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Sanjeevi M, Mohan A, Ramachandran D, Jeyaraman J, Sekar K. CSSP-2.0: A refined consensus method for accurate protein secondary structure prediction. Comput Biol Chem 2024; 112:108158. [PMID: 39053174 DOI: 10.1016/j.compbiolchem.2024.108158] [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: 12/23/2023] [Revised: 06/19/2024] [Accepted: 07/18/2024] [Indexed: 07/27/2024]
Abstract
Studying the relationship between sequences and their corresponding three-dimensional structure assists structural biologists in solving the protein-folding problem. Despite several experimental and in-silico approaches, still understanding or decoding the three-dimensional structures from the sequence remains a mystery. In such cases, the accuracy of the structure prediction plays an indispensable role. To address this issue, an updated web server (CSSP-2.0) has been created to improve the accuracy of our previous version of CSSP by deploying the existing algorithms. It uses input as probabilities and predicts the consensus for the secondary structure as a highly accurate three-state Q3 (helix, strand, and coil). This prediction is achieved using six recent top-performing methods: MUFOLD-SS, RaptorX, PSSpred v4, PSIPRED, JPred v4, and Porter 5.0. CSSP-2.0 validation includes datasets involving various protein classes from the PDB, CullPDB, and AlphaFold databases. Our results indicate a significant improvement in the accuracy of the consensus Q3 prediction. Using CSSP-2.0, crystallographers can sort out the stable regular secondary structures from the entire complex structure, which would aid in inferring the functional annotation of hypothetical proteins. The web server is freely available at https://bioserver3.physics.iisc.ac.in/cgi-bin/cssp-2/.
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Affiliation(s)
- Madhumathi Sanjeevi
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore 560012, India; Structural Biology and Bio-Computing Laboratory, Department of Bioinformatics, Alagappa University, Karaikudi 630004, India
| | - Ajitha Mohan
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore 560012, India
| | | | - Jeyakanthan Jeyaraman
- Structural Biology and Bio-Computing Laboratory, Department of Bioinformatics, Alagappa University, Karaikudi 630004, India.
| | - Kanagaraj Sekar
- Department of Computational and Data Sciences, Indian Institute of Science, Bangalore 560012, India.
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2
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Weber DK, Reddy UV, Robia SL, Veglia G. Pathological mutations in the phospholamban cytoplasmic region affect its topology and dynamics modulating the extent of SERCA inhibition. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184370. [PMID: 38986894 DOI: 10.1016/j.bbamem.2024.184370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/26/2024] [Accepted: 07/02/2024] [Indexed: 07/12/2024]
Abstract
Phospholamban (PLN) is a 52 amino acid regulin that allosterically modulates the activity of the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) in the heart muscle. In its unphosphorylated form, PLN binds SERCA within its transmembrane (TM) domains, approximately 20 Å away from the Ca2+ binding site, reducing SERCA's apparent Ca2+ affinity (pKCa) and decreasing cardiac contractility. During the enzymatic cycle, the inhibitory TM domain of PLN remains anchored to SERCA, whereas its cytoplasmic region transiently binds the ATPase's headpiece. Phosphorylation of PLN at Ser16 by protein kinase A increases the affinity of its cytoplasmic domain to SERCA, weakening the TM interactions with the ATPase, reversing its inhibitory function, and augmenting muscle contractility. How the structural changes caused by pathological mutations in the PLN cytoplasmic region are transmitted to its inhibitory TM domain is still unclear. Using solid-state NMR spectroscopy and activity assays, we analyzed the structural and functional effects of a series of mutations and their phosphorylated forms located in the PLN cytoplasmic region and linked to dilated cardiomyopathy. We found that these missense mutations affect the overall topology and dynamics of PLN and ultimately modulate its inhibitory potency. Also, the changes in the TM tilt angle and cytoplasmic dynamics of PLN caused by these mutations correlate well with the extent of SERCA inhibition. Our study unveils new molecular determinants for designing variants of PLN that outcompete endogenous PLN to regulate SERCA in a tunable manner.
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Affiliation(s)
- Daniel K Weber
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - U Venkateswara Reddy
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
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Yu Q, Barndt RJ, Shen Y, Sallam K, Tang Y, Chan SY, Wu JC, Liu Q, Wu H. Mitigation of Stress-induced Structural Remodeling and Functional Deficiency in iPSC-CMs with PLN R9C Mutation by Promoting Autophagy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.589921. [PMID: 38659742 PMCID: PMC11042320 DOI: 10.1101/2024.04.17.589921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Background Phospholamban (PLN) is a key regulator of cardiac function connecting adrenergic signaling and calcium homeostasis. The R9C mutation of PLN is known to cause early onset dilated cardiomyopathy (DCM) and premature death, yet the detailed mechanisms underlie the pathologic remodeling process are not well defined in human cardiomyocytes. The aim of this study is to unravel the role of PLN R9C in DCM and identify potential therapeutic targets. Methods PLN R9C knock-in (KI) and patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated and comprehensively examined for their expression profile, contractile function, and cellular signaling under both baseline conditions and following functional challenges. Results PLN R9C KI iPSC-CMs exhibited near-normal morphology and calcium handling, slightly increased contractility, and an attenuated response to β-adrenergic activation compared to wild-type (WT) cells. However, treatment with a maturation medium (MM) has induced fundamentally different remodeling in the two groups: while it improved the structural integrity and functional performance of WT cells, the same treatment result in sarcomere disarrangement, calcium handling deficiency, and further disrupted adrenergic signaling in PLN R9C KI cells. To understand the mechanism, transcriptomic analysis showed the enrichment of protein homeostasis signaling pathways specifically in PLN R9C KI cells in response to the MM treatment and increased contractile demands. Further studies also indicated elevated ROS levels, interrupted autophagic flux, and increased pentamer PLN aggregation in functionally challenged KI cells. These results were further confirmed in patient-specific iPSC-CM models, suggesting that functional stresses exacerbate the deficiencies in PLN R9C cells through disrupting protein homeostasis. Indeed, treating stressed patient cells with autophagy-accelerating reagents, such as metformin and rapamycin, has restored autophagic flux, mitigated sarcomere disarrangement, and partially rescued β-adrenergic signaling and cardiac function. Conclusions PLN R9C leads to a mild increase of calcium recycling and contractility. Functional challenges further enhanced contractile and proteostasis stress, leading to autophagic overload, structural remodeling, and functional deficiencies in PLN R9C cardiomyocytes. Activation of autophagy signaling partially rescues these effects, revealing a potential therapeutic target for DCM patients with the PLN R9C mutation. Graphic abstracts A graphic abstract is available for this article.
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Armanious GP, Lemieux MJ, Espinoza-Fonseca LM, Young HS. Missense variants in phospholamban and cardiac myosin binding protein identified in patients with a family history and clinical diagnosis of dilated cardiomyopathy. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119699. [PMID: 38387507 DOI: 10.1016/j.bbamcr.2024.119699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 11/07/2023] [Accepted: 02/15/2024] [Indexed: 02/24/2024]
Abstract
As the genetic landscape of cardiomyopathies continues to expand, the identification of missense variants in disease-associated genes frequently leads to a classification of variant of uncertain significance (VUS). For the proper reclassification of such variants, functional characterization is an important contributor to the proper assessment of pathogenic potential. Several missense variants in the calcium transport regulatory protein phospholamban have been associated with dilated cardiomyopathy. However, >40 missense variants in this transmembrane peptide are currently known and most remain classified as VUS with little clinical information. Similarly, missense variants in cardiac myosin binding protein have been associated with hypertrophic cardiomyopathy. However, hundreds of variants are known and many have low penetrance and are often found in control populations. Herein, we focused on novel missense variants in phospholamban, an Ala15-Thr variant found in a 4-year-old female and a Pro21-Thr variant found in a 60-year-old female, both with a family history and clinical diagnosis of dilated cardiomyopathy. The patients also harbored a Val896-Met variant in cardiac myosin binding protein. The phospholamban variants caused defects in the function, phosphorylation, and dephosphorylation of this calcium transport regulatory peptide, and we classified these variants as potentially pathogenic. The variant in cardiac myosin binding protein alters the structure of the protein. While this variant has been classified as benign, it has the potential to be a low-risk susceptibility variant because of the structural change in cardiac myosin binding protein. Our studies provide new biochemical evidence for missense variants previously classified as benign or VUS.
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Affiliation(s)
- Gareth P Armanious
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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Cleary SR, Teng ACT, Kongmeneck AD, Fang X, Phillips TA, Cho EE, Kekenes-Huskey P, Gramolini AO, Robia SL. Dilated cardiomyopathy variant R14del increases phospholamban pentamer stability, blunting dynamic regulation of cardiac calcium handling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542463. [PMID: 37292897 PMCID: PMC10245957 DOI: 10.1101/2023.05.26.542463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The sarco(endo)plasmic reticulum Ca 2+ ATPase (SERCA) is a membrane transporter that creates and maintains intracellular Ca 2+ stores. In the heart, SERCA is regulated by an inhibitory interaction with the monomeric form of the transmembrane micropeptide phospholamban (PLB). PLB also forms avid homo-pentamers, and dynamic exchange of PLB between pentamers and the regulatory complex with SERCA is an important determinant of cardiac responsiveness to exercise. Here, we investigated two naturally occurring pathogenic mutations of PLB, a cysteine substitution of arginine 9 (R9C) and an in-frame deletion of arginine 14 (R14del). Both mutations are associated with dilated cardiomyopathy. We previously showed that the R9C mutation causes disulfide crosslinking and hyperstabilization of pentamers. While the pathogenic mechanism of R14del is unclear, we hypothesized that this mutation may also alter PLB homo-oligomerization and disrupt the PLB-SERCA regulatory interaction. SDS-PAGE revealed a significantly increased pentamer:monomer ratio for R14del-PLB when compared to WT-PLB. In addition, we quantified homo-oligomerization and SERCA-binding in live cells using fluorescence resonance energy transfer (FRET) microscopy. R14del-PLB showed an increased affinity for homo-oligomerization and decreased binding affinity for SERCA compared to WT, suggesting that, like R9C, the R14del mutation stabilizes PLB in its pentameric form, decreasing its ability to regulate SERCA. Moreover, the R14del mutation reduces the rate of PLB unbinding from the pentamer after a transient Ca 2+ elevation, limiting the rate of re-binding to SERCA. A computational model predicted that hyperstabilization of PLB pentamers by R14del impairs the ability of cardiac Ca 2+ handling to respond to changing heart rates between rest and exercise. We postulate that impaired responsiveness to physiological stress contributes to arrhythmogenesis in human carriers of the R14del mutation.
