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Zhang H, Chang M, Chen D, Yang J, Zhang Y, Sun J, Yao X, Sun H, Gu X, Li M, Shen Y, Dai B. Congenital myopathies: pathophysiological mechanisms and promising therapies. J Transl Med 2024; 22:815. [PMID: 39223631 PMCID: PMC11370226 DOI: 10.1186/s12967-024-05626-5] [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: 01/03/2024] [Accepted: 08/15/2024] [Indexed: 09/04/2024] Open
Abstract
Congenital myopathies (CMs) are a kind of non-progressive or slow-progressive muscle diseases caused by genetic mutations, which are currently defined and categorized mainly according to their clinicopathological features. CMs exhibit pleiotropy and genetic heterogeneity. Currently, supportive treatment and pharmacological remission are the mainstay of treatment, with no cure available. Some adeno-associated viruses show promising prospects in the treatment of MTM1 and BIN1-associated myopathies; however, such gene-level therapeutic interventions target only specific mutation types and are not generalizable. Thus, it is particularly crucial to identify the specific causative genes. Here, we outline the pathogenic mechanisms based on the classification of causative genes: excitation-contraction coupling and triadic assembly (RYR1, MTM1, DNM2, BIN1), actin-myosin interaction and production of myofibril forces (NEB, ACTA1, TNNT1, TPM2, TPM3), as well as other biological processes. Furthermore, we provide a comprehensive overview of recent therapeutic advancements and potential treatment modalities of CMs. Despite ongoing research endeavors, targeted strategies and collaboration are imperative to address diagnostic uncertainties and explore potential treatments.
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Affiliation(s)
- Han Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Mengyuan Chang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Daiyue Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Jiawen Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Yijie Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Jiacheng Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Xinlei Yao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China
| | - Meiyuan Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China.
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Medical College, Nantong University, Nantong, Jiangsu Province, 226001, P. R. China.
| | - Bin Dai
- Department of Orthopedics, Binhai County People's Hospital, Binhai, Jiangsu Province, 224500, P. R. China.
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Katow H, Ryoo HD. eEF1α2 is required for actin cytoskeleton homeostasis in the aging muscle. Dis Model Mech 2024; 17:dmm050729. [PMID: 39207054 PMCID: PMC11381931 DOI: 10.1242/dmm.050729] [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: 01/29/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024] Open
Abstract
The translation elongation factor eEF1α (eukaryotic elongation factor 1α) mediates mRNA translation by delivering aminoacyl-tRNAs to ribosomes. eEF1α also has other reported roles, including the regulation of actin dynamics. However, these distinct roles of eEF1α are often challenging to uncouple and remain poorly understood in aging metazoan tissues. The genomes of mammals and Drosophila encode two eEF1α paralogs, with eEF1α1 expressed ubiquitously and eEF1α2 expression more limited to neurons and muscle cells. Here, we report that eEF1α2 plays a unique role in maintaining myofibril homeostasis during aging in Drosophila. Specifically, we generated an eEF1α2 null allele, which was viable and showed two distinct muscle phenotypes. In young flies, the mutants had thinner myofibrils in indirect flight muscles that could be rescued by expressing eEF1α1. With aging, the muscles of the mutant flies began showing abnormal distribution of actin and myosin in muscles, but without a change in actin and myosin protein levels. This age-related phenotype could not be rescued by eEF1α1 overexpression. These findings support an unconventional role of Drosophila eEF1α2 in age-related homeostasis of muscle myofibers.
