1
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Yao X, Gao S, Yan N. Structural biology of voltage-gated calcium channels. Channels (Austin) 2024; 18:2290807. [PMID: 38062897 PMCID: PMC10761187 DOI: 10.1080/19336950.2023.2290807] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Voltage-gated calcium (Cav) channels mediate Ca2+ influx in response to membrane depolarization, playing critical roles in diverse physiological processes. Dysfunction or aberrant regulation of Cav channels can lead to life-threatening consequences. Cav-targeting drugs have been clinically used to treat cardiovascular and neuronal disorders for several decades. This review aims to provide an account of recent developments in the structural dissection of Cav channels. High-resolution structures have significantly advanced our understanding of the working and disease mechanisms of Cav channels, shed light on the molecular basis for their modulation, and elucidated the modes of actions (MOAs) of representative drugs and toxins. The progress in structural studies of Cav channels lays the foundation for future drug discovery efforts targeting Cav channelopathies.
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Affiliation(s)
- Xia Yao
- TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Shuai Gao
- TaiKang Center for Life and Medical Sciences, School of Pharmaceutical Sciences, Wuhan University, Wuhan, China
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Shenzhen Medical Academy of Research and Translation, Shenzhen, China
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2
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Greene D, Shiferaw Y. Identifying Key Binding Interactions Between the Cardiac L-Type Calcium Channel and Calmodulin Using Molecular Dynamics Simulations. J Phys Chem B 2024; 128:6097-6111. [PMID: 38870543 PMCID: PMC11215769 DOI: 10.1021/acs.jpcb.4c02251] [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: 04/05/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/15/2024]
Abstract
Defects in the binding of the calcium sensing protein calmodulin (CaM) to the L-type calcium channel (CaV1.2) or to the ryanodine receptor type 2 (RyR2) can lead to dangerous cardiac arrhythmias with distinct phenotypes, such as long-QT syndrome (LQTS) and catecholaminergic ventricular tachycardia (CPVT). Certain CaM mutations lead to LQTS while other mutations lead to CPVT, but the mechanisms by which a specific mutation can lead to each disease phenotype are not well-understood. In this study, we use long, 2 μs molecular dynamics simulations and a multitrajectory approach to identify the key binding interactions between the IQ domain of CaV1.2 and CaM. Five key interactions are found between CaV1.2 and CaM in the C-lobe, 1 in the central linker, and 2 in the N-lobe. In addition, while 5 key interactions appear between residues 120-149 in the C-lobe of CaM when it interacts with CaV1.2, only 1 key interaction is found within this region of CaM when it interacts with the RyR2. We show that this difference in the distribution of key interactions correlates with the known distribution of CaM mutations that lead to LQTS or CPVT. This correlation suggests that a disruption of key binding interactions is a plausible mechanism that can lead to these two different disease phenotypes.
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Affiliation(s)
- D’Artagnan Greene
- Department of Physics and
Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, United States of
America
| | - Yohannes Shiferaw
- Department of Physics and
Astronomy, California State University Northridge, 18111 Nordhoff Street, Northridge, California 91330-8268, United States of
America
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3
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Huang J, Fan X, Jin X, Lyu C, Guo Q, Liu T, Chen J, Davakan A, Lory P, Yan N. Structural basis for human Ca v3.2 inhibition by selective antagonists. Cell Res 2024; 34:440-450. [PMID: 38605177 PMCID: PMC11143251 DOI: 10.1038/s41422-024-00959-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/02/2024] [Indexed: 04/13/2024] Open
Abstract
The Cav3.2 subtype of T-type calcium channels has been targeted for developing analgesics and anti-epileptics for its role in pain and epilepsy. Here we present the cryo-EM structures of Cav3.2 alone and in complex with four T-type calcium channel selective antagonists with overall resolutions ranging from 2.8 Å to 3.2 Å. The four compounds display two binding poses. ACT-709478 and TTA-A2 both place their cyclopropylphenyl-containing ends in the central cavity to directly obstruct ion flow, meanwhile extending their polar tails into the IV-I fenestration. TTA-P2 and ML218 project their 3,5-dichlorobenzamide groups into the II-III fenestration and place their hydrophobic tails in the cavity to impede ion permeation. The fenestration-penetrating mode immediately affords an explanation for the state-dependent activities of these antagonists. Structure-guided mutational analysis identifies several key residues that determine the T-type preference of these drugs. The structures also suggest the role of an endogenous lipid in stabilizing drug binding in the central cavity.
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Affiliation(s)
- Jian Huang
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY, USA.
| | - Xueqin Jin
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Chen Lyu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qinmeng Guo
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tao Liu
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiaofeng Chen
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Amaël Davakan
- IGF, Université de Montpellier, CNRS, INSERM, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, Université de Montpellier, CNRS, INSERM, LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Nieng Yan
- Beijing Frontier Research Center for Biological Structures, State Key Laboratory of Membrane Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
- Institute of Bio-Architecture and Bio-Interactions, Shenzhen Medical Academy of Research and Translation, Shenzhen, Guangdong, China.
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4
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del Rivero Morfin PJ, Kochiss AL, Liedl KR, Flucher BE, Fernández-Quintero ML, Ben-Johny M. Asymmetric contribution of a selectivity filter gate in triggering inactivation of CaV1.3 channels. J Gen Physiol 2024; 156:e202313365. [PMID: 38175169 PMCID: PMC10771039 DOI: 10.1085/jgp.202313365] [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: 02/01/2023] [Revised: 10/08/2023] [Accepted: 12/14/2023] [Indexed: 01/05/2024] Open
Abstract
Voltage-dependent and Ca2+-dependent inactivation (VDI and CDI, respectively) of CaV channels are two biologically consequential feedback mechanisms that fine-tune Ca2+ entry into neurons and cardiomyocytes. Although known to be initiated by distinct molecular events, how these processes obstruct conduction through the channel pore remains poorly defined. Here, focusing on ultrahighly conserved tryptophan residues in the interdomain interfaces near the selectivity filter of CaV1.3, we demonstrate a critical role for asymmetric conformational changes in mediating VDI and CDI. Specifically, mutagenesis of the domain III-IV interface, but not others, enhanced VDI. Molecular dynamics simulations demonstrate that mutations in distinct selectivity filter interfaces differentially impact conformational flexibility. Furthermore, mutations in distinct domains preferentially disrupt CDI mediated by the N- versus C-lobes of CaM, thus uncovering a scheme of structural bifurcation of CaM signaling. These findings highlight the fundamental importance of the asymmetric arrangement of the pseudotetrameric CaV pore domain for feedback inhibition.
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Affiliation(s)
| | - Audrey L. Kochiss
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | | | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
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5
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Xue Y, Zhou S, Yan L, Li Y, Xu X, Wang X, Minobe E, Kameyama M, Hao L, Hu H. Ahf-Caltide, a Novel Polypeptide Derived from Calpastatin, Protects against Oxidative Stress Injury by Stabilizing the Expression of Ca V1.2 Calcium Channel. Int J Mol Sci 2023; 24:15729. [PMID: 37958713 PMCID: PMC10648788 DOI: 10.3390/ijms242115729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Reperfusion after ischemia would cause massive myocardial injury, which leads to oxidative stress (OS). Calcium homeostasis imbalance plays an essential role in myocardial OS injury. CaV1.2 calcium channel mediates calcium influx into cardiomyocytes, and its activity is modulated by a region of calpastatin (CAST) domain L, CSL54-64. In this study, the effect of Ahf-caltide, derived from CSL54-64, on myocardial OS injury was investigated. Ahf-caltide decreased the levels of LDH, MDA and ROS and increased heart rate, coronary flow, cell survival and SOD activity during OS. In addition, Ahf-caltide permeated into H9c2 cells and increased CaV1.2, CaVβ2 and CAST levels by inhibiting protein degradation. At different Ca2+ concentrations (25 nM, 10 μM, 1 mM), the binding of CSL to the IQ motif in the C terminus of the CaV1.2 channel was increased in a H2O2 concentration-dependent manner. CSL54-64 was predicted to be responsible for the binding of CSL to CaV1.2. In conclusion, Ahf-caltide exerted a cardioprotective effect on myocardial OS injury by stabilizing CaV1.2 protein expression. Our study, for the first time, proposed that restoring calcium homeostasis by targeting the CaV1.2 calcium channel and its regulating factor CAST could be a novel treatment for myocardial OS injury.
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Affiliation(s)
- Yingchun Xue
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Shi Zhou
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Ling Yan
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Yuelin Li
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Xingrong Xu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Xianghui Wang
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Etsuko Minobe
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; (E.M.); (M.K.)
| | - Masaki Kameyama
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan; (E.M.); (M.K.)
| | - Liying Hao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
| | - Huiyuan Hu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China; (Y.X.); (S.Z.); (L.Y.); (Y.L.); (X.X.); (X.W.)
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6
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del Rivero Morfin PJ, Kochiss AL, Liedl KR, Flucher BE, Fernández-Quintero ML, Ben-Johny M. Asymmetric Contribution of a Selectivity Filter Gate in Triggering Inactivation of Ca V1.3 Channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.21.558864. [PMID: 37790368 PMCID: PMC10542529 DOI: 10.1101/2023.09.21.558864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Voltage-dependent and Ca2+-dependent inactivation (VDI and CDI, respectively) of CaV channels are two biologically consequential feedback mechanisms that fine-tune Ca2+ entry into neurons and cardiomyocytes. Although known to be initiated by distinct molecular events, how these processes obstruct conduction through the channel pore remains poorly defined. Here, focusing on ultra-highly conserved tryptophan residues in the inter-domain interfaces near the selectivity filter of CaV1.3, we demonstrate a critical role for asymmetric conformational changes in mediating VDI and CDI. Specifically, mutagenesis of the domain III-IV interface, but not others, enhanced VDI. Molecular dynamics simulations demonstrate that mutations in distinct selectivity filter interfaces differentially impact conformational flexibility. Furthermore, mutations in distinct domains preferentially disrupt CDI mediated by the N- versus C-lobes of CaM, thus uncovering a scheme of structural bifurcation of CaM signaling. These findings highlight the fundamental importance of the asymmetric arrangement of the pseudo-tetrameric CaV pore domain for feedback inhibition.
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Affiliation(s)
| | - Audrey L. Kochiss
- Department of Physiology and Cellular Biophysics, Columbia University
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innsbruck, Austria
| | - Bernhard E. Flucher
- Institute of Physiology, Department of Physiology and Medical Physics, Medical University Innsbruck, Innsbruck, Austria
| | | | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University
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7
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Kameyama M, Minobe E, Shao D, Xu J, Gao Q, Hao L. Regulation of Cardiac Cav1.2 Channels by Calmodulin. Int J Mol Sci 2023; 24:ijms24076409. [PMID: 37047381 PMCID: PMC10094977 DOI: 10.3390/ijms24076409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 03/19/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023] Open
Abstract
Cav1.2 Ca2+ channels, a type of voltage-gated L-type Ca2+ channel, are ubiquitously expressed, and the predominant Ca2+ channel type, in working cardiac myocytes. Cav1.2 channels are regulated by the direct interactions with calmodulin (CaM), a Ca2+-binding protein that causes Ca2+-dependent facilitation (CDF) and inactivation (CDI). Ca2+-free CaM (apoCaM) also contributes to the regulation of Cav1.2 channels. Furthermore, CaM indirectly affects channel activity by activating CaM-dependent enzymes, such as CaM-dependent protein kinase II and calcineurin (a CaM-dependent protein phosphatase). In this article, we review the recent progress in identifying the role of apoCaM in the channel ‘rundown’ phenomena and related repriming of channels, and CDF, as well as the role of Ca2+/CaM in CDI. In addition, the role of CaM in channel clustering is reviewed.
