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Da'as SI, Thanassoulas A, Calver BL, Saleh A, Abdelrahman D, Hasan W, Safieh-Garabedian B, Kontogianni I, Nasrallah GK, Nounesis G, Lai FA, Nomikos M. Divergent Biochemical Properties and Disparate Impact of Arrhythmogenic Calmodulin Mutations on Zebrafish Cardiac Function. J Cell Biochem 2024; 125:e30619. [PMID: 38946237 DOI: 10.1002/jcb.30619] [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: 12/28/2023] [Revised: 06/04/2024] [Accepted: 06/12/2024] [Indexed: 07/02/2024]
Abstract
Calmodulin (CaM) is a ubiquitous, small cytosolic calcium (Ca2+)-binding sensor that plays a vital role in many cellular processes by binding and regulating the activity of over 300 protein targets. In cardiac muscle, CaM modulates directly or indirectly the activity of several proteins that play a key role in excitation-contraction coupling (ECC), such as ryanodine receptor type 2 (RyR2), l-type Ca2+ (Cav1.2), sodium (NaV1.5) and potassium (KV7.1) channels. Many recent clinical and genetic studies have reported a series of CaM mutations in patients with life-threatening arrhythmogenic syndromes, such as long QT syndrome (LQTS) and catecholaminergic polymorphic ventricular tachycardia (CPVT). We recently showed that four arrhythmogenic CaM mutations (N98I, D132E, D134H, and Q136P) significantly reduce the binding of CaM to RyR2. Herein, we investigate in vivo functional effects of these CaM mutations on the normal zebrafish embryonic heart function by microinjecting complementary RNA corresponding to CaMN98I, CaMD132E, CaMD134H, and CaMQ136P mutants. Expression of CaMD132E and CaMD134H mutants results in significant reduction of the zebrafish heart rate, mimicking a severe form of human bradycardia, whereas expression of CaMQ136P results in an increased heart rate mimicking human ventricular tachycardia. Moreover, analysis of cardiac ventricular rhythm revealed that the CaMD132E and CaMN98I zebrafish groups display an irregular pattern of heart beating and increased amplitude in comparison to the control groups. Furthermore, circular dichroism spectroscopy experiments using recombinant CaM proteins reveals a decreased structural stability of the four mutants compared to the wild-type CaM protein in the presence of Ca2+. Finally, Ca2+-binding studies indicates that all CaM mutations display reduced CaM Ca2+-binding affinities, with CaMD132E exhibiting the most prominent change. Our data suggest that CaM mutations can trigger different arrhythmogenic phenotypes through multiple and complex molecular mechanisms.
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Affiliation(s)
- Sahar I Da'as
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | | | - Brian L Calver
- Sir Geraint Evans Wales Heart Research Institute, College of Biomedical and Life Science, Cardiff University, Cardiff, UK
| | - Alaaeldin Saleh
- College of Medicine, QU Health, Qatar University, Doha, Qatar
| | | | - Waseem Hasan
- Department of Human Genetics, Sidra Medicine, Doha, Qatar
| | | | - Iris Kontogianni
- National Centre for Scientific Research "Demokritos", Agia Paraskevi, Greece
- National Technical University of Athens, Athens, Greece
| | - Gheyath K Nasrallah
- Biomedical Research Center, Qatar University, Doha, Qatar
- Department of Biological Sciences, College of Health Sciences, QU Health, Qatar University, Doha, Qatar
| | - George Nounesis
- National Centre for Scientific Research "Demokritos", Agia Paraskevi, Greece
| | - F Anthony Lai
- College of Medicine, QU Health, Qatar University, Doha, Qatar
- Sir Geraint Evans Wales Heart Research Institute, College of Biomedical and Life Science, Cardiff University, Cardiff, UK
| | - Michail Nomikos
- College of Medicine, QU Health, Qatar University, Doha, Qatar
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Dal Cortivo G, Marino V, Zamboni D, Dell'Orco D. Impact of calmodulin missense variants associated with congenital arrhythmia on the thermal stability and the degree of unfolding. Hum Genet 2023:10.1007/s00439-023-02629-y. [PMID: 38153589 DOI: 10.1007/s00439-023-02629-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/27/2023] [Indexed: 12/29/2023]
Abstract
Thermal denaturation profiles of proteins that bind several ligands may deviate from the single transition, making their thermodynamic description challenging. We report an empirical method that estimates melting temperatures (Tm) from multi-transition thermal denaturation profiles of 16 variants of calmodulin (CaM) associated with congenital arrhythmia. Differences in Tm estimated by empirical fitting correlate (for apo CaM variants) with those obtained by thermodynamic models. Most CaM variants were more stable than the wild type (WT) in the absence of Ca2+, but less stable in the presence of Ca2+, and displayed either WT-like or higher unfolding percentages in their apo-form, as evaluated by circular dichroism spectroscopy.