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Affiliation(s)
- Hidetaka Katow
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Hyung Don Ryoo
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
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Ioannou IA, Brooks NJ, Kuimova MK, Elani Y. Visualizing Actin Packing and the Effects of Actin Attachment on Lipid Membrane Viscosity Using Molecular Rotors. JACS AU 2024; 4:2041-2049. [PMID: 38818078 PMCID: PMC11134356 DOI: 10.1021/jacsau.4c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 06/01/2024]
Abstract
The actin cytoskeleton and its elaborate interplay with the plasma membrane participate in and control numerous biological processes in eukaryotic cells. Malfunction of actin networks and changes in their dynamics are related to various diseases, from actin myopathies to uncontrolled cell growth and tumorigenesis. Importantly, the biophysical and mechanical properties of actin and its assemblies are deeply intertwined with the biological functions of the cytoskeleton. Novel tools to study actin and its associated biophysical features are, therefore, of prime importance. Here we develop a new approach which exploits fluorescence lifetime imaging microscopy (FLIM) and environmentally sensitive fluorophores termed molecular rotors, acting as quantitative microviscosity sensors, to monitor dynamic viscoelastic properties of both actin structures and lipid membranes. In order to reproduce a minimal actin cortex in synthetic cell models, we encapsulated and attached actin networks to the lipid bilayer of giant unilamellar vesicles (GUVs). Using a cyanine-based molecular rotor, DiSC2(3), we show that different types of actin bundles are characterized by distinct packing, which can be spatially resolved using FLIM. Similarly, we show that a lipid bilayer-localized molecular rotor can monitor the effects of attaching cross-linked actin networks to the lipid membrane, revealing an increase in membrane viscosity upon actin attachment. Our approach bypasses constraints associated with existing methods for actin imaging, many of which lack the capability for direct visualization of biophysical properties. It can therefore contribute to a deeper understanding of the role that actin plays in fundamental biological processes and help elucidate the underlying biophysics of actin-related diseases.
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Affiliation(s)
- Ion A. Ioannou
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
| | - Nickolas J. Brooks
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Marina K. Kuimova
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Yuval Elani
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
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Piga D, Rimoldi M, Magri F, Zanotti S, Napoli L, Ripolone M, Pagliarani S, Ciscato P, Velardo D, D’Amico A, Bertini E, Comi GP, Ronchi D, Corti S. Case report: A novel ACTA1 variant in a patient with nemaline rods and increased glycogen deposition. Front Neurol 2024; 15:1340693. [PMID: 38500810 PMCID: PMC10944937 DOI: 10.3389/fneur.2024.1340693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 02/22/2024] [Indexed: 03/20/2024] Open
Abstract
Background Congenital myopathies are a group of heterogeneous inherited disorders, mainly characterized by early-onset hypotonia and muscle weakness. The spectrum of clinical phenotype can be highly variable, going from very mild to severe presentations. The course also varies broadly resulting in a fatal outcome in the most severe cases but can either be benign or lead to an amelioration even in severe presentations. Muscle biopsy analysis is crucial for the identification of pathognomonic morphological features, such as core areas, nemaline bodies or rods, nuclear centralizations and congenital type 1 fibers disproportion. However, multiple abnormalities in the same muscle can be observed, making more complex the myopathological scenario. Case presentation Here, we describe an Italian newborn presenting with severe hypotonia, respiratory insufficiency, inability to suck and swallow, requiring mechanical ventilation and gastrostomy feeding. Muscle biopsy analyzed by light microscopy showed the presence of vacuoles filled with glycogen, suggesting a metabolic myopathy, but also fuchsinophilic inclusions. Ultrastructural studies confirmed the presence of normally structured glycogen, and the presence of minirods, directing the diagnostic hypothesis toward a nemaline myopathy. An expanded Next Generation Sequencing analysis targeting congenital myopathies genes revealed the presence of a novel heterozygous c.965 T > A p. (Leu322Gln) variant in the ACTA1 gene, which encodes the skeletal muscle alpha-actin. Conclusion Our case expands the repertoire of molecular and pathological features observed in actinopathies. We highlight the value of ultrastructural examination to investigate the abnormalities detected at the histological level. We also emphasized the use of expanded gene panels in the molecular analysis of neuromuscular patients, especially for those ones presenting multiple bioptic alterations.
