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Jiang Y, Shen L, Wang B. Non-electrophysiological techniques targeting transient receptor potential (TRP) gene of gastrointestinal tract. Int J Biol Macromol 2024; 262:129551. [PMID: 38367416 DOI: 10.1016/j.ijbiomac.2024.129551] [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: 10/25/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 02/19/2024]
Abstract
Transient receptor potential (TRP) channels are cation channels related to a wide range of physical and chemical stimuli, they are expressed all along the gastrointestinal system, and a myriad of diseases are often associated with aberrant expression or mutation of the TRP gene, suggesting that TRPs are promising targets for drug therapy. Therefore, a better understanding of the information of TRPs in health and disease could facilitate the development of effective drugs for the treatment of gastrointestinal diseases like IBD. But there are very few generalizations about the experimental techniques studied in this field. In view of the promise of TRP as a therapeutic target, we discuss experimental methods that can be used for TRPs including their distribution, function and interaction with other proteins, as well as some promising emerging technologies to provide experimental methods for future studies.
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Affiliation(s)
- Yuting Jiang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Center for Pharmaceutics Research, Shanghai Institute of Materia Medica Chinese Academy of Sciences, Shanghai 201203, China
| | - Lan Shen
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Bing Wang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Center for Pharmaceutics Research, Shanghai Institute of Materia Medica Chinese Academy of Sciences, Shanghai 201203, China.
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2
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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated calmodulin variants interact with KCNQ1 to confer aberrant membrane trafficking and function. PNAS NEXUS 2023; 2:pgad335. [PMID: 37965565 PMCID: PMC10642763 DOI: 10.1093/pnasnexus/pgad335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 10/04/2023] [Indexed: 11/16/2023]
Abstract
Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates ("calmodulinopathy"). As CaM regulates many key cardiac ion channels, an understanding of disease mechanism associated with CaM variant arrhythmias requires elucidating individual CaM variant effects on distinct channels. One key CaM regulatory target is the KCNQ1 (KV7.1) voltage-gated potassium channel that carries the IKs current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Here, we take a multipronged approach employing a live-cell fluorescence resonance energy transfer binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants for effect on KCNQ1 CaM binding, membrane trafficking, and channel function. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared with CaM wild-type over physiological Ca2+ ranges. We further identify several CaM variants that affect KCNQ1 and IKs membrane trafficking and/or baseline current activation kinetics, thereby delineating KCNQ1 dysfunction in calmodulinopathy. Lastly, we identify CaM variants with no effect on KCNQ1 function. This study provides extensive functional data that reveal how CaM variants contribute to creating a proarrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function, suggesting how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels. Classification: Biological, Health, and Medical Sciences, Physiology.
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Affiliation(s)
- Po wei Kang
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Lucy Woodbury
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Paweorn Angsutararux
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Namit Sambare
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jingyi Shi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Martina Marras
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Carlota Abella
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Anish Bedi
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - DeShawn Zinn
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St.Louis, St. Louis, MO 63130, USA
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Feldmann C, Schänzler M, Ben-Johny M, Wahl-Schott C. Protocol for deriving proximity, affinity, and stoichiometry of protein interactions using image-based quantitative two-hybrid FRET. STAR Protoc 2023; 4:102459. [PMID: 37516972 PMCID: PMC10400964 DOI: 10.1016/j.xpro.2023.102459] [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: 02/17/2023] [Revised: 05/26/2023] [Accepted: 06/22/2023] [Indexed: 08/01/2023] Open
Abstract
Two-hybrid Förster resonance energy transfer (FRET) provides proximity, affinity, and stoichiometry information in binding interactions. We present an image-based approach that surpasses traditional two-hybrid FRET assays in precision and robustness. We outline instrument setup and image acquisition and further describe steps for image preprocessing and two-hybrid FRET analysis using provided software to simplify the workflow. This protocol is compatible with confocal microscopes for high-precision and imaging plate readers for high-throughput applications. A plasmid-based reference system supports fast establishment of the protocol. For complete details on the use and execution of this protocol, please refer to Rivas et al.1.
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Affiliation(s)
- Colin Feldmann
- Institute of Cardiovascular Physiology and Pathophysiology, Faculty of Medicine, Biomedical Center, LMU-Munich, 82152 Planegg-Martinsried, Germany; Institute of Neurophysiology, Medizinische Hochschule Hannover, 30625 Hannover, Germany
| | - Michael Schänzler
- Institute of Neurophysiology, Medizinische Hochschule Hannover, 30625 Hannover, Germany
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, Medical Center, New York 10032, NY, USA
| | - Christian Wahl-Schott
- Institute of Cardiovascular Physiology and Pathophysiology, Faculty of Medicine, Biomedical Center, LMU-Munich, 82152 Planegg-Martinsried, Germany; Institute of Neurophysiology, Medizinische Hochschule Hannover, 30625 Hannover, Germany.
