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Vasileva F, Font-Lladó R, Carreras-Badosa G, Roman-Viñas B, Cadellans-Arróniz A, López-Bermejo A, Prats-Puig A. Salivary cardiac-enriched FHL2-interacting protein is associated with higher diastolic-to-systolic-blood pressure ratio, sedentary time and center of pressure displacement in healthy 7-9 years old school-children. Front Endocrinol (Lausanne) 2024; 15:1292653. [PMID: 38304464 PMCID: PMC10830845 DOI: 10.3389/fendo.2024.1292653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/04/2024] [Indexed: 02/03/2024] Open
Abstract
Introduction Cardiac-enriched FHL2-interacting protein (CEFIP) is a recently identified protein, first found in the z-disc of striated muscles, and related to cardiovascular diseases. Our objectives are: 1) to quantify CEFIP in saliva in healthy 7-9 years old school-children; and 2) to assess the associations of salivary CEFIP concentration and blood pressure, physical (in)activity and physical fitness in these children. Methods A total of 72 children (7.6 ± 0.3 years) were included in the study, recruited in primary schools in Girona (Spain). A sandwich enzyme-linked immunosorbent assay was used (abx506878; Abbexa, United Kingdom) to quantify CEFIP in saliva. Anthropometric evaluation was performed [body mass, height and body mass index (BMI)]. Systolic and diastolic blood pressure were measured by means of an electronic oscillometer and the diastolic-to-systolic blood pressure ratio (D/S BP ratio) was calculated. Physical (in)activity [sedentary time and time spent in physical activity (PA)] were assessed by means of a triaxial Actigraph GT3X accelerometer (Actigraph, Pensacola, FL, USA) that children were instructed to wear for 24h during 7 conssecutive days. Finally, physical fitness (speed and agility, explosive power of legs, handgrip strength, flexibility and balance) were assessed through validated and standardized testing batteries. Results CEFIP was easily detected and measured in all saliva samples (mean concentration: 0.6 ± 0.2 pg/ml). Salivary CEFIP was positively associated with D/S BP ratio (r=0.305, p=0.010) and sedentary time (r=0.317, p=0.012), but negatively associated with PA in 7-9 years old school-children (r=-0.350, p=0.002). Furthermore, salivary CEFIP was related to lower level of balance i.e., higher center of pressure (CoP) displacement in these children (r=0.411, p<0.001). The associations of salivary CEFIP with D/S BP ratio (Beta=0.349, p=0.004), sedentary time (Beta=0.354, p=0.009) and CoP displacement (Beta=0.401, p=0.001), were maintained significant after adjustment for potential confounding variables such as age, gender and BMI in linear regression analyses. Conclusion CEFIP can be easily assessed in saliva as a promising biomarker associated with cardiovascular health in 7-9 years old school-children. Interestingly, higher salivary CEFIP concentration was related to higher D/S BP ratio, more sedentary time and higher CoP displacement i.e., lower level of balance in these children.
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Affiliation(s)
- Fidanka Vasileva
- Pediatric Endocrinology Research Group, Girona Institute for Biomedical Research, Girona, Spain
- University School of Health and Sport, University of Girona, Girona, Spain
| | - Raquel Font-Lladó
- University School of Health and Sport, University of Girona, Girona, Spain
- Research Group of Culture and Education, Institute of Educational Research, University of Girona, Girona, Spain
| | - Gemma Carreras-Badosa
- Pediatric Endocrinology Research Group, Girona Institute for Biomedical Research, Girona, Spain
| | - Blanca Roman-Viñas
- University School of Health and Sport, University of Girona, Girona, Spain
- Department of Physical Activity and Sport Sciences, Blanquerna-Universitat Ramon Llull, Barcelona, Spain
| | - Aïda Cadellans-Arróniz
- Department of Physiotherapy, Faculty of Medicine and Health Sciences, International University of Catalonia, Barcelona, Spain
| | - Abel López-Bermejo
- Pediatric Endocrinology Research Group, Girona Institute for Biomedical Research, Girona, Spain
- Department of Medical Sciences, University of Girona, Girona, Spain
- Pediatric Endocrinology, Dr. Josep Trueta Hospital, Girona, Spain
| | - Anna Prats-Puig
- University School of Health and Sport, University of Girona, Girona, Spain
- Research Group of Clinical Anatomy, Embryology and Neuroscience, Department of Medical Sciences, University of Girona, Girona, Spain
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2
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Libiseller-Egger J, Phelan JE, Attia ZI, Benavente ED, Campino S, Friedman PA, Lopez-Jimenez F, Leon DA, Clark TG. Deep learning-derived cardiovascular age shares a genetic basis with other cardiac phenotypes. Sci Rep 2022; 12:22625. [PMID: 36587059 PMCID: PMC9805465 DOI: 10.1038/s41598-022-27254-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 12/28/2022] [Indexed: 01/01/2023] Open
Abstract
Artificial intelligence (AI)-based approaches can now use electrocardiograms (ECGs) to provide expert-level performance in detecting heart abnormalities and diagnosing disease. Additionally, patient age predicted from ECGs by AI models has shown great potential as a biomarker for cardiovascular age, where recent work has found its deviation from chronological age ("delta age") to be associated with mortality and co-morbidities. However, despite being crucial for understanding underlying individual risk, the genetic underpinning of delta age is unknown. In this work we performed a genome-wide association study using UK Biobank data (n=34,432) and identified eight loci associated with delta age ([Formula: see text]), including genes linked to cardiovascular disease (CVD) (e.g. SCN5A) and (heart) muscle development (e.g. TTN). Our results indicate that the genetic basis of cardiovascular ageing is predominantly determined by genes directly involved with the cardiovascular system rather than those connected to more general mechanisms of ageing. Our insights inform the epidemiology of CVD, with implications for preventative and precision medicine.