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Affiliation(s)
- Masaki Kameyama
- Department of Physiology, Graduate School of Medical & Dental Sciences, Kagoshima University, Sakura-ga-oka, Kagoshima 890-8544, Japan
- Correspondence:
| | - Etsuko Minobe
- Department of Physiology, Graduate School of Medical & Dental Sciences, Kagoshima University, Sakura-ga-oka, Kagoshima 890-8544, Japan
| | - Dongxue Shao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110012, China (L.H.)
| | - Jianjun Xu
- Department of Physiology, Graduate School of Medical & Dental Sciences, Kagoshima University, Sakura-ga-oka, Kagoshima 890-8544, Japan
| | - Qinghua Gao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110012, China (L.H.)
| | - Liying Hao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110012, China (L.H.)
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8
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Dürvanger Z, Juhász T, Liliom K, Harmat V. Structures of calmodulin-melittin complexes show multiple binding modes lacking classical anchoring interactions. J Biol Chem 2023; 299:104596. [PMID: 36906144 PMCID: PMC10140167 DOI: 10.1016/j.jbc.2023.104596] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 03/02/2023] [Accepted: 03/03/2023] [Indexed: 03/11/2023] Open
Abstract
Calmodulin (CaM) is a Ca2+ sensor protein found in all eukaryotic cells that regulates a large number of target proteins in a Ca2+ concentration-dependent manner. As a transient type hub protein, it recognizes linear motifs of its targets, though for the Ca2+-dependent binding no consensus sequence was identified. Its complex with melittin, a major component of bee venom, is often used as a model system of protein - protein complexes. Yet, the structural aspects of the binding are not well understood, as only diverse, low-resolution data are available concerning the association. We present the crystal structure of melittin in complex with Ca2+-saturated calmodulins from two, evolutionarily distant species, Homo sapiens and Plasmodium falciparum representing three binding modes of the peptide. Results - augmented by molecular dynamics simulations - indicate that multiple binding modes can exist for CaM-melittin complexes, as an intrinsic characteristic of the binding. While the helical structure of melittin remains, swapping of its salt bridges and partial unfolding of its C-terminal segment can occur. In contrast to the classical way of target recognition by CaM, we found that different sets of residues can anchor at the hydrophobic pockets of CaM, which were considered as main recognition sites. Finally, the nanomolar binding affinity of the CaM-melittin complex is created by an ensemble of arrangements of similar stability - tight binding is achieved not by optimized specific interactions but by simultaneously satisfying less optimal interaction patterns in co-existing different conformers.
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Affiliation(s)
- Zsolt Dürvanger
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Tünde Juhász
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Budapest, Hungary
| | - Károly Liliom
- Department of Biophysics and Radiation Biology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Budapest, Hungary; ELKH-ELTE Protein Modelling Research Group, Eötvös Loránd Research Network, Budapest, Hungary.
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9
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Calmodulin variant E140G associated with long QT syndrome impairs CaMKIIδ autophosphorylation and L-type calcium channel inactivation. J Biol Chem 2023; 299:102777. [PMID: 36496072 PMCID: PMC9830374 DOI: 10.1016/j.jbc.2022.102777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Long QT syndrome (LQTS) is a human inherited heart condition that can cause life-threatening arrhythmia including sudden cardiac death. Mutations in the ubiquitous Ca2+-sensing protein calmodulin (CaM) are associated with LQTS, but the molecular mechanism by which these mutations lead to irregular heartbeats is not fully understood. Here, we use a multidisciplinary approach including protein biophysics, structural biology, confocal imaging, and patch-clamp electrophysiology to determine the effect of the disease-associated CaM mutation E140G on CaM structure and function. We present novel data showing that mutant-regulated CaMKIIδ kinase activity is impaired with a significant reduction in enzyme autophosphorylation rate. We report the first high-resolution crystal structure of a LQTS-associated CaM variant in complex with the CaMKIIδ peptide, which shows significant structural differences, compared to the WT complex. Furthermore, we demonstrate that the E140G mutation significantly disrupted Cav1.2 Ca2+/CaM-dependent inactivation, while cardiac ryanodine receptor (RyR2) activity remained unaffected. In addition, we show that the LQTS-associated mutation alters CaM's Ca2+-binding characteristics, secondary structure content, and interaction with key partners involved in excitation-contraction coupling (CaMKIIδ, Cav1.2, RyR2). In conclusion, LQTS-associated CaM mutation E140G severely impacts the structure-function relationship of CaM and its regulation of CaMKIIδ and Cav1.2. This provides a crucial insight into the molecular factors contributing to CaM-mediated arrhythmias with a central role for CaMKIIδ.
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10
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Bartels P, Salveson I, Coleman AM, Anderson DE, Jeng G, Estrada-Tobar ZM, Man KNM, Yu Q, Kuzmenkina E, Nieves-Cintron M, Navedo MF, Horne MC, Hell JW, Ames JB. Half-calcified calmodulin promotes basal activity and inactivation of the L-type calcium channel Ca V1.2. J Biol Chem 2022; 298:102701. [PMID: 36395884 PMCID: PMC9764201 DOI: 10.1016/j.jbc.2022.102701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
The L-type Ca2+ channel CaV1.2 controls gene expression, cardiac contraction, and neuronal activity. Calmodulin (CaM) governs CaV1.2 open probability (Po) and Ca2+-dependent inactivation (CDI) but the mechanisms remain unclear. Here, we present electrophysiological data that identify a half Ca2+-saturated CaM species (Ca2/CaM) with Ca2+ bound solely at the third and fourth EF-hands (EF3 and EF4) under resting Ca2+ concentrations (50-100 nM) that constitutively preassociates with CaV1.2 to promote Po and CDI. We also present an NMR structure of a complex between the CaV1.2 IQ motif (residues 1644-1665) and Ca2/CaM12', a calmodulin mutant in which Ca2+ binding to EF1 and EF2 is completely disabled. We found that the CaM12' N-lobe does not interact with the IQ motif. The CaM12' C-lobe bound two Ca2+ ions and formed close contacts with IQ residues I1654 and Y1657. I1654A and Y1657D mutations impaired CaM binding, CDI, and Po, as did disabling Ca2+ binding to EF3 and EF4 in the CaM34 mutant when compared to WT CaM. Accordingly, a previously unappreciated Ca2/CaM species promotes CaV1.2 Po and CDI, identifying Ca2/CaM as an important mediator of Ca signaling.
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Affiliation(s)
- Peter Bartels
- Department of Pharmacology, University of California, Davis, California, USA
| | - Ian Salveson
- Department of Chemistry, University of California, Davis, California, USA
| | - Andrea M Coleman
- Department of Pharmacology, University of California, Davis, California, USA; Department of Chemistry, University of California, Davis, California, USA
| | - David E Anderson
- Department of Chemistry, University of California, Davis, California, USA
| | - Grace Jeng
- Department of Pharmacology, University of California, Davis, California, USA
| | | | - Kwun Nok Mimi Man
- Department of Pharmacology, University of California, Davis, California, USA
| | - Qinhong Yu
- Department of Chemistry, University of California, Davis, California, USA
| | - Elza Kuzmenkina
- Center for Pharmacology, University of Cologne, Cologne, Germany
| | | | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, California, USA
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, California, USA.
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, California, USA.
| | - James B Ames
- Department of Chemistry, University of California, Davis, California, USA.
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11
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Yadav DK, Anderson DE, Hell JW, Ames JB. Calmodulin promotes a Ca 2+ -dependent conformational change in the C-terminal regulatory domain of Ca V 1.2. FEBS Lett 2022; 596:2974-2985. [PMID: 36310389 PMCID: PMC9719739 DOI: 10.1002/1873-3468.14529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/07/2022] [Accepted: 10/10/2022] [Indexed: 11/10/2023]
Abstract
Calmodulin (CaM) binds to the membrane-proximal cytosolic C-terminal domain of CaV 1.2 (residues 1520-1669, CT(1520-1669)) and causes Ca2+ -induced conformational changes that promote Ca2+ -dependent channel inactivation (CDI). We report biophysical studies that probe the structural interaction between CT(1520-1669) and CaM. The recombinantly expressed CT(1520-1669) is insoluble, but can be solubilized in the presence of Ca2+ -saturated CaM (Ca4 /CaM), but not in the presence of Ca2+ -free CaM (apoCaM). We show that half-calcified CaM (Ca2 /CaM12 ) forms a complex with CT(1520-1669) that is less soluble than CT(1520-1669) bound to Ca4 /CaM. The NMR spectrum of CT(1520-1669) reveals spectral differences caused by the binding of Ca2 /CaM12 versus Ca4 /CaM, suggesting that the binding of Ca2+ to the CaM N-lobe may induce a conformational change in CT(1520-1669).
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Affiliation(s)
| | - David E. Anderson
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Johannes W. Hell
- Department of Pharmacology, University of California, Davis, CA 95616, USA
| | - James B. Ames
- Department of Chemistry, University of California, Davis, CA 95616, USA
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12
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Zhao J, Segura E, Marsolais M, Parent L. A CACNA1C variant associated with cardiac arrhythmias provides mechanistic insights in the calmodulation of L-type Ca 2+ channels. J Biol Chem 2022; 298:102632. [PMID: 36273583 PMCID: PMC9691931 DOI: 10.1016/j.jbc.2022.102632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/12/2022] [Accepted: 10/15/2022] [Indexed: 11/07/2022] Open
Abstract
We recently reported the identification of a de novo single nucleotide variant in exon 9 of CACNA1C associated with prolonged repolarization interval. Recombinant expression of the glycine to arginine variant at position 419 produced a gain in the function of the L-type CaV1.2 channel with increased peak current density and activation gating but without significant decrease in the inactivation kinetics. We herein reveal that these properties are replicated by overexpressing calmodulin (CaM) with CaV1.2 WT and are reversed by exposure to the CaM antagonist W-13. Phosphomimetic (T79D or S81D), but not phosphoresistant (T79A or S81A), CaM surrogates reproduced the impact of CaM WT on the function of CaV1.2 WT. The increased channel activity of CaV1.2 WT following overexpression of CaM was found to arise in part from enhanced cell surface expression. In contrast, the properties of the variant remained unaffected by any of these treatments. CaV1.2 substituted with the α-helix breaking proline residue were more reluctant to open than CaV1.2 WT but were upregulated by phosphomimetic CaM surrogates. Our results indicate that (1) CaM and its phosphomimetic analogs promote a gain in the function of CaV1.2 and (2) the structural properties of the first intracellular linker of CaV1.2 contribute to its CaM-induced modulation. We conclude that the CACNA1C clinical variant mimics the increased activity associated with the upregulation of CaV1.2 by Ca2+-CaM, thus maintaining a majority of channels in a constitutively active mode that could ultimately promote ventricular arrhythmias.
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Affiliation(s)
- Juan Zhao
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Emilie Segura
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Mireille Marsolais
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada
| | - Lucie Parent
- Centre de recherche de l’Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada,Département de Pharmacologie et Physiologie, Faculté de Médecine, Montréal, Québec, Canada,For correspondence: Lucie Parent
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13
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Karschin N, Becker S, Griesinger C. Interdomain Dynamics via Paramagnetic NMR on the Highly Flexible Complex Calmodulin/Munc13-1. J Am Chem Soc 2022; 144:17041-17053. [PMID: 36082939 PMCID: PMC9501808 DOI: 10.1021/jacs.2c06611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Paramagnetic NMR constraints are very useful to study protein interdomain motion, but their interpretation is not always straightforward. On the example of the particularly flexible complex Calmodulin/Munc13-1, we present a new approach to characterize this motion with pseudocontact shifts and residual dipolar couplings. Using molecular mechanics, we sampled the conformational space of the complex and used a genetic algorithm to find ensembles that are in agreement with the data. We used the Bayesian information criterion to determine the ideal ensemble size. This way, we were able to make an accurate, unambiguous, reproducible model of the interdomain motion of Calmodulin/Munc13-1 without prior knowledge about the domain orientation from crystallography.