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Affiliation(s)
- Daniela Piga
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Martina Rimoldi
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Medical Genetics Unit, Milan, Italy
| | - Francesca Magri
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Simona Zanotti
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
| | - Laura Napoli
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
| | - Michela Ripolone
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
| | - Serena Pagliarani
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
| | - Patrizia Ciscato
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
| | - Daniele Velardo
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
| | - Adele D’Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu’ Children’s Research Hospital, IRCCS, Rome, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu’ Children’s Research Hospital, IRCCS, Rome, Italy
| | - Giacomo Pietro Comi
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
- Department of Pathophysiology and Transplantation, Dino Ferrari Center, University of Milan, Milan, Italy
| | - Dario Ronchi
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neurology Unit, Milan, Italy
- Department of Pathophysiology and Transplantation, Dino Ferrari Center, University of Milan, Milan, Italy
| | - Stefania Corti
- IRCCS Fondazione Cà Granda Ospedale Maggiore Policlinico, Neuromuscular and Rare Disease Unit, Milan, Italy
- Department of Pathophysiology and Transplantation, Dino Ferrari Center, University of Milan, Milan, Italy
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Nolte DD. Coherent light scattering from cellular dynamics in living tissues. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:036601. [PMID: 38433567 DOI: 10.1088/1361-6633/ad2229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/24/2024] [Indexed: 03/05/2024]
Abstract
This review examines the biological physics of intracellular transport probed by the coherent optics of dynamic light scattering from optically thick living tissues. Cells and their constituents are in constant motion, composed of a broad range of speeds spanning many orders of magnitude that reflect the wide array of functions and mechanisms that maintain cellular health. From the organelle scale of tens of nanometers and upward in size, the motion inside living tissue is actively driven rather than thermal, propelled by the hydrolysis of bioenergetic molecules and the forces of molecular motors. Active transport can mimic the random walks of thermal Brownian motion, but mean-squared displacements are far from thermal equilibrium and can display anomalous diffusion through Lévy or fractional Brownian walks. Despite the average isotropic three-dimensional environment of cells and tissues, active cellular or intracellular transport of single light-scattering objects is often pseudo-one-dimensional, for instance as organelle displacement persists along cytoskeletal tracks or as membranes displace along the normal to cell surfaces, albeit isotropically oriented in three dimensions. Coherent light scattering is a natural tool to characterize such tissue dynamics because persistent directed transport induces Doppler shifts in the scattered light. The many frequency-shifted partial waves from the complex and dynamic media interfere to produce dynamic speckle that reveals tissue-scale processes through speckle contrast imaging and fluctuation spectroscopy. Low-coherence interferometry, dynamic optical coherence tomography, diffusing-wave spectroscopy, diffuse-correlation spectroscopy, differential dynamic microscopy and digital holography offer coherent detection methods that shed light on intracellular processes. In health-care applications, altered states of cellular health and disease display altered cellular motions that imprint on the statistical fluctuations of the scattered light. For instance, the efficacy of medical therapeutics can be monitored by measuring the changes they induce in the Doppler spectra of livingex vivocancer biopsies.
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Affiliation(s)
- David D Nolte
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907, United States of America
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Baskar D, Polavarapu K, Preethish-Kumar V, Vengalil S, Nashi S, Töpf A, Thomas A, Sanka SB, Menon D, Srivastava K, Arunachal G, Nandeesh BN, Lochmüller H, Nalini A. Childhood-Onset Myopathy With Preserved Ambulation Caused by a Recurrent ADSSL1 Missense Variant. Neurol Genet 2024; 10:e200122. [PMID: 38229919 PMCID: PMC10790204 DOI: 10.1212/nxg.0000000000200122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/09/2023] [Indexed: 01/18/2024]
Abstract
Background and Objectives Distal myopathies are a heterogeneous group of primary muscle disorders with recessive or dominant inheritance. ADSSL1 is a muscle-specific adenylosuccinate synthase isoform involved in adenine nucleotide synthesis. Recessive pathogenic variants in the ADSSL1 gene located in chromosome 14q32.33 cause a distal myopathy phenotype. In this study, we present the clinical and genetic attributes of 6 Indian patients with this myopathy. Methods This was a retrospective study describing on Indian patients with genetically confirmed ADSSL1 myopathy. Details were obtained from the medical records. Results All patients presented in their first or early second decade. All had onset in the first decade with a mean age at presentation being 17.7 ± 8.4 years (range: 3-27 years) and M:F ratio being 1:2. The mean disease duration was 9.3 ± 5.2 years ranging from 2 to 15 years. All patients were ambulant with wheelchair bound state in 1 patient due to respiratory involvement. The median serum creatine kinase (CK) level was 185.5 IU/L (range: 123-1564 IU/L). In addition to salient features of ptosis, cardiac involvement, bulbar weakness, and proximo-distal limb weakness with fatigue, there were significant seasonal fluctuations and decremental response to repetitive nerve stimulation, which have not been previously reported. Muscle histopathology was heterogenous with the presence of rimmed vacuoles, nemaline rods, intracellular lipid droplets along with chronic myopathic changes. Subtle response to pyridostigmine treatment was reported. While 5 of 6 patients had homozygous c.781G>A (p.Asp261Asn) variation, 1 had homozygous c.794G>A (p.Gly265Glu) in ADSSL1 gene. Discussion This study expands the phenotypic spectrum and variability of ADSSL1 myopathy with unusual manifestations in this rare disorder. Because the variant c.781G>A (p.Asp261Asn) is the most common mutation among Indian patients similar to other Asian cohorts, this finding could be useful for genetic screening of suspected patients.