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Affiliation(s)
- Julian Libiseller-Egger
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Jody E Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Zachi I Attia
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Laboratory of Experimental Cardiology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Paul A Friedman
- Department of Cardiovascular Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | | | - David A Leon
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
- Department of Community Medicine, UiT the Arctic University of Norway, Tromsø, Norway
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK.
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3
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Wang J, Fan Y, Mittal B, Sanger JM, Sanger JW. Comparison of incorporation of wild type and mutated actins into sarcomeres in skeletal muscle cells: A fluorescence recovery after photobleaching study. Cytoskeleton (Hoboken) 2022; 79:105-115. [PMID: 36085566 DOI: 10.1002/cm.21725] [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: 06/08/2022] [Revised: 08/11/2022] [Accepted: 08/31/2022] [Indexed: 01/30/2023]
Abstract
The α-actin mutation G15R in the nucleotide-binding pocket of skeletal muscle, causes severe actin myopathy in human skeletal muscles. Expressed in cultured embryonic quail skeletal myotubes, YFP-G15R-α-actin incorporates in sarcomeres in a pattern indistinguishable from wildtype YFP-α-actin. However, patches of YFP-G15R-α-actin form, resembling those in patients. Analyses with FRAP of incorporation of YFP-G15R-α-actin showed major differences between fast-exchanging plus ends of overlapping actin filaments in Z-bands, versus slow exchanging ends of overlapping thin filaments in the middle of sarcomeres. Wildtype skeletal muscle YFP-α-actin shows a faster rate of incorporation at plus ends of F-actin than at their minus ends. Incorporation of YFP-G15R-α-actin molecules is reduced at plus ends, increased at minus ends. The same relationship of wildtype YFP-α-actin incorporation is seen in myofibrils treated with cytochalasin-D: decreased dynamics at plus ends, increased dynamics at minus ends, and F-actin aggregates. Speculation: imbalance of normal polarized assembly of F-actin creates excess monomers that form F-actin aggregates. Two other severe skeletal muscle YFP-α-actin mutations (H40Y and V163L) not in the nucleotide pocket do not affect actin dynamics, and lack F-actin aggregates. These results indicate that normal α-actin plus and minus end dynamics are needed to maintain actin filament stability, and avoid F-actin patches.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Balraj Mittal
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
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4
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Wang J, Fan Y, Wang C, Dube S, Poiesz BJ, Dube DK, Ma Z, Sanger JM, Sanger JW. Inhibitors of the Ubiquitin Proteasome System block myofibril assembly in cardiomyocytes derived from chick embryos and human pluripotent stem cells. Cytoskeleton (Hoboken) 2022; 78:461-491. [PMID: 35502133 DOI: 10.1002/cm.21697] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/14/2022] [Accepted: 04/19/2022] [Indexed: 11/06/2022]
Abstract
Details of sarcomeric protein assembly during de novo myofibril formation closely resemble myofibrillogenesis in skeletal and cardiac myocytes in birds, rodents and zebrafish. The arrangement of proteins during myofibrillogenesis follows a three-step process: beginning with premyofibrils, followed by nascent myofibrils, and concluding with mature myofibrils (reviewed in Sanger et al., 2017). Our aim is to determine if the same pathway is followed in human cardiomyocytes derived from human inducible pluripotent stem cells. We found that the human cardiomyocytes developed patterns of protein organization identical to the three-step series seen in the model organisms cited above. Further experiments showed that myofibril assembly can be blocked at the nascent myofibril by five different inhibitors of the Ubiquitin Proteasome System (UPS) stage in both avian and human cardiomyocytes. With the exception of Carfilzomib, removal of the UPS inhibitors allows nascent myofibrils to proceed to mature myofibrils. Some proteasomal inhibitors, such as Bortezomib and Carfilzomib, used to treat multiple myeloma patients, have off-target effects of damage to hearts in three to six percent of these patients. These cardiovascular adverse events may result from prevention of mature myofibril formation in the cardiomyocytes. In summary, our results support a common three-step model for the formation of myofibrils ranging from avian to human cardiomyocytes. The Ubiquitin Proteasome System is required for progression from nascent myofibrils to mature myofibrils. Our experiments suggest a possible explanation for the cardiac and skeletal muscle off-target effects reported in multiple myeloma patients treated with proteasome inhibitors. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Chenyan Wang
- Department of Biomedical & Chemical Engineering, The BioInspired Institute for Materials and Living Systems, Syracuse University, Syracuse, NY
| | - Syamalima Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Bernard J Poiesz
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Dipak K Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY
| | - Zhen Ma
