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Lopergolo D, Gallus GN, Pieraccini G, Boscaro F, Berti G, Serni G, Volpi N, Formichi P, Bianchi S, Cassandrini D, Sorrentino V, Rossi D, Santorelli FM, De Stefano N, Malandrini A. CCDC78: Unveiling the Function of a Novel Gene Associated with Hereditary Myopathy. Cells 2024; 13:1504. [PMID: 39273074 PMCID: PMC11394131 DOI: 10.3390/cells13171504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2024] [Revised: 09/03/2024] [Accepted: 09/04/2024] [Indexed: 09/15/2024] Open
Abstract
CCDC78 was identified as a novel candidate gene for autosomal dominant centronuclear myopathy-4 (CNM4) approximately ten years ago. However, to date, only one family has been described, and the function of CCDC78 remains unclear. Here, we analyze for the first time a family harboring a CCDC78 nonsense mutation to better understand the role of CCDC78 in muscle. METHODS We conducted a comprehensive histopathological analysis on muscle biopsies, including immunofluorescent assays to detect multiple sarcoplasmic proteins. We examined CCDC78 transcripts and protein using WB in CCDC78-mutated muscle tissue; these analyses were also performed on muscle, lymphocytes, and fibroblasts from healthy subjects. Subsequently, we conducted RT-qPCR and transcriptome profiling through RNA-seq to evaluate changes in gene expression associated with CCDC78 dysfunction in muscle. Lastly, coimmunoprecipitation (Co-Ip) assays and mass spectrometry (LC-MS/MS) studies were carried out on extracted muscle proteins from both healthy and mutated subjects. RESULTS The histopathological features in muscle showed novel histological hallmarks, which included areas of dilated and swollen sarcoplasmic reticulum (SR). We provided evidence of nonsense-mediated mRNA decay (NMD), identified the presence of novel CCDC78 transcripts in muscle and lymphocytes, and identified 1035 muscular differentially expressed genes, including several involved in the SR. Through the Co-Ip assays and LC-MS/MS studies, we demonstrated that CCDC78 interacts with two key SR proteins: SERCA1 and CASQ1. We also observed interactions with MYH1, ACTN2, and ACTA1. CONCLUSIONS Our findings provide insight, for the first time, into the interactors and possible role of CCDC78 in skeletal muscle, locating the protein in the SR. Furthermore, our data expand on the phenotype previously associated with CCDC78 mutations, indicating potential histopathological hallmarks of the disease in human muscle. Based on our data, we can consider CCDC78 as the causative gene for CNM4.
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Affiliation(s)
- Diego Lopergolo
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Gian Nicola Gallus
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Giuseppe Pieraccini
- CISM-Mass Spectrometry Centre, University of Florence, 50139 Florence, Italy
| | - Francesca Boscaro
- CISM-Mass Spectrometry Centre, University of Florence, 50139 Florence, Italy
| | - Gianna Berti
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Giovanni Serni
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Nila Volpi
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Patrizia Formichi
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Silvia Bianchi
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Denise Cassandrini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, 53100 Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Nicola De Stefano
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
| | - Alessandro Malandrini
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy
- UOC Neurologia, Azienda Ospedaliero-Universitaria Senese, 53100 Siena, Italy
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Gamberucci A, Nanni C, Pierantozzi E, Serano M, Protasi F, Rossi D, Sorrentino V. TAM-associated CASQ1 mutants diminish intracellular Ca 2+ content and interfere with regulation of SOCE. J Muscle Res Cell Motil 2024:10.1007/s10974-024-09681-9. [PMID: 39126637 DOI: 10.1007/s10974-024-09681-9] [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: 05/13/2024] [Accepted: 07/31/2024] [Indexed: 08/12/2024]
Abstract
Tubular aggregate myopathy (TAM) is a rare myopathy characterized by muscle weakness and myalgia. Muscle fibers from TAM patients show characteristic accumulation of membrane tubules that contain proteins from the sarcoplasmic reticulum (SR). Gain-of-function mutations in STIM1 and ORAI1, the key proteins participating in the Store-Operated Ca2+ Entry (SOCE) mechanism, were identified in patients with TAM. Recently, the CASQ1 gene was also found to be mutated in patients with TAM. CASQ1 is the main Ca2+ buffer of the SR and a negative regulator of SOCE. Previous characterization of CASQ1 mutants in non-muscle cells revealed that they display altered Ca2+dependent polymerization, reduced Ca2+storage capacity and alteration in SOCE inhibition. We thus aimed to assess how mutations in CASQ1 affect calcium regulation in skeletal muscles, where CASQ1 is naturally expressed. We thus expressed CASQ1 mutants in muscle fibers from Casq1 knockout mice, which provide a valuable model for studying the Ca2+ storage capacity of TAM-associated mutants. Moreover, since Casq1 knockout mice display a constitutively active SOCE, the effect of CASQ1 mutants on SOCE inhibition can be also properly examined in fibers from these mice. Analysis of intracellular Ca2+ confirmed that CASQ1 mutants have impaired ability to store Ca2+and lose their ability to inhibit skeletal muscle SOCE; this is in agreement with the evidence that alterations in Ca2+entry due to mutations in either STIM1, ORAI1 or CASQ1 represents a hallmark of TAM.
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Affiliation(s)
- Alessandra Gamberucci
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy
| | - Claudio Nanni
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy
| | - Matteo Serano
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy
| | - Feliciano Protasi
- Center for Advanced Studies and Technology, CAST, University G. d'Annunzio of Chieti-Pescara, Chieti, I-66100, Italy
- DMSI, Department of Medicine and Aging Sciences, University G. d'Annunzio of Chieti-Pescara, Chieti, I-66100, Italy
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, I-53100, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, I-53100, Italy.