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Costa A, Cruz AC, Martins F, Rebelo S. Protein Phosphorylation Alterations in Myotonic Dystrophy Type 1: A Systematic Review. Int J Mol Sci 2023; 24:ijms24043091. [PMID: 36834509 PMCID: PMC9965115 DOI: 10.3390/ijms24043091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/21/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Among the most common muscular dystrophies in adults is Myotonic Dystrophy type 1 (DM1), an autosomal dominant disorder characterized by myotonia, muscle wasting and weakness, and multisystemic dysfunctions. This disorder is caused by an abnormal expansion of the CTG triplet at the DMPK gene that, when transcribed to expanded mRNA, can lead to RNA toxic gain of function, alternative splicing impairments, and dysfunction of different signaling pathways, many regulated by protein phosphorylation. In order to deeply characterize the protein phosphorylation alterations in DM1, a systematic review was conducted through PubMed and Web of Science databases. From a total of 962 articles screened, 41 were included for qualitative analysis, where we retrieved information about total and phosphorylated levels of protein kinases, protein phosphatases, and phosphoproteins in DM1 human samples and animal and cell models. Twenty-nine kinases, 3 phosphatases, and 17 phosphoproteins were reported altered in DM1. Signaling pathways that regulate cell functions such as glucose metabolism, cell cycle, myogenesis, and apoptosis were impaired, as seen by significant alterations to pathways such as AKT/mTOR, MEK/ERK, PKC/CUGBP1, AMPK, and others in DM1 samples. This explains the complexity of DM1 and its different manifestations and symptoms, such as increased insulin resistance and cancer risk. Further studies can be done to complement and explore in detail specific pathways and how their regulation is altered in DM1, to find what key phosphorylation alterations are responsible for these manifestations, and ultimately to find therapeutic targets for future treatments.
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Vafiadaki E, Glijnis PC, Doevendans PA, Kranias EG, Sanoudou D. Phospholamban R14del disease: The past, the present and the future. Front Cardiovasc Med 2023; 10:1162205. [PMID: 37144056 PMCID: PMC10151546 DOI: 10.3389/fcvm.2023.1162205] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/03/2023] [Indexed: 05/06/2023] Open
Abstract
Arrhythmogenic cardiomyopathy affects significant number of patients worldwide and is characterized by life-threatening ventricular arrhythmias and sudden cardiac death. Mutations in multiple genes with diverse functions have been reported to date including phospholamban (PLN), a key regulator of sarcoplasmic reticulum (SR) Ca2+ homeostasis and cardiac contractility. The PLN-R14del variant in specific is recognized as the cause in an increasing number of patients worldwide, and extensive investigations have enabled rapid advances towards the delineation of PLN-R14del disease pathogenesis and discovery of an effective treatment. We provide a critical overview of current knowledge on PLN-R14del disease pathophysiology, including clinical, animal model, cellular and biochemical studies, as well as diverse therapeutic approaches that are being pursued. The milestones achieved in <20 years, since the discovery of the PLN R14del mutation (2006), serve as a paradigm of international scientific collaboration and patient involvement towards finding a cure.
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Affiliation(s)
- Elizabeth Vafiadaki
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
| | - Pieter C. Glijnis
- Stichting Genetische Hartspierziekte PLN, Phospholamban Foundation, Wieringerwerf, Netherlands
| | - Pieter A. Doevendans
- Netherlands Heart Institute, Utrecht, Netherlands
- Department of Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Evangelia G. Kranias
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Despina Sanoudou
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
- Clinical Genomics and Pharmacogenomics Unit, 4th Department of Internal Medicine, Attikon Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
- Correspondence: Elizabeth Vafiadaki Despina Sanoudou
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Vicente M, Salgado-Almario J, Valiente-Gabioud AA, Collins MM, Vincent P, Domingo B, Llopis J. Early calcium and cardiac contraction defects in a model of phospholamban R9C mutation in zebrafish. J Mol Cell Cardiol 2022; 173:127-140. [PMID: 36273660 DOI: 10.1016/j.yjmcc.2022.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/28/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
The phospholamban mutation Arg 9 to Cys (R9C) has been found to cause a dilated cardiomyopathy in humans and in transgenic mice, with ventricular dilation and premature death. Emerging evidence suggests that phospholamban R9C is a loss-of-function mutation with dominant negative effect on SERCA2a activity. We imaged calcium and cardiac contraction simultaneously in 3 and 9 days-post-fertilization (dpf) zebrafish larvae expressing plnbR9C in the heart to unveil the early pathological pathway that triggers the disease. We generated transgenic zebrafish lines expressing phospholamban wild-type (Tg(myl7:plnbwt)) and phospholamban R9C (Tg(myl7:plnbR9C)) in the heart of zebrafish. To measure calcium and cardiac contraction in 3 and 9 dpf larvae, Tg(myl7:plnbwt) and Tg(myl7:plnbR9C) fish were outcrossed with a transgenic line expressing the ratiometric fluorescent calcium biosensor mCyRFP1-GCaMP6f. We found that PlnbR9C raised calcium transient amplitude, induced positive inotropy and lusitropy, and blunted the β-adrenergic response to isoproterenol in 3 dpf larvae. These effects can be attributed to enhanced SERCA2a activity induced by the PlnbR9C mutation. In contrast, Tg(myl7:plnbR9C) larvae at 9 dpf exhibited ventricular dilation, systolic dysfunction and negative lusitropy, hallmarks of a dilated cardiomyopathy in humans. Importantly, N-acetyl-L-cysteine rescued this deleterious phenotype, suggesting that reactive oxygen species contribute to the pathological pathway. These results also imply that dysregulation of calcium homeostasis during embryo development contributes to the disease progression at later stages. Our in vivo model in zebrafish allows characterization of pathophysiological mechanisms leading to heart disease, and can be used for screening of potential therapeutical agents.
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Affiliation(s)
- Manuel Vicente
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Jussep Salgado-Almario
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain
| | - Ariel A Valiente-Gabioud
- Tools for Bio-Imaging, Max-Planck-Institut für biologische Intelligenz, Am Klopferspitz 18, Martinsried 82152, Germany
| | - Michelle M Collins
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, College of Medicine, SK S7N 5E5, Canada
| | - Pierre Vincent
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Beatriz Domingo
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
| | - Juan Llopis
- Physiology and Cell Dynamics Group, Centro Regional de Investigaciones Biomédicas (CRIB) and Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha, C/Almansa 14, 02006 Albacete, Spain.
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Al-hadlaq SM, Balto HA, Hassan WM, Marraiki NA, El-Ansary AK. Biomarkers of non-communicable chronic disease: an update on contemporary methods. PeerJ 2022; 10:e12977. [PMID: 35233297 PMCID: PMC8882335 DOI: 10.7717/peerj.12977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 01/31/2022] [Indexed: 01/11/2023] Open
Abstract
Chronic diseases constitute a major global burden with significant impact on health systems, economies, and quality of life. Chronic diseases include a broad range of diseases that can be communicable or non-communicable. Chronic diseases are often associated with modifications of normal physiological levels of various analytes that are routinely measured in serum and other body fluids, as well as pathological findings, such as chronic inflammation, oxidative stress, and mitochondrial dysfunction. Identification of at-risk populations, early diagnosis, and prediction of prognosis play a major role in preventing or reducing the burden of chronic diseases. Biomarkers are tools that are used by health professionals to aid in the identification and management of chronic diseases. Biomarkers can be diagnostic, predictive, or prognostic. Several individual or grouped biomarkers have been used successfully in the diagnosis and prediction of certain chronic diseases, however, it is generally accepted that a more sophisticated approach to link and interpret various biomarkers involved in chronic disease is necessary to improve our current procedures. In order to ensure a comprehensive and unbiased coverage of the literature, first a primary frame of the manuscript (title, headings and subheadings) was drafted by the authors working on this paper. Second, based on the components drafted in the preliminary skeleton a comprehensive search of the literature was performed using the PubMed and Google Scholar search engines. Multiple keywords related to the topic were used. Out of screened papers, only 190 papers, which are the most relevant, and recent articles were selected to cover the topic in relation to etiological mechanisms of different chronic diseases, the most recently used biomarkers of chronic diseases and finally the advances in the applications of multivariate biomarkers of chronic diseases as statistical and clinically applied tool for the early diagnosis of chronic diseases was discussed. Recently, multivariate biomarkers analysis approach has been employed with promising prospect. A brief discussion of the multivariate approach for the early diagnosis of the most common chronic diseases was highlighted in this review. The use of diagnostic algorithms might show the way for novel criteria and enhanced diagnostic effectiveness inpatients with one or numerous non-communicable chronic diseases. The search for new relevant biomarkers for the better diagnosis of patients with non-communicable chronic diseases according to the risk of progression, sickness, and fatality is ongoing. It is important to determine whether the newly identified biomarkers are purely associations or real biomarkers of underlying pathophysiological processes. Use of multivariate analysis could be of great importance in this regard.
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Affiliation(s)
- Solaiman M. Al-hadlaq
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Hanan A. Balto
- Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia,Central Research Laboratory, Female Campus, King Saud University, Riyadh, Saudi Arabia
| | - Wail M. Hassan
- Department of Biomedical Sciences, University of Missouri-Kansas City School of Medicine, Kansas City, KS, United States of America
| | - Najat A. Marraiki
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Afaf K. El-Ansary
- Central Research Laboratory, Female Campus, King Saud University, Riyadh, Saudi Arabia
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Qin J, Zhang J, Lin L, Haji-Ghassemi O, Lin Z, Woycechowsky KJ, Van Petegem F, Zhang Y, Yuchi Z. Structures of PKA-phospholamban complexes reveal a mechanism of familial dilated cardiomyopathy. eLife 2022; 11:75346. [PMID: 35297759 PMCID: PMC8970585 DOI: 10.7554/elife.75346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/16/2022] [Indexed: 01/07/2023] Open
Abstract
Several mutations identified in phospholamban (PLN) have been linked to familial dilated cardiomyopathy (DCM) and heart failure, yet the underlying molecular mechanism remains controversial. PLN interacts with sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) and regulates calcium uptake, which is modulated by the protein kinase A (PKA)-dependent phosphorylation of PLN during the fight-or-flight response. Here, we present the crystal structures of the catalytic domain of mouse PKA in complex with wild-type and DCM-mutant PLNs. Our structures, combined with the results from other biophysical and biochemical assays, reveal a common disease mechanism: the mutations in PLN reduce its phosphorylation level by changing its conformation and weakening its interactions with PKA. In addition, we demonstrate that another more ubiquitous SERCA-regulatory peptide, called another-regulin (ALN), shares a similar mechanism mediated by PKA in regulating SERCA activity.