- Department of Biomedical & Chemical Engineering, The BioInspired Institute for Materials and Living Systems, Syracuse University, Syracuse, NY
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
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5
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Kostan J, Pavšič M, Puž V, Schwarz TC, Drepper F, Molt S, Graewert MA, Schreiner C, Sajko S, van der Ven PFM, Onipe A, Svergun DI, Warscheid B, Konrat R, Fürst DO, Lenarčič B, Djinović-Carugo K. Molecular basis of F-actin regulation and sarcomere assembly via myotilin. PLoS Biol 2021; 19:e3001148. [PMID: 33844684 PMCID: PMC8062120 DOI: 10.1371/journal.pbio.3001148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/22/2021] [Accepted: 02/16/2021] [Indexed: 12/25/2022] Open
Abstract
Sarcomeres, the basic contractile units of striated muscle cells, contain arrays of thin (actin) and thick (myosin) filaments that slide past each other during contraction. The Ig-like domain-containing protein myotilin provides structural integrity to Z-discs-the boundaries between adjacent sarcomeres. Myotilin binds to Z-disc components, including F-actin and α-actinin-2, but the molecular mechanism of binding and implications of these interactions on Z-disc integrity are still elusive. To illuminate them, we used a combination of small-angle X-ray scattering, cross-linking mass spectrometry, and biochemical and molecular biophysics approaches. We discovered that myotilin displays conformational ensembles in solution. We generated a structural model of the F-actin:myotilin complex that revealed how myotilin interacts with and stabilizes F-actin via its Ig-like domains and flanking regions. Mutant myotilin designed with impaired F-actin binding showed increased dynamics in cells. Structural analyses and competition assays uncovered that myotilin displaces tropomyosin from F-actin. Our findings suggest a novel role of myotilin as a co-organizer of Z-disc assembly and advance our mechanistic understanding of myotilin's structural role in Z-discs.
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Affiliation(s)
- Julius Kostan
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Miha Pavšič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Vid Puž
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Thomas C. Schwarz
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Friedel Drepper
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Sibylle Molt
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | | | - Claudia Schreiner
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Peter F. M. van der Ven
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Adekunle Onipe
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, c/o DESY, Hamburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Robert Konrat
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Dieter O. Fürst
- Institute for Cell Biology, Department of Molecular Cell Biology, University of Bonn, Bonn, Germany
| | - Brigita Lenarčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
- Department of Biochemistry, Molecular and Structural Biology, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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6
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Wang J, Fan Y, Dube S, Agassy NW, Dube DK, Sanger JM, Sanger JW. Myofibril assembly and the roles of the ubiquitin proteasome system. Cytoskeleton (Hoboken) 2020; 77:456-479. [PMID: 33124174 DOI: 10.1002/cm.21641] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 10/07/2020] [Accepted: 10/19/2020] [Indexed: 12/12/2022]
Abstract
De novo assembly of myofibrils in vertebrate cross-striated muscles progresses in three distinct steps, first from a minisarcomeric alignment of several nonmuscle and muscle proteins in premyofibrils, followed by insertions of additional proteins and increased organization in nascent myofibrils, ending with mature contractile myofibrils. In a search for controls of the process of myofibril assembly, we discovered that the transition from nascent to mature myofibrils could be halted by inhibitors of three distinct functions of the ubiquitin proteasome system (UPS). First, inhibition of pathway to E3 Cullin ligases that ubiquitinate proteins led to an arrest of myofibrillogenesis at the nascent myofibril stage. Second, inhibition of p97 protein extractions of ubiquitinated proteins led to a similar arrest of myofibrillogenesis at the nascent myofibril stage. Third, inhibitors of proteolytic action by proteasomes also blocked nascent myofibrils from transitioning to mature myofibrils. In contrast, inhibitors of autophagy or lysosomes did not affect myofibrillogenesis. To probe for differences in the effects of UPS inhibitors during myofibrillogenesis, we analyzed by fluorescence recovery after photobleaching the exchange rates of two selected sarcomeric proteins (muscle myosin II heavy chains and light chains). In the presence of p97 and proteasomal inhibitors, the dynamics of each of these two myosin proteins decreased in the nascent myofibril stage, but were unaffected in the mature myofibril stage. The increased stability of myofibrils occurring in the transition from nascent to mature myofibril assembly indicates the importance of dynamics and selective destruction in the muscle myosin II proteins for the remodeling of nascent to mature myofibrils.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Syamalima Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Nicodeme Wanko Agassy