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Affiliation(s)
- Dipti Baskar
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Kiran Polavarapu
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Veeramani Preethish-Kumar
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Seena Vengalil
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Saraswati Nashi
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Ana Töpf
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Aneesha Thomas
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Sai Bhargava Sanka
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Deepak Menon
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Kosha Srivastava
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Gautham Arunachal
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Bevinahalli N Nandeesh
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Hanns Lochmüller
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
| | - Atchayaram Nalini
- From the Department of Neurology (D.B., S.V., S.N., A. Thomas, S.B.S., D.M., K.S., A.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India; Children's Hospital of Eastern Ontario Research Institute (K.P., H.L.), Ottawa, Canada; Department of Neurology (V.P.-K.), Swansea University, Wales, United Kingdom; Brain and Mind Research Institute (H.L.), University of Ottawa; Division of Neurology (H.L.), Department of Medicine, The Ottawa Hospital, Canada; Centro Nacional de Análisis Genómico (CNAG-CRG) (H.L.), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Catalonia, Spain; Department of Neuropediatrics and Muscle Disorders (H.L.), Medical Center-University of Freiburg, Faculty of Medicine, Germany; John Walton Muscular Dystrophy Research Centre (A. Töpf), Translational and Clinical Research Institute, Newcastle University and Newcastle Hospitals NHS Foundation Trust, United Kingdom; Department of Human Genetics (G.A.); and Department of Neuropathology (B.N.N.), National Institute of Mental Health and Neuro Sciences (NIMHANS), Bengaluru, India
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7
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Rostami MW, Bannish BE, Gasior K, Pinals RL, Copos C, Dawes AT. Inferring local molecular dynamics from the global actin network structure: A case study of 2D synthetic branching actin networks. J Theor Biol 2023; 575:111613. [PMID: 37774939 PMCID: PMC10842209 DOI: 10.1016/j.jtbi.2023.111613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/14/2023] [Accepted: 08/29/2023] [Indexed: 10/01/2023]
Abstract
Cells rely on their cytoskeleton for key processes including division and directed motility. Actin filaments are a primary constituent of the cytoskeleton. Although actin filaments can create a variety of network architectures linked to distinct cell functions, the microscale molecular interactions that give rise to these macroscale structures are not well understood. In this work, we investigate the microscale mechanisms that produce different branched actin network structures using an iterative classification approach. First, we employ a simple yet comprehensive agent-based model that produces synthetic actin networks with precise control over the microscale dynamics. Then we apply machine learning techniques to classify actin networks based on measurable network density and geometry, identifying key mechanistic processes that lead to particular branched actin network architectures. Extensive computational experiments reveal that the most accurate method uses a combination of supervised learning based on network density and unsupervised learning based on network symmetry. This framework can potentially serve as a powerful tool to discover the molecular interactions that produce the wide variety of actin network configurations associated with normal development as well as pathological conditions such as cancer.