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Affiliation(s)
- Juan Qin
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology, Tianjin UniversityTianjinChina
| | - Jingfeng Zhang
- Wuhan Institute of Physics and Mathematics, Chinese Academy of SciencesWuhanChina
| | - Lianyun Lin
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology, Tianjin UniversityTianjinChina
| | - Omid Haji-Ghassemi
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British ColumbiaVancouverCanada
| | - Zhi Lin
- School of Life Sciences, Tianjin UniversityTianjinChina
| | - Kenneth J Woycechowsky
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology, Tianjin UniversityTianjinChina
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Centre, University of British ColumbiaVancouverCanada
| | - Yan Zhang
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology, Tianjin UniversityTianjinChina
| | - Zhiguang Yuchi
- Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology, Tianjin UniversityTianjinChina,Department of Molecular Pharmacology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy, Tianjin; Tianjin’s Clinical Research Center for CancerTianjinChina
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11
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Raad N, Bittihn P, Cacheux M, Jeong D, Ilkan Z, Ceholski D, Kohlbrenner E, Zhang L, Cai CL, Kranias EG, Hajjar RJ, Stillitano F, Akar FG. Arrhythmia Mechanism and Dynamics in a Humanized Mouse Model of Inherited Cardiomyopathy Caused by Phospholamban R14del Mutation. Circulation 2021; 144:441-454. [PMID: 34024116 DOI: 10.1161/circulationaha.119.043502] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Arginine (Arg) 14 deletion (R14del) in the calcium regulatory protein phospholamban (hPLNR14del) has been identified as a disease-causing mutation in patients with an inherited cardiomyopathy. Mechanisms underlying the early arrhythmogenic phenotype that predisposes carriers of this mutation to sudden death with no apparent structural remodeling remain unclear. METHODS To address this, we performed high spatiotemporal resolution optical mapping of intact hearts from adult knock-in mice harboring the human PLNWT (wildtype [WT], n=12) or the heterozygous human PLNR14del mutation (R14del, n=12) before and after ex vivo challenge with isoproterenol and rapid pacing. RESULTS Adverse electrophysiological remodeling was evident in the absence of significant structural or hemodynamic changes. R14del hearts exhibited increased arrhythmia susceptibility compared with wildtype. Underlying this susceptibility was preferential right ventricular action potential prolongation that was unresponsive to β-adrenergic stimulation. A steep repolarization gradient at the left ventricular/right ventricular interface provided the substrate for interventricular activation delays and ultimately local conduction block during rapid pacing. This was followed by the initiation of macroreentrant circuits supporting the onset of ventricular tachycardia. Once sustained, these circuits evolved into high-frequency rotors, which in their majority were pinned to the right ventricle. These rotors exhibited unique spatiotemporal dynamics that promoted their increased stability in R14del compared with wildtype hearts. CONCLUSIONS Our findings highlight the crucial role of primary electric remodeling caused by the hPLNR14del mutation. These inherently arrhythmogenic features form the substrate for adrenergic-mediated VT at early stages of PLNR14del induced cardiomyopathy.
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Affiliation(s)
- Nour Raad
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.).,Poliklinik für Innere Medizin I, Rechts der Isar Hospital, Technical University Munich, Germany (N.R.).,German Center for Cardiovascular Research, Munich Heart Alliance (N.R.)
| | - Philip Bittihn
- BioCircuits Institute, University of California, San Diego (P.B.).,Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany (P.B.)
| | - Marine Cacheux
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Dongtak Jeong
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Zeki Ilkan
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Delaine Ceholski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Erik Kohlbrenner
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Lu Zhang
- Indiana University School of Medicine, Indianapolis (L.Z., C.C.)
| | - Chen-Leng Cai
- Indiana University School of Medicine, Indianapolis (L.Z., C.C.)
| | | | - Roger J Hajjar
- Phospholamban Foundation, Middenmeer, The Netherlands (R.J.H.)
| | - Francesca Stillitano
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.)
| | - Fadi G Akar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY (N.R., M.C., D.J., Z.I., D.C., E.K., F.S., F.G.A.).,School of Medicine (F.G.A.), Yale University, New Haven, CT.,Department of Biomedical Engineering (F.G.A.). Yale University, New Haven, CT
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12
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Leal-Gutiérrez JD, Elzo MA, Carr C, Mateescu RG. RNA-seq analysis identifies cytoskeletal structural genes and pathways for meat quality in beef. PLoS One 2020; 15:e0240895. [PMID: 33175867 PMCID: PMC7657496 DOI: 10.1371/journal.pone.0240895] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 10/05/2020] [Indexed: 01/03/2023] Open
Abstract
RNA sequencing (RNA-seq) has allowed for transcriptional profiling of biological systems through the identification of differentially expressed (DE) genes and pathways. A total of 80 steers with extreme phenotypes were selected from the University of Florida multibreed Angus-Brahman herd. The average slaughter age was 12.91±8.69 months. Tenderness, juiciness and connective tissue assessed by sensory panel, along with marbling, Warner-Bratzler Shear Force (WBSF) and cooking loss, were measured in longissimus dorsi muscle. Total RNA was extracted from muscle and one RNA-seq library per sample was constructed, multiplexed, and sequenced based on protocols by Illumina HiSeq-3000 platform to generate 2×101 bp paired-end reads. The overall read mapping rate using the Btau_4.6.1 reference genome was 63%. A total of 8,799 genes were analyzed using two different methodologies, an expression association and a DE analysis. A gene and exon expression association analysis was carried out using a meat quality index on all 80 samples as a continuous response variable. The expression of 208 genes and 3,280 exons from 1,565 genes was associated with the meat quality index (p-value ≤ 0.05). A gene and isoform DE evaluation was performed analyzing two groups with extreme WBSF, tenderness and marbling. A total of 676 (adjusted p-value≤0.05), 70 (adjusted p-value≤0.1) and 198 (adjusted p-value≤0.1) genes were DE for WBSF, tenderness and marbling, respectively. A total of 106 isoforms from 98 genes for WBSF, 13 isoforms from 13 genes for tenderness and 43 isoforms from 42 genes for marbling (FDR≤0.1) were DE. Cytoskeletal and transmembrane anchoring genes and pathways were identified in the expression association, DE and the gene enrichment analyses; these proteins can have a direct effect on meat quality. Cytoskeletal proteins and transmembrane anchoring molecules can influence meat quality by allowing cytoskeletal interaction with myocyte and organelle membranes, contributing to cytoskeletal structure and architecture maintenance postmortem.
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Affiliation(s)
- Joel D. Leal-Gutiérrez
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Mauricio A. Elzo
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Chad Carr
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Raluca G. Mateescu
- Department of Animal Sciences, University of Florida, Gainesville, Florida, United States of America
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13
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Jiang X, Xu Y, Sun J, Wang L, Guo X, Chen Y. The phenotypic characteristic observed by cardiac magnetic resonance in a PLN-R14del family. Sci Rep 2020; 10:16478. [PMID: 33020536 PMCID: PMC7536202 DOI: 10.1038/s41598-020-73359-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 09/03/2020] [Indexed: 02/05/2023] Open
Abstract
Phospholamban (PLN) is an important regulator for sarcoendoplasmic reticulum (SR) calcium transport ATPase (SERCA), which uptakes Ca2+ to SR during the diastolic phase of cardiomyocytes to maintain intracellular calcium homeostasis. Mutations on PLN result in intracellular calcium disorder, myocardial contraction defect, and eventually heart failure and/or malignant ventricular arrhythmia. Since 2003, several kinds of PLN mutations have been identified in familial dilated cardiomyopathy (DCM) patients, illustrating a few clinical characteristics that differs from classical DCM patients. Herein, we report a large PLN-R14del family with typical clinical characteristics reported including relatively late-onset clinical symptoms, low-voltage in ECG, as well as frequent ventricular arrythmias. Moreover, members underwent cardiac magnetic resonance (CMR) examination showed a strikingly similar pattern of late gadolinium enhancement (LGE)—Sub-epicardial involvement in the left ventricular (LV) lateral wall with or without linear mid-wall enhancement in the interventricular septum. The former one can also present in younger PLN-R14del carriers despite completely normal LV structure and function. Meanwhile, T1 mapping also found significantly increased extracellular volume (ECV) in PLN-R14del carriers. These findings highlight the special role of CMR to phenotyping PLN-induced cardiomyopathy patients and distinguish them from other types of cardiomyopathy.
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Affiliation(s)
- Xincheng Jiang
- Department of Cardiology, West China Hospital, Sichuan University, Guoxue Xiang No. 37, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yuanwei Xu
- Department of Cardiology, West China Hospital, Sichuan University, Guoxue Xiang No. 37, Chengdu, Sichuan, 610041, People's Republic of China
| | - Jiayu Sun
- Department of Radiology, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Lili Wang
- Department of Cardiology, West China Hospital, Sichuan University, Guoxue Xiang No. 37, Chengdu, Sichuan, 610041, People's Republic of China
| | - Xinli Guo
- Department of Cardiology, West China Hospital, Sichuan University, Guoxue Xiang No. 37, Chengdu, Sichuan, 610041, People's Republic of China
| | - Yucheng Chen
- Department of Cardiology, West China Hospital, Sichuan University, Guoxue Xiang No. 37, Chengdu, Sichuan, 610041, People's Republic of China.
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14
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Menzel J, Kownatzki-Danger D, Tokar S, Ballone A, Unthan-Fechner K, Kilisch M, Lenz C, Urlaub H, Mori M, Ottmann C, Shattock MJ, Lehnart SE, Schwappach B. 14-3-3 binding creates a memory of kinase action by stabilizing the modified state of phospholamban. Sci Signal 2020; 13:13/647/eaaz1436. [DOI: 10.1126/scisignal.aaz1436] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The cardiac membrane protein phospholamban (PLN) is targeted by protein kinase A (PKA) at Ser16and by Ca2+/calmodulin-dependent protein kinase II (CaMKII) at Thr17. β-Adrenergic stimulation and PKA-dependent phosphorylation of Ser16acutely stimulate the sarcoplasmic reticulum calcium pump (SERCA) by relieving its inhibition by PLN. CaMKII-dependent phosphorylation may lead to longer-lasting SERCA stimulation and may sustain maladaptive Ca2+handling. Here, we demonstrated that phosphorylation at either Ser16or Thr17converted PLN into a target for the phosphoadaptor protein 14-3-3 with different affinities. 14-3-3 proteins were localized within nanometers of PLN and endogenous 14-3-3 coimmunoprecipitated with pentameric PLN from cardiac membranes. Molecular dynamics simulations predicted different molecular contacts for peptides phosphorylated at Ser16or Thr17with the binding groove of 14-3-3, resulting in varied binding affinities. 14-3-3 binding protected either PLN phosphosite from dephosphorylation. β-Adrenergic stimulation of isolated adult cardiomyocytes resulted in the membrane recruitment of endogenous 14-3-3. The exogenous addition of 14-3-3 to β-adrenergic–stimulated cardiomyocytes led to prolonged SERCA activation, presumably because 14-3-3 protected PLN pentamers from dephosphorylation. Phosphorylation of Ser16was disrupted by the cardiomyopathy-associated ∆Arg14mutation, implying that phosphorylation of Thr17by CaMKII may become crucial for 14-3-3 recruitment to ∆Arg14PLN. Consistent with PLN acting as a dynamic hub in the control of Ca2+handling, our results identify 14-3-3 binding to PLN as a contractility-augmenting mechanism.