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, I-53100, Italy.
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3
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Hall DD, Takeshima H, Song LS. Structure, Function, and Regulation of the Junctophilin Family. Annu Rev Physiol 2024; 86:123-147. [PMID: 37931168 PMCID: PMC10922073 DOI: 10.1146/annurev-physiol-042022-014926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
In both excitable and nonexcitable cells, diverse physiological processes are linked to different calcium microdomains within nanoscale junctions that form between the plasma membrane and endo-sarcoplasmic reticula. It is now appreciated that the junctophilin protein family is responsible for establishing, maintaining, and modulating the structure and function of these junctions. We review foundational findings from more than two decades of research that have uncovered how junctophilin-organized ultrastructural domains regulate evolutionarily conserved biological processes. We discuss what is known about the junctophilin family of proteins. Our goal is to summarize the current knowledge of junctophilin domain structure, function, and regulation and to highlight emerging avenues of research that help our understanding of the transcriptional, translational, and post-translational regulation of this gene family and its roles in health and during disease.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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4
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Cala SE, Carruthers NJ, Stemmer PM, Chen Z, Chen X. Activation of Ca 2+ transport in cardiac microsomes enriches functional sets of ER and SR proteins. Mol Cell Biochem 2024; 479:85-98. [PMID: 37036634 PMCID: PMC10786961 DOI: 10.1007/s11010-023-04708-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/12/2023] [Indexed: 04/11/2023]
Abstract
The importance of sarcoplasmic reticulum (SR) Ca2+-handling in heart has led to detailed understanding of Ca2+-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca2+-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Proteins from 20.0 μg of MV, MedSR, and HighSR protein were fractionated using SDS-PAGE, then trypsinized from 20 separate gel pieces, and analyzed by LC-MS/MS to determine protein content. From 62,000 individual peptide spectra obtained, we identified 1105 different proteins, of which 354 were enriched ≥ 2.0-fold in SR fractions compared to the crude membrane preparation. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca2+ leak co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins constituting other putative ER/SR subdomains also exhibited average Esub enrichment values (mean ± S.D.) that spanned the range of possible Esub values, suggesting that functional sets of proteins are localized to the same areas of the ER/SR membrane. We conclude that active Ca2+ loading of cardiac microsomes, reflecting the combined activities of Ca2+ uptake by SERCA, and Ca2+ leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.
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Affiliation(s)
- Steven E Cala
- Department of Physiology, Wayne State University, Detroit, MI, 48201, USA.
| | | | - Paul M Stemmer
- Institute of Environmental Health Sciences, Wayne State University, Detroit, USA
| | - Zhenhui Chen
- Krannert Institute of Cardiology, Indiana University, Indianapolis, IN, USA
| | - Xuequn Chen
- Department of Physiology, Wayne State University, Detroit, MI, 48201, USA
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5
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Lee CS, Jung SY, Yee RSZ, Agha NH, Hong J, Chang T, Babcock LW, Fleischman JD, Clayton B, Hanna AD, Ward CS, Lanza D, Hurley AE, Zhang P, Wehrens XHT, Lagor WR, Rodney GG, Hamilton SL. Speg interactions that regulate the stability of excitation-contraction coupling protein complexes in triads and dyads. Commun Biol 2023; 6:942. [PMID: 37709832 PMCID: PMC10502019 DOI: 10.1038/s42003-023-05330-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 09/07/2023] [Indexed: 09/16/2023] Open
Abstract
Here we show that striated muscle preferentially expressed protein kinase α (Spegα) maintains cardiac function in hearts with Spegβ deficiency. Speg is required for stability of excitation-contraction coupling (ECC) complexes and interacts with esterase D (Esd), Cardiomyopathy-Associated Protein 5 (Cmya5), and Fibronectin Type III and SPRY Domain Containing 2 (Fsd2) in cardiac and skeletal muscle. Mice with a sequence encoding a V5/HA tag inserted into the first exon of the Speg gene (HA-Speg mice) display a >90% decrease in Spegβ but Spegα is expressed at ~50% of normal levels. Mice deficient in both Spegα and Speg β (Speg KO mice) develop a severe dilated cardiomyopathy and muscle weakness and atrophy, but HA-Speg mice display mild muscle weakness with no cardiac involvement. Spegα in HA-Speg mice suppresses Ca2+ leak, proteolytic cleavage of Jph2, and disruption of transverse tubules. Despite it's low levels, HA-Spegβ immunoprecipitation identified Esd, Cmya5 and Fsd2 as Spegβ binding partners that localize to triads and dyads to stabilize ECC complexes. This study suggests that Spegα and Spegβ display functional redundancy, identifies Esd, Cmya5 and Fsd2 as components of both cardiac dyads and skeletal muscle triads and lays the groundwork for the identification of new therapeutic targets for centronuclear myopathy.
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Affiliation(s)
- Chang Seok Lee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Sung Yun Jung
- Department of Biochemistry, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Rachel Sue Zhen Yee
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Nadia H Agha
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jin Hong
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ting Chang
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Lyle W Babcock
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Jorie D Fleischman
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Benjamin Clayton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Amy D Hanna
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Christopher S Ward
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Denise Lanza
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Ayrea E Hurley
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Pumin Zhang
- The First Affiliated Hospital, Zhejiang University Medical School, Hangzhou, China
| | - Xander H T Wehrens
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - William R Lagor
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - George G Rodney
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA
| | - Susan L Hamilton
- Department of Integrative Physiology, Baylor College of Medicine, Houston, TX, 77096, USA.