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Affiliation(s)
- Minghao W Rostami
- Department of Mathematics and Statistics, Binghamton University, Binghamton, NY, USA.
| | - Brittany E Bannish
- Department of Mathematics and Statistics, University of Central Oklahoma, Edmond, OK, USA.
| | - Kelsey Gasior
- Department of Applied and Computational Mathematics and Statistics, University of Notre Dame, Notre Dame, IN, USA.
| | - Rebecca L Pinals
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Boston, MA, USA.
| | - Calina Copos
- Department of Biology and Department of Mathematics, Northeastern University, Boston, MA, USA.
| | - Adriana T Dawes
- Department of Mathematics and Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA.
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8
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Clemens Z, Wang K, Ambrosio F, Barchowsky A. Arsenic disrupts extracellular vesicle-mediated signaling in regenerating myofibers. Toxicol Sci 2023; 195:231-245. [PMID: 37527016 PMCID: PMC10535782 DOI: 10.1093/toxsci/kfad075] [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: 08/03/2023] Open
Abstract
Chronic exposure to environmental arsenic is a public health crisis affecting hundreds of millions of individuals worldwide. Though arsenic is known to contribute to many pathologies and diseases, including cancers, cardiovascular and pulmonary diseases, and neurological impairment, the mechanisms for arsenic-promoted disease remain unresolved. This is especially true for arsenic impacts on skeletal muscle function and metabolism, despite the crucial role that skeletal muscle health plays in maintaining cardiovascular health, systemic homeostasis, and cognition. A barrier to researching this area is the challenge of interrogating muscle cell-specific effects in biologically relevant models. Ex vivo studies investigating mechanisms for muscle-specific responses to arsenic or other environmental contaminants primarily utilize traditional 2-dimensional culture models that cannot elucidate effects on muscle physiology or function. Therefore, we developed a contractile 3-dimensional muscle construct model-composed of primary mouse muscle progenitor cells differentiated in a hydrogel matrix-to study arsenic exposure impacts on skeletal muscle regeneration. Muscle constructs exposed to low-dose (50 nM) arsenic exhibited reduced strength and myofiber diameter following recovery from muscle injury. These effects were attributable to dysfunctional paracrine signaling mediated by extracellular vesicles (EVs) released from muscle cells. Specifically, we found that EVs collected from arsenic-exposed muscle constructs recapitulated the inhibitory effects of direct arsenic exposure on myofiber regeneration. In addition, muscle constructs treated with EVs isolated from muscles of arsenic-exposed mice displayed significantly decreased strength. Our findings highlight a novel model for muscle toxicity research and uncover a mechanism of arsenic-induced muscle dysfunction by the disruption of EV-mediated intercellular communication.
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Affiliation(s)
- Zachary Clemens
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Kai Wang
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Boston, Massachusetts, USA
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA
| | - Fabrisia Ambrosio
- Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Boston, Massachusetts, USA
- Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, USA
| | - Aaron Barchowsky
- Department of Environmental and Occupational Health, University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania, USA
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9
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Fricke AL, Mühlhäuser WWD, Reimann L, Zimmermann JP, Reichenbach C, Knapp B, Peikert CD, Heberle AM, Faessler E, Schäuble S, Hahn U, Thedieck K, Radziwill G, Warscheid B. Phosphoproteomics Profiling Defines a Target Landscape of the Basophilic Protein Kinases AKT, S6K, and RSK in Skeletal Myotubes. J Proteome Res 2023; 22:768-789. [PMID: 36763541 DOI: 10.1021/acs.jproteome.2c00505] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Phosphorylation-dependent signal transduction plays an important role in regulating the functions and fate of skeletal muscle cells. Central players in the phospho-signaling network are the protein kinases AKT, S6K, and RSK as part of the PI3K-AKT-mTOR-S6K and RAF-MEK-ERK-RSK pathways. However, despite their functional importance, knowledge about their specific targets is incomplete because these kinases share the same basophilic substrate motif RxRxxp[ST]. To address this, we performed a multifaceted quantitative phosphoproteomics study of skeletal myotubes following kinase inhibition. Our data corroborate a cross talk between AKT and RAF, a negative feedback loop of RSK on ERK, and a putative connection between RSK and PI3K signaling. Altogether, we report a kinase target landscape containing 49 so far unknown target sites. AKT, S6K, and RSK phosphorylate numerous proteins involved in muscle development, integrity, and functions, and signaling converges on factors that are central for the skeletal muscle cytoskeleton. Whereas AKT controls insulin signaling and impinges on GTPase signaling, nuclear signaling is characteristic for RSK. Our data further support a role of RSK in glucose metabolism. Shared targets have functions in RNA maturation, stability, and translation, which suggests that these basophilic kinases establish an intricate signaling network to orchestrate and regulate processes involved in translation.