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Affiliation(s)
- Julia Menzel
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Daniel Kownatzki-Danger
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, Universitätsmedizin Göttingen, Robert-Koch-Straße 42a, 37075 Göttingen, Germany
| | - Sergiy Tokar
- School of Cardiovascular Medicine and Sciences, King’s College London, Westminster Bridge Road, London SE17H, UK
| | - Alice Ballone
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, P. O. Box 513, 5600MB Eindhoven, Netherlands
| | - Kirsten Unthan-Fechner
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Markus Kilisch
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
| | - Christof Lenz
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
| | - Henning Urlaub
- Bioanalytics Group, Institute of Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
| | - Mattia Mori
- Department of Biotechnology, Chemistry and Pharmacy, Department of Excellence 2018-2022, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Christian Ottmann
- Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, P. O. Box 513, 5600MB Eindhoven, Netherlands
| | - Michael J. Shattock
- School of Cardiovascular Medicine and Sciences, King’s College London, Westminster Bridge Road, London SE17H, UK
| | - Stephan E. Lehnart
- Heart Research Center Göttingen, Department of Cardiology & Pneumology, Universitätsmedizin Göttingen, Robert-Koch-Straße 42a, 37075 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, 37073 Göttingen, Germany
- Max-Planck Institute for Biophysical Chemistry, Am Faßberg 11, 37077 Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells” (MBExC), University of Goettingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
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15
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Morales A, Kinnamon DD, Jordan E, Platt J, Vatta M, Dorschner MO, Starkey CA, Mead JO, Ai T, Burke W, Gastier-Foster J, Jarvik GP, Rehm HL, Nickerson DA, Hershberger RE. Variant Interpretation for Dilated Cardiomyopathy: Refinement of the American College of Medical Genetics and Genomics/ClinGen Guidelines for the DCM Precision Medicine Study. CIRCULATION-GENOMIC AND PRECISION MEDICINE 2020; 13:e002480. [PMID: 32160020 DOI: 10.1161/circgen.119.002480] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The hypothesis of the Dilated Cardiomyopathy Precision Medicine Study is that most dilated cardiomyopathy has a genetic basis. The study returns results to probands and, when indicated, to relatives. While both the American College of Medical Genetics and Genomics/Association for Molecular Pathology and ClinGen's MYH7-cardiomyopathy specifications provide relevant guidance for variant interpretation, further gene- and disease-specific considerations were required for dilated cardiomyopathy. To this end, we tailored the ClinGen MYH7-cardiomyopathy variant interpretation framework; the specifications implemented for the study are presented here. METHODS Modifications were created and approved by an external Variant Adjudication Oversight Committee. After a pilot using 81 probands, further adjustments were made, resulting in 27 criteria (9 modifications of the ClinGen MYH7 framework and reintroduction of 2 American College of Medical Genetics and Genomics/Association of Molecular Pathology criteria that were deemed not applicable by the ClinGen MYH7 working group). RESULTS These criteria were applied to 2059 variants in a test set of 97 probands. Variants were classified as benign (n=1702), likely benign (n=33), uncertain significance (n=71), likely pathogenic (likely pathogenic; n=12), and pathogenic (P; n=3). Only 2/15 likely pathogenic/P variants were identified in Non-Hispanic African ancestry probands. CONCLUSIONS We tailored the ClinGen MYH7 criteria for our study. Our preliminary data show that 15/97 (15.5%) probands have likely pathogenic/P variants, most of which were identified in probands of Non-Hispanic European ancestry. We anticipate continued evolution of our approach, one that will be informed by new insights on variant interpretation and a greater understanding of the genetic architecture of dilated cardiomyopathy. CLINICAL TRIAL REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT03037632.
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Affiliation(s)
- Ana Morales
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Daniel D Kinnamon
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Elizabeth Jordan
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Julia Platt
- Stanford Center for Inherited Cardiovascular Disease, Stanford University, Palo Alto, CA (J.P.)
| | - Matteo Vatta
- Department of Medical and Molecular Genetics, Indiana University, Indianapolis (M.V.).,Invitae, San Francisco, CA (M.V.)
| | | | - Carl A Starkey
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Jonathan O Mead
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Tomohiko Ai
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus
| | - Wylie Burke
- Department of Bioethics and Humanities (W.B.), University of Washington, SA
| | - Julie Gastier-Foster
- Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, OH (J.G.-F.)
| | - Gail P Jarvik
- Division of Medical Genetics, Department of Medicine (G.P.J.), University of Washington, SA.,Department of Genome Sciences (G.P.J.), University of Washington, SA
| | - Heidi L Rehm
- Center for Genomic Medicine, Massachusetts General Hospital, Boston (H.L.R.).,Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA (H.L.R.)
| | | | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine (A.M., D.D.K., E.J., C.S., J.M., T.A., R.E.H.), The Ohio State University, Columbus.,Division of Cardiovascular Medicine, Department of Internal Medicine (R.E.H.), The Ohio State University, Columbus
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16
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Glaves JP, Primeau JO, Gorski PA, Espinoza-Fonseca LM, Lemieux MJ, Young HS. Interaction of a Sarcolipin Pentamer and Monomer with the Sarcoplasmic Reticulum Calcium Pump, SERCA. Biophys J 2019; 118:518-531. [PMID: 31858977 DOI: 10.1016/j.bpj.2019.11.3385] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 10/30/2019] [Accepted: 11/18/2019] [Indexed: 11/27/2022] Open
Abstract
The sequential rise and fall of cytosolic calcium underlies the contraction-relaxation cycle of muscle cells. Whereas contraction is initiated by the release of calcium from the sarcoplasmic reticulum, muscle relaxation involves the active transport of calcium back into the sarcoplasmic reticulum. This reuptake of calcium is catalyzed by the sarcoendoplasmic reticulum Ca2+-ATPase (SERCA), which plays a lead role in muscle contractility. The activity of SERCA is regulated by small membrane protein subunits, the most well-known being phospholamban (PLN) and sarcolipin (SLN). SLN physically interacts with SERCA and differentially regulates contractility in skeletal and atrial muscle. SLN has also been implicated in skeletal muscle thermogenesis. Despite these important roles, the structural mechanisms by which SLN modulates SERCA-dependent contractility and thermogenesis remain unclear. Here, we functionally characterized wild-type SLN and a pair of mutants, Asn4-Ala and Thr5-Ala, which yielded gain-of-function behavior comparable to what has been found for PLN. Next, we analyzed two-dimensional crystals of SERCA in the presence of wild-type SLN by electron cryomicroscopy. The fundamental units of the crystals are antiparallel dimer ribbons of SERCA, known for decades as an assembly of calcium-free SERCA molecules induced by the addition of decavanadate. A projection map of the SERCA-SLN complex was determined to a resolution of 8.5 Å, which allowed the direct visualization of an SLN pentamer. The SLN pentamer was found to interact with transmembrane segment M3 of SERCA, although the interaction appeared to be indirect and mediated by an additional density consistent with an SLN monomer. This SERCA-SLN complex correlated with the ability of SLN to decrease the maximal activity of SERCA, which is distinct from the ability of PLN to increase the maximal activity of SLN. Protein-protein docking and molecular dynamics simulations provided models for the SLN pentamer and the novel interaction between SERCA and an SLN monomer.
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Affiliation(s)
- John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph O Primeau
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Przemek A Gorski
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada.
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17
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Alterations of protein expression of phospholamban, ZASP and plakoglobin in human atria in subgroups of seniors. Sci Rep 2019; 9:5610. [PMID: 30948763 PMCID: PMC6449388 DOI: 10.1038/s41598-019-42141-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 03/22/2019] [Indexed: 01/20/2023] Open
Abstract
The mature mammalian myocardium contains composite junctions (areae compositae) that comprise proteins of adherens junctions as well as desmosomes. Mutations or deficiency of many of these proteins are linked to heart failure and/or arrhythmogenic cardiomyopathy in patients. We firstly wanted to address the question whether the expression of these proteins shows an age-dependent alteration in the atrium of the human heart. Right atrial biopsies, obtained from patients undergoing routine bypass surgery for coronary heart disease were subjected to immunohistology and/or western blotting for the plaque proteins plakoglobin (γ-catenin) and plakophilin 2. Moreover, the Z-band protein cypher 1 (Cypher/ZASP) and calcium handling proteins of the sarcoplasmic reticulum (SR) like phospholamban, SERCA and calsequestrin were analyzed. We noted expression of plakoglobin, plakophilin 2 and Cypher/ZASP in these atrial preparations on western blotting and/or immunohistochemistry. There was an increase of Cypher/ZASP expression with age. The present data extend our knowledge on the expression of anchoring proteins and SR regulatory proteins in the atrium of the human heart and indicate an age-dependent variation in protein expression. It is tempting to speculate that increased expression of Cypher/ZASP may contribute to mechanical changes in the aging human myocardium.
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18
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Sun B, Stewart BD, Kucharski AN, Kekenes-Huskey PM. Thermodynamics of Cation Binding to the Sarcoendoplasmic Reticulum Calcium ATPase Pump and Impacts on Enzyme Function. J Chem Theory Comput 2019; 15:2692-2705. [PMID: 30807147 DOI: 10.1021/acs.jctc.8b01312] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) is a transmembrane pump that plays an important role in transporting calcium into the sarcoplasmic reticulum (SR). While calcium (Ca2+) binds SERCA with micromolar affinity, magnesium (Mg2+) and potassium (K+) also compete with Ca2+ binding. However, the molecular bases for these competing ions' influence on the SERCA function and the selectivity of the pump for Ca2+ are not well-established. We therefore used in silico methods to resolve molecular determinants of cation binding in the canonical site I and II Ca2+ binding sites via (1) triplicate molecular dynamics (MD) simulations of Mg2+, Ca2+, and K+-bound SERCA, (2) mean spherical approximation (MSA) theory to score the affinity and selectivity of cation binding to the MD-resolved structures, and (3) state models of SERCA turnover informed from MSA-derived affinity data. Our key findings are that (a) coordination at sites I and II is optimized for Ca2+ and to a lesser extent for Mg2+ and K+, as determined by MD-derived cation-amino acid oxygen and bound water configurations, (b) the impaired coordination and high desolvation cost for Mg2+ precludes favorable Mg2+ binding relative to Ca2+, while K+ has limited capacity to bind site I, and (c) Mg2+ most likely acts as inhibitor and K+ as intermediate in SERCA's reaction cycle, based on a best-fit state model of SERCA turnover. These findings provide a quantitative basis for SERCA function that leverages molecular-scale thermodynamic data and rationalizes enzyme activity across broad ranges of K+, Ca2+, and Mg2+ concentrations.
