eur J Pharmacol 2015; 765:140-53. [PMID: 26297975 DOI: 10.1016/j.ejphar.2015.08.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/05/2015] [Accepted: 08/17/2015] [Indexed: 12/20/2022]
Abstract
Fenoterol, a β2-adrenoceptor agonist, has anti-apoptotic action in cardiomyocytes and induces a specific pattern of downstream signaling. We have previously reported that exposure to fenoterol (5 μM) results in a delayed positive inotropic effect which is related to changes in both Ca2+ transient and NO. Here, the changes in reactive oxygen species (ROS) production in response to the fenoterol administration and the involvement of ROS in effect of this agonist on contractility were investigated in mouse isolated atria. Stimulation of β2-adrenoceptor increases a level of extracellular ROS, while intracellular ROS level rises only after removal of fenoterol from the bath. NADPH-oxidase inhibitor (apocynin) prevents the increase in ROS production and the Nox2 isoform is immunofluorescently colocalized with β2-adrenoceptor at the atrial myocytes. Treatments with antioxidants (N-acetyl-L-cysteine, NADPH inhibitors, exogenous catalases) significantly inhibit the fenoterol induced increase in the contraction amplitude, probably by attenuating Ca2+ transient and up-regulating NO production. ROS generated in a β2-adrenoceptor-dependent manner can potentiate the activity of some Ca2+ channels. Indeed, inhibition of ryanodine receptors, TRPV-or L-type Ca2+- channels shows a similar efficacy in reduction of positive inotropic effect of both fenoterol and H2O2. In addition, detection of mitochondrial ROS indicates that fenoterol triggers a slow increase in ROS which is prevented by rotenone, but rotenone has no impact on the inotropic effect of fenoterol. We suggest that stimulation of β2-adrenoceptor with fenoterol causes the activation of NADPH-oxidase and after the agonist removal extracellularly generated ROS penetrates into the cell, increasing the atrial contractions probably via Ca2+ channels.
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Affiliation(s)
- Ulia G Odnoshivkina
- Department of Normal Physiology, Kazan State Medical University, Butlerova st., 49, Kazan 420012, Russia
| | - Vaycheslav I Sytchev
- Department of Normal Physiology, Kazan State Medical University, Butlerova st., 49, Kazan 420012, Russia
| | - Leniz F Nurullin
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of Russian Academy of Sciences, Laboratory of Biophysics of Synaptic Processes, Lobatchevsky str. 2/31, P.O. 30, Kazan 420111, Russia
| | - Arthur R Giniatullin
- Department of Normal Physiology, Kazan State Medical University, Butlerova st., 49, Kazan 420012, Russia
| | - Andrei L Zefirov
- Department of Normal Physiology, Kazan State Medical University, Butlerova st., 49, Kazan 420012, Russia
| | - Alexey M Petrov
- Department of Normal Physiology, Kazan State Medical University, Butlerova st., 49, Kazan 420012, Russia.
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28
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Li Y. Split-inteins and their bioapplications. Biotechnol Lett 2015; 37:2121-37. [DOI: 10.1007/s10529-015-1905-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 06/29/2015] [Indexed: 01/01/2023]
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29
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Bachmann AL, Matern JCJ, Schütz V, Mootz HD. Chemical-tag labeling of proteins using fully recombinant split inteins. Methods Mol Biol 2015; 1266:145-159. [PMID: 25560073 DOI: 10.1007/978-1-4939-2272-7_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chemical-tag labeling of proteins involving split inteins is an approach for the selective chemical modification of proteins without the requirement of any chemical synthesis to be performed. In a two-step protocol, a very short tag fused to a split intein auxiliary protein is first labeled in a bioconjugation reaction with a synthetic moiety either at its N-terminus (amine-tag) or at the side chain of an unnatural amino acid (click-tag). The labeled protein is then mixed with the protein of interest fused to the complementary intein fragment. In the resulting spontaneous protein trans-splicing reaction the split intein fragments remove themselves and ligate the tag to the protein of interest in a virtually traceless fashion. The reaction can be performed either using a purified protein of interest or to label a protein in the context of a living cell. All protein components are recombinantly expressed and all chemical reagents are commercially available.