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Dipak K Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
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7
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Goeminne LJE, Sticker A, Martens L, Gevaert K, Clement L. MSqRob Takes the Missing Hurdle: Uniting Intensity- and Count-Based Proteomics. Anal Chem 2020; 92:6278-6287. [PMID: 32227882 DOI: 10.1021/acs.analchem.9b04375] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Missing values are a major issue in quantitative data-dependent mass spectrometry-based proteomics. We therefore present an innovative solution to this key issue by introducing a hurdle model, which is a mixture between a binomial peptide count and a peptide intensity-based model component. It enables dramatically enhanced quantification of proteins with many missing values without having to resort to harmful assumptions for missingness. We demonstrate the superior performance of our method by comparing it with state-of-the-art methods in the field.
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Affiliation(s)
- Ludger J E Goeminne
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Krijgslaan 281-S9, B9000 Ghent, Belgium.,VIB-UGent Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, B9052 Ghent, Belgium
| | - Adriaan Sticker
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Krijgslaan 281-S9, B9000 Ghent, Belgium.,VIB-UGent Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, B9052 Ghent, Belgium
| | - Lennart Martens
- VIB-UGent Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, B9052 Ghent, Belgium
| | - Kris Gevaert
- VIB-UGent Center for Medical Biotechnology, VIB, Albert Baertsoenkaai 3, B9000 Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Albert Baertsoenkaai 3, B9000 Ghent, Belgium
| | - Lieven Clement
- Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Krijgslaan 281-S9, B9000 Ghent, Belgium.,Bioinformatics Institute Ghent, Ghent University, Technologiepark 927, B9052 Ghent, Belgium
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8
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Wang J, Fan Y, Sanger JM, Sanger JW. Nonmuscle myosin II in cardiac and skeletal muscle cells. Cytoskeleton (Hoboken) 2019; 75:339-351. [PMID: 29781105 DOI: 10.1002/cm.21454] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/27/2018] [Accepted: 05/05/2018] [Indexed: 11/08/2022]
Abstract
De novo assembly of contractile myofibrils begins with the formation of premyofibrils where filaments of non-muscle myosin (NM II), and actin organize in sarcomeric patterns with Z-Bodies containing muscle-specific alpha-actinin. Interactions of muscle specific myosin (MM II) with NM II occur in a nascent myofibril stage that precedes the assembly of mature myofibrils. By the final stage of myofibrillogenesis, the only myosin II present in the mature myofibrils is MM II. In this current study of myofibril assembly, the three vertebrate isoforms of NM II (A, B, and C) and sarcomeric alpha-actinin, ligated to GFP family proteins, were coexpressed in avian embryonic skeletal and cardiac muscle cells. Each isoform of NM II localized only in the mini-A-Bands of premyofibrils and nascent myofibrils. There was no evidence of localization of NM II in Z-Bodies of premyofibrils and nascent myofibrils or in Z-Bands of mature myofibrils. Fluorescence Recovery After Photobleaching (FRAP) experiments indicated similar exchange rates in premyofibrils for NM II isoforms A and B, whereas the IIC isoform was significantly less dynamic. Fluorescence Resonance Energy Transfer (FRET) measurements of colocalized fluorescent pairs of different NM II isoforms yielded signals similar to identical pairs, indicating copolymerization of the different NM II pairs. The role of NM II may reside in establishing the future sarcomere pattern in mature myofibrils by binding to the oppositely polarized actin filaments that extend between pairs of Z-Bodies along premyofibrils prior to their transformation into mature myofibrils.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, 13210
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9
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Rudolf G, Suominen T, Penttilä S, Hackman P, Evilä A, Lannes B, Echaniz-Laguna A, Bierry G, Tranchant C, Udd B. Homozygosity of the Dominant Myotilin c.179C>T (p.Ser60Phe) Mutation Causes a More Severe and Proximal Muscular Dystrophy. J Neuromuscul Dis 2018; 3:275-281. [PMID: 27854214 DOI: 10.3233/jnd-150143] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Most myotilinopathy patients present with a dominant late onset distal phenotype and myofibrillar pathology, although the first MYOT mutation in a family reported to have LGMD phenotype. We report here a French family affected with a late onset proximal and distal muscle weakness and myofibrillar myopathy on muscle pathology, in which the siblings known to be clinically affected were homozygous for the c.179C>T (p.Ser60Phe) myotilin gene mutation. One subjectively asymptomatic member of the family was heterozygous for this mutation. This is the first report of a family with patients being homozygous for a known dominant MYOT mutation. Dominant negative mutations are generally considered not to cause a more severe disease in homozygosity, but our data clearly demonstrate the existence of dominant MYOT mutations with a possible dose effect causing a more severe disease phenotype in homozygosity in the spectrum of myofibrillar myopathies (MFM).