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Affiliation(s)
- Anna L Fricke
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Wignand W D Mühlhäuser
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Lena Reimann
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Johannes P Zimmermann
- Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Christa Reichenbach
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Bettina Knapp
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Christian D Peikert
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Alexander M Heberle
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria
| | - Erik Faessler
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Sascha Schäuble
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany.,Systems Biology and Bioinformatics Unit, Leibniz Institute for Natural Product Research and Infection Biology─Leibniz-HKI, 07745 Jena, Germany
| | - Udo Hahn
- Jena University Language & Information Engineering (JULIE) Lab, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Kathrin Thedieck
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck, University of Innsbruck, 6020 Innsbruck, Austria.,Department of Pediatrics, Section Systems Medicine of Metabolism and Signaling, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands.,Department for Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg 26129, Germany
| | - Gerald Radziwill
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany.,Biochemistry II, Theodor Boveri-Institute, Biocenter, University of Würzburg, 97074 Würzburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
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10
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Campellone KG, Lebek NM, King VL. Branching out in different directions: Emerging cellular functions for the Arp2/3 complex and WASP-family actin nucleation factors. Eur J Cell Biol 2023; 102:151301. [PMID: 36907023 DOI: 10.1016/j.ejcb.2023.151301] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 02/07/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
The actin cytoskeleton impacts practically every function of a eukaryotic cell. Historically, the best-characterized cytoskeletal activities are in cell morphogenesis, motility, and division. The structural and dynamic properties of the actin cytoskeleton are also crucial for establishing, maintaining, and changing the organization of membrane-bound organelles and other intracellular structures. Such activities are important in nearly all animal cells and tissues, although distinct anatomical regions and physiological systems rely on different regulatory factors. Recent work indicates that the Arp2/3 complex, a broadly expressed actin nucleator, drives actin assembly during several intracellular stress response pathways. These newly described Arp2/3-mediated cytoskeletal rearrangements are coordinated by members of the Wiskott-Aldrich Syndrome Protein (WASP) family of actin nucleation-promoting factors. Thus, the Arp2/3 complex and WASP-family proteins are emerging as crucial players in cytoplasmic and nuclear activities including autophagy, apoptosis, chromatin dynamics, and DNA repair. Characterizations of the functions of the actin assembly machinery in such stress response mechanisms are advancing our understanding of both normal and pathogenic processes, and hold great promise for providing insights into organismal development and interventions for disease.
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Affiliation(s)
- Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA.
| | - Nadine M Lebek
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
| | - Virginia L King
- Department of Molecular and Cell Biology, Institute for Systems Genomics; University of Connecticut; Storrs, CT, USA
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11
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Sokolova A, Galic M. Modulation of self-organizing circuits at deforming membranes by intracellular and extracellular factors. Biol Chem 2023; 404:417-425. [PMID: 36626681 DOI: 10.1515/hsz-2022-0290] [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: 09/26/2022] [Accepted: 12/16/2022] [Indexed: 01/12/2023]
Abstract
Mechanical forces exerted to the plasma membrane induce cell shape changes. These transient shape changes trigger, among others, enrichment of curvature-sensitive molecules at deforming membrane sites. Strikingly, some curvature-sensing molecules not only detect membrane deformation but can also alter the amplitude of forces that caused to shape changes in the first place. This dual ability of sensing and inducing membrane deformation leads to the formation of curvature-dependent self-organizing signaling circuits. How these cell-autonomous circuits are affected by auxiliary parameters from inside and outside of the cell has remained largely elusive. Here, we explore how such factors modulate self-organization at the micro-scale and its emerging properties at the macroscale.