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Affiliation(s)
- Niels Karschin
- Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, Niedersachsen D-37077, Germany
| | - Stefan Becker
- Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, Niedersachsen D-37077, Germany
| | - Christian Griesinger
- Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, Niedersachsen D-37077, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen D-37075, Germany
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14
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Ruiz-Fernández AR, Campos L, Gutierrez-Maldonado SE, Núñez G, Villanelo F, Perez-Acle T. Nanosecond Pulsed Electric Field (nsPEF): Opening the Biotechnological Pandora’s Box. Int J Mol Sci 2022; 23:ijms23116158. [PMID: 35682837 PMCID: PMC9181413 DOI: 10.3390/ijms23116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 02/04/2023] Open
Abstract
Nanosecond Pulsed Electric Field (nsPEF) is an electrostimulation technique first developed in 1995; nsPEF requires the delivery of a series of pulses of high electric fields in the order of nanoseconds into biological tissues or cells. They primary effects in cells is the formation of membrane nanopores and the activation of ionic channels, leading to an incremental increase in cytoplasmic Ca2+ concentration, which triggers a signaling cascade producing a variety of effects: from apoptosis up to cell differentiation and proliferation. Further, nsPEF may affect organelles, making nsPEF a unique tool to manipulate and study cells. This technique is exploited in a broad spectrum of applications, such as: sterilization in the food industry, seed germination, anti-parasitic effects, wound healing, increased immune response, activation of neurons and myocites, cell proliferation, cellular phenotype manipulation, modulation of gene expression, and as a novel cancer treatment. This review thoroughly explores both nsPEF’s history and applications, with emphasis on the cellular effects from a biophysics perspective, highlighting the role of ionic channels as a mechanistic driver of the increase in cytoplasmic Ca2+ concentration.
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Affiliation(s)
- Alvaro R. Ruiz-Fernández
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
| | - Leonardo Campos
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Sebastian E. Gutierrez-Maldonado
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Gonzalo Núñez
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
| | - Felipe Villanelo
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
| | - Tomas Perez-Acle
- Computational Biology Lab, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Santiago 7780272, Chile; (L.C.); (S.E.G.-M.); (G.N.); (F.V.)
- Facultad de Ingeniería y Tecnología, Universidad San Sebastian, Bellavista 7, Santiago 8420524, Chile
- Correspondence: (A.R.R.-F.); (T.P.-A.)
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15
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Yang Y, Yu Z, Geng J, Liu M, Liu N, Li P, Hong W, Yue S, Jiang H, Ge H, Qian F, Xiong W, Wang P, Song S, Li X, Fan Y, Liu X. Cytosolic peptides encoding Ca V1 C-termini downregulate the calcium channel activity-neuritogenesis coupling. Commun Biol 2022; 5:484. [PMID: 35589958 PMCID: PMC9120191 DOI: 10.1038/s42003-022-03438-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 05/03/2022] [Indexed: 12/31/2022] Open
Abstract
L-type Ca2+ (CaV1) channels transduce channel activities into nuclear signals critical to neuritogenesis. Also, standalone peptides encoded by CaV1 DCT (distal carboxyl-terminus) act as nuclear transcription factors reportedly promoting neuritogenesis. Here, by focusing on exemplary CaV1.3 and cortical neurons under basal conditions, we discover that cytosolic DCT peptides downregulate neurite outgrowth by the interactions with CaV1's apo-calmodulin binding motif. Distinct from nuclear DCT, various cytosolic peptides exert a gradient of inhibitory effects on Ca2+ influx via CaV1 channels and neurite extension and arborization, and also the intermediate events including CREB activation and c-Fos expression. The inhibition efficacies of DCT are quantitatively correlated with its binding affinities. Meanwhile, cytosolic inhibition tends to facilitate neuritogenesis indirectly by favoring Ca2+-sensitive nuclear retention of DCT. In summary, DCT peptides as a class of CaV1 inhibitors specifically regulate the channel activity-neuritogenesis coupling in a variant-, affinity-, and localization-dependent manner.
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Affiliation(s)
- Yaxiong Yang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China.,X-Laboratory for Ion-Channel Engineering, Beihang University, Beijing, 100083, China
| | - Zhen Yu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China.,X-Laboratory for Ion-Channel Engineering, Beihang University, Beijing, 100083, China
| | - Jinli Geng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China.,X-Laboratory for Ion-Channel Engineering, Beihang University, Beijing, 100083, China
| | - Min Liu
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Nan Liu
- Center for Life Sciences, School of Life Sciences, Yunnan University, Kunming, 650091, China
| | - Ping Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Weili Hong
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Shuhua Yue
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - He Jiang
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Haiyan Ge
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Feng Qian
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Ping Wang
- Laboratory for Biomedical Engineering of Ministry of Education, Zhejiang University, Hangzhou, 310027, China
| | - Sen Song
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Xiaomei Li
- School of Medicine, Tsinghua University, Beijing, 100084, China.
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China.
| | - Xiaodong Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, School of Engineering Medicine, Beihang University, Beijing, 100083, China. .,X-Laboratory for Ion-Channel Engineering, Beihang University, Beijing, 100083, China.
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16
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Sosa-Peinado A, León-Cruz E, Velázquez-López I, Matuz-Mares D, Cano-Sánchez P, González-Andrade M. Theoretical-experimental studies of calmodulin-peptide interactions at different calcium equivalents. J Biomol Struct Dyn 2022; 40:2689-2700. [DOI: 10.1080/07391102.2020.1841679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Erika León-Cruz
- Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, México
| | | | - Deyamira Matuz-Mares
- Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Patricia Cano-Sánchez
- Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, México
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17
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Gauberg J, Elkhatib W, Smith CL, Singh A, Senatore A. Divergent Ca 2+/calmodulin feedback regulation of Ca V1 and Ca V2 voltage-gated calcium channels evolved in the common ancestor of Placozoa and Bilateria. J Biol Chem 2022; 298:101741. [PMID: 35182524 PMCID: PMC8980814 DOI: 10.1016/j.jbc.2022.101741] [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: 08/07/2021] [Revised: 02/10/2022] [Accepted: 02/13/2022] [Indexed: 11/04/2022] Open
Abstract
CaV1 and CaV2 voltage-gated calcium channels evolved from an ancestral CaV1/2 channel via gene duplication somewhere near the stem animal lineage. The divergence of these channel types led to distinguishing functional properties that are conserved among vertebrates and bilaterian invertebrates and contribute to their unique cellular roles. One key difference pertains to their regulation by calmodulin (CaM), wherein bilaterian CaV1 channels are uniquely subject to pronounced, buffer-resistant Ca2+/CaM-dependent inactivation, permitting negative feedback regulation of calcium influx in response to local cytoplasmic Ca2+ rises. Early diverging, nonbilaterian invertebrates also possess CaV1 and CaV2 channels, but it is unclear whether they share these conserved functional features. The most divergent animals to possess both CaV1 and CaV2 channels are placozoans such as Trichoplax adhaerens, which separated from other animals over 600 million years ago shortly after their emergence. Hence, placozoans can provide important insights into the early evolution of CaV1 and CaV2 channels. Here, we build upon previous characterization of Trichoplax CaV channels by determining the cellular expression and ion-conducting properties of the CaV1 channel orthologue, TCaV1. We show that TCaV1 is expressed in neuroendocrine-like gland cells and contractile dorsal epithelial cells. In vitro, this channel conducts dihydropyridine-insensitive, high-voltage–activated Ca2+ currents with kinetics resembling those of rat CaV1.2 but with left-shifted voltage sensitivity for activation and inactivation. Interestingly, TCaV1, but not TCaV2, exhibits buffer-resistant Ca2+/CaM-dependent inactivation, indicating that this functional divergence evolved prior to the emergence of bilaterian animals and may have contributed to their unique adaptation for cytoplasmic Ca2+ signaling within various cellular contexts.
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Affiliation(s)
- Julia Gauberg
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Wassim Elkhatib
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Carolyn L Smith
- NINDS, National Institutes of Health, Bethesda Maryland, 20892 USA
| | - Anhadvir Singh
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Adriano Senatore
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada.
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18
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Prakash O, Held M, McCormick LF, Gupta N, Lian LY, Antonyuk S, Haynes LP, Thomas NL, Helassa N. CPVT-associated calmodulin variants N53I and A102V dysregulate Ca2+ signalling via different mechanisms. J Cell Sci 2022; 135:274029. [PMID: 34888671 PMCID: PMC8917356 DOI: 10.1242/jcs.258796] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 11/29/2021] [Indexed: 12/26/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited condition that can cause fatal cardiac arrhythmia. Human mutations in the Ca2+ sensor calmodulin (CaM) have been associated with CPVT susceptibility, suggesting that CaM dysfunction is a key driver of the disease. However, the detailed molecular mechanism remains unclear. Focusing on the interaction with the cardiac ryanodine receptor (RyR2), we determined the effect of CPVT-associated variants N53I and A102V on the structural characteristics of CaM and on Ca2+ fluxes in live cells. We provide novel data showing that interaction of both Ca2+/CaM-N53I and Ca2+/CaM-A102V with the RyR2 binding domain is decreased. Ca2+/CaM-RyR23583-3603 high-resolution crystal structures highlight subtle conformational changes for the N53I variant, with A102V being similar to wild type (WT). We show that co-expression of CaM-N53I or CaM-A102V with RyR2 in HEK293 cells significantly increased the duration of Ca2+ events; CaM-A102V exhibited a lower frequency of Ca2+ oscillations. In addition, we show that CaMKIIδ (also known as CAMK2D) phosphorylation activity is increased for A102V, compared to CaM-WT. This paper provides novel insight into the molecular mechanisms of CPVT-associated CaM variants and will facilitate the development of strategies for future therapies.