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Affiliation(s)
- Gabrielle Rudolf
- IGBMC, CNRS UMR 7104, INSERM U964, Strasbourg University, France.,Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Tiina Suominen
- Neuromuscular Research Unit, University of Tampere and Tampere University Hospital, Tampere, Finland
| | - Sini Penttilä
- Neuromuscular Research Unit, University of Tampere and Tampere University Hospital, Tampere, Finland
| | - Peter Hackman
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Anni Evilä
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Béatrice Lannes
- Département d'Anatomopathologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | | | - Guillaume Bierry
- Département de Radiologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Christine Tranchant
- IGBMC, CNRS UMR 7104, INSERM U964, Strasbourg University, France.,Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, Universitdé Strasbourg, INSERM, Illkirch, France
| | - Bjarne Udd
- Folkhälsan Institute of Genetics and Department of Medical Genetics, Haartman Institute, University of Helsinki, Helsinki, Finland.,Département d'Anatomopathologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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10
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Dierck F, Kuhn C, Rohr C, Hille S, Braune J, Sossalla S, Molt S, van der Ven PFM, Fürst DO, Frey N. The novel cardiac z-disc protein CEFIP regulates cardiomyocyte hypertrophy by modulating calcineurin signaling. J Biol Chem 2017; 292:15180-15191. [PMID: 28717008 DOI: 10.1074/jbc.m117.786764] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 07/04/2017] [Indexed: 11/06/2022] Open
Abstract
The z-disc is a structural component at the lateral borders of the sarcomere and is important for mechanical stability and contractility of both cardiac and skeletal muscles. Of note, the sarcomeric z-disc also represents a nodal point in cardiomyocyte function and signaling. Mutations of numerous z-disc proteins are associated with cardiomyopathies and muscle diseases. To identify additional z-disc proteins that might contribute to cardiac disease, we employed an in silico screen for cardiac-enriched cDNAs. This screen yielded a previously uncharacterized protein named cardiac-enriched FHL2-interacting protein (CEFIP), which exhibited a heart- and skeletal muscle-specific expression profile. Importantly, CEFIP was located at the z-disc and was up-regulated in several models of cardiomyopathy. We also found that CEFIP overexpression induced the fetal gene program and cardiomyocyte hypertrophy. Yeast two-hybrid screens revealed that CEFIP interacts with the calcineurin-binding protein four and a half LIM domains 2 (FHL2). Because FHL2 binds calcineurin, a phosphatase controlling hypertrophic signaling, we examined the effects of CEFIP on the calcineurin/nuclear factor of activated T-cell (NFAT) pathway. These experiments revealed that CEFIP overexpression further enhances calcineurin-dependent hypertrophic signal transduction, and its knockdown repressed hypertrophy and calcineurin/NFAT activity. In summary, we report on a previously uncharacterized protein CEFIP that modulates calcineurin/NFAT signaling in cardiomyocytes, a finding with possible implications for the pathogenesis of cardiomyopathy.
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Affiliation(s)
- Franziska Dierck
- From the Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, 24105 Kiel.,the DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105 Kiel
| | - Christian Kuhn
- From the Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, 24105 Kiel.,the DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105 Kiel
| | - Claudia Rohr
- the Department of Internal Medicine III, University of Heidelberg, 69120 Heidelberg, and
| | - Susanne Hille
- From the Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, 24105 Kiel.,the DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105 Kiel
| | - Julia Braune
- the Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Samuel Sossalla
- From the Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, 24105 Kiel.,the DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105 Kiel
| | - Sibylle Molt
- the Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Peter F M van der Ven
- the Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Dieter O Fürst
- the Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Norbert Frey
- From the Department of Internal Medicine III, University Medical Center of Schleswig-Holstein, 24105 Kiel, .,the DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105 Kiel
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11
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Abstract
Myotilin is a component of the sarcomere where it plays an important role in organisation and maintenance of Z-disk integrity. This involves direct binding to F-actin and filamin C, a function mediated by its Ig domain pair. While the structures of these two individual domains are known, information about their relative orientation and flexibility remains limited. We set on to characterise the Ig domain pair of myotilin with emphasis on its molecular structure, dynamics and phylogeny. First, sequence conservation analysis of myotilin shed light on the molecular basis of myotilinopathies and revealed several motifs in Ig domains found also in I-band proteins. In particular, a highly conserved Glu344 mapping to Ig domain linker, was identified as a critical component of the inter-domain hinge mechanism. Next, SAXS and molecular dynamics revealed that Ig domain pair exists as a multi-conformation species with dynamic exchange between extended and compact orientations. Mutation of AKE motif to AAA further confirmed its impact on inter-domain flexibility. We hypothesise that the conformational plasticity of the Ig domain pair in its unbound form is part of the binding partner recognition mechanism.