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Affiliation(s)
- Anne-Lena Bachmann
- Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Muenster, Wilhelm-Klemm-Str. 2, 48149, Münster, Germany
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Aromolaran AS, Subramanyam P, Chang DD, Kobertz WR, Colecraft HM. LQT1 mutations in KCNQ1 C-terminus assembly domain suppress IKs using different mechanisms. Cardiovasc Res 2014; 104:501-11. [PMID: 25344363 DOI: 10.1093/cvr/cvu231] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AIMS Long QT syndrome 1 (LQT1) mutations in KCNQ1 that decrease cardiac IKs (slowly activating delayed rectifier K(+) current) underlie ventricular arrhythmias and sudden death. LQT1 mutations may suppress IKs by preventing KCNQ1 assembly, disrupting surface trafficking, or inhibiting gating. We investigated mechanisms underlying how three LQT1 mutations in KCNQ1 C-terminus assembly domain (R555H/G589D/L619M) decrease IKs in heterologous cells and cardiomyocytes. METHODS AND RESULTS In Chinese hamster ovary (CHO) cells, mutant KCNQ1 + KCNE1 channels either produced no currents (G589D/L619M) or displayed markedly reduced IKs with a right-shifted voltage-dependence of activation (R555H). When co-expressed with wild-type (wt) KCNQ1, the mutant KCNQ1s displayed varying intrinsic dominant-negative capacities that were affected by auxiliary KCNE1. All three mutant KCNQ1s assembled with wt KCNQ1 as determined by fluorescence resonance energy transfer (FRET). We developed an optical quantum dot labelling assay to measure channel surface density. G589D/R555H displayed substantial reductions in surface density, which were either partially (G589D) or fully (R555H) rescued by wt KCNQ1. Unexpectedly, L619M showed no trafficking defect. In adult rat cardiomyocytes, adenovirus-expressed homotetrameric G589D/L619M + KCNE1 channels yielded no currents, whereas R555H + KCNE1 produced diminished IKs with a right-shifted voltage-dependence of activation, mimicking observations in CHO cells. In contrast to heterologous cells, homotetrameric R555H channels showed no trafficking defect in cardiomyocytes. CONCLUSION Distinct LQT1 mutations in KCNQ1 assembly domain decrease IKs using unique combinations of biophysical and trafficking mechanisms. Functional deficits in IKs observed in heterologous cells are mostly, but not completely, recapitulated in adult rat cardiomyocytes. A 'methodological chain' combining approaches in heterologous cells and cardiomyocytes provides mechanistic insights that may help advance personalized therapy for LQT1 mutations.
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Affiliation(s)
- Ademuyiwa S Aromolaran
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - Donald D Chang
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
| | - William R Kobertz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School Worcester, MA 01605, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, College of Physicians and Surgeons, 1150 St. Nicholas Avenue, 504 Russ Berrie, New York, NY 10032, USA
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31
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Subramanyam P, Colecraft HM. Ion channel engineering: perspectives and strategies. J Mol Biol 2014; 427:190-204. [PMID: 25205552 DOI: 10.1016/j.jmb.2014.09.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 09/01/2014] [Indexed: 01/19/2023]
Abstract
Ion channels facilitate the passive movement of ions down an electrochemical gradient and across lipid bilayers in cells. This phenomenon is essential for life and underlies many critical homeostatic processes in cells. Ion channels are diverse and differ with respect to how they open and close (gating) and to their ionic conductance/selectivity (permeation). Fundamental understanding of ion channel structure-function mechanisms, their physiological roles, how their dysfunction leads to disease, their utility as biosensors, and development of novel molecules to modulate their activity are important and active research frontiers. In this review, we focus on ion channel engineering approaches that have been applied to investigate these aspects of ion channel function, with a major emphasis on voltage-gated ion channels.
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Affiliation(s)
- Prakash Subramanyam
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, NY, 10032, USA.
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