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Affiliation(s)
- Ohm Prakash
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Marie Held
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Liam F. McCormick
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Nitika Gupta
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - Lu-Yun Lian
- Nuclear Magnetic Resonance Centre for Structural Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Svetlana Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK
| | - Lee P. Haynes
- Department of Molecular Physiology and Cell Signalling, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK
| | - N. Lowri Thomas
- School of Pharmacy & Pharmaceutical Sciences, Cardiff University, Cardiff, Redwood Building, CF10 3NB, UK
| | - Nordine Helassa
- Liverpool Centre for Cardiovascular Science, Department of Cardiovascular Science and Metabolic Medicine, Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 3BX, UK,Author for correspondence ()
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19
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Ames JB. L-Type Ca 2+ Channel Regulation by Calmodulin and CaBP1. Biomolecules 2021; 11:1811. [PMID: 34944455 PMCID: PMC8699282 DOI: 10.3390/biom11121811] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/30/2021] [Accepted: 11/30/2021] [Indexed: 01/12/2023] Open
Abstract
L-type voltage-gated Ca2+ channels (CaV1.2 and CaV1.3, called CaV) interact with the Ca2+ sensor proteins, calmodulin (CaM) and Ca2+ binding Protein 1 (CaBP1), that oppositely control Ca2+-dependent channel activity. CaM and CaBP1 can each bind to the IQ-motif within the C-terminal cytosolic domain of CaV, which promotes increased channel open probability under basal conditions. At elevated cytosolic Ca2+ levels (caused by CaV channel opening), Ca2+-bound CaM binding to CaV is essential for promoting rapid Ca2+-dependent channel inactivation (CDI). By contrast, CaV binding to CaBP1 prevents CDI and promotes Ca2+-induced channel opening (called CDF). In this review, I provide an overview of the known structures of CaM and CaBP1 and their structural interactions with the IQ-motif to help understand how CaM promotes CDI, whereas CaBP1 prevents CDI and instead promotes CDF. Previous electrophysiology studies suggest that Ca2+-free forms of CaM and CaBP1 may pre-associate with CaV under basal conditions. However, previous Ca2+ binding data suggest that CaM and CaBP1 are both calculated to bind to Ca2+ with an apparent dissociation constant of ~100 nM when CaM or CaBP1 is bound to the IQ-motif. Since the neuronal basal cytosolic Ca2+ concentration is ~100 nM, nearly half of the neuronal CaV channels are suggested to be bound to Ca2+-bound forms of either CaM or CaBP1 under basal conditions. The pre-association of CaV with calcified forms of CaM or CaBP1 are predicted here to have functional implications. The Ca2+-bound form of CaBP1 is proposed to bind to CaV under basal conditions to block CaV binding to CaM, which could explain how CaBP1 might prevent CDI.
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Affiliation(s)
- James B Ames
- Department of Chemistry, University of California, Davis, CA 95616, USA
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20
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Hoang-Trong MT, Ullah A, Lederer WJ, Jafri MS. Cardiac Alternans Occurs through the Synergy of Voltage- and Calcium-Dependent Mechanisms. MEMBRANES 2021; 11:794. [PMID: 34677560 PMCID: PMC8539281 DOI: 10.3390/membranes11100794] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 11/24/2022]
Abstract
Cardiac alternans is characterized by alternating weak and strong beats of the heart. This signaling at the cellular level may appear as alternating long and short action potentials (APs) that occur in synchrony with alternating large and small calcium transients, respectively. Previous studies have suggested that alternans manifests itself through either a voltage dependent mechanism based upon action potential restitution or as a calcium dependent mechanism based on refractoriness of calcium release. We use a novel model of cardiac excitation-contraction (EC) coupling in the rat ventricular myocyte that includes 20,000 calcium release units (CRU) each with 49 ryanodine receptors (RyR2s) and 7 L-type calcium channels that are all stochastically gated. The model suggests that at the cellular level in the case of alternans produced by rapid pacing, the mechanism requires a synergy of voltage- and calcium-dependent mechanisms. The rapid pacing reduces AP duration and magnitude reducing the number of L-type calcium channels activating individual CRUs during each AP and thus increases the population of CRUs that can be recruited stochastically. Elevated myoplasmic and sarcoplasmic reticulum (SR) calcium, [Ca2+]myo and [Ca2+]SR respectively, increases ryanodine receptor open probability (Po) according to our model used in this simulation and this increased the probability of activating additional CRUs. A CRU that opens in one beat is less likely to open the subsequent beat due to refractoriness caused by incomplete refilling of the junctional sarcoplasmic reticulum (jSR). Furthermore, the model includes estimates of changes in Na+ fluxes and [Na+]i and thus provides insight into how changes in electrical activity, [Na+]i and sodium-calcium exchanger activity can modulate alternans. The model thus tracks critical elements that can account for rate-dependent changes in [Na+]i and [Ca2+]myo and how they contribute to the generation of Ca2+ signaling alternans in the heart.
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Affiliation(s)
- Minh Tuan Hoang-Trong
- Krasnow Institute for Advanced Study and School of Systems Biology, George Mason University, Fairfax, VA 22030, USA; (M.T.H.-T.); (A.U.)
| | - Aman Ullah
- Krasnow Institute for Advanced Study and School of Systems Biology, George Mason University, Fairfax, VA 22030, USA; (M.T.H.-T.); (A.U.)
| | - William Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Mohsin Saleet Jafri
- Krasnow Institute for Advanced Study and School of Systems Biology, George Mason University, Fairfax, VA 22030, USA; (M.T.H.-T.); (A.U.)
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
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21
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Yaduvanshi S, Ero R, Kumar V. The mechanism of complex formation between calmodulin and voltage gated calcium channels revealed by molecular dynamics. PLoS One 2021; 16:e0258112. [PMID: 34610038 PMCID: PMC8491939 DOI: 10.1371/journal.pone.0258112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/18/2021] [Indexed: 11/18/2022] Open
Abstract
Calmodulin, a ubiquitous eukaryotic calcium sensor responsible for the regulation of many fundamental cellular processes, is a highly flexible protein and exhibits an unusually wide range of conformations. Furthermore, CaM is known to interact with more than 300 cellular targets. Molecular dynamics (MD) simulation trajectories suggest that EF-hand loops show different magnitudes of flexibility. Therefore, the four EF-hand motifs have different affinities for Ca2+ ions, which enables CaM to function on wide range of Ca2+ ion concentrations. EF-hand loops are 2-3 times more flexible in apo CaM whereas least flexible in Ca2+/CaM-IQ motif complexes. We report a unique intermediate conformation of Ca2+/CaM while transitioning from extended to compact form. We also report the complex formation process between Ca2+/CaM and IQ CaM-binding motifs. Our results showed how IQ motif recognise its binding site on the CaM and how CaM transforms from extended to compact form upon binding to IQ motif.
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Affiliation(s)
- Shivani Yaduvanshi
- Amity Institute of Molecular Medicine and Stem Cell Research (AIMMSCR), Amity University Noida, Noida, Uttar Pradesh, India
| | - Rya Ero
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - Veerendra Kumar
- Amity Institute of Molecular Medicine and Stem Cell Research (AIMMSCR), Amity University Noida, Noida, Uttar Pradesh, India
- * E-mail:
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22
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Yu Q, Anderson DE, Kaur R, Fisher AJ, Ames JB. The Crystal Structure of Calmodulin Bound to the Cardiac Ryanodine Receptor (RyR2) at Residues Phe4246-Val4271 Reveals a Fifth Calcium Binding Site. Biochemistry 2021; 60:1088-1096. [PMID: 33754699 PMCID: PMC8211408 DOI: 10.1021/acs.biochem.1c00152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Calmodulin (CaM) regulates the activity of a Ca2+ channel known as the cardiac ryanodine receptor (RyR2), which facilitates the release of Ca2+ from the sarcoplasmic reticulum during excitation-contraction coupling in cardiomyocytes. Mutations that disrupt this CaM-dependent channel inactivation result in cardiac arrhythmias. RyR2 contains three different CaM binding sites: CaMBD1 (residues 1940-1965), CaMBD2 (residues 3580-3611), and CaMBD3 (residues 4246-4275). Here, we report a crystal structure of Ca2+-bound CaM bound to RyR2 CaMBD3. The structure reveals Ca2+ bound to the four EF-hands of CaM as well as a fifth Ca2+ bound to CaM in the interdomain linker region involving Asp81 and Glu85. The CaM mutant E85A abolishes the binding of the fifth Ca2+ and weakens the binding of CaMBD3 to Ca2+-bound CaM. Thus, the binding of the fifth Ca2+ is important for stabilizing the complex in solution and is not a crystalline artifact. The CaMBD3 peptide in the complex adopts an α-helix (between Phe4246 and Val4271) that interacts with both lobes of CaM. Hydrophobic residues in the CaMBD3 helix (Leu4255 and Leu4259) form intermolecular contacts with the CaM N-lobe, and the CaMBD3 mutations (L4255A and L4259A) each weaken the binding of CaM to RyR2. Aromatic residues on the opposite side of the CaMBD3 helix (Phe4246 and Tyr4250) interact with the CaM C-lobe, but the mutants (F4246A and Y4250A) have no detectable effect on CaM binding in solution. We suggest that the binding of CaM to CaMBD3 and the binding of a fifth Ca2+ to CaM may contribute to the regulation of RyR2 channel function.
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Affiliation(s)
- Qinhong Yu
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - David E Anderson
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Ramanjeet Kaur
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Andrew J Fisher
- Department of Chemistry, University of California, Davis, California 95616, United States
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616, United States
| | - James B Ames
- Department of Chemistry, University of California, Davis, California 95616, United States
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23
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Liu Z, Zhang L, Yan Z, Ren Z, Han F, Tan X, Xiang Z, Dong F, Yang Z, Liu G, Wang Z, Zhang J, Que T, Tang C, Li Y, Wang S, Wu J, Li L, Huang C, Roos C, Li M. Genomic Mechanisms of Physiological and Morphological Adaptations of Limestone Langurs to Karst Habitats. Mol Biol Evol 2021; 37:952-968. [PMID: 31846031 DOI: 10.1093/molbev/msz301] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Knowledge of the physiological and morphological evolution and adaptation of nonhuman primates is critical to understand hominin origins, physiological ecology, morphological evolution, and applications in biomedicine. Particularly, limestone langurs represent a direct example of adaptations to the challenges of exploiting a high calcium and harsh environment. Here, we report a de novo genome assembly (Tfra_2.0) of a male François's langur (Trachypithecus francoisi) with contig N50 of 16.3 Mb and resequencing data of 23 individuals representing five limestone and four forest langur species. Comparative genomics reveals evidence for functional evolution in genes and gene families related to calcium signaling in the limestone langur genome, probably as an adaptation to naturally occurring high calcium levels present in water and plant resources in karst habitats. The genomic and functional analyses suggest that a single point mutation (Lys1905Arg) in the α1c subunit of the L-type voltage-gated calcium channel Cav1.2 (CACNA1C) attenuates the inward calcium current into the cells in vitro. Population genomic analyses and RNA-sequencing indicate that EDNRB is less expressed in white tail hair follicles of the white-headed langur (T. leucocephalus) compared with the black-colored François's langur and hence might be responsible for species-specific differences in body coloration. Our findings contribute to a new understanding of gene-environment interactions and physiomorphological adaptative mechanisms in ecologically specialized primate taxa.