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Affiliation(s)
- Bin Sun
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Bradley D Stewart
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Amir N Kucharski
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States
| | - Peter M Kekenes-Huskey
- Department of Chemistry , University of Kentucky , 505 Rose Street, Chemistry-Physics Building , Lexington , Kentucky 40506 , United States.,Department of Chemical and Materials Engineering , University of Kentucky , 177 F. Paul Anderson Tower , Lexington , Kentucky 40506 , United States
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19
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Marrocco V, Bogomolovas J, Ehler E, Dos Remedios CG, Yu J, Gao C, Lange S. PKC and PKN in heart disease. J Mol Cell Cardiol 2019; 128:212-226. [PMID: 30742812 PMCID: PMC6408329 DOI: 10.1016/j.yjmcc.2019.01.029] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 01/30/2019] [Accepted: 01/31/2019] [Indexed: 12/22/2022]
Abstract
The protein kinase C (PKC) and closely related protein kinase N (PKN) families of serine/threonine protein kinases play crucial cellular roles. Both kinases belong to the AGC subfamily of protein kinases that also include the cAMP dependent protein kinase (PKA), protein kinase B (PKB/AKT), protein kinase G (PKG) and the ribosomal protein S6 kinase (S6K). Involvement of PKC family members in heart disease has been well documented over the years, as their activity and levels are mis-regulated in several pathological heart conditions, such as ischemia, diabetic cardiomyopathy, as well as hypertrophic or dilated cardiomyopathy. This review focuses on the regulation of PKCs and PKNs in different pathological heart conditions and on the influences that PKC/PKN activation has on several physiological processes. In addition, we discuss mechanisms by which PKCs and the closely related PKNs are activated and turned-off in hearts, how they regulate cardiac specific downstream targets and pathways, and how their inhibition by small molecules is explored as new therapeutic target to treat cardiomyopathies and heart failure.
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Affiliation(s)
- Valeria Marrocco
- Division of Cardiology, School of Medicine, University of California-San Diego, La Jolla, USA
| | - Julius Bogomolovas
- Division of Cardiology, School of Medicine, University of California-San Diego, La Jolla, USA; Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Basic and Medical Biosciences, School of Cardiovascular Medicine and Sciences, British Heart Foundation Research Excellence Centre, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
| | | | - Jiayu Yu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Department of Pathophysiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Gao
- Division of Molecular Medicine, Department of Anesthesiology, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, USA.
| | - Stephan Lange
- Division of Cardiology, School of Medicine, University of California-San Diego, La Jolla, USA; University of Gothenburg, Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, Gothenburg, Sweden.
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20
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Yost O, Friedenberg SG, Jesty SA, Olby NJ, Meurs KM. The R9H phospholamban mutation is associated with highly penetrant dilated cardiomyopathy and sudden death in a spontaneous canine model. Gene 2019; 697:118-122. [PMID: 30794913 DOI: 10.1016/j.gene.2019.02.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 01/04/2019] [Accepted: 02/01/2019] [Indexed: 12/30/2022]
Abstract
Causative mutations for familial dilated cardiomyopathy (DCM) have been identified in the phospholamban gene. There are many poorly understood aspects about familial DCM (variable penetrance, expression) which may be studied in natural animal models. We characterized genetic aspects of familial DCM in a canine model with a high incidence of sudden death. A missense G > A mutation in exon 1 of the phospholamban gene that changed an amino acid from arginine to histidine was identified in affected dogs. This variant was predicted to be deleterious. We describe a spontaneous canine model of familial DCM and sudden death with the R9H mutation. In comparison to a reported human family, the variant was highly penetrant and resulted in sudden death. Genetic penetrance of this mutation may be influenced by genetic or environmental modifiers. The dog provides an excellent model in which to study complex aspects of familial DCM.
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Affiliation(s)
- Oriana Yost
- Department of Clinical Sciences, North Carolina State College of Veterinary Medicine, 1060 William Moore Drive, Raleigh, NC 27607, USA
| | - Steven G Friedenberg
- Department of Veterinary Clinical Sciences, University of Minnesota, Saint Paul, MN 55108, USA
| | | | - Natasha J Olby
- Department of Clinical Sciences, North Carolina State College of Veterinary Medicine, 1060 William Moore Drive, Raleigh, NC 27607, USA
| | - Kathryn M Meurs
- Department of Clinical Sciences, North Carolina State College of Veterinary Medicine, 1060 William Moore Drive, Raleigh, NC 27607, USA.
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Glaves JP, Primeau JO, Espinoza-Fonseca LM, Lemieux MJ, Young HS. The Phospholamban Pentamer Alters Function of the Sarcoplasmic Reticulum Calcium Pump SERCA. Biophys J 2019; 116:633-647. [PMID: 30712785 DOI: 10.1016/j.bpj.2019.01.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/30/2018] [Accepted: 01/11/2019] [Indexed: 11/17/2022] Open
Abstract
The interaction of phospholamban (PLN) with the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) pump is a major regulatory axis in cardiac muscle contractility. The prevailing model involves reversible inhibition of SERCA by monomeric PLN and storage of PLN as an inactive pentamer. However, this paradigm has been challenged by studies demonstrating that PLN remains associated with SERCA and that the PLN pentamer is required for the regulation of cardiac contractility. We have previously used two-dimensional (2D) crystallization and electron microscopy to study the interaction between SERCA and PLN. To further understand this interaction, we compared small helical crystals and large 2D crystals of SERCA in the absence and presence of PLN. In both crystal forms, SERCA molecules are organized into identical antiparallel dimer ribbons. The dimer ribbons pack together with distinct crystal contacts in the helical versus large 2D crystals, which allow PLN differential access to potential sites of interaction with SERCA. Nonetheless, we show that a PLN oligomer interacts with SERCA in a similar manner in both crystal forms. In the 2D crystals, a PLN pentamer interacts with transmembrane segments M3 of SERCA and participates in a crystal contact that bridges neighboring SERCA dimer ribbons. In the helical crystals, an oligomeric form of PLN also interacts with M3 of SERCA, though the PLN oligomer straddles a SERCA-SERCA crystal contact. We conclude that the pentameric form of PLN interacts with M3 of SERCA and that it plays a distinct structural and functional role in SERCA regulation. The interaction of the pentamer places the cytoplasmic domains of PLN at the membrane surface proximal to the calcium entry funnel of SERCA. This interaction may cause localized perturbation of the membrane bilayer as a mechanism for increasing the turnover rate of SERCA.
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Affiliation(s)
- John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Joseph O Primeau
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - L Michel Espinoza-Fonseca
- Center for Arrhythmia Research, Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada.
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22
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Ceholski DK, Turnbull IC, Kong CW, Koplev S, Mayourian J, Gorski PA, Stillitano F, Skodras AA, Nonnenmacher M, Cohen N, Björkegren JLM, Stroik DR, Cornea RL, Thomas DD, Li RA, Costa KD, Hajjar RJ. Functional and transcriptomic insights into pathogenesis of R9C phospholamban mutation using human induced pluripotent stem cell-derived cardiomyocytes. J Mol Cell Cardiol 2018; 119:147-154. [PMID: 29752948 DOI: 10.1016/j.yjmcc.2018.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/07/2018] [Accepted: 05/08/2018] [Indexed: 12/27/2022]
Abstract
Dilated cardiomyopathy (DCM) can be caused by mutations in the cardiac protein phospholamban (PLN). We used CRISPR/Cas9 to insert the R9C PLN mutation at its endogenous locus into a human induced pluripotent stem cell (hiPSC) line from an individual with no cardiovascular disease. R9C PLN hiPSC-CMs display a blunted β-agonist response and defective calcium handling. In 3D human engineered cardiac tissues (hECTs), a blunted lusitropic response to β-adrenergic stimulation was observed with R9C PLN. hiPSC-CMs harboring the R9C PLN mutation showed activation of a hypertrophic phenotype, as evidenced by expression of hypertrophic markers and increased cell size and capacitance of cardiomyocytes. RNA-seq suggests that R9C PLN results in an altered metabolic state and profibrotic signaling, which was confirmed by gene expression analysis and picrosirius staining of R9C PLN hECTs. The expression of several miRNAs involved in fibrosis, hypertrophy, and cardiac metabolism were also perturbed in R9C PLN hiPSC-CMs. This study contributes to better understanding of the pathogenic mechanisms of the hereditary R9C PLN mutation in the context of human cardiomyocytes.
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Affiliation(s)
- Delaine K Ceholski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Irene C Turnbull
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Chi-Wing Kong
- Department of Paediatrics and Adolescent Medicine, Hong Kong University, Pokfulam, Hong Kong
| | - Simon Koplev
- Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Joshua Mayourian
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Przemek A Gorski
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Francesca Stillitano
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Angelos A Skodras
- Microscopy Core, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Mathieu Nonnenmacher
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Ninette Cohen
- Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Johan L M Björkegren
- Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Daniel R Stroik
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, United States
| | - Ronald A Li
- Department of Paediatrics and Adolescent Medicine, Hong Kong University, Pokfulam, Hong Kong; Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Solna SE-171, Sweden
| | - Kevin D Costa
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Roger J Hajjar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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23
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Han SK, Kim D, Lee H, Kim I, Kim S. Divergence of Noncoding Regulatory Elements Explains Gene–Phenotype Differences between Human and Mouse Orthologous Genes. Mol Biol Evol 2018; 35:1653-1667. [DOI: 10.1093/molbev/msy056] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Seong Kyu Han
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
| | - Donghyo Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
| | - Heetak Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
| | - Inhae Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
| | - Sanguk Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Korea
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24
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Patrick R, Kobe B, Lê Cao KA, Bodén M. PhosphoPICK-SNP: quantifying the effect of amino acid variants on protein phosphorylation. Bioinformatics 2018; 33:1773-1781. [PMID: 28186228 DOI: 10.1093/bioinformatics/btx072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 02/07/2017] [Indexed: 12/15/2022] Open
Abstract
Motivation Genome-wide association studies are identifying single nucleotide variants (SNVs) linked to various diseases, however the functional effect caused by these variants is often unknown. One potential functional effect, the loss or gain of protein phosphorylation sites, can be induced through variations in key amino acids that disrupt or introduce valid kinase binding patterns. Current methods for predicting the effect of SNVs on phosphorylation operate on the sequence content of reference and variant proteins. However, consideration of the amino acid sequence alone is insufficient for predicting phosphorylation change, as context factors determine kinase-substrate selection. Results We present here a method for quantifying the effect of SNVs on protein phosphorylation through an integrated system of motif analysis and context-based assessment of kinase targets. By predicting the effect that known variants across the proteome have on phosphorylation, we are able to use this background of proteome-wide variant effects to quantify the significance of novel variants for modifying phosphorylation. We validate our method on a manually curated set of phosphorylation change-causing variants from the primary literature, showing that the method predicts known examples of phosphorylation change at high levels of specificity. We apply our approach to data-sets of variants in phosphorylation site regions, showing that variants causing predicted phosphorylation loss are over-represented among disease-associated variants. Availability and Implementation The method is freely available as a web-service at the website http://bioinf.scmb.uq.edu.au/phosphopick/snp. Contact m.boden@uq.edu.au. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Ralph Patrick
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia.,Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, Australia
| | - Kim-Anh Lê Cao
- The University of Queensland Diamantina Institute, Translational Research Institute, Woolloongabba, QLD, Australia
| | - Mikael Bodén
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia.,Institute for Molecular Bioscience, The University of Queensland, St Lucia, Australia
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25
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Abstract
3′,5′-cyclic adenosine monophosphate (cAMP) signalling plays a major role in the cardiac myocyte response to extracellular stimulation by hormones and neurotransmitters. In recent years, evidence has accumulated demonstrating that the cAMP response to different extracellular agonists is not uniform: depending on the stimulus, cAMP signals of different amplitudes and kinetics are generated in different subcellular compartments, eliciting defined physiological effects. In this review, we focus on how real-time imaging using fluorescence resonance energy transfer (FRET)-based reporters has provided mechanistic insight into the compartmentalisation of the cAMP signalling pathway and allowed for the precise definition of the regulation and function of subcellular cAMP nanodomains.