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12
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Leber Y, Ruparelia AA, Kirfel G, van der Ven PFM, Hoffmann B, Merkel R, Bryson-Richardson RJ, Fürst DO. Filamin C is a highly dynamic protein associated with fast repair of myofibrillar microdamage. Hum Mol Genet 2016; 25:2776-2788. [PMID: 27206985 DOI: 10.1093/hmg/ddw135] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 11/12/2022] Open
Abstract
Filamin c (FLNc) is a large dimeric actin-binding protein located at premyofibrils, myofibrillar Z-discs and myofibrillar attachment sites of striated muscle cells, where it is involved in mechanical stabilization, mechanosensation and intracellular signaling. Mutations in the gene encoding FLNc give rise to skeletal muscle diseases and cardiomyopathies. Here, we demonstrate by fluorescence recovery after photobleaching that a large fraction of FLNc is highly mobile in cultured neonatal mouse cardiomyocytes and in cardiac and skeletal muscles of live transgenic zebrafish embryos. Analysis of cardiomyocytes from Xirp1 and Xirp2 deficient animals indicates that both Xin actin-binding repeat-containing proteins stabilize FLNc selectively in premyofibrils. Using a novel assay to analyze myofibrillar microdamage and subsequent repair in cultured contracting cardiomyocytes by live cell imaging, we demonstrate that repair of damaged myofibrils is achieved within only 4 h, even in the absence of de novo protein synthesis. FLNc is immediately recruited to these sarcomeric lesions together with its binding partner aciculin and precedes detectable assembly of filamentous actin and recruitment of other myofibrillar proteins. These data disclose an unprecedented degree of flexibility of the almost crystalline contractile machinery and imply FLNc as a dynamic signaling hub, rather than a primarily structural protein. Our myofibrillar damage/repair model illustrates how (cardio)myocytes are kept functional in their mechanically and metabolically strained environment. Our results help to better understand the pathomechanisms and pathophysiology of early stages of FLNc-related myofibrillar myopathy and skeletal and cardiac diseases preceding pathological protein aggregation.
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Affiliation(s)
- Yvonne Leber
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D53121 Bonn, Germany
| | - Avnika A Ruparelia
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Gregor Kirfel
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D53121 Bonn, Germany
| | - Peter F M van der Ven
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D53121 Bonn, Germany
| | - Bernd Hoffmann
- Department of Biomechanics (ICS-7), Institute of Complex Systems, Forschungszentrum Jülich, D52428 Jülich, Germany and
| | - Rudolf Merkel
- Department of Biomechanics (ICS-7), Institute of Complex Systems, Forschungszentrum Jülich, D52428 Jülich, Germany and.,Department of Biomechanics, Institute for Physical and Theoretical Chemistry, University of Bonn, D53115 Bonn, Germany
| | | | - Dieter O Fürst
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, D53121 Bonn, Germany
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13
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Wang J, Fan Y, Dube DK, Sanger JM, Sanger JW. Jasplakinolide reduces actin and tropomyosin dynamics during myofibrillogenesis. Cytoskeleton (Hoboken) 2014; 71:513-29. [PMID: 25145272 DOI: 10.1002/cm.21189] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 08/12/2014] [Indexed: 12/20/2022]
Abstract
The premyofibril model proposes a three-stage process for the de novo assembly of myofibrils in cardiac and skeletal muscles: premyofibrils to nascent myofibrils to mature myofibrils. FRAP experiments and jasplakinolide, a drug that stabilizes F-actin, permitted us to determine how decreasing the dynamics of actin filaments affected the dynamics of tropomyosin, troponin-T, troponin-C, and two Z-Band proteins (alpha-actinin, FATZ) in premyofibrils versus mature myofibrils. Jasplakinolide reduced markedly the dynamics of actin in premyofibrils and in mature myofibrils in skeletal muscles. Two isoforms of tropomyosin-1 (TPM1α, TPM1κ) are more dynamic in premyofibrils than in mature myofibrils in control skeletal muscles. Jasplakinolide reduced the exchange rates of tropomyosins in premyofibrils but not in mature myofibrils. The reduced tropomyosin recoveries did not match the YFP-actin recoveries in premyofibrils in jasplakinolide. There were no significant differences in the effects of jasplakinolide on the dynamics of troponins in the thin filaments or of two Z-band proteins in premyofibrils or skeletal mature myofibrils. Cardiac control mature myofibrils lack nebulin, and small decreases in actin (∼5%) and two tropomyosin isoforms (∼10-15%) dynamics are detected in premyofibril to mature myofibril transformations compared with skeletal muscle. In contrast to skeletal muscle, jasplakinolide lowered the dynamics of actin and tropomyosin isoforms in the cardiac mature myofibrils. These results suggest that the dynamics of tropomyosins in control muscle cells are related to actin exchange. These results also suggest a stabilizing role for nebulin, an actin and tropomyosin-binding protein, present in mature myofibrils but not in premyofibrils of skeletal muscles.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