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Affiliation(s)
- Zhijin Liu
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Liye Zhang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhongze Yan
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Zhijie Ren
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Fengming Han
- Biomarker Technologies Corporation, Beijing 101300, China
| | - Xinxin Tan
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyuan Xiang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Dong
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Zuomin Yang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,School of Life Sciences, Qufu Normal University, Qufu 273165, Shandong, China
| | - Guangjian Liu
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China
| | - Ziming Wang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiali Zhang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China
| | - Tengcheng Que
- Guangxi Zhuang Autonomous Region Terrestrial Wildlife Medical-Aid Monitoring Epidemic Diseases Research Center, Nanning 530001, Guangxi Province, China
| | - Chaohui Tang
- Wuzhou Langur Breeding and Research Center, Wuzhou 543002, Guangxi Province, China
| | - Yifeng Li
- Wuzhou Langur Breeding and Research Center, Wuzhou 543002, Guangxi Province, China
| | - Song Wang
- Nanning Zoo, Nanning 530000, Guangxi Province, China
| | - Junyi Wu
- Nanning Zoo, Nanning 530000, Guangxi Province, China
| | - Legong Li
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - Chengming Huang
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China
| | - Christian Roos
- Gene Bank of Primates and Primate Genetics Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen 37077, Germany
| | - Ming Li
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Beijing 100101, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
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24
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Mahling R, Rahlf CR, Hansen SC, Hayden MR, Shea MA. Ca 2+-saturated calmodulin binds tightly to the N-terminal domain of A-type fibroblast growth factor homologous factors. J Biol Chem 2021; 296:100458. [PMID: 33639159 PMCID: PMC8059062 DOI: 10.1016/j.jbc.2021.100458] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 01/12/2023] Open
Abstract
Voltage-gated sodium channels (Navs) are tightly regulated by multiple conserved auxiliary proteins, including the four fibroblast growth factor homologous factors (FGFs), which bind the Nav EF-hand like domain (EFL), and calmodulin (CaM), a multifunctional messenger protein that binds the NaV IQ motif. The EFL domain and IQ motif are contiguous regions of NaV cytosolic C-terminal domains (CTD), placing CaM and FGF in close proximity. However, whether the FGFs and CaM act independently, directly associate, or operate through allosteric interactions to regulate channel function is unknown. Titrations monitored by steady-state fluorescence spectroscopy, structural studies with solution NMR, and computational modeling demonstrated for the first time that both domains of (Ca2+)4-CaM (but not apo CaM) directly bind two sites in the N-terminal domain (NTD) of A-type FGF splice variants (FGF11A, FGF12A, FGF13A, and FGF14A) with high affinity. The weaker of the (Ca2+)4-CaM-binding sites was known via electrophysiology to have a role in long-term inactivation of the channel but not known to bind CaM. FGF12A binding to a complex of CaM associated with a fragment of the NaV1.2 CTD increased the Ca2+-binding affinity of both CaM domains, consistent with (Ca2+)4-CaM interacting preferentially with its higher-affinity site in the FGF12A NTD. Thus, A-type FGFs can compete with NaV IQ motifs for (Ca2+)4-CaM. During spikes in the cytosolic Ca2+ concentration that accompany an action potential, CaM may translocate from the NaV IQ motif to the FGF NTD, or the A-type FGF NTD may recruit a second molecule of CaM to the channel.
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Affiliation(s)
- Ryan Mahling
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Cade R Rahlf
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Samuel C Hansen
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Matthew R Hayden
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Madeline A Shea
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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25
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Ma XF, Zhang YY, Guo FY, Luo JX, Ding W, Zhang YQ. Molecular characterization of a voltage-gated calcium channel and its potential role in the acaricidal action of scopoletin against Tetranychus cinnabarinus. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 168:104618. [PMID: 32711759 DOI: 10.1016/j.pestbp.2020.104618] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 04/18/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is a polyphagous agricultural pest with an extensive host plant range. Scopoletin is a promising acaricidal compound whose acaricidal mechanism may occur by disrupting intracellular Ca2+ homeostasis and calcium signaling pathways. However, the underlying mechanism of scopoletin for specific target locations of T. cinnabarinus remains unclear. In this study, a full-length cDNA of the L-type voltage-gated calcium channel (TcLTCC) subunit gene from T. cinnabarinus was cloned and characterized. The expression pattern of the TcLTCC gene in all developmental stages of T. cinnabarinus was analyzed. The gene was highly expressed in larval and nymphal stages and was significantly upregulated after treatment with scopoletin. Knocking down the TcLTCC transcript reduced the sensitivity of T. cinnabarinus to scopoletin. Homology modeling and molecular docking were also conducted. The interaction between scopoletin and TcLTCC showed that scopoletin inserted into the cavity bound to the site of the TcLTCC protein by the driving force of hydrogen bonding. This study provides insights into the mechanism by which scopoletin interacts with TcLTCC. Results can improve the understanding of the toxicity of scopoletin to T. cinnabarinus and provide valuable information for the design of new LTCC inhibitors.
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Affiliation(s)
- Xiao-Feng Ma
- College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Yuan-Yuan Zhang
- College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Fu-You Guo
- College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Jin-Xiang Luo
- College of Plant Protection, Southwest University, Chongqing 400715, China
| | - Wei Ding
- College of Plant Protection, Southwest University, Chongqing 400715, China; State Cultivation Base of Crop Stress Biology for Southern Mountainous Land Southwest University, Chongqing 400715, China
| | - Yong-Qiang Zhang
- College of Plant Protection, Southwest University, Chongqing 400715, China; State Cultivation Base of Crop Stress Biology for Southern Mountainous Land Southwest University, Chongqing 400715, China; Chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing, Southwest University, Chongqing 400715, China.
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26
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Wang J, Yeckel G, Kandoth PK, Wasala L, Hussey RS, Davis EL, Baum TJ, Mitchum MG. Targeted suppression of soybean BAG6-induced cell death in yeast by soybean cyst nematode effectors. MOLECULAR PLANT PATHOLOGY 2020; 21:1227-1239. [PMID: 32686295 PMCID: PMC7411569 DOI: 10.1111/mpp.12970] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 05/29/2023]
Abstract
While numerous effectors that suppress plant immunity have been identified from bacteria, fungi, and oomycete pathogens, relatively little is known for nematode effectors. Several dozen effectors have been reported from the soybean cyst nematode (SCN). Previous studies suggest that a hypersensitive response-like programmed cell death is triggered at nematode feeding sites in soybean during an incompatible interaction. However, virulent SCN populations overcome this incompatibility using unknown mechanisms. A soybean BAG6 (Bcl-2 associated anthanogene 6) gene previously reported by us to be highly up-regulated in degenerating feeding sites induced by SCN in a resistant soybean line was attenuated in response to a virulent SCN population. We show that GmBAG6-1 induces cell death in yeast like its Arabidopsis homolog AtBAG6 and also in soybean. This led us to hypothesize that virulent SCN may target GmBAG6-1 as part of their strategy to overcome soybean defence responses during infection. Thus, we used a yeast viability assay to screen SCN effector candidates for their ability to specifically suppress GmBAG6-1-induced cell death. We identified several effectors that strongly suppressed cell death mediated by GmBAG6-1. Two effectors identified as suppressors showed direct interaction with GmBAG6-1 in yeast, suggesting that one mechanism of cell death suppression may occur through an interaction with this host protein.
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Affiliation(s)
- Jianying Wang
- Division of Plant Sciences and Bond Life Sciences CenterUniversity of MissouriColumbiaMOUSA
| | - Greg Yeckel
- Division of Plant Sciences and Bond Life Sciences CenterUniversity of MissouriColumbiaMOUSA
- Present address:
Corteva AgriscienceJohnstonIAUSA
| | - Pramod K. Kandoth
- Division of Plant Sciences and Bond Life Sciences CenterUniversity of MissouriColumbiaMOUSA
- Present address:
National Agri‐food Biotechnology InstituteMohaliIndia
| | - Lakmini Wasala
- Division of Plant Sciences and Bond Life Sciences CenterUniversity of MissouriColumbiaMOUSA
- Present address:
Department of Veterinary PathobiologyUniversity of MissouriColumbiaMOUSA
| | | | - Eric L. Davis
- Department of Entomology and Plant PathologyNorth Carolina State UniversityRaleighNCUSA
| | - Thomas J. Baum
- Department of Plant Pathology and MicrobiologyIowa State UniversityAmesIAUSA
| | - Melissa G. Mitchum
- Division of Plant Sciences and Bond Life Sciences CenterUniversity of MissouriColumbiaMOUSA
- Department of Plant Pathology and Institute of Plant Breeding, Genetics, and GenomicsUniversity of GeorgiaAthensGAUSA
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27
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Chakouri N, Diaz J, Yang PS, Ben-Johny M. Ca V channels reject signaling from a second CaM in eliciting Ca 2+-dependent feedback regulation. J Biol Chem 2020; 295:14948-14962. [PMID: 32820053 DOI: 10.1074/jbc.ra120.013777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 08/18/2020] [Indexed: 11/06/2022] Open
Abstract
Calmodulin (CaM) regulation of voltage-gated calcium (CaV1-2) channels is a powerful Ca2+-feedback mechanism to adjust channel activity in response to Ca2+ influx. Despite progress in resolving mechanisms of CaM-CaV feedback, the stoichiometry of CaM interaction with CaV channels remains ambiguous. Functional studies that tethered CaM to CaV1.2 suggested that a single CaM sufficed for Ca2+ feedback, yet biochemical, FRET, and structural studies showed that multiple CaM molecules interact with distinct interfaces within channel cytosolic segments, suggesting that functional Ca2+ regulation may be more nuanced. Resolving this ambiguity is critical as CaM is enriched in subcellular domains where CaV channels reside, such as the cardiac dyad. We here localized multiple CaMs to the CaV nanodomain by tethering either WT or mutant CaM that lack Ca2+-binding capacity to the pore-forming α-subunit of CaV1.2, CaV1.3, and CaV2.1 and/or the auxiliary β2A subunit. We observed that a single CaM tethered to either the α or β2A subunit tunes Ca2+ regulation of CaV channels. However, when multiple CaMs are localized concurrently, CaV channels preferentially respond to signaling from the α-subunit-tethered CaM. Mechanistically, the introduction of a second IQ domain to the CaV1.3 carboxyl tail switched the apparent functional stoichiometry, permitting two CaMs to mediate functional regulation. In all, Ca2+ feedback of CaV channels depends exquisitely on a single CaM preassociated with the α-subunit carboxyl tail. Additional CaMs that colocalize with the channel complex are unable to trigger Ca2+-dependent feedback of channel gating but may support alternate regulatory functions.
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Affiliation(s)
- Nourdine Chakouri
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA
| | - Johanna Diaz
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA
| | - Philemon S Yang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Manu Ben-Johny
- Department of Physiology and Cellular Biophysics, Columbia University, New York, New York, USA.
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28
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Colecraft HM. Designer genetically encoded voltage-dependent calcium channel inhibitors inspired by RGK GTPases. J Physiol 2020; 598:1683-1693. [PMID: 32104913 PMCID: PMC7195252 DOI: 10.1113/jp276544] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/07/2020] [Indexed: 12/28/2022] Open
Abstract
High‐voltage‐activated calcium (CaV1/CaV2) channels translate action potentials into Ca2+ influx in excitable cells to control essential biological processes that include; muscle contraction, synaptic transmission, hormone secretion and activity‐dependent regulation of gene expression. Modulation of CaV1/CaV2 channel activity is a powerful mechanism to regulate physiology, and there are a host of intracellular signalling molecules that tune different aspects of CaV channel trafficking and gating for this purpose. Beyond normal physiological regulation, the diverse CaV channel modulatory mechanisms may potentially be co‐opted or interfered with for therapeutic benefits. CaV1/CaV2 channels are potently inhibited by a four‐member sub‐family of Ras‐like GTPases known as RGK (Rad, Rem, Rem2, Gem/Kir) proteins. Understanding the mechanisms by which RGK proteins inhibit CaV1/CaV2 channels has led to the development of novel genetically encoded CaV channel blockers with unique properties; including, chemo‐ and optogenetic control of channel activity, and blocking channels either on the basis of their subcellular localization or by targeting an auxiliary subunit. These genetically encoded CaV channel inhibitors have outstanding utility as enabling research tools and potential therapeutics.
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Affiliation(s)
- Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Department of Pharmacology and Molecular Signaling, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
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29
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Dürvanger Z, Harmat V. Structural Diversity in Calmodulin - Peptide Interactions. Curr Protein Pept Sci 2020; 20:1102-1111. [PMID: 31553290 DOI: 10.2174/1389203720666190925101937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 03/13/2019] [Accepted: 04/12/2019] [Indexed: 01/17/2023]
Abstract
Calmodulin (CaM) is a highly conserved eukaryotic Ca2+ sensor protein that is able to bind a large variety of target sequences without a defined consensus sequence. The recognition of this diverse target set allows CaM to take part in the regulation of several vital cell functions. To fully understand the structural basis of the regulation functions of CaM, the investigation of complexes of CaM and its targets is essential. In this minireview we give an outline of the different types of CaM - peptide complexes with 3D structure determined, also providing an overview of recently determined structures. We discuss factors defining the orientations of peptides within the complexes, as well as roles of anchoring residues. The emphasis is on complexes where multiple binding modes were found.