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Abstract
The calcium pump (a.k.a. Ca2+-ATPase or SERCA) is a membrane transport protein ubiquitously found in the endoplasmic reticulum (ER) of all eukaryotic cells. As a calcium transporter, SERCA maintains the low cytosolic calcium level that enables a vast array of signaling pathways and physiological processes (e.g. synaptic transmission, muscle contraction, fertilization). In muscle cells, SERCA promotes relaxation by pumping calcium ions from the cytosol into the lumen of the sarcoplasmic reticulum (SR), the main storage compartment for intracellular calcium. X-ray crystallographic studies have provided an extensive understanding of the intermediate states that SERCA populates as it progresses through the calcium transport cycle. Historically, SERCA is also known to be regulated by small transmembrane peptides, phospholamban (PLN) and sarcolipin (SLN). PLN is expressed in cardiac muscle, whereas SLN predominates in skeletal and atrial muscle. These two regulatory subunits play critical roles in cardiac contractility. While our understanding of these regulatory mechanisms are still developing, SERCA and PLN are one of the best understood examples of peptide-transporter regulatory interactions. Nonetheless, SERCA appeared to have only two regulatory subunits, while the related sodium pump (a.k.a. Na+, K+-ATPase) has at least nine small transmembrane peptides that provide tissue specific regulation. The last few years have seen a renaissance in our understanding of SERCA regulatory subunits. First, structures of the SERCA-SLN and SERCA-PLN complexes revealed molecular details of their interactions. Second, an array of micropeptides concealed within long non-coding RNAs have been identified as new SERCA regulators. This chapter will describe our current understanding of SERCA structure, function, and regulation.
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27
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Mutation analysis of the phospholamban gene in 315 South Africans with dilated, hypertrophic, peripartum and arrhythmogenic right ventricular cardiomyopathies. Sci Rep 2016; 6:22235. [PMID: 26917049 PMCID: PMC4808831 DOI: 10.1038/srep22235] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 02/09/2016] [Indexed: 02/07/2023] Open
Abstract
Cardiomyopathy is an important cause of heart failure in Sub-Saharan Africa, accounting for up to 30% of adult heart failure hospitalisations. This high prevalence poses a challenge in societies without access to resources and interventions essential for disease management. Over 80 genes have been implicated as a cause of cardiomyopathy. Mutations in the phospholamban (PLN) gene are associated with dilated cardiomyopathy (DCM) and severe heart failure. In Africa, the prevalence of PLN mutations in cardiomyopathy patients is unknown. Our aim was to screen 315 patients with arrhythmogenic right ventricular cardiomyopathy (n = 111), DCM (n = 95), hypertrophic cardiomyopathy (n = 40) and peripartum cardiomyopathy (n = 69) for disease-causing PLN mutations by high resolution melt analysis and DNA sequencing. We detected the previously reported PLN c.25C > T (p.R9C) mutation in a South African family with severe autosomal dominant DCM. Haplotype analysis revealed that this mutation occurred against a different haplotype background to that of the original North American family and was therefore unlikely to have been inherited from a common ancestor. No other mutations in PLN were detected (mutation prevalence = 0.2%). We conclude that PLN is a rare cause of cardiomyopathy in African patients. The PLN p.R9C mutation is not well-tolerated, emphasising the importance of this gene in cardiac function.
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28
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Truszkowska GT, Bilińska ZT, Kosińska J, Śleszycka J, Rydzanicz M, Sobieszczańska-Małek M, Franaszczyk M, Bilińska M, Stawiński P, Michalak E, Małek ŁA, Chmielewski P, Foss-Nieradko B, Machnicki MM, Stokłosa T, Ponińska J, Szumowski Ł, Grzybowski J, Piwoński J, Drygas W, Zieliński T, Płoski R. A study in Polish patients with cardiomyopathy emphasizes pathogenicity of phospholamban (PLN) mutations at amino acid position 9 and low penetrance of heterozygous null PLN mutations. BMC MEDICAL GENETICS 2015; 16:21. [PMID: 25928149 PMCID: PMC4421997 DOI: 10.1186/s12881-015-0167-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 03/23/2015] [Indexed: 12/16/2022]
Abstract
Background In humans mutations in the PLN gene, encoding phospholamban - a regulator of sarcoplasmic reticulum calcium ATPase (SERCA), cause cardiomyopathy with prevalence depending on the population. Our purpose was to identify PLN mutations in Polish cardiomyopathy patients. Methods We studied 161 unrelated subjects referred for genetic testing for cardiomyopathies: 135 with dilated cardiomyopathy, 22 with hypertrophic cardiomyopathy and 4 with other cardiomyopathies. In 23 subjects multiple genes were sequenced by next generation sequencing and in all subjects PLN exons were analyzed by Sanger sequencing. Control group included 200 healthy subjects matched with patients for ethnicity, sex and age. Large deletions/insertions were screened by real time polymerase chain reaction. Results We detected three different heterozygous mutations in the PLN gene: a novel null c.9_10insA:(p.Val4Serfs*15) variant and two missense variants: c.25C > T:(p.Arg9Cys) and c.26G > T:(p.Arg9Leu). The (p.Val4Serfs*15) variant occurred in the patient with Wolff-Parkinson-White syndrome in whom the diagnosis of cardiomyopathy was not confirmed and his mother who had concentric left ventricular remodeling but normal left ventricular mass and function. We did not detect large deletions/insertions in PLN in cohort studied. Conclusions In Poland, similar to most populations, PLN mutations rarely cause cardiomyopathy. The 9thPLN residue is apparently a mutation hot spot whereas a single dose of c.9_10insA, and likely other null PLN mutations, cause the disease only with low penetrance or are not pathogenic. Electronic supplementary material The online version of this article (doi:10.1186/s12881-015-0167-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Grażyna T Truszkowska
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Zofia T Bilińska
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Joanna Kosińska
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
| | - Justyna Śleszycka
- Department of Cardiomyopathies, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
| | | | - Maria Franaszczyk
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Maria Bilińska
- Department of Arrhythmia, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Piotr Stawiński
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Ewa Michalak
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Łukasz A Małek
- Department of Interventional Cardiology and Angiology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Przemysław Chmielewski
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Bogna Foss-Nieradko
- Unit for Screening Studies in Inherited Cardiovascular Diseases, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Marcin M Machnicki
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Tomasz Stokłosa
- Department of Immunology, Center for Biostructure Research, Medical University of Warsaw, Warszawa, Poland.
| | - Joanna Ponińska
- Laboratory of Molecular Biology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Łukasz Szumowski
- Department of Arrhythmia, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Jacek Grzybowski
- Department of Cardiomyopathies, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Jerzy Piwoński
- Department of Epidemiology, Cardiovascular Diseases Prevention and Promotion of Health, Institute of Cardiology, ul. Niemodlińska 33, 04-635, Warszawa, Poland.
| | - Wojciech Drygas
- Department of Epidemiology, Cardiovascular Diseases Prevention and Promotion of Health, Institute of Cardiology, ul. Niemodlińska 33, 04-635, Warszawa, Poland.
| | - Tomasz Zieliński
- Department of Heart Failure and Transplantology, Institute of Cardiology, ul. Alpejska 42, 04-628, Warszawa, Poland.
| | - Rafał Płoski
- Department of Medical Genetics, Warsaw Medical University, ul. Pawińskiego 3C, 02-106, Warszawa, Poland.
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Dysfunctional conformational dynamics of protein kinase A induced by a lethal mutant of phospholamban hinder phosphorylation. Proc Natl Acad Sci U S A 2015; 112:3716-21. [PMID: 25775607 DOI: 10.1073/pnas.1502299112] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The dynamic interplay between kinases and substrates is crucial for the formation of catalytically committed complexes that enable phosphoryl transfer. However, a clear understanding on how substrates modulate kinase structural dynamics to control catalytic efficiency is still missing. Here, we used solution NMR spectroscopy to study the conformational dynamics of two complexes of the catalytic subunit of the cAMP-dependent protein kinase A with WT and R14 deletion phospholamban, a lethal human mutant linked to familial dilated cardiomyopathy. Phospholamban is a central regulator of heart muscle contractility, and its phosphorylation by protein kinase A constitutes a primary response to β-adrenergic stimulation. We found that the single deletion of arginine in phospholamban's recognition sequence for the kinase reduces its binding affinity and dramatically reduces phosphorylation kinetics. Structurally, the mutant prevents the enzyme from adopting conformations and motions committed for catalysis, with concomitant reduction in catalytic efficiency. Overall, these results underscore the importance of a well-tuned structural and dynamic interplay between the kinase and its substrates to achieve physiological phosphorylation levels for proper Ca(2+) signaling and normal cardiac function.