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Kang PW, Woodbury L, Angsutararux P, Sambare N, Shi J, Marras M, Abella C, Bedi A, Zinn D, Cui J, Silva JR. Arrhythmia-associated Calmodulin Variants Interact with KCNQ1 to Confer Aberrant Membrane Trafficking and Function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.28.526031. [PMID: 36747728 PMCID: PMC9900995 DOI: 10.1101/2023.01.28.526031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Rationale Missense variants in calmodulin (CaM) predispose patients to arrhythmias associated with high mortality rates. As CaM regulates several key cardiac ion channels, a mechanistic understanding of CaM variant-associated arrhythmias requires elucidating individual CaM variant effect on distinct channels. One key CaM regulatory target is the KCNQ1 (K V 7.1) voltage-gated potassium channel that underlie the I Ks current. Yet, relatively little is known as to how CaM variants interact with KCNQ1 or affect its function. Objective To observe how arrhythmia-associated CaM variants affect binding to KCNQ1, channel membrane trafficking, and KCNQ1 function. Methods and Results We combine a live-cell FRET binding assay, fluorescence trafficking assay, and functional electrophysiology to characterize >10 arrhythmia-associated CaM variants effect on KCNQ1. We identify one variant (G114W) that exhibits severely weakened binding to KCNQ1 but find that most other CaM variants interact with similar binding affinity to KCNQ1 when compared to CaM wild-type over physiological Ca 2+ ranges. We further identify several CaM variants that affect KCNQ1 and I Ks membrane trafficking and/or baseline current activation kinetics, thereby contextualizing KCNQ1 dysfunction in calmodulinopathy. Lastly, we delineate CaM variants with no effect on KCNQ1 function. Conclusions This study provides comprehensive functional data that reveal how CaM variants contribute to creating a pro-arrhythmic substrate by causing abnormal KCNQ1 membrane trafficking and current conduction. We find that CaM variant regulation of KCNQ1 is not uniform with effects varying from benign to significant loss of function. This study provides a new approach to collecting details of CaM binding that are key for understanding how CaM variants predispose patients to arrhythmia via the dysregulation of multiple cardiac ion channels.
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Morgenstern TJ, Nirwan N, Hernández-Ochoa EO, Bibollet H, Choudhury P, Laloudakis YD, Ben Johny M, Bannister RA, Schneider MF, Minor DL, Colecraft HM. Selective posttranslational inhibition of Ca Vβ 1-associated voltage-dependent calcium channels with a functionalized nanobody. Nat Commun 2022; 13:7556. [PMID: 36494348 PMCID: PMC9734117 DOI: 10.1038/s41467-022-35025-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/15/2022] [Indexed: 12/13/2022] Open
Abstract
Ca2+ influx through high-voltage-activated calcium channels (HVACCs) controls diverse cellular functions. A critical feature enabling a singular signal, Ca2+ influx, to mediate disparate functions is diversity of HVACC pore-forming α1 and auxiliary CaVβ1-CaVβ4 subunits. Selective CaVα1 blockers have enabled deciphering their unique physiological roles. By contrast, the capacity to post-translationally inhibit HVACCs based on CaVβ isoform is non-existent. Conventional gene knockout/shRNA approaches do not adequately address this deficit owing to subunit reshuffling and partially overlapping functions of CaVβ isoforms. Here, we identify a nanobody (nb.E8) that selectively binds CaVβ1 SH3 domain and inhibits CaVβ1-associated HVACCs by reducing channel surface density, decreasing open probability, and speeding inactivation. Functionalizing nb.E8 with Nedd4L HECT domain yielded Chisel-1 which eliminated current through CaVβ1-reconstituted CaV1/CaV2 and native CaV1.1 channels in skeletal muscle, strongly suppressed depolarization-evoked Ca2+ influx and excitation-transcription coupling in hippocampal neurons, but was inert against CaVβ2-associated CaV1.2 in cardiomyocytes. The results introduce an original method for probing distinctive functions of ion channel auxiliary subunit isoforms, reveal additional dimensions of CaVβ1 signaling in neurons, and describe a genetically-encoded HVACC inhibitor with unique properties.