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14
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Dube DK, Wang J, Pellenz C, Fan Y, Dube S, Han M, Linask K, Sanger JM, Sanger JW. Expression of myotilin during chicken development. Anat Rec (Hoboken) 2014; 297:1596-603. [PMID: 25125173 PMCID: PMC4135462 DOI: 10.1002/ar.22964] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 12/07/2013] [Indexed: 12/12/2022]
Abstract
Several missense mutations in the Z-band protein, myotilin, have been implicated in human muscle diseases such as myofibrillar myopathy, spheroid body myopathy, and distal myopathy. Recently, we have reported the cloning of chicken myotilin cDNA. In this study, we have investigated the expression of myotilin in cross-striated muscles from developing chicken by qRT-PCR and in situ hybridizations. In situ hybridization of embryonic stages shows myotilin gene expression in heart, somites, neural tissue, eyes and otocysts. RT-PCR and qRT-PCR data, together with in situ hybridization results point to a biphasic transcriptional pattern for MYOT gene during early heart development with maximum expression level in the adult. In skeletal muscle, the expression level starts decreasing after embryonic day 20 and declines in the adult skeletal muscles. Western blot assays of myotilin in adult skeletal muscle reveal a decrease in myotilin protein compared with levels in embryonic skeletal muscle. Our results suggest that MYOT gene may undergo transcriptional activation and repression that varies between tissues in developing chicken. We believe this is the first report of the developmental regulation on myotilin expression in non-mammalian species.
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Affiliation(s)
- Dipak K. Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Christopher Pellenz
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Syamalima Dube
- Department of Medicine, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Mingda Han
- Department of Pediatrics, University of South Morsani College of Medicine Florida, Tampa, FL 33701
| | - Kersti Linask
- Department of Pediatrics, University of South Morsani College of Medicine Florida, Tampa, FL 33701
| | - Jean M. Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210
| | - Joseph W. Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210
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15
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Dube DK, Wang J, Fan Y, Sanger JM, Sanger JW. Does Nebulin Make Tropomyosin Less Dynamic in Mature Myofibrils in Cross-Striated Myocytes? ACTA ACUST UNITED AC 2014; 5. [PMID: 26798563 PMCID: PMC4718571 DOI: 10.4172/2157-7099/1000239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Myofibrils in vertebrate cardiac and skeletal muscles are characterized by groups of proteins arranged in contractile units or sarcomeres, which consist of four major components – thin filaments, thick filaments, titin and Z-bands. The thin actin/tropomyosin-containing filaments are embedded in the Z-bands and interdigitate with the myosin-containing thick filaments aligned in A-bands. Titin is attached to the Z-band and extends upto the middle of the A-Band. In this mini review, we have addressed the mechanism of myofibril assembly as well as the dynamics and maintenance of the myofibrils in cardiac and skeletal muscle cells. Evidence from our research as well as from other laboratories favors the premyofibril model of myofibrillogenesis. This three-step model (premyofibril to nascent myofibril to mature myofibril) not only provides a reasonable mechanism for sequential interaction of various proteins during assembly of myofibrils, but also suggests why the dynamics of a thin filament protein like tropomyosin is higher in cardiac muscle than in skeletal muscles. The dynamics of tropomyosin not only varies in different muscle types (cardiac vs. skeletal), but also varies during myofibrillogenesis, for example, premyofibril versus mature myofibrils in skeletal muscle. One of the major differences in protein composition between cardiac and skeletal muscle is nebulin localized along the thin filaments (two nebulins/thin filament) of mature myofibrils in skeletal muscle cells, but which is expressed in a minimal quantity (one nebulin/50 actin filaments) in ventricular cardiomyocytes. Interestingly, nebulin is not associated with premyofibrils in skeletal muscle. Our FRAP(Fluorescence Recovery After Photobleaching) results suggest that tropomyosin is more dynamic in premyofibrils than in mature myofibrils in skeletal muscle, and also, the dynamics of tropomyosin in mature myofibrils is significantly higher in cardiac muscle compared to skeletal muscle. Our working hypothesis is that the association of nebulin in mature myofibrils renders tropomyosin less dynamic in skeletal muscle.