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Affiliation(s)
- Zsolt Dürvanger
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary
| | - Veronika Harmat
- Laboratory of Structural Chemistry and Biology, Institute of Chemistry, Eötvös Loránd University, Budapest, Hungary.,MTA-ELTE Protein Modelling Research Group, Budapest, Hungary
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30
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Calmodulin Mutations Associated with Heart Arrhythmia: A Status Report. Int J Mol Sci 2020; 21:ijms21041418. [PMID: 32093079 PMCID: PMC7073091 DOI: 10.3390/ijms21041418] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 02/06/2023] Open
Abstract
Calmodulin (CaM) is a ubiquitous intracellular Ca2+ sensing protein that modifies gating of numerous ion channels. CaM has an extraordinarily high level of evolutionary conservation, which led to the fundamental assumption that mutation would be lethal. However, in 2012, complete exome sequencing of infants suffering from recurrent cardiac arrest revealed de novo mutations in the three human CALM genes. The correlation between mutations and pathophysiology suggests defects in CaM-dependent ion channel functions. Here, we review the current state of the field for all reported CaM mutations associated with cardiac arrhythmias, including knowledge of their biochemical and structural characteristics, and progress towards understanding how these mutations affect cardiac ion channel function.
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31
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Wang K, Brohus M, Holt C, Overgaard MT, Wimmer R, Van Petegem F. Arrhythmia mutations in calmodulin can disrupt cooperativity of Ca 2+ binding and cause misfolding. J Physiol 2020; 598:1169-1186. [PMID: 32012279 DOI: 10.1113/jp279307] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/28/2020] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Mutations in the calmodulin protein (CaM) are associated with arrhythmia syndromes. This study focuses on understanding the structural characteristics of CaM disease mutants and their interactions with the voltage-gated calcium channel CaV 1.2. Arrhythmia mutations in CaM can lead to loss of Ca2+ binding, uncoupling of Ca2+ binding cooperativity, misfolding of the EF-hands and altered affinity for the calcium channel. These results help us to understand how different CaM mutants have distinct effects on structure and interactions with protein targets to cause disease. ABSTRACT Calmodulinopathies are life-threatening arrhythmia syndromes that arise from mutations in calmodulin (CaM), a calcium sensing protein whose sequence is completely conserved across all vertebrates. These mutations have been shown to interfere with the function of cardiac ion channels, including the voltage-gated Ca2+ channel CaV 1.2 and the ryanodine receptor (RyR2), in a mutation-specific manner. The ability of different CaM disease mutations to discriminate between these channels has been enigmatic. We present crystal structures of several C-terminal lobe mutants and an N-terminal lobe mutant in complex with the CaV 1.2 IQ domain, in conjunction with binding assays and complementary structural biology techniques. One mutation (D130G) causes a pathological conformation, with complete separation of EF-hands within the C-lobe and loss of Ca2+ binding in EF-hand 4. Another variant (Q136P) has severely reduced affinity for the IQ domain, and shows changes in the CD spectra under Ca2+ -saturating conditions when unbound to the IQ domain. Ca2+ binding to a pair of EF-hands normally proceeds with very high cooperativity, but we found that N98S CaM can adopt different conformations with either one or two Ca2+ ions bound to the C-lobe, possibly disrupting the cooperativity. An N-lobe variant (N54I), which causes severe stress-induced arrhythmia, does not show any major changes in complex with the IQ domain, providing a structural basis for why this mutant does not affect function of CaV 1.2. These findings show that different CaM mutants have distinct effects on both the CaM structure and interactions with protein targets, and act via distinct pathological mechanisms to cause disease.
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Affiliation(s)
- Kaiqian Wang
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, V6T 1Z3 Vancouver, BC, Canada
| | - Malene Brohus
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Christian Holt
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | | | - Reinhard Wimmer
- Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, V6T 1Z3 Vancouver, BC, Canada
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32
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Turner M, Anderson DE, Bartels P, Nieves-Cintron M, Coleman AM, Henderson PB, Man KNM, Tseng PY, Yarov-Yarovoy V, Bers DM, Navedo MF, Horne MC, Ames JB, Hell JW. α-Actinin-1 promotes activity of the L-type Ca 2+ channel Ca v 1.2. EMBO J 2020; 39:e102622. [PMID: 31985069 DOI: 10.15252/embj.2019102622] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 12/04/2019] [Accepted: 12/06/2019] [Indexed: 01/05/2023] Open
Abstract
The L-type Ca2+ channel CaV 1.2 governs gene expression, cardiac contraction, and neuronal activity. Binding of α-actinin to the IQ motif of CaV 1.2 supports its surface localization and postsynaptic targeting in neurons. We report a bi-functional mechanism that restricts CaV 1.2 activity to its target sites. We solved separate NMR structures of the IQ motif (residues 1,646-1,664) bound to α-actinin-1 and to apo-calmodulin (apoCaM). The CaV 1.2 K1647A and Y1649A mutations, which impair α-actinin-1 but not apoCaM binding, but not the F1658A and K1662E mutations, which impair apoCaM but not α-actinin-1 binding, decreased single-channel open probability, gating charge movement, and its coupling to channel opening. Thus, α-actinin recruits CaV 1.2 to defined surface regions and simultaneously boosts its open probability so that CaV 1.2 is mostly active when appropriately localized.
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Affiliation(s)
- Matthew Turner
- Department of Chemistry, University of California, Davis, CA, USA
| | - David E Anderson
- Department of Chemistry, University of California, Davis, CA, USA
| | - Peter Bartels
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Andrea M Coleman
- Department of Chemistry, University of California, Davis, CA, USA.,Department of Pharmacology, University of California, Davis, CA, USA
| | - Peter B Henderson
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Kwun Nok Mimi Man
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Pang-Yen Tseng
- Department of Pharmacology, University of California, Davis, CA, USA
| | | | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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33
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Cao-Pham AH, Hiong KC, Boo MV, Choo CYL, Wong WP, Chew SF, Ip YK. Calcium absorption in the fluted giant clam, Tridacna squamosa, may involve a homolog of voltage-gated calcium channel subunit α1 (CACNA1) that has an apical localization and displays light-enhanced protein expression in the ctenidium. J Comp Physiol B 2019; 189:693-706. [DOI: 10.1007/s00360-019-01238-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 09/06/2019] [Accepted: 09/23/2019] [Indexed: 12/21/2022]
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Mellor GJ, Panwar P, Lee AK, Steinberg C, Hathaway JA, Bartels K, Christian S, Balaji S, Roberts JD, Simpson CS, Boczek NJ, Tester DJ, Radbill AE, Mok NS, Hamilton RM, Kaufman ES, Eugenio PL, Weiss R, January C, McDaniel GM, Leather RA, Erickson C, Falik S, Behr ER, Wilde AAM, Sanatani S, Ackerman MJ, Van Petegem F, Krahn AD, Laksman Z. Type 8 long QT syndrome: pathogenic variants in CACNA1C-encoded Cav1.2 cluster in STAC protein binding site. Europace 2019; 21:1725-1732. [DOI: 10.1093/europace/euz215] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/18/2019] [Indexed: 11/12/2022] Open
Abstract
Abstract
Aims
Pathogenic gain-of-function variants in CACAN1C cause type-8 long QT syndrome (LQT8). We sought to describe the electrocardiographic features in LQT8 and utilize molecular modelling to gain mechanistic insights into its genetic culprits.
Methods and results
Rare variants in CACNA1C were identified from genetic testing laboratories. Treating physicians provided clinical information. Variant pathogenicity was independently assessed according to recent guidelines. Pathogenic (P) and likely pathogenic (LP) variants were mapped onto a 3D modelled structure of the Cav1.2 protein. Nine P/LP variants, identified in 23 patients from 19 families with non-syndromic LQTS were identified. Six variants, found in 79% of families, clustered to a 4-residue section in the cytosolic II–III loop region which forms a region capable of binding STAC SH3 domains. Therefore, variants may affect binding of SH3-domain containing proteins. Arrhythmic events occurred in similar proportions of patients with II–III loop variants and with other P/LP variants (53% vs. 48%, P = 0.41) despite shorter QTc intervals (477 ± 31 ms vs. 515 ± 37 ms, P = 0.03). A history of sudden death was reported only in families with II–III loop variants (60% vs. 0%, P = 0.03). The predominant T-wave morphology was a late peaking T wave with a steep descending limb. Exercise testing demonstrated QTc prolongation on standing and at 4 min recovery after exercise.
Conclusion
The majority of P/LP variants in patients with CACNA1C-mediated LQT8 cluster in an SH3-binding domain of the cytosolic II–III loop. This represents a ‘mutation hotspot’ in LQT8. A late-peaking T wave with a steep descending limb and QT prolongation on exercise are commonly seen.
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Affiliation(s)
- Greg J Mellor
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
- Cardiology Department, Royal Papworth Hospital, Cambridge, UK
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Andrea K Lee
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
| | - Christian Steinberg
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
| | - Julie A Hathaway
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
| | - Kirsten Bartels
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
| | - Susan Christian
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
| | - Seshadri Balaji
- Division of Cardiology, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
| | - Jason D Roberts
- Section of Cardiac Electrophysiology, Division of Cardiology, Department of Medicine, Western University, London, ON, Canada
| | - Chris S Simpson
- Heart Rhythm Service, Division of Cardiology, Queen’s University, Kingston, ON, Canada
| | - Nicole J Boczek
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Pediatric Cardiology, Department of Pediatrics, Mayo Clinic, Rochester, MN, USA
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - David J Tester
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Pediatric Cardiology, Department of Pediatrics, Mayo Clinic, Rochester, MN, USA
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | | | - Ngai-Shing Mok
- Department of Medicine & Geriatrics, Princess Margaret Hospital, Kowloon, Hong Kong
| | - Robert M Hamilton
- Labatt Family Heart Centre and Division of Cardiology, Department of Pediatrics, and Translational Medicine, The Hospital for Sick Children and University of Toronto, Toronto, ON, Canada
| | | | - Paul L Eugenio
- Division of Cardiology, Montefiore Medical Center, Bronx, NY, USA
| | - Raul Weiss
- Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Craig January
- School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - George M McDaniel
- Division of Pediatric Cardiology, University of Virginia, Charlottesville, VA, USA
| | | | - Christopher Erickson
- Pediatric Cardiology, Children’s Hospital & Medical Center/University of Nebraska Medical Center, Omaha, NA, USA
| | - Shelley Falik
- Division of Cardiology, Department of Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Elijah R Behr
- Cardiology Clinical Academic Group, St. George’s, University of London, London, UK
| | - Arthur A M Wilde
- Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Centre, Amsterdam, the Netherlands
| | | | - Michael J Ackerman
- Division of Heart Rhythm Services, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
- Division of Pediatric Cardiology, Department of Pediatrics, Mayo Clinic, Rochester, MN, USA
- Windland Smith Rice Sudden Death Genomics Laboratory, Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Andrew D Krahn
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
| | - Zachary Laksman
- Division of Cardiology, University of British Columbia, 1033 Davie St., Rm 211, Vancouver, BC, Canada
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Trigo-Mourino P, Thestrup T, Griesbeck O, Griesinger C, Becker S. Dynamic tuning of FRET in a green fluorescent protein biosensor. SCIENCE ADVANCES 2019; 5:eaaw4988. [PMID: 31457088 PMCID: PMC6685724 DOI: 10.1126/sciadv.aaw4988] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 06/27/2019] [Indexed: 06/01/2023]
Abstract
Förster resonance energy transfer (FRET) between mutants of green fluorescent protein is widely used to monitor protein-protein interactions and as a readout mode in fluorescent biosensors. Despite the fundamental importance of distance and molecular angles of fluorophores to each other, structural details on fluorescent protein FRET have been missing. Here, we report the high-resolution x-ray structure of the fluorescent proteins mCerulean3 and cpVenus within the biosensor Twitch-2B, as they undergo FRET and characterize the dynamics of this biosensor with B 0 2 -dependent paramagnetic nuclear magnetic resonance at 900 MHz and 1.1 GHz. These structural data provide the unprecedented opportunity to calculate FRET from the x-ray structure and to compare it to experimental data in solution. We find that interdomain dynamics limits the FRET effect and show that a rigidification of the sensor further enhances FRET.