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Affiliation(s)
- Travis J. Morgenstern
- grid.239585.00000 0001 2285 2675Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY USA
| | - Neha Nirwan
- grid.266102.10000 0001 2297 6811Cardiovascular Research Institute, University of California, San Francisco, CA USA
| | - Erick O. Hernández-Ochoa
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Hugo Bibollet
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Papiya Choudhury
- grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
| | - Yianni D. Laloudakis
- grid.239585.00000 0001 2285 2675Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY USA
| | - Manu Ben Johny
- grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
| | - Roger A. Bannister
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA ,grid.411024.20000 0001 2175 4264Department of Pathology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Martin F. Schneider
- grid.411024.20000 0001 2175 4264Department of Biochemistry and Biology, University of Maryland School of Medicine, Baltimore, MD USA
| | - Daniel L. Minor
- grid.266102.10000 0001 2297 6811Cardiovascular Research Institute, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Department of Biochemistry and Biophysics, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA USA ,grid.266102.10000 0001 2297 6811Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA USA ,grid.184769.50000 0001 2231 4551Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Henry M. Colecraft
- grid.239585.00000 0001 2285 2675Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY USA ,grid.239585.00000 0001 2285 2675Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY USA
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Owji AP, Yu K, Kittredge A, Wang J, Zhang Y, Yang T. Bestrophin-2 and glutamine synthetase form a complex for glutamate release. Nature 2022; 611:180-187. [PMID: 36289327 PMCID: PMC9873481 DOI: 10.1038/s41586-022-05373-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 09/21/2022] [Indexed: 01/26/2023]
Abstract
Bestrophin-2 (BEST2) is a member of the bestrophin family of calcium-activated anion channels that has a critical role in ocular physiology1-4. Here we uncover a directional permeability of BEST2 to glutamate that heavily favours glutamate exit, identify glutamine synthetase (GS) as a binding partner of BEST2 in the ciliary body of the eye, and solve the structure of the BEST2-GS complex. BEST2 reduces cytosolic GS activity by tethering GS to the cell membrane. GS extends the ion conducting pathway of BEST2 through its central cavity and inhibits BEST2 channel function in the absence of intracellular glutamate, but sensitizes BEST2 to intracellular glutamate, which promotes the opening of BEST2 and thus relieves the inhibitory effect of GS. We demonstrate the physiological role of BEST2 in conducting chloride and glutamate and the influence of GS in non-pigmented ciliary epithelial cells. Together, our results reveal a novel mechanism of glutamate release through BEST2-GS.
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Affiliation(s)
- Aaron P Owji
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Pharmacology, Columbia University, New York, NY, USA
| | - Kuai Yu
- Department of Cell Biology, Emory University, School of Medicine, Atlanta, GA, USA
| | - Alec Kittredge
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Pharmacology, Columbia University, New York, NY, USA
| | - Jiali Wang
- Department of Ophthalmology, Columbia University, New York, NY, USA
| | - Yu Zhang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
| | - Tingting Yang
- Department of Ophthalmology, Columbia University, New York, NY, USA.
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Development of High affinity Nanobodies Specific for Na V1.4 and Na V1.5 Voltage-Gated Sodium Channel Isoforms. J Biol Chem 2022; 298:101763. [PMID: 35202650 PMCID: PMC8935509 DOI: 10.1016/j.jbc.2022.101763] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 11/22/2022] Open
Abstract
Voltage-gated sodium channels, NaVs, are responsible for the rapid rise of action potentials in excitable tissues. NaV channel mutations have been implicated in several human genetic diseases, such as hypokalemic periodic paralysis, myotonia, and long-QT and Brugada syndromes. Here, we generated high-affinity anti-NaV nanobodies (Nbs), Nb17 and Nb82, that recognize the NaV1.4 (skeletal muscle) and NaV1.5 (cardiac muscle) channel isoforms. These Nbs were raised in llama (Lama glama) and selected from a phage display library for high affinity to the C-terminal (CT) region of NaV1.4. The Nbs were expressed in Escherichia coli, purified, and biophysically characterized. Development of high-affinity Nbs specifically targeting a given human NaV isoform has been challenging because they usually show undesired crossreactivity for different NaV isoforms. Our results show, however, that Nb17 and Nb82 recognize the CTNaV1.4 or CTNaV1.5 over other CTNav isoforms. Kinetic experiments by biolayer interferometry determined that Nb17 and Nb82 bind to the CTNaV1.4 and CTNaV1.5 with high affinity (KD ∼ 40–60 nM). In addition, as proof of concept, we show that Nb82 could detect NaV1.4 and NaV1.5 channels in mammalian cells and tissues by Western blot. Furthermore, human embryonic kidney cells expressing holo NaV1.5 channels demonstrated a robust FRET-binding efficiency for Nb17 and Nb82. Our work lays the foundation for developing Nbs as anti-NaV reagents to capture NaVs from cell lysates and as molecular visualization agents for NaVs.
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