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Affiliation(s)
- D K Dube
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, USA
| | - J Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, USA
| | - Y Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, USA
| | - J M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, USA
| | - J W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY, USA
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16
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Molt S, Bührdel JB, Yakovlev S, Schein P, Orfanos Z, Kirfel G, Winter L, Wiche G, van der Ven PFM, Rottbauer W, Just S, Belkin AM, Fürst DO. Aciculin interacts with filamin C and Xin and is essential for myofibril assembly, remodeling and maintenance. J Cell Sci 2014; 127:3578-92. [PMID: 24963132 DOI: 10.1242/jcs.152157] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Filamin C (FLNc) and Xin actin-binding repeat-containing proteins (XIRPs) are multi-adaptor proteins that are mainly expressed in cardiac and skeletal muscles and which play important roles in the assembly and repair of myofibrils and their attachment to the membrane. We identified the dystrophin-binding protein aciculin (also known as phosphoglucomutase-like protein 5, PGM5) as a new interaction partner of FLNc and Xin. All three proteins colocalized at intercalated discs of cardiac muscle and myotendinous junctions of skeletal muscle, whereas FLNc and aciculin also colocalized in mature Z-discs. Bimolecular fluorescence complementation experiments in developing cultured mammalian skeletal muscle cells demonstrated that Xin and aciculin also interact in FLNc-containing immature myofibrils and areas of myofibrillar remodeling and repair induced by electrical pulse stimulation (EPS). Fluorescence recovery after photobleaching (FRAP) experiments showed that aciculin is a highly dynamic and mobile protein. Aciculin knockdown in myotubes led to failure in myofibril assembly, alignment and membrane attachment, and a massive reduction in myofibril number. A highly similar phenotype was found upon depletion of aciculin in zebrafish embryos. Our results point to a thus far unappreciated, but essential, function of aciculin in myofibril formation, maintenance and remodeling.
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Affiliation(s)
- Sibylle Molt
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - John B Bührdel
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Sergiy Yakovlev
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Peter Schein
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | | | - Gregor Kirfel
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Lilli Winter
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Gerhard Wiche
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | | | - Wolfgang Rottbauer
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Steffen Just
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Alexey M Belkin
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Dieter O Fürst
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
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17
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Wang J, Dube DK, White J, Fan Y, Sanger JM, Sanger JW. Clock is not a component of Z-bands. Cytoskeleton (Hoboken) 2012; 69:1021-31. [PMID: 22907924 DOI: 10.1002/cm.21058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 07/23/2012] [Indexed: 01/16/2023]
Abstract
The process of Z-band assembly begins with the formation of small Z-bodies composed of a complex of proteins rich in alpha-actinin. As additional proteins are added to nascent myofibrils, Z-bodies are transformed into continuous bands that form coherent discs of interacting proteins at the boundaries of sarcomeres. The steps controlling the transition of Z-bodies to Z-bands are not known. The report that a circadian protein, Clock, was localized in the Z-bands of neonatal rat cardiomyocytes raised the question whether this transcription factor could be involved in Z-band assembly. We found that the anti-Clock antibody used in the reported study also stained the Z-bands and Z-bodies of mouse and avian cardiac and skeletal muscle cells. YFP constructs of Clock that were assembled, however, did not localize to the Z-bands of muscle cells. Controls of Clock's activity showed that cotransfection of muscle cells with pYFP-Clock and pCeFP-BMAL1 led to the expected nuclear localization of YFP-Clock with its binding partner CeFP-BMAL1. Neither CeFP-BMAL1 nor antibodies directed against BMAL1 localized to Z-bands. A bimolecular fluorescence complementation assay (VC-BMAL1 and VN-Clock) confirmed the absence of Clock and BMAL1 from Z-bands, and their nuclear colocalization. A second anti-Clock antibody stained nuclei, but not Z-bands, of cells cotransfected with Clock and BMAL1 plasmids. Western blots of reactions of muscle extracts and purified alpha-actinins with the two anti-Clock antibodies showed that the original antibody cross-reacted with alpha-actinin and the second did not. These results cannot confirm Clock as an active component of Z-bands. © 2012 Wiley Periodicals, Inc.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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