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Affiliation(s)
- Pablo Trigo-Mourino
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- Structural Elucidation Group, Analytic Enabling Technologies, Merck & Co., 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA
| | | | | | - Christian Griesinger
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Stefan Becker
- Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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36
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Gan N, Zhen X, Liu Y, Xu X, He C, Qiu J, Liu Y, Fujimoto GM, Nakayasu ES, Zhou B, Zhao L, Puvar K, Das C, Ouyang S, Luo ZQ. Regulation of phosphoribosyl ubiquitination by a calmodulin-dependent glutamylase. Nature 2019; 572:387-391. [PMID: 31330531 PMCID: PMC6855250 DOI: 10.1038/s41586-019-1439-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 07/09/2019] [Indexed: 01/07/2023]
Abstract
The bacterial pathogen Legionella pneumophila creates an intracellular niche permissive for its replication by extensively modulating host-cell functions using hundreds of effector proteins delivered by its Dot/Icm secretion system1. Among these, members of the SidE family (SidEs) regulate several cellular processes through a unique phosphoribosyl ubiquitination mechanism that bypasses the canonical ubiquitination machinery2-4. The activity of SidEs is regulated by another Dot/Icm effector known as SidJ5; however, the mechanism of this regulation is not completely understood6,7. Here we demonstrate that SidJ inhibits the activity of SidEs by inducing the covalent attachment of glutamate moieties to SdeA-a member of the SidE family-at E860, one of the catalytic residues that is required for the mono-ADP-ribosyltransferase activity involved in ubiquitin activation2. This inhibition by SidJ is spatially restricted in host cells because its activity requires the eukaryote-specific protein calmodulin (CaM). We solved a structure of SidJ-CaM in complex with AMP and found that the ATP used in this reaction is cleaved at the α-phosphate position by SidJ, which-in the absence of glutamate or modifiable SdeA-undergoes self-AMPylation. Our results reveal a mechanism of regulation in bacterial pathogenicity in which a glutamylation reaction that inhibits the activity of virulence factors is activated by host-factor-dependent acyl-adenylation.
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Affiliation(s)
- Ninghai Gan
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xiangkai Zhen
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Yao Liu
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Xiaolong Xu
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Chunlin He
- Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, Department of Respiratory Medicine and Center of Infection and Immunity, The First Hospital of Jilin University, Changchun 130021, China
| | - Jiazhang Qiu
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, Jilin 130001, China
| | - Yancheng Liu
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Grant M. Fujimoto
- Biological Science Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Ernesto S. Nakayasu
- Biological Science Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Biao Zhou
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Lan Zhao
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China
| | - Kedar Puvar
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Chittaranjan Das
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Songying Ouyang
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of the Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou, 350117, China.,Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China.,Correspondence: ,
| | - Zhao-Qing Luo
- Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA,Correspondence: ,
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Flucher BE, Campiglio M. STAC proteins: The missing link in skeletal muscle EC coupling and new regulators of calcium channel function. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:1101-1110. [PMID: 30543836 DOI: 10.1016/j.bbamcr.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 01/19/2023]
Abstract
Excitation-contraction coupling is the signaling process by which action potentials control calcium release and consequently the force of muscle contraction. Until recently, three triad proteins were known to be essential for skeletal muscle EC coupling: the voltage-gated calcium channel CaV1.1 acting as voltage sensor, the SR calcium release channel RyR1 representing the only relevant calcium source, and the auxiliary CaV β1a subunit. Whether CaV1.1 and RyR1 are directly coupled or whether their interaction is mediated by another triad protein is still unknown. The recent identification of the adaptor protein STAC3 as fourth essential component of skeletal muscle EC coupling prompted vigorous research to reveal its role in this signaling process. Accumulating evidence supports its possible involvement in linking CaV1.1 and RyR1 in skeletal muscle EC coupling, but also indicates a second, much broader role of STAC proteins in the regulation of calcium/calmodulin-dependent feedback regulation of L-type calcium channels.
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Affiliation(s)
- Bernhard E Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria.
| | - Marta Campiglio
- Department of Physiology and Medical Physics, Medical University Innsbruck, Schöpfstraße 41, A6020 Innsbruck, Austria
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Dual Sensing of Physiologic pH and Calcium by EFCAB9 Regulates Sperm Motility. Cell 2019; 177:1480-1494.e19. [PMID: 31056283 PMCID: PMC8808721 DOI: 10.1016/j.cell.2019.03.047] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 02/08/2019] [Accepted: 03/25/2019] [Indexed: 11/24/2022]
Abstract
Varying pH of luminal fluid along the female reproductive tract is a physiological cue that modulates sperm motility. CatSper is a sperm-specific, pH-sensitive calcium channel essential for hyperactivated motility and male fertility. Multi-subunit CatSper channel complexes organize linear Ca2+ signaling nanodomains along the sperm tail. Here, we identify EF-hand calcium-binding domain-containing protein 9 (EFCAB9) as a bifunctional, cytoplasmic machine modulating the channel activity and the domain organization of CatSper. Knockout mice studies demonstrate that EFCAB9, in complex with the CatSper subunit, CATSPERζ, is essential for pH-dependent and Ca2+-sensitive activation of the CatSper channel. In the absence of EFCAB9, sperm motility and fertility is compromised, and the linear arrangement of the Ca2+ signaling domains is disrupted. EFCAB9 interacts directly with CATSPERζ in a Ca2+-dependent manner and dissociates at elevated pH. These observations suggest that EFCAB9 is a long-sought, intracellular, pH-dependent Ca2+ sensor that triggers changes in sperm motility.
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Crystal structures of Ca 2+-calmodulin bound to Na V C-terminal regions suggest role for EF-hand domain in binding and inactivation. Proc Natl Acad Sci U S A 2019; 116:10763-10772. [PMID: 31072926 DOI: 10.1073/pnas.1818618116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium (NaV) and calcium channels (CaV) form targets for calmodulin (CaM), which affects channel inactivation properties. A major interaction site for CaM resides in the C-terminal (CT) region, consisting of an IQ domain downstream of an EF-hand domain. We present a crystal structure of fully Ca2+-occupied CaM, bound to the CT of NaV1.5. The structure shows that the C-terminal lobe binds to a site ∼90° rotated relative to a previous site reported for an apoCaM complex with the NaV1.5 CT and for ternary complexes containing fibroblast growth factor homologous factors (FHF). We show that the binding of FHFs forces the EF-hand domain in a conformation that does not allow binding of the Ca2+-occupied C-lobe of CaM. These observations highlight the central role of the EF-hand domain in modulating the binding mode of CaM. The binding sites for Ca2+-free and Ca2+-occupied CaM contain targets for mutations linked to long-QT syndrome, a type of inherited arrhythmia. The related NaV1.4 channel has been shown to undergo Ca2+-dependent inactivation (CDI) akin to CaVs. We present a crystal structure of Ca2+/CaM bound to the NaV1.4 IQ domain, which shows a binding mode that would clash with the EF-hand domain. We postulate the relative reorientation of the EF-hand domain and the IQ domain as a possible conformational switch that underlies CDI.
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40
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Abstract
Large scale functional motions of molecules are studied experimentally using numerous molecular and biophysics techniques, the data from which are subsequently interpreted using diverse models of Brownian molecular dynamics. To unify all rotational physics techniques and motional models, the frame order tensor - a universal statistical mechanics theory based on the rotational ordering of rigid body frames - is herein formulated. The frame ordering is the fundamental physics that governs how motions modulate rotational molecular physics and it defines the properties and maximum information content encoded in the observable physics. Using the tensor to link residual dipolar couplings and pseudo-contact shifts, two distinct information-rich and atomic-level biophysical measurements from the field of nuclear magnetic resonance spectroscopy, to a number of basic mechanical joint models, a highly dynamic state of calmodulin (CaM) bound to a target peptide in a tightly closed conformation was observed. Intra- and inter-domain motions reveal the CaM complex to be entropically primed for peptide release.
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41
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Salveson I, Anderson DE, Hell JW, Ames JB. Chemical shift assignments of a calmodulin intermediate with two Ca 2+ bound in complex with the IQ-motif of voltage-gated Ca 2+ channels (Ca V1.2). BIOMOLECULAR NMR ASSIGNMENTS 2019; 13:233-237. [PMID: 30788773 PMCID: PMC6440834 DOI: 10.1007/s12104-019-09883-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 02/16/2019] [Indexed: 06/09/2023]
Abstract
Calcium-dependent inactivation (CDI) of neuronal voltage-gated Ca2+ channels (CaV1.2) is important for synaptic plasticity, which is associated with learning and memory. The Ca2+-dependent binding of calmodulin (CaM) to CaV1.2 is essential for CDI. Here we report NMR assignments for a CaM mutant (D21A/D23A/D25A/E32Q/D57A/D59A/N61A/E68Q, called CaMEF12) that contains two Ca2+ bound at the third and fourth EF-hands (EF3 and EF4) and is bound to the IQ-motif (residues 1644-1665) from CaV1.2 (BMRB accession no. 27692).
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Affiliation(s)
- Ian Salveson
- Department of Chemistry, University of California, 95616, Davis, CA, USA
| | - David E Anderson
- Department of Chemistry, University of California, 95616, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, 95616, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, 95616, Davis, CA, USA.
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42
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A Selectivity Filter Gate Controls Voltage-Gated Calcium Channel Calcium-Dependent Inactivation. Neuron 2019; 101:1134-1149.e3. [DOI: 10.1016/j.neuron.2019.01.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 11/12/2018] [Accepted: 12/31/2018] [Indexed: 11/22/2022]
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43
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Pancaroglu R, Van Petegem F. Calcium Channelopathies: Structural Insights into Disorders of the Muscle Excitation–Contraction Complex. Annu Rev Genet 2018; 52:373-396. [DOI: 10.1146/annurev-genet-120417-031311] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ion channels are membrane proteins responsible for the passage of ions down their electrochemical gradients and across biological membranes. In this, they generate and shape action potentials and provide secondary messengers for various signaling pathways. They are often part of larger complexes containing auxiliary subunits and regulatory proteins. Channelopathies arise from mutations in the genes encoding ion channels or their associated proteins. Recent advances in cryo-electron microscopy have resulted in an explosion of ion channel structures in multiple states, generating a wealth of new information on channelopathies. Disease-associated mutations fall into different categories, interfering with ion permeation, protein folding, voltage sensing, ligand and protein binding, and allosteric modulation of channel gating. Prime examples of these are Ca2+-selective channels expressed in myocytes, for which multiple structures in distinct conformational states have recently been uncovered. We discuss the latest insights into these calcium channelopathies from a structural viewpoint.