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6
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Pierantozzi E, Raucci L, Buonocore S, Rubino EM, Ding Q, Laurino A, Fiore F, Soldaini M, Chen J, Rossi D, Vangheluwe P, Chen H, Sorrentino V. Skeletal muscle overexpression of sAnk1.5 in transgenic mice does not predispose to type 2 diabetes. Sci Rep 2023; 13:8195. [PMID: 37210436 PMCID: PMC10199891 DOI: 10.1038/s41598-023-35393-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/17/2023] [Indexed: 05/22/2023] Open
Abstract
Genome-wide association studies (GWAS) and cis-expression quantitative trait locus (cis-eQTL) analyses indicated an association of the rs508419 single nucleotide polymorphism (SNP) with type 2 diabetes (T2D). rs508419 is localized in the muscle-specific internal promoter (P2) of the ANK1 gene, which drives the expression of the sAnk1.5 isoform. Functional studies showed that the rs508419 C/C variant results in increased transcriptional activity of the P2 promoter, leading to higher levels of sAnk1.5 mRNA and protein in skeletal muscle biopsies of individuals carrying the C/C genotype. To investigate whether sAnk1.5 overexpression in skeletal muscle might predispose to T2D development, we generated transgenic mice (TgsAnk1.5/+) in which the sAnk1.5 coding sequence was selectively overexpressed in skeletal muscle tissue. TgsAnk1.5/+ mice expressed up to 50% as much sAnk1.5 protein as wild-type (WT) muscles, mirroring the difference reported between individuals with the C/C or T/T genotype at rs508419. However, fasting glucose levels, glucose tolerance, insulin levels and insulin response in TgsAnk1.5/+ mice did not differ from those of age-matched WT mice monitored over a 12-month period. Even when fed a high-fat diet, TgsAnk1.5/+ mice only presented increased caloric intake, but glucose disposal, insulin tolerance and weight gain were comparable to those of WT mice fed a similar diet. Altogether, these data indicate that sAnk1.5 overexpression in skeletal muscle does not predispose mice to T2D susceptibility.
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Affiliation(s)
- E Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - L Raucci
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - S Buonocore
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - E M Rubino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - Q Ding
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
| | - A Laurino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - F Fiore
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - M Soldaini
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
| | - J Chen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), 3000, Leuven, Belgium
| | - D Rossi
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy
| | - P Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), 3000, Leuven, Belgium
| | - H Chen
- Department of Cardio-Thoracic Surgery, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, 210008, Jiangsu, China
- Programme in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - V Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, 53100, Siena, Italy.
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliera Universitaria Senese, 53100, Siena, Italy.
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7
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Dixon RE, Trimmer JS. Endoplasmic Reticulum-Plasma Membrane Junctions as Sites of Depolarization-Induced Ca 2+ Signaling in Excitable Cells. Annu Rev Physiol 2023; 85:217-243. [PMID: 36202100 PMCID: PMC9918718 DOI: 10.1146/annurev-physiol-032122-104610] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Membrane contact sites between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are found in all eukaryotic cells. In excitable cells they play unique roles in organizing diverse forms of Ca2+ signaling as triggered by membrane depolarization. ER-PM junctions underlie crucial physiological processes such as excitation-contraction coupling, smooth muscle contraction and relaxation, and various forms of activity-dependent signaling and plasticity in neurons. In many cases the structure and molecular composition of ER-PM junctions in excitable cells comprise important regulatory feedback loops linking depolarization-induced Ca2+ signaling at these sites to the regulation of membrane potential. Here, we describe recent findings on physiological roles and molecular composition of native ER-PM junctions in excitable cells. We focus on recent studies that provide new insights into canonical forms of depolarization-induced Ca2+ signaling occurring at junctional triads and dyads of striated muscle, as well as the diversity of ER-PM junctions in these cells and in smooth muscle and neurons.
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Affiliation(s)
- Rose E Dixon
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California, USA;
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8
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Cala SE, Carruthers NJ, Stemmer PM, Chen Z, Chen X. Activation of Ca transport in cardiac microsomes enriches functional sets of ER and SR proteins. RESEARCH SQUARE 2023:rs.3.rs-2557992. [PMID: 36798315 PMCID: PMC9934757 DOI: 10.21203/rs.3.rs-2557992/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
The importance of sarcoplasmic reticulum (SR) Ca-handling in heart has led to detailed understanding of Ca-release and re-uptake protein complexes, while less is known about other endoplasmic reticulum (ER) functions in the heart. To more fully understand cardiac SR and ER functions, we analyzed cardiac microsomes based on their increased density through the actions of the SR Ca-ATPase (SERCA) and the ryanodine receptor that are highly active in cardiomyocytes. Crude cardiac microsomal vesicles loaded with Ca oxalate produced two higher density subfractions, MedSR and HighSR. Analyses of protein enrichments from the 3 membrane preparations (crude microsomes, MedSR, and HighSR), showed that only a third of microsomal proteins in heart, or 354 proteins, were enriched ≥2.0-fold in SR. Previously studied SR proteins were all enriched, as were proteins associated with canonical ER functions. Contractile, mitochondrial, and sarcolemmal proteins were not enriched. Comparing the levels of SERCA-positive SR proteins in MedSR versus HighSR vesicles produced a range of SR subfraction enrichments signifying differing levels of Ca leak (ryanodine receptor) co-localized in the same membrane patch. All known junctional SR proteins were more enriched in MedSR, while canonical ER proteins were more enriched in HighSR membrane. Proteins from other putative ER/SR subdomains also showed characteristic distributions among SR subpopulations. We conclude that active Ca loading of cardiac microsomes, reflecting the combined activities of Ca uptake by SERCA, and Ca leak by RyR, permits evaluation of multiple functional ER/SR subdomains. Sets of proteins from these subdomains exhibited similar enrichment patterns across membrane subfractions, reflecting the relative levels of SERCA and RyR present within individual patches of cardiac ER and SR.