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30
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Phospholamban pentamers attenuate PKA-dependent phosphorylation of monomers. J Mol Cell Cardiol 2015; 80:90-7. [DOI: 10.1016/j.yjmcc.2014.12.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/29/2014] [Accepted: 12/23/2014] [Indexed: 11/18/2022]
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31
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Altered myocardial calcium cycling and energetics in heart failure--a rational approach for disease treatment. Cell Metab 2015; 21:183-194. [PMID: 25651173 PMCID: PMC4338997 DOI: 10.1016/j.cmet.2015.01.005] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Cardiomyocyte function depends on coordinated movements of calcium into and out of the cell and the proper delivery of ATP to energy-utilizing enzymes. Defects in calcium-handling proteins and abnormal energy metabolism are features of heart failure. Recent discoveries have led to gene-based therapies targeting calcium-transporting or -binding proteins, such as the cardiac sarco(endo)plasmic reticulum calcium ATPase (SERCA2a), leading to improvements in calcium homeostasis and excitation-contraction coupling. Here we review impaired calcium cycling and energetics in heart failure, assessing their roles from both a mutually exclusive and interdependent viewpoint, and discuss therapies that may improve the failing myocardium.
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32
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Ablorh NAD, Thomas DD. Phospholamban phosphorylation, mutation, and structural dynamics: a biophysical approach to understanding and treating cardiomyopathy. Biophys Rev 2015; 7:63-76. [PMID: 28509982 DOI: 10.1007/s12551-014-0157-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 11/26/2014] [Indexed: 01/16/2023] Open
Abstract
We review the recent development of novel biochemical and spectroscopic methods to determine the site-specific phosphorylation, expression, mutation, and structural dynamics of phospholamban (PLB), in relation to its function (inhibition of the cardiac calcium pump, SERCA2a), with specific focus on cardiac physiology, pathology, and therapy. In the cardiomyocyte, SERCA2a actively transports Ca2+ into the sarcoplasmic reticulum (SR) during relaxation (diastole) to create the concentration gradient that drives the passive efflux of Ca2+ required for cardiac contraction (systole). Unphosphorylated PLB (U-PLB) inhibits SERCA2a, but phosphorylation at S16 and/or T17 (producing P-PLB) changes the structure of PLB to relieve SERCA2a inhibition. Because insufficient SERCA2a activity is a hallmark of heart failure, SERCA2a activation, by gene therapy (Andino et al. 2008; Fish et al. 2013; Hoshijima et al. 2002; Jessup et al. 2011) or drug therapy (Ferrandi et al. 2013; Huang 2013; Khan et al. 2009; Rocchetti et al. 2008; Zhang et al. 2012), is a widely sought goal for treatment of heart failure. This review describes rational approaches to this goal. Novel biophysical assays, using site-directed labeling and high-resolution spectroscopy, have been developed to resolve the structural states of SERCA2a-PLB complexes in vitro and in living cells. Novel biochemical assays, using synthetic standards and multidimensional immunofluorescence, have been developed to quantitate PLB expression and phosphorylation states in cells and human tissues. The biochemical and biophysical properties of U-PLB, P-PLB, and mutant PLB will ultimately resolve the mechanisms of loss of inhibition and gain of inhibition to guide therapeutic development. These assays will be powerful tools for investigating human tissue samples from the Sydney Heart Bank, for the purpose of analyzing and diagnosing specific disorders.
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Affiliation(s)
- Naa-Adjeley D Ablorh
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
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33
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Gorski PA, Trieber CA, Ashrafi G, Young HS. Regulation of the sarcoplasmic reticulum calcium pump by divergent phospholamban isoforms in zebrafish. J Biol Chem 2015; 290:6777-88. [PMID: 25593315 DOI: 10.1074/jbc.m114.585604] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum calcium pump (SERCA) is regulated by the small integral membrane proteins phospholamban (PLN) and sarcolipin (SLN). These regulators have homologous transmembrane regions, yet they differ in their cytoplasmic and luminal domains. Although the sequences of PLN and SLN are practically invariant among mammals, they vary in fish. Zebrafish (zf) appear to harbor multiple PLN isoforms, one of which contains 18 sequence variations and a unique luminal extension. Characterization of this isoform (zfPLN) revealed that SERCA inhibition and reversal by phosphorylation were comparable with human PLN. To understand the sequence variations in zfPLN, chimeras were created by transferring the N terminus, linker, and C terminus of zfPLN onto human PLN. A chimera containing the N-terminal domain resulted in a mild loss of function, whereas a chimera containing the linker domain resulted in a gain of function. This latter effect was due to changes in basic residues in the linker region of PLN. Removing the unique luminal domain of zfPLN ((53)SFHGM) resulted in loss of function, whereas adding this domain to human PLN had a minimal effect on SERCA inhibition. We conclude that the luminal extension contributes to SERCA inhibition but only in the context of zfPLN. Although this domain is distinct from the SLN luminal tail, zfPLN appears to use a hybrid PLN-SLN inhibitory mechanism. Importantly, the different zebrafish PLN isoforms raise the interesting possibility that sarcoplasmic reticulum calcium handling and cardiac contractility may be regulated by the differential expression of PLN functional variants.
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Affiliation(s)
| | - Catharine A Trieber
- From the Department of Biochemistry and National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | | | - Howard S Young
- From the Department of Biochemistry and National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Abrol N, de Tombe PP, Robia SL. Acute inotropic and lusitropic effects of cardiomyopathic R9C mutation of phospholamban. J Biol Chem 2015; 290:7130-40. [PMID: 25593317 DOI: 10.1074/jbc.m114.630319] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A naturally occurring R9C mutation of phospholamban (PLB) triggers cardiomyopathy and premature death by altering regulation of sarco/endoplasmic reticulum calcium-ATPase (SERCA). The goal of this study was to investigate the acute physiological consequences of the R9C-PLB mutation on cardiomyocyte calcium kinetics and contractility. We measured the physiological consequences of R9C-PLB mutation on calcium transients and sarcomere shortening in adult cardiomyocytes. In contrast to studies of chronic R9C-PLB expression in transgenic mice, we found that acute expression of R9C-PLB exerts a positively inotropic and lusitropic effect in cardiomyocytes. Importantly, R9C-PLB exhibited blunted sensitivity to frequency potentiation and β-adrenergic stimulation, two major physiological mechanisms for the regulation of cardiac performance. To identify the molecular mechanism of R9C pathology, we quantified the effect of R9C on PLB oligomerization and PLB-SERCA binding. FRET measurements in live cells revealed that R9C-PLB exhibited an increased propensity for oligomerization, and this was further increased by oxidative stress. The R9C also decreased PLB binding to SERCA and altered the structure of the PLB-SERCA regulatory complex. The structural change after oxidative modification of R9C-PLB was similar to that observed after PLB phosphorylation. We conclude that R9C mutation of PLB decreases SERCA inhibition by decreasing the amount of the regulatory complex and altering its conformation. This has an acute inotropic/lusitropic effect but yields negative consequences of impaired frequency potentiation and blunted β-adrenergic responsiveness. We envision a self-reinforcing mechanism beginning with phosphomimetic R9C-PLB oxidation and loss of SERCA inhibition, leading to impaired calcium regulation and heart failure.
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Affiliation(s)
- Neha Abrol
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60163
| | - Pieter P de Tombe
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60163
| | - Seth L Robia
- From the Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, Illinois 60163
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Young HS, Ceholski DK, Trieber CA. Deception in simplicity: hereditary phospholamban mutations in dilated cardiomyopathy. Biochem Cell Biol 2014; 93:1-7. [PMID: 25563649 DOI: 10.1139/bcb-2014-0080] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The sarcoplasmic reticulum (SR) calcium pump (SERCA) and its regulator phospholamban are required for cardiovascular function. Phospholamban alters the apparent calcium affinity of SERCA in a process that is modulated by phosphorylation via the β-adrenergic pathway. This regulatory axis allows for the dynamic control of SR calcium stores and cardiac contractility. Herein we focus on hereditary mutants of phospholamban that are associated with heart failure, such as Arg(9)-Cys, Arg(9)-Leu, Arg(9)-His, and Arg(14)-deletion. Each mutant has a distinct effect on PLN function and SR calcium homeostasis. Arg(9)-Cys and Arg(9)-Leu do not inhibit SERCA, Arg(14)-deletion is a partial inhibitor, and Arg(9)-His is comparable to wild-type. While the mutants have distinct functional effects on SERCA, they have in common that they cannot be phosphorylated by protein kinase A (PKA). Arg(9) and Arg(14) are required for PKA recognition and phosphorylation of PLN. Thus, mutations at these positions eliminate β-adrenergic control and dynamic cardiac contractility. Hydrophobic mutations of Arg(9) cause more complex changes in function, including loss of PLN function and dominant negative interaction with SERCA in heterozygous individuals. In addition, aberrant interaction with PKA may prevent phosphorylation of wild-type PLN and sequester PKA from other local subcellular targets. Herein we consider what is known about each mutant and how the synergistic changes in SR calcium homeostasis lead to impaired cardiac contractility and dilated cardiomyopathy.
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Affiliation(s)
- Howard S Young
- a Department of Biochemistry, University of Alberta, 327 Medical Sciences Building, Edmonton, AB T6G 2H7, Canada
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36
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Vostrikov VV, Soller KJ, Ha KN, Gopinath T, Veglia G. Effects of naturally occurring arginine 14 deletion on phospholamban conformational dynamics and membrane interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:315-22. [PMID: 25251363 DOI: 10.1016/j.bbamem.2014.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/12/2014] [Accepted: 09/13/2014] [Indexed: 01/10/2023]
Abstract
Phospholamban (PLN) is a single-pass membrane protein that regulates the sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA). Phosphorylation of PLN at Ser16 reverses its inhibitory function under β-adrenergic stimulation, augmenting Ca²⁺ uptake in the sarcoplasmic reticulum and muscle contractility. PLN exists in two conformations; a T state, where the cytoplasmic domain is helical and adsorbed on the membrane surface, and an R state, where the cytoplasmic domain is unfolded and membrane detached. Previous studies have shown that the PLN conformational equilibrium is crucial to SERCA regulation. Here, we used a combination of solution and solid-state NMR to compare the structural topology and conformational dynamics of monomeric PLN (PLN(AFA)) with that of the PLN(R14del), a naturally occurring deletion mutant that is linked to the progression of dilated cardiomyopathy. We found that the behavior of the inhibitory transmembrane domain of PLN(R14del) is similar to that of the native sequence. Conversely, the conformational dynamics of R14del both in micelles and lipid membranes are enhanced. We conclude that the deletion of Arg14 in the cytoplasmic region weakens the interactions with the membrane and shifts the conformational equilibrium of PLN toward the disordered R state. This conformational transition is correlated with the loss-of-function character of this mutant and is corroborated by SERCA's activity assays. These findings support our hypothesis that SERCA function is fine-tuned by PLN conformational dynamics and begin to explain the aberrant regulation of SERCA by the R14del mutant.