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Affiliation(s)
- Raika Pancaroglu
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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Williams B, Haeseleer F, Lee A. Splicing of an automodulatory domain in Ca v1.4 Ca 2+ channels confers distinct regulation by calmodulin. J Gen Physiol 2018; 150:1676-1687. [PMID: 30355583 PMCID: PMC6279360 DOI: 10.1085/jgp.201812140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/03/2018] [Indexed: 12/17/2022] Open
Abstract
Cav1.4 Ca2+ channels provide maintained Ca2+ entry to support sustained neurotransmitter release, but a retinal splice variant exhibits calmodulin-dependent inactivation. Williams et al. show that the N lobe of calmodulin is involved in this process as well as Ca2+-dependent enhancement of channel activation. Ca2+ influx through Cav1.4 L-type Ca2+ channels supports the sustained release of glutamate from photoreceptor synaptic terminals in darkness, a process that is critical for vision. Consistent with this role, Cav1.4 exhibits weak Ca2+-dependent inactivation (CDI)—a negative feedback regulation mediated by Ca2+-bound calmodulin (CaM). CaM binds to a conserved IQ domain in the proximal C-terminal domain of Cav channels, but in Cav1.4, a C-terminal modulatory domain (CTM) disrupts interactions with CaM. Exon 47 encodes a portion of the CTM and is deleted in a Cav1.4 splice variant (Cav1.4Δex47) that is highly expressed in the human retina. Cav1.4Δex47 exhibits CDI and enhanced voltage-dependent activation, similar to that caused by a mutation that is associated with congenital stationary night blindness type 2, in which the CTM is deleted (K1591X). The presence of CDI and very negative activation thresholds in a naturally occurring variant of Cav1.4 are perplexing considering that these properties are expected to be maladaptive for visual signaling and result in night blindness in the case of K1591X. Here we show that Cav1.4Δex47 and K1591X exhibit fundamental differences in their regulation by CaM. In Cav1.4Δex47, CDI requires both the N-terminal (N lobe) and C-terminal (C lobe) lobes of CaM to bind Ca2+, whereas CDI in K1591X is driven mainly by Ca2+ binding to the C lobe. Moreover, the CaM N lobe causes a Ca2+-dependent enhancement of activation of Cav1.4Δex47 but not K1591X. We conclude that the residual CTM in Cav1.4Δex47 enables a form of CaM N lobe regulation of activation and CDI that is absent in K1591X. Interaction with the N lobe of CaM, which is more sensitive to global elevations in cytosolic Ca2+ than the C lobe, may allow Cav1.4Δex47 to be modulated by a wider range of synaptic Ca2+ concentrations than K1591X; this may distinguish the normal physiological function of Cav1.4Δex47 from the pathological consequences of K1591X.
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Affiliation(s)
- Brittany Williams
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA.,Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA
| | - Françoise Haeseleer
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Amy Lee
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA .,Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA.,Iowa Neuroscience Institute, University of Iowa, Iowa City, IA.,Department of Otolaryngology Head-Neck Surgery, University of Iowa, Iowa City, IA.,Department of Neurology, University of Iowa, Iowa City, IA
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45
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Arrhythmia mutations in calmodulin cause conformational changes that affect interactions with the cardiac voltage-gated calcium channel. Proc Natl Acad Sci U S A 2018; 115:E10556-E10565. [PMID: 30348784 DOI: 10.1073/pnas.1808733115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Calmodulin (CaM) represents one of the most conserved proteins among eukaryotes and is known to bind and modulate more than a 100 targets. Recently, several disease-associated mutations have been identified in the CALM genes that are causative of severe cardiac arrhythmia syndromes. Although several mutations have been shown to affect the function of various cardiac ion channels, direct structural insights into any CaM disease mutation have been lacking. Here we report a crystallographic and NMR investigation of several disease mutant CaMs, linked to long-QT syndrome, in complex with the IQ domain of the cardiac voltage-gated calcium channel (CaV1.2). Surprisingly, two mutants (D95V, N97I) cause a major distortion of the C-terminal lobe, resulting in a pathological conformation not reported before. These structural changes result in altered interactions with the CaV1.2 IQ domain. Another mutation (N97S) reduces the affinity for Ca2+ by introducing strain in EF hand 3. A fourth mutant (F141L) shows structural changes in the Ca2+-free state that increase the affinity for the IQ domain. These results thus show that different mechanisms underlie the ability of CaM disease mutations to affect Ca2+-dependent inactivation of the voltage-gated calcium channel.
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Stac Proteins Suppress Ca 2+-Dependent Inactivation of Neuronal l-type Ca 2+ Channels. J Neurosci 2018; 38:9215-9227. [PMID: 30201773 DOI: 10.1523/jneurosci.0695-18.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/30/2018] [Accepted: 09/01/2018] [Indexed: 01/28/2023] Open
Abstract
Stac protein (named for its SH3- and cysteine-rich domains) was first identified in brain 20 years ago and is currently known to have three isoforms. Stac2, Stac1, and Stac3 transcripts are found at high, modest, and very low levels, respectively, in the cerebellum and forebrain, but their neuronal functions have been little investigated. Here, we tested the effects of Stac proteins on neuronal, high-voltage-activated Ca2+ channels. Overexpression of the three Stac isoforms eliminated Ca2+-dependent inactivation (CDI) of l-type current in rat neonatal hippocampal neurons (sex unknown), but not CDI of non-l-type current. Using heterologous expression in tsA201 cells (together with β and α2-δ1 auxiliary subunits), we found that CDI for CaV1.2 and CaV1.3 (the predominant, neuronal l-type Ca2+ channels) was suppressed by all three Stac isoforms, whereas CDI for the P/Q channel, CaV2.1, was not. For CaV1.2, the inhibition of CDI by the Stac proteins appeared to involve their direct interaction with the channel's C terminus. Within the Stac proteins, a weakly conserved segment containing ∼100 residues and linking the structurally conserved PKC C1 and SH3_1 domains was sufficient to fully suppress CDI. The presence of CDI for l-type current in control neonatal neurons raised the possibility that endogenous Stac levels are low in these neurons and Western blotting indicated that the expression of Stac2 was substantially increased in adult forebrain and cerebellum compared with neonate. Together, our results indicate that one likely function of neuronal Stac proteins is to tune Ca2+ entry via neuronal l-type channels.SIGNIFICANCE STATEMENT Stac protein, first identified 20 years ago in brain, has recently been found to be essential for proper trafficking and function of the skeletal muscle l-type Ca2+ channel and is the site of mutations causing a severe, inherited human myopathy. In neurons, however, functions for Stac protein have remained unexplored. Here, we report that one likely function of neuronal Stac proteins is tuning Ca2+ entry via l-type, but not that via non-l-type, Ca2+ channels. Moreover, there is a large postnatal increase in protein levels of the major neuronal isoform (Stac2) in forebrain and cerebellum, which could provide developmental regulation of l-type channel Ca2+ signaling in these brain regions.
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Thomas CM, Timson DJ. Calmodulins from Schistosoma mansoni: Biochemical analysis and interaction with IQ-motifs from voltage-gated calcium channels. Cell Calcium 2018; 74:1-13. [DOI: 10.1016/j.ceca.2018.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/08/2018] [Accepted: 05/16/2018] [Indexed: 01/27/2023]
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Waldner DM, Bech-Hansen NT, Stell WK. Channeling Vision: Ca V1.4-A Critical Link in Retinal Signal Transmission. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7272630. [PMID: 29854783 PMCID: PMC5966690 DOI: 10.1155/2018/7272630] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/15/2018] [Indexed: 01/09/2023]
Abstract
Voltage-gated calcium channels (VGCC) are key to many biological functions. Entry of Ca2+ into cells is essential for initiating or modulating important processes such as secretion, cell motility, and gene transcription. In the retina and other neural tissues, one of the major roles of Ca2+-entry is to stimulate or regulate exocytosis of synaptic vesicles, without which synaptic transmission is impaired. This review will address the special properties of one L-type VGCC, CaV1.4, with particular emphasis on its role in transmission of visual signals from rod and cone photoreceptors (hereafter called "photoreceptors," to the exclusion of intrinsically photoreceptive retinal ganglion cells) to the second-order retinal neurons, and the pathological effects of mutations in the CACNA1F gene which codes for the pore-forming α1F subunit of CaV1.4.
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Affiliation(s)
- D. M. Waldner
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - N. T. Bech-Hansen
- Department of Medical Genetics and Department of Surgery, Alberta Children's Hospital Research Institute, and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - W. K. Stell
- Department of Cell Biology and Anatomy and Department of Surgery, Hotchkiss Brain Institute, and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Abstract
Calmodulin (CaM) regulation of voltage-gated calcium (CaV) channels is a powerful Ca2+ feedback mechanism that adjusts Ca2+ influx, affording rich mechanistic insights into Ca2+ decoding. CaM possesses a dual-lobed architecture, a salient feature of the myriad Ca2+-sensing proteins, where two homologous lobes that recognize similar targets hint at redundant signaling mechanisms. Here, by tethering CaM lobes, we demonstrate that bilobal architecture is obligatory for signaling to CaV channels. With one lobe bound, CaV carboxy tail rearranges itself, resulting in a preinhibited configuration precluded from Ca2+ feedback. Reconstitution of two lobes, even as separate molecules, relieves preinhibition and restores Ca2+ feedback. CaV channels thus detect the coincident binding of two Ca2+-free lobes to promote channel opening, a molecular implementation of a logical NOR operation that processes spatiotemporal Ca2+ signals bifurcated by CaM lobes. Overall, a unified scheme of CaV channel regulation by CaM now emerges, and our findings highlight the versatility of CaM to perform exquisite Ca2+ computations.
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Abdelsayed M, Ruprai M, Ruben PC. The efficacy of Ranolazine on E1784K is altered by temperature and calcium. Sci Rep 2018; 8:3643. [PMID: 29483621 PMCID: PMC5827758 DOI: 10.1038/s41598-018-22033-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 02/15/2018] [Indexed: 12/19/2022] Open
Abstract
E1784K is the most common mixed syndrome SCN5a mutation underpinning both Brugada syndrome type 1 (BrS1) and Long-QT syndrome type 3 (LQT3). The charge reversal mutant enhances the late sodium current (INa) passed by the cardiac voltage-gated sodium channel (NaV1.5), delaying cardiac repolarization. Exercise-induced triggers, like elevated temperature and cytosolic calcium, exacerbate E1784K late INa. In this study, we tested the effects of Ranolazine, the late INa blocker, on voltage-dependent and kinetic properties of E1784K at elevated temperature and cytosolic calcium. We used whole-cell patch clamp to measure INa from wild type and E1784K channels expressed in HEK293 cells. At elevated temperature, Ranolazine attenuated gain-of-function in E1784K by decreasing late INa, hyperpolarizing steady-state fast inactivation, and increasing use-dependent inactivation. Both elevated temperature and cytosolic calcium hampered the capacity of Ranolazine to suppress E1784K late INa. In-silico action potential (AP) simulations were done using a modified O'Hara Rudy (ORd) cardiac model. Simulations showed that Ranolazine failed to shorten AP duration, an effect augmented at febrile temperatures. The drug-channel interaction is clearly affected by external triggers, as reported previously with ischemia. Determining drug efficacy under various physiological states in SCN5a cohorts is crucial for accurate management of arrhythmias.
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Affiliation(s)
- Mena Abdelsayed
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Manpreet Ruprai
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada.
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