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9
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Tammineni ER, Figueroa L, Manno C, Varma D, Kraeva N, Ibarra CA, Klip A, Riazi S, Rios E. Muscle calcium stress cleaves junctophilin1, unleashing a gene regulatory program predicted to correct glucose dysregulation. eLife 2023; 12:e78874. [PMID: 36724092 PMCID: PMC9891728 DOI: 10.7554/elife.78874] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 01/11/2023] [Indexed: 02/02/2023] Open
Abstract
Calcium ion movements between cellular stores and the cytosol govern muscle contraction, the most energy-consuming function in mammals, which confers skeletal myofibers a pivotal role in glycemia regulation. Chronic myoplasmic calcium elevation ("calcium stress"), found in malignant hyperthermia-susceptible (MHS) patients and multiple myopathies, has been suggested to underlie the progression from hyperglycemia to insulin resistance. What drives such progression remains elusive. We find that muscle cells derived from MHS patients have increased content of an activated fragment of GSK3β - a specialized kinase that inhibits glycogen synthase, impairing glucose utilization and delineating a path to hyperglycemia. We also find decreased content of junctophilin1, an essential structural protein that colocalizes in the couplon with the voltage-sensing CaV1.1, the calcium channel RyR1 and calpain1, accompanied by an increase in a 44 kDa junctophilin1 fragment (JPh44) that moves into nuclei. We trace these changes to activated proteolysis by calpain1, secondary to increased myoplasmic calcium. We demonstrate that a JPh44-like construct induces transcriptional changes predictive of increased glucose utilization in myoblasts, including less transcription and translation of GSK3β and decreased transcription of proteins that reduce utilization of glucose. These effects reveal a stress-adaptive response, mediated by the novel regulator of transcription JPh44.
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Affiliation(s)
- Eshwar R Tammineni
- Department of Physiology and Biophysics, Rush UniversityChicagoUnited States
| | - Lourdes Figueroa
- Department of Physiology and Biophysics, Rush UniversityChicagoUnited States
| | - Carlo Manno
- Department of Physiology and Biophysics, Rush UniversityChicagoUnited States
| | - Disha Varma
- Department of Internal Medicine, Division of Nephrology, Rush UniversityChicagoUnited States
| | - Natalia Kraeva
- Department of Anesthesia & Pain Management, University of TorontoTorontoCanada
| | - Carlos A Ibarra
- Department of Anesthesia & Pain Management, University of TorontoTorontoCanada
| | - Amira Klip
- Cell Biology Program, The Hospital for Sick ChildrenTorontoCanada
| | - Sheila Riazi
- Department of Anesthesia & Pain Management, University of TorontoTorontoCanada
| | - Eduardo Rios
- Department of Physiology and Biophysics, Rush UniversityChicagoUnited States
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10
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Rossi D, Catallo MR, Pierantozzi E, Sorrentino V. Mutations in proteins involved in E-C coupling and SOCE and congenital myopathies. J Gen Physiol 2022; 154:e202213115. [PMID: 35980353 PMCID: PMC9391951 DOI: 10.1085/jgp.202213115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 07/15/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
In skeletal muscle, Ca2+ necessary for muscle contraction is stored and released from the sarcoplasmic reticulum (SR), a specialized form of endoplasmic reticulum through the mechanism known as excitation-contraction (E-C) coupling. Following activation of skeletal muscle contraction by the E-C coupling mechanism, replenishment of intracellular stores requires reuptake of cytosolic Ca2+ into the SR by the activity of SR Ca2+-ATPases, but also Ca2+ entry from the extracellular space, through a mechanism called store-operated calcium entry (SOCE). The fine orchestration of these processes requires several proteins, including Ca2+ channels, Ca2+ sensors, and Ca2+ buffers, as well as the active involvement of mitochondria. Mutations in genes coding for proteins participating in E-C coupling and SOCE are causative of several myopathies characterized by a wide spectrum of clinical phenotypes, a variety of histological features, and alterations in intracellular Ca2+ balance. This review summarizes current knowledge on these myopathies and discusses available knowledge on the pathogenic mechanisms of disease.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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11
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Zhou J, Liu H, Lin Y, Zhao J. Membrane Occupation and Recognition Nexus (MORN) motif controls protein localization and function. FEBS Lett 2022; 596:1839-1850. [PMID: 35568981 DOI: 10.1002/1873-3468.14378] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/23/2022] [Accepted: 05/07/2022] [Indexed: 11/06/2022]
Abstract
Membrane Occupation and Recognition Nexus (MORN) motif was first defined in 2000, when it was identified in the junctophilin protein family. Dozens of studies have been published ever since, mainly focusing on the function of a given MORN motif-containing protein in parasites, plants or animal cells. Proteins with MORN motifs are not only expressed in most animal and plant cell types but also significantly differ in their intracellular localization, suggesting that the MORN motifs may fulfil multiple physiological functions. Recent studies have found that MORN motif-containing proteins junctophilin 1/2 and MORN3 play a role in cardiac hypertrophy, skeletal muscle fiber stability and cancer. Hence, MORN motif-containing proteins may be exploited to develop improved treatments for various pathological conditions, such as cardiovascular diseases. Here, we review current research on MORN motif-containing proteins in different organisms and provide both ideas and approaches for follow-up exploration of their functions and applications.