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Affiliation(s)
- Giuditta Dal Cortivo
- Department of Neurosciences, Biomedicine, and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Valerio Marino
- Department of Neurosciences, Biomedicine, and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Davide Zamboni
- Department of Neurosciences, Biomedicine, and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Daniele Dell'Orco
- Department of Neurosciences, Biomedicine, and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada Le Grazie 8, 37134, Verona, Italy.
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McCormick L, Wadmore K, Milburn A, Gupta N, Morris R, Held M, Prakash O, Carr J, Barrett‐Jolley R, Dart C, Helassa N. Long QT syndrome-associated calmodulin variants disrupt the activity of the slowly activating delayed rectifier potassium channel. J Physiol 2023; 601:3739-3764. [PMID: 37428651 PMCID: PMC10952621 DOI: 10.1113/jp284994] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/21/2023] [Indexed: 07/12/2023] Open
Abstract
Calmodulin (CaM) is a highly conserved mediator of calcium (Ca2+ )-dependent signalling and modulates various cardiac ion channels. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS). LQTS patients display prolonged ventricular recovery times (QT interval), increasing their risk of incurring life-threatening arrhythmic events. Loss-of-function mutations to Kv7.1 (which drives the slow delayed rectifier potassium current, IKs, a key ventricular repolarising current) are the largest contributor to congenital LQTS (>50% of cases). CaM modulates Kv7.1 to produce a Ca2+ -sensitive IKs, but little is known about the consequences of LQTS-associated CaM mutations on Kv7.1 function. Here, we present novel data characterising the biophysical and modulatory properties of three LQTS-associated CaM variants (D95V, N97I and D131H). We showed that mutations induced structural alterations in CaM and reduced affinity for Kv7.1, when compared with wild-type (WT). Using HEK293T cells expressing Kv7.1 channel subunits (KCNQ1/KCNE1) and patch-clamp electrophysiology, we demonstrated that LQTS-associated CaM variants reduced current density at systolic Ca2+ concentrations (1 μm), revealing a direct QT-prolonging modulatory effect. Our data highlight for the first time that LQTS-associated perturbations to CaM's structure impede complex formation with Kv7.1 and subsequently result in reduced IKs. This provides a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype. KEY POINTS: Calmodulin (CaM) is a ubiquitous, highly conserved calcium (Ca2+ ) sensor playing a key role in cardiac muscle contraction. Genotyping has revealed several CaM mutations associated with long QT syndrome (LQTS), a life-threatening cardiac arrhythmia syndrome. LQTS-associated CaM variants (D95V, N97I and D131H) induced structural alterations, altered binding to Kv7.1 and reduced IKs. Our data provide a novel mechanistic insight into how the perturbed structure-function relationship of CaM variants contributes to the LQTS phenotype.
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Affiliation(s)
- Liam McCormick
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
- Manchester Centre for Genomic Medicine, North West Genomic Laboratory HubSaint Mary's HospitalManchesterUK
| | - Kirsty Wadmore
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Amy Milburn
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Nitika Gupta
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Rachael Morris
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Marie Held
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Ohm Prakash
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Joseph Carr
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Richard Barrett‐Jolley
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Caroline Dart
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
| | - Nordine Helassa
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life SciencesUniversity of LiverpoolLiverpoolUK
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Marino V, Cortivo GD, Dell'Orco D. Ionic displacement of Ca 2+ by Pb 2+ in calmodulin is affected by arrhythmia-associated mutations. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119490. [PMID: 37201768 DOI: 10.1016/j.bbamcr.2023.119490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/14/2023] [Accepted: 05/10/2023] [Indexed: 05/20/2023]
Abstract
Lead is a highly toxic metal that severely perturbs physiological processes even at sub-micromolar levels, often by disrupting the Ca2+ signaling pathways. Recently, Pb2+-associated cardiac toxicity has emerged, with potential involvement of both the ubiquitous Ca2+ sensor protein calmodulin (CaM) and ryanodine receptors. In this work, we explored the hypothesis that Pb2+ contributes to the pathological phenotype of CaM variants associated with congenital arrhythmias. We performed a thorough spectroscopic and computational characterization of CaM conformational switches in the co-presence of Pb2+ and four missense mutations associated with congenital arrhythmias, namely N53I, N97S, E104A and F141L, and analyzed their effects on the recognition of a target peptide of RyR2. When bound to any of the CaM variants, Pb2+ is difficult to displace even under equimolar Ca2+ concentrations, thus locking all CaM variants in a specific conformation, which exhibits characteristics of coiled-coil assemblies. All arrhythmia-associated variants appear to be more susceptible to Pb2+ than WT CaM, as the conformational transition towards the coiled-coil conformation occurs at lower Pb2+, regardless of the presence of Ca2+, with altered cooperativity. The presence of arrhythmia-associated mutations specifically alters the cation coordination of CaM variants, in some cases involving allosteric communication between the EF-hands in the two domains. Finally, while wild type CaM increases the affinity for the RyR2 target in the presence of Pb2+, no specific pattern could be detected for all other variants, ruling out a synergistic effect of Pb2+ and mutations in the recognition process.