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Affiliation(s)
- Vitaly V Vostrikov
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kailey J Soller
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Kim N Ha
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Chemistry and Biochemistry, St. Catherine University, St. Paul, MN 55105, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Chemistry, University of Minnesota, Minneapolis, MN 55455, USA.
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Hughes E, Middleton DA. Comparison of the structure and function of phospholamban and the arginine-14 deficient mutant associated with dilated cardiomyopathy. PLoS One 2014; 9:e106746. [PMID: 25225809 PMCID: PMC4165587 DOI: 10.1371/journal.pone.0106746] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/01/2014] [Indexed: 12/20/2022] Open
Abstract
Phospholamban (PLB) is a pentameric protein that plays an important role in regulating cardiac contractility via a reversible inhibitory association with the sarcoplasmic reticulum Ca2+ATPase (SERCA), the enzyme responsible for maintaining correct calcium homeostasis. Here we study the functional and biophysical characteristics of a PLB mutant associated with human dilated cardiomyopathy (DCM), with a deletion of arginine at position 14 (PLBR14Δ). In agreement with recent findings, we find that PLBR14Δ has a reduced inhibitory effect on SERCA compared to wild type PLB (PLBWT) when reconstituted into lipid membranes. The mutation also leads to a large reduction in the protein kinase A-catalysed phosphorylation of Ser-16 in the cytoplasmic domain of PLBR14Δ. Measurements on SERCA co-reconstituted with an equimolar mixture of PLBWT and PLBR14Δ (representing the lethal heterozygous state associated with DCM) indicates that the loss-of-function mutation has a dominant effect on PLBWT functionality and phosphorylation capacity, suggesting that mixed PLBWT/PLBR14Δ pentamers are formed that have characteristics typical of the mutant protein. Structural and biophysical analysis of PLBR14Δ indicates that the mutation perturbs slightly the helical structure of the PLB cytoplasmic domain and reduces its affinity for the phospholipid bilayer surface, thereby altering the orientation of the cytoplasmic domain relative to the wild-type protein. These results indicate that the structure and function consequences of the R14 deletion have profound effects on the regulation of SERCA which may contribute to the aetiology of DCM.
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Affiliation(s)
- Eleri Hughes
- Department of Chemistry, Lancaster University, Lancaster, United Kingdom
| | - David A Middleton
- Department of Chemistry, Lancaster University, Lancaster, United Kingdom
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Yu X, Lorigan GA. Secondary structure, backbone dynamics, and structural topology of phospholamban and its phosphorylated and Arg9Cys-mutated forms in phospholipid bilayers utilizing 13C and 15N solid-state NMR spectroscopy. J Phys Chem B 2014; 118:2124-33. [PMID: 24511878 PMCID: PMC3983341 DOI: 10.1021/jp500316s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Phospholamban (PLB) is a membrane protein that regulates heart muscle relaxation rates via interactions with the sarcoplasmic reticulum Ca(2+) ATPase (SERCA). When PLB is phosphorylated or Arg9Cys (R9C) is mutated, inhibition of SERCA is relieved. (13)C and (15)N solid-state NMR spectroscopy is utilized to investigate conformational changes of PLB upon phosphorylation and R9C mutation. (13)C═O NMR spectra of the cytoplasmic domain reveal two α-helical structural components with population changes upon phosphorylation and R9C mutation. The appearance of an unstructured component is observed on domain Ib. (15)N NMR spectra indicate an increase in backbone dynamics of the cytoplasmic domain. Wild-type PLB (WT-PLB), Ser16-phosphorylated PLB (P-PLB), and R9C-mutated PLB (R9C-PLB) all have a very dynamic domain Ib, and the transmembrane domain has an immobile component. (15)N NMR spectra indicate that the cytoplasmic domain of R9C-PLB adopts an orientation similar to P-PLB and shifts away from the membrane surface. Domain Ib (Leu28) of P-PLB and R9C-PLB loses the alignment. The R9C-PLB adopts a conformation similar to P-PLB with a population shift to a more extended and disordered state. The NMR data suggest the more extended and disordered forms of PLB may relate to inhibition relief.
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Affiliation(s)
- Xueting Yu
- Department of Chemistry and Biochemistry, Miami University , Oxford, Ohio 45056, United States
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Kemp G, Fliegel L, Young HS. Membrane transport piece by piece: production of transmembrane peptides for structural and functional studies. CURRENT PROTOCOLS IN PROTEIN SCIENCE 2014; 75:29.8.1-29.8.28. [PMID: 24510677 DOI: 10.1002/0471140864.ps2908s75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane proteins are involved in all cellular processes from signaling cascades to nutrient uptake and waste disposal. Because of these essential functions, many membrane proteins are recognized as important, yet elusive, clinical targets. Recent advances in structural biology have answered many questions about how membrane proteins function, yet one of the major bottlenecks remains the ability to obtain sufficient quantities of pure and homogeneous protein. This is particularly true for human membrane proteins, where novel expression strategies and structural techniques are needed to better characterize their function and therapeutic potential. One way to approach this challenge is to determine the structure of smaller pieces of membrane proteins that can be assembled into models of the complete protein. This unit describes the rationale for working with single or multiple transmembrane segments and provides a description of strategies and methods to express and purify them for structural and functional studies using a maltose binding protein (MBP) fusion. The bulk of the unit outlines a detailed methodology and justification for producing these peptides under native-like conditions.
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Affiliation(s)
- Grant Kemp
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Larry Fliegel
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Howard S Young
- Department of Biochemistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta, Canada
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Vostrikov VV, Mote KR, Verardi R, Veglia G. Structural dynamics and topology of phosphorylated phospholamban homopentamer reveal its role in the regulation of calcium transport. Structure 2013; 21:2119-30. [PMID: 24207128 DOI: 10.1016/j.str.2013.09.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/07/2013] [Accepted: 09/11/2013] [Indexed: 01/25/2023]
Abstract
Phospholamban (PLN) inhibits the sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA), thereby regulating cardiac diastole. In membranes, PLN assembles into homopentamers that in both the phosphorylated and nonphosphorylated states have been proposed to form ion-selective channels. Here, we determined the structure of the phosphorylated pentamer using a combination of solution and solid-state nuclear magnetic resonance methods. We found that the pinwheel architecture of the homopentamer is preserved upon phosphorylation, with each monomer having an L-shaped conformation. The TM domains form a hydrophobic pore approximately 24 Å long and 2 Å in diameter, which is inconsistent with canonical Ca²⁺-selective channels. Phosphorylation, however, enhances the conformational dynamics of the cytoplasmic region of PLN, causing partial unwinding of the amphipathic helix. We propose that PLN oligomers act as storage for active monomers, keeping SERCA function within a physiological window.
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Affiliation(s)
- Vitaly V Vostrikov
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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41
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Yu X, Lorigan GA. Probing the interaction of Arg9Cys mutated phospholamban with phospholipid bilayers by solid-state NMR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2444-9. [PMID: 23850636 DOI: 10.1016/j.bbamem.2013.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 06/10/2013] [Accepted: 07/01/2013] [Indexed: 01/05/2023]
Abstract
Phospholamban (PLB) is a 52 amino acid integral membrane protein that interacts with the sarcoplasmic reticulum Ca(2+) ATPase (SERCA) and helps to regulate Ca(2+) flow. PLB inhibits SERCA impairing Ca(2+) translocation. The inhibition can be relieved upon phosphorylation of PLB. The Arg9 to Cys (R9C) mutation is a loss of function mutation with reduced inhibitory potency. The effect R9C PLB has on the membrane surface and the hydrophobic region dynamics was investigated by (31)P and (2)H solid-state NMR spectroscopy in multilamellar vesicles (MLVs). The (31)P NMR spectra indicate that, like the phosphorylated PLB (P-PLB), the mutated R9C-PLB protein has significantly less interaction with the lipid bilayer headgroup when compared to wild-type PLB (WT-PLB). Similar to P-PLB, R9C-PLB slightly decreases (31)P T1 values in the lipid headgroup region. (2)H SCD order parameters of (2)H nuclei along the lipid acyl chain decrease less dramatically for R9C-PLB and P-PLB when compared to WT-PLB. The results suggest that R9C-PLB interacts less with the membrane surface and hydrophobic region than WT-PLB. Detachment of the cytoplasmic domain of R9C-PLB from the membrane surface could be related to its loss of function.
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Affiliation(s)
- Xueting Yu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
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Abstract
Acute heart failure is a public health issue with morbidity and mortality exceeding that of myocardial infarction. Novel compounds for the treatment of acute heart failure are clearly needed and fall into the general categories of inotropic, vasodilatory and other compounds in phase I to III of development. Furthest along are omecamtiv mecarbil (a cardiac myosin activator), ularitide (a natriuretic and diuretic peptide) and relaxin (a vasodilator). Each compound has a unique set of assets and liabilities that will aid in the understanding of the syndrome and application to the right patients at the right time in this heterogeneous syndrome. This review will explore current and future novel pharmacologic therapies for the treatment of acute heart failure.
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Gorski PA, Glaves JP, Vangheluwe P, Young HS. Sarco(endo)plasmic reticulum calcium ATPase (SERCA) inhibition by sarcolipin is encoded in its luminal tail. J Biol Chem 2013; 288:8456-8467. [PMID: 23362265 DOI: 10.1074/jbc.m112.446161] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The sarco(endo)plasmic reticulum calcium ATPase (SERCA) is regulated in a tissue-dependent manner via interaction with the short integral membrane proteins phospholamban (PLN) and sarcolipin (SLN). Although defects in SERCA activity are known to cause heart failure, the regulatory mechanisms imposed by PLN and SLN could have clinical implications for both heart and skeletal muscle diseases. PLN and SLN have significant sequence homology in their transmembrane regions, suggesting a similar mode of binding to SERCA. However, unlike PLN, SLN has a conserved C-terminal luminal tail composed of five amino acids ((27)RSYQY), which may contribute to a distinct SERCA regulatory mechanism. We have functionally characterized alanine mutants of the C-terminal tail of SLN using co-reconstituted proteoliposomes of SERCA and SLN. We found that Arg(27) and Tyr(31) are essential for SLN function. We also tested the effect of a truncated variant of SLN (Arg(27)stop) and extended chimeras of PLN with the five luminal residues of SLN added to its C terminus. The Arg(27)stop form of SLN resulted in loss of function, whereas the PLN chimeras resulted in superinhibition with characteristics of both PLN and SLN. Based on our results, we propose that the C-terminal tail of SLN is a distinct, essential domain in the regulation of SERCA and that the functional properties of the SLN tail can be transferred to PLN.
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Affiliation(s)
- Przemek A Gorski
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - John Paul Glaves
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2M9, Canada
| | - Peter Vangheluwe
- Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven, B3000 Leuven, Belgium
| | - Howard S Young
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada; National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2M9, Canada.
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