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Affiliation(s)
- Jinrun Zhou
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, 266237, P. R. China
| | - Honghong Liu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, 266237, P. R. China
| | - Yushuang Lin
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, 266237, P. R. China
| | - Jing Zhao
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Science, Shandong University, Qingdao, 266237, P. R. China
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12
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Zhang T, Wang T, Niu Q, Xu L, Chen Y, Gao X, Gao H, Zhang L, Liu GE, Li J, Xu L. Transcriptional atlas analysis from multiple tissues reveals the expression specificity patterns in beef cattle. BMC Biol 2022; 20:79. [PMID: 35351103 PMCID: PMC8966188 DOI: 10.1186/s12915-022-01269-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/03/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND A comprehensive analysis of gene expression profiling across tissues can provide necessary information for an in-depth understanding of their biological functions. We performed a large-scale gene expression analysis and generated a high-resolution atlas of the transcriptome in beef cattle. RESULTS Our transcriptome atlas was generated from 135 bovine tissues in adult beef cattle, covering 51 tissue types of major organ systems (e.g., muscular system, digestive system, immune system, reproductive system). Approximately 94.76% of sequencing reads were successfully mapped to the reference genome assembly ARS-UCD1.2. We detected a total of 60,488 transcripts, and 32% of them were not reported before. We identified 2654 housekeeping genes (HKGs) and 477 tissue-specific genes (TSGs) across tissues. Using weighted gene co-expression network analysis, we obtained 24 modules with 237 hub genes (HUBGs). Functional enrichment analysis showed that HKGs mainly maintain the basic biological activities of cells, while TSGs were involved in tissue differentiation and specific physiological processes. HKGs in bovine tissues were more conserved in terms of expression pattern as compared to TSGs and HUBGs among multiple species. Finally, we obtained a subset of tissue-specific differentially expressed genes (DEGs) between beef and dairy cattle and several functional pathways, which may be involved in production and health traits. CONCLUSIONS We generated a large-scale gene expression atlas across the major tissues in beef cattle, providing valuable information for enhancing genome assembly and annotation. HKGs, TSGs, and HUBGs further contribute to better understanding the biology and evolution of multiple tissues in cattle. DEGs between beef and dairy cattle also fill in the knowledge gaps about differential transcriptome regulation of bovine tissues underlying economically important traits.
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Affiliation(s)
- Tianliu Zhang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Tianzhen Wang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Qunhao Niu
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Lei Xu
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Yan Chen
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Xue Gao
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Huijiang Gao
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Lupei Zhang
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - George E. Liu
- Animal Genomics and Improvement Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705 USA
| | - Junya Li
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
| | - Lingyang Xu
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193 People’s Republic of China
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13
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Rossi D, Pierantozzi E, Amadsun DO, Buonocore S, Rubino EM, Sorrentino V. The Sarcoplasmic Reticulum of Skeletal Muscle Cells: A Labyrinth of Membrane Contact Sites. Biomolecules 2022; 12:488. [PMID: 35454077 PMCID: PMC9026860 DOI: 10.3390/biom12040488] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 12/17/2022] Open
Abstract
The sarcoplasmic reticulum of skeletal muscle cells is a highly ordered structure consisting of an intricate network of tubules and cisternae specialized for regulating Ca2+ homeostasis in the context of muscle contraction. The sarcoplasmic reticulum contains several proteins, some of which support Ca2+ storage and release, while others regulate the formation and maintenance of this highly convoluted organelle and mediate the interaction with other components of the muscle fiber. In this review, some of the main issues concerning the biology of the sarcoplasmic reticulum will be described and discussed; particular attention will be addressed to the structure and function of the two domains of the sarcoplasmic reticulum supporting the excitation-contraction coupling and Ca2+-uptake mechanisms.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy; (E.P.); (D.O.A.); (S.B.); (E.M.R.); (V.S.)
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14
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Yang ZF, Panwar P, McFarlane CR, Tuinte WE, Campiglio M, Van Petegem F. Structures of the junctophilin/voltage-gated calcium channel interface reveal hot spot for cardiomyopathy mutations. Proc Natl Acad Sci U S A 2022; 119:e2120416119. [PMID: 35238659 PMCID: PMC8916002 DOI: 10.1073/pnas.2120416119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/31/2022] [Indexed: 01/19/2023] Open
Abstract
SignificanceIon channels have evolved the ability to communicate with one another, either through protein-protein interactions, or indirectly via intermediate diffusible messenger molecules. In special cases, the channels are part of different membranes. In muscle tissue, the T-tubule membrane is in proximity to the sarcoplasmic reticulum, allowing communication between L-type calcium channels and ryanodine receptors. This process is critical for excitation-contraction coupling and requires auxiliary proteins like junctophilin (JPH). JPHs are targets for disease-associated mutations, most notably hypertrophic cardiomyopathy mutations in the JPH2 isoform. Here we provide high-resolution snapshots of JPH, both alone and in complex with a calcium channel peptide, and show how this interaction is targeted by cardiomyopathy mutations.