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Affiliation(s)
- Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, I-37134 Verona, Italy
| | - Giuditta Dal Cortivo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, I-37134 Verona, Italy
| | - Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, I-37134 Verona, Italy.
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Dal Cortivo G, Marino V, Bianconi S, Dell'Orco D. Calmodulin variants associated with congenital arrhythmia impair selectivity for ryanodine receptors. Front Mol Biosci 2023; 9:1100992. [PMID: 36685279 PMCID: PMC9849693 DOI: 10.3389/fmolb.2022.1100992] [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: 11/17/2022] [Accepted: 12/12/2022] [Indexed: 01/06/2023] Open
Abstract
Among its many molecular targets, the ubiquitous calcium sensor protein calmodulin (CaM) recognizes and regulates the activity of ryanodine receptors type 1 (RyR1) and 2 (RyR2), mainly expressed in skeletal and cardiac muscle, respectively. Such regulation is essential to achieve controlled contraction of muscle cells. To unravel the molecular mechanisms underlying the target recognition process, we conducted a comprehensive biophysical investigation of the interaction between two calmodulin variants associated with congenital arrhythmia, namely N97I and Q135P, and a highly conserved calmodulin-binding region in RyR1 and RyR2. The structural, thermodynamic, and kinetic properties of protein-peptide interactions were assessed together with an in-depth structural and topological investigation based on molecular dynamics simulations. This integrated approach allowed us to identify amino acids that are crucial in mediating allosteric processes, which enable high selectivity in molecular target recognition. Our results suggest that the ability of calmodulin to discriminate between RyR1 an RyR2 targets depends on kinetic discrimination and robust allosteric communication between Ca2+-binding sites (EF1-EF3 and EF3-EF4 pairs), which is perturbed in both N97I and Q135P arrhythmia-associated variants.
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Young BD, Cook ME, Costabile BK, Samanta R, Zhuang X, Sevdalis SE, Varney KM, Mancia F, Matysiak S, Lattman E, Weber DJ. Binding and Functional Folding (BFF): A Physiological Framework for Studying Biomolecular Interactions and Allostery. J Mol Biol 2022; 434:167872. [PMID: 36354074 PMCID: PMC10871162 DOI: 10.1016/j.jmb.2022.167872] [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: 05/26/2022] [Revised: 09/20/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
EF-hand Ca2+-binding proteins (CBPs), such as S100 proteins (S100s) and calmodulin (CaM), are signaling proteins that undergo conformational changes upon increasing intracellular Ca2+. Upon binding Ca2+, S100 proteins and CaM interact with protein targets and induce important biological responses. The Ca2+-binding affinity of CaM and most S100s in the absence of target is weak (CaKD > 1 μM). However, upon effector protein binding, the Ca2+ affinity of these proteins increases via heterotropic allostery (CaKD < 1 μM). Because of the high number and micromolar concentrations of EF-hand CBPs in a cell, at any given time, allostery is required physiologically, allowing for (i) proper Ca2+ homeostasis and (ii) strict maintenance of Ca2+-signaling within a narrow dynamic range of free Ca2+ ion concentrations, [Ca2+]free. In this review, mechanisms of allostery are coalesced into an empirical "binding and functional folding (BFF)" physiological framework. At the molecular level, folding (F), binding and folding (BF), and BFF events include all atoms in the biomolecular complex under study. The BFF framework is introduced with two straightforward BFF types for proteins (type 1, concerted; type 2, stepwise) and considers how homologous and nonhomologous amino acid residues of CBPs and their effector protein(s) evolved to provide allosteric tightening of Ca2+ and simultaneously determine how specific and relatively promiscuous CBP-target complexes form as both are needed for proper cellular function.
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Affiliation(s)
- Brianna D Young
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mary E Cook
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brianna K Costabile
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Riya Samanta
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Xinhao Zhuang
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Spiridon E Sevdalis
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kristen M Varney
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Filippo Mancia
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
| | - Silvina Matysiak
- Biophysics Graduate Program, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA
| | - Eaton Lattman
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Physics, Arizona State University, Tempe, AZ 85287, USA
| | - David J Weber
- The Center for Biomolecular Therapeutics (CBT), Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; The Institute of Bioscience and Biotechnology Research (IBBR), Rockville, MD 20850, USA.
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