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Affiliation(s)
- Zheng Fang Yang
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ciaran R. McFarlane
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Wietske E. Tuinte
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Marta Campiglio
- Institute of Physiology, Medical University of Innsbruck, Innsbruck, 6020 Austria
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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15
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Abstract
Junctophilins (JPHs) comprise a family of structural proteins that connect the plasma membrane to intracellular organelles such as the endo/sarcoplasmic reticulum. Tethering of these membrane structures results in the formation of highly organized subcellular junctions that play important signaling roles in all excitable cell types. There are four JPH isoforms, expressed primarily in muscle and neuronal cell types. Each JPH protein consists of 6 'membrane occupation and recognition nexus' (MORN) motifs, a joining region connecting these to another set of 2 MORN motifs, a putative alpha-helical region, a divergent region exhibiting low homology between JPH isoforms, and a carboxy-terminal transmembrane region anchoring into the ER/SR membrane. JPH isoforms play essential roles in developing and maintaining subcellular membrane junctions. Conversely, inherited mutations in JPH2 cause hypertrophic or dilated cardiomyopathy, while trinucleotide expansions in the JPH3 gene cause Huntington Disease-Like 2. Loss of JPH1 protein levels can cause skeletal myopathy, while loss of cardiac JPH2 levels causes heart failure and atrial fibrillation, among other disease. This review will provide a comprehensive overview of the JPH gene family, phylogeny, and evolutionary analysis of JPH genes and other MORN domain proteins. JPH biogenesis, membrane tethering, and binding partners will be discussed, as well as functional roles of JPH isoforms in excitable cells. Finally, potential roles of JPH isoform deficits in human disease pathogenesis will be reviewed.
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Affiliation(s)
- Stephan E Lehnart
- Cellular Biophysics and Translational Cardiology Section, Heart Research Center Göttingen, University Medical Center Göttingen, Department of Cardiology and Pneumology, Georg-August University Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Göttingen, Germany
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, Texas, United States; Departments of Molecular Physiology and Biophysics, Medicine (Cardiology), Pediatrics (Cardiology), Neuroscience, and Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States
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16
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Perni S. The Builders of the Junction: Roles of Junctophilin1 and Junctophilin2 in the Assembly of the Sarcoplasmic Reticulum–Plasma Membrane Junctions in Striated Muscle. Biomolecules 2022; 12:biom12010109. [PMID: 35053257 PMCID: PMC8774113 DOI: 10.3390/biom12010109] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 02/06/2023] Open
Abstract
Contraction of striated muscle is triggered by a massive release of calcium from the sarcoplasmic reticulum (SR) into the cytoplasm. This intracellular calcium release is initiated by membrane depolarization, which is sensed by voltage-gated calcium channels CaV1.1 (in skeletal muscle) and CaV1.2 (in cardiac muscle) in the plasma membrane (PM), which in turn activate the calcium-releasing channel ryanodine receptor (RyR) embedded in the SR membrane. This cross-communication between channels in the PM and in the SR happens at specialized regions, the SR-PM junctions, where these two compartments come in close proximity. Junctophilin1 and Junctophilin2 are responsible for the formation and stabilization of SR-PM junctions in striated muscle and actively participate in the recruitment of the two essential players in intracellular calcium release, CaV and RyR. This short review focuses on the roles of junctophilins1 and 2 in the formation and organization of SR-PM junctions in skeletal and cardiac muscle and on the functional consequences of the absence or malfunction of these proteins in striated muscle in light of recently published data and recent advancements in protein structure prediction.
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Affiliation(s)
- Stefano Perni
- Department of Physiology and Biophysics, Anschutz Medical Campus, University of Colorado, Aurora, CO 80045, USA
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17
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Rossi D, Lorenzini S, Pierantozzi E, Van Petegem F, Amadsun DO, Sorrentino V. Multiple regions of junctin drive interaction with calsequestrin-1 and localization at triads in skeletal muscle. J Cell Sci 2021; 135:274105. [PMID: 34913055 DOI: 10.1242/jcs.259185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/08/2021] [Indexed: 11/20/2022] Open
Abstract
Junctin is a transmembrane protein of striated muscles, localized at the junctional sarcoplasmic reticulum (j-SR). It is characterized by a luminal C-terminal tail, through which it functionally interacts with calsequestrin and the ryanodine receptor. Interaction with calsequestrin was ascribed to the presence of stretches of charged amino acids. However, the regions able to bind calsequestrin have not been defined in detail. We report here that, in non-muscle cells, junctin and calsequestrin assemble in long linear regions within the endoplasmic reticulum, mirroring the formation of calsequestrin polymers. In differentiating myotubes, the two proteins co-localize at triads, where they assemble with other j-SR proteins. By performing GST pull-down assays with distinct regions of the junctin tail, we identified two KEKE motifs able to bind calsequestrin. In addition, stretches of charged amino acids downstream these motifs were found to be also able to bind calsequestrin and the ryanodine receptor. Deletion of even one of these regions impaired the ability of junctin to localize at the j-SR, suggesting that interaction with other proteins at this site represents a key element in junctin targeting.
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Affiliation(s)
- Daniela Rossi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Stefania Lorenzini
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | | | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, University of Siena, Siena, Italy
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18
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Targeting JP2: A New Treatment for Pulmonary Hypertension. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:2003446. [PMID: 34394822 PMCID: PMC8363443 DOI: 10.1155/2021/2003446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022]
Abstract
Pulmonary hypertension (PH) is a disease with a complex etiology and high mortality rate. Abnormal pulmonary vasoconstriction and pulmonary vascular remodeling lead to an increase in mean pulmonary arterial blood pressure for which, and there is currently no cure. Junctophilin-2 (JP2) is beneficial for the assembly of junctional membrane complexes, the structural basis for excitation-contraction coupling that tethers the plasma membrane to the sarcoplasmic reticulum/endoplasmic reticulum and is involved in maintaining intracellular calcium concentration homeostasis and normal muscle contraction function. Recent studies have shown that JP2 maintains normal contraction and relaxation of vascular smooth muscle. In some experimental studies of drug treatments for PH, JP2 expression was increased, which improved pulmonary vascular remodeling and right ventricular function. Based on JP2 research to date, this paper summarizes the current understanding of JP2 protein structure, function, and related heart diseases and mechanisms and analyzes the feasibility and possible therapeutic strategies for targeting JP2 in PH.
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19
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Barefield DY, Sell JJ, Tahtah I, Kearns SD, McNally EM, Demonbreun AR. Loss of dysferlin or myoferlin results in differential defects in excitation-contraction coupling in mouse skeletal muscle. Sci Rep 2021; 11:15865. [PMID: 34354129 PMCID: PMC8342512 DOI: 10.1038/s41598-021-95378-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022] Open
Abstract
Muscular dystrophies are disorders characterized by progressive muscle loss and weakness that are both genotypically and phenotypically heterogenous. Progression of muscle disease arises from impaired regeneration, plasma membrane instability, defective membrane repair, and calcium mishandling. The ferlin protein family, including dysferlin and myoferlin, are calcium-binding, membrane-associated proteins that regulate membrane fusion, trafficking, and tubule formation. Mice lacking dysferlin (Dysf), myoferlin (Myof), and both dysferlin and myoferlin (Fer) on an isogenic inbred 129 background were previously demonstrated that loss of both dysferlin and myoferlin resulted in more severe muscle disease than loss of either gene alone. Furthermore, Fer mice had disordered triad organization with visibly malformed transverse tubules and sarcoplasmic reticulum, suggesting distinct roles of dysferlin and myoferlin. To assess the physiological role of disorganized triads, we now assessed excitation contraction (EC) coupling in these models. We identified differential abnormalities in EC coupling and ryanodine receptor disruption in flexor digitorum brevis myofibers isolated from ferlin mutant mice. We found that loss of dysferlin alone preserved sensitivity for EC coupling and was associated with larger ryanodine receptor clusters compared to wildtype myofibers. Loss of myoferlin alone or together with a loss of dysferlin reduced sensitivity for EC coupling, and produced disorganized and smaller ryanodine receptor cluster size compared to wildtype myofibers. These data reveal impaired EC coupling in Myof and Fer myofibers and slightly potentiated EC coupling in Dysf myofibers. Despite high homology, dysferlin and myoferlin have differential roles in regulating sarcotubular formation and maintenance resulting in unique impairments in calcium handling properties.
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Affiliation(s)
- David Y Barefield
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA. .,Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA.
| | - Jordan J Sell
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA
| | - Ibrahim Tahtah
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA
| | - Samuel D Kearns
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA
| | - Alexis R Demonbreun
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, 303 E Superior Lurie 5-500, Chicago, IL, 60611, USA. .,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. .,Center for Genetic Medicine, Northwestern University, 303 E Superior Lurie 5-512, Chicago, IL, 60611, USA.
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20
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Woll KA, Van Petegem F. Calcium Release Channels: Structure and Function of IP3 Receptors and Ryanodine Receptors. Physiol Rev 2021; 102:209-268. [PMID: 34280054 DOI: 10.1152/physrev.00033.2020] [Citation(s) in RCA: 87] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ca2+-release channels are giant membrane proteins that control the release of Ca2+ from the endoplasmic and sarcoplasmic reticulum. The two members, ryanodine receptors (RyRs) and inositol-1,4,5-trisphosphate Receptors (IP3Rs), are evolutionarily related and are both activated by cytosolic Ca2+. They share a common architecture, but RyRs have evolved additional modules in the cytosolic region. Their massive size allows for the regulation by tens of proteins and small molecules, which can affect the opening and closing of the channels. In addition to Ca2+, other major triggers include IP3 for the IP3Rs, and depolarization of the plasma membrane for a particular RyR subtype. Their size has made them popular targets for study via electron microscopic methods, with current structures culminating near 3Å. The available structures have provided many new mechanistic insights int the binding of auxiliary proteins and small molecules, how these can regulate channel opening, and the mechanisms of disease-associated mutations. They also help scrutinize previously proposed binding sites, as some of these are now incompatible with the structures. Many questions remain around the structural effects of post-translational modifications, additional binding partners, and the higher-order complexes these channels can make in situ. This review summarizes our current knowledge about the structures of Ca2+-release channels and how this informs on their function.
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Affiliation(s)
- Kellie A Woll
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
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21
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Hewlett B, Singh NP, Vannier C, Galli T. ER-PM Contact Sites - SNARING Actors in Emerging Functions. Front Cell Dev Biol 2021; 9:635518. [PMID: 33681218 PMCID: PMC7928305 DOI: 10.3389/fcell.2021.635518] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
The compartmentalisation achieved by confining cytoplasm into membrane-enclosed organelles in eukaryotic cells is essential for maintaining vital functions including ATP production, synthetic and degradative pathways. While intracellular organelles are highly specialised in these functions, the restricting membranes also impede exchange of molecules responsible for the synchronised and responsive cellular activities. The initial identification of contact sites between the ER and plasma membrane (PM) provided a potential candidate structure for communication between organelles without mixing by fusion. Over the past decades, research has revealed a far broader picture of the events. Membrane contact sites (MCSs) have been recognized as increasingly important actors in cell differentiation, plasticity and maintenance, and, upon dysfunction, responsible for pathological conditions such as cancer and neurodegenerative diseases. Present in multiple organelles and cell types, MCSs promote transport of lipids and Ca2+ homoeostasis, with a range of associated protein families. Interestingly, each MCS displays a unique molecular signature, adapted to organelle functions. This review will explore the literature describing the molecular components and interactions taking place at ER-PM contact sites, their functions, and implications in eukaryotic cells, particularly neurons, with emphasis on lipid transfer proteins and emerging function of SNAREs.
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Affiliation(s)
- Bailey Hewlett
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Neha Pratap Singh
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Christian Vannier
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Thierry Galli
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,GHU PARIS Psychiatrie and Neurosciences, Paris, France
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22
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Sanchez C, Berthier C, Tourneur Y, Monteiro L, Allard B, Csernoch L, Jacquemond V. Detection of Ca2+ transients near ryanodine receptors by targeting fluorescent Ca2+ sensors to the triad. J Gen Physiol 2021; 153:211757. [PMID: 33538764 PMCID: PMC7868779 DOI: 10.1085/jgp.202012592] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 12/03/2020] [Accepted: 12/23/2020] [Indexed: 11/23/2022] Open
Abstract
In intact muscle fibers, functional properties of ryanodine receptor (RYR)–mediated sarcoplasmic reticulum (SR) Ca2+ release triggered by activation of the voltage sensor CaV1.1 have so far essentially been addressed with diffusible Ca2+-sensitive dyes. Here, we used a domain (T306) of the protein triadin to target the Ca2+-sensitive probe GCaMP6f to the junctional SR membrane, in the immediate vicinity of RYR channels, within the triad region. Fluorescence of untargeted GCaMP6f was distributed throughout the muscle fibers and experienced large Ca2+-dependent changes, with obvious kinetic delays, upon application of voltage-clamp depolarizing pulses. Conversely, T306-GCaMP6f localized to the triad and generated Ca2+-dependent fluorescence transients of lower amplitude and faster kinetics for low and intermediate levels of Ca2+ release than those of untargeted GCaMP6f. By contrast, model simulation of the spatial gradients of Ca2+ following Ca2+ release predicted limited kinetic differences under the assumptions that the two probes were present at the same concentration and suffered from identical kinetic limitations. At the spatial level, T306-GCaMP6f transients within distinct regions of a same fiber yielded a uniform time course, even at low levels of Ca2+ release activation. Similar observations were made using GCaMP6f fused to the γ1 auxiliary subunit of CaV1.1. Despite the probe's limitations, our results point out the remarkable synchronicity of voltage-dependent Ca2+ release activation and termination among individual triads and highlight the potential of the approach to visualize activation or closure of single groups of RYR channels. We anticipate targeting of improved Ca2+ sensors to the triad will provide illuminating insights into physiological normal RYR function and its dysfunction under stress or pathological conditions.
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Affiliation(s)
- Colline Sanchez
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Christine Berthier
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Yves Tourneur
- Departamento Nutrição, Universidade Federal de Pernambuco, Recife, Brazil
| | - Laloé Monteiro
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Bruno Allard
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
| | - Laszlo Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Vincent Jacquemond
- Université Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique UMR-5310, Institut National de la Santé et de la Recherche Médicale U-1217, Institut NeuroMyoGène, Lyon, France
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23
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Sajko S, Grishkovskaya I, Kostan J, Graewert M, Setiawan K, Trübestein L, Niedermüller K, Gehin C, Sponga A, Puchinger M, Gavin AC, Leonard TA, Svergun DI, Smith TK, Morriswood B, Djinovic-Carugo K. Structures of three MORN repeat proteins and a re-evaluation of the proposed lipid-binding properties of MORN repeats. PLoS One 2020; 15:e0242677. [PMID: 33296386 PMCID: PMC7725318 DOI: 10.1371/journal.pone.0242677] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/08/2020] [Indexed: 11/19/2022] Open
Abstract
MORN (Membrane Occupation and Recognition Nexus) repeat proteins have a wide taxonomic distribution, being found in both prokaryotes and eukaryotes. Despite this ubiquity, they remain poorly characterised at both a structural and a functional level compared to other common repeats. In functional terms, they are often assumed to be lipid-binding modules that mediate membrane targeting. We addressed this putative activity by focusing on a protein composed solely of MORN repeats-Trypanosoma brucei MORN1. Surprisingly, no evidence for binding to membranes or lipid vesicles by TbMORN1 could be obtained either in vivo or in vitro. Conversely, TbMORN1 did interact with individual phospholipids. High- and low-resolution structures of the MORN1 protein from Trypanosoma brucei and homologous proteins from the parasites Toxoplasma gondii and Plasmodium falciparum were obtained using a combination of macromolecular crystallography, small-angle X-ray scattering, and electron microscopy. This enabled a first structure-based definition of the MORN repeat itself. Furthermore, all three structures dimerised via their C-termini in an antiparallel configuration. The dimers could form extended or V-shaped quaternary structures depending on the presence of specific interface residues. This work provides a new perspective on MORN repeats, showing that they are protein-protein interaction modules capable of mediating both dimerisation and oligomerisation.
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Affiliation(s)
- Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Julius Kostan
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Melissa Graewert
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Kim Setiawan
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Linda Trübestein
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Korbinian Niedermüller
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Charlotte Gehin
- European Molecular Biology Laboratory, Heidelberg Unit, Heidelberg, Germany
- Institute of Bioengineering, Laboratory of Lipid Cell Biology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Antonio Sponga
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Martin Puchinger
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Anne-Claude Gavin
- European Molecular Biology Laboratory, Heidelberg Unit, Heidelberg, Germany
- Department for Cell Physiology and Metabolism, University of Geneva, Centre Medical Universitaire, Geneva, Switzerland
| | - Thomas A. Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | - Terry K. Smith
- School of Biology, BSRC, University of St. Andrews, St. Andrews, United Kingdom
| | - Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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