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Affiliation(s)
- Anastasiia Sokolova
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch-Straße 31, 48149 Münster, Germany.,CiM-IMRPS Graduate Program, Schlossplatz 5, 48149 Münster, Germany
| | - Milos Galic
- Institute of Medical Physics and Biophysics, University of Münster, Robert-Koch-Straße 31, 48149 Münster, Germany.,'Cells in Motion' Interfaculty Centre, University of Münster, Röntgenstraße 16, 48149 Münster, Germany
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12
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Suppression of RBFox2 by Multiple MiRNAs in Pressure Overload-Induced Heart Failure. Int J Mol Sci 2023; 24:ijms24021283. [PMID: 36674797 PMCID: PMC9867119 DOI: 10.3390/ijms24021283] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/25/2022] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
Heart failure is the final stage of various cardiovascular diseases and seriously threatens human health. Increasing mediators have been found to be involved in the pathogenesis of heart failure, including the RNA binding protein RBFox2. It participates in multiple aspects of the regulation of cardiac function and plays a critical role in the process of heart failure. However, how RBFox2 itself is regulated remains unclear. Here, we dissected transcriptomic signatures, including mRNAs and miRNAs, in a mouse model of heart failure after TAC surgery. A global analysis showed that an asymmetric alternation in gene expression and a large-scale upregulation of miRNAs occurred in heart failure. An association analysis revealed that the latter not only contributed to the degradation of numerous mRNA transcripts, but also suppressed the translation of key proteins such as RBFox2. With the aid of Ago2 CLIP-seq data, luciferase assays verified that RBFox2 was targeted by multiple miRNAs, including Let-7, miR-16, and miR-200b, which were significantly upregulated in heart failure. The overexpression of these miRNAs suppressed the RBFox2 protein and its downstream effects in cardiomyocytes, which was evidenced by the suppressed alternative splicing of the Enah gene and impaired E-C coupling via the repression of the Jph2 protein. The inhibition of Let-7, the most abundant miRNA family targeting RBFox2, could restore the RBFox2 protein as well as its downstream effects in dysfunctional cardiomyocytes induced by ISO treatment. In all, these findings revealed the molecular mechanism leading to RBFox2 depression in heart failure, and provided an approach to rescue RBFox2 through miRNA inhibition for the treatment of heart failure.
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13
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Djalinac N, Kolesnik E, Maechler H, Scheruebel-Posch S, Pelzmann B, Rainer PP, Foessl I, Wallner M, Scherr D, Heinemann A, Sedej S, Ljubojevic-Holzer S, von Lewinski D, Bisping E. miR-1183 Is a Key Marker of Remodeling upon Stretch and Tachycardia in Human Myocardium. Int J Mol Sci 2022; 23:ijms23136962. [PMID: 35805966 PMCID: PMC9266684 DOI: 10.3390/ijms23136962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 11/16/2022] Open
Abstract
Many cardiac insults causing atrial remodeling are linked to either stretch or tachycardia, but a comparative characterization of their effects on early remodeling events in human myocardium is lacking. Here, we applied isometric stretch or sustained tachycardia at 2.5 Hz in human atrial trabeculae for 6 h followed by microarray gene expression profiling. Among largely independent expression patterns, we found a small common fraction with the microRNA miR-1183 as the highest up-regulated transcript (up to 4-fold). Both, acute stretch and tachycardia induced down-regulation of the predicted miR-1183 target genes ADAM20 and PLA2G7. Furthermore, miR-1183 was also significantly up-regulated in chronically remodeled atrial samples from patients with persistent atrial fibrillation (3-fold up-regulation versus sinus rhythm samples), and in ventricular myocardium from dilative cardiomyopathy hearts (2-fold up-regulation) as compared to non-failing controls. In sum, although stretch and tachycardia show distinct transcriptomic signatures in human atrial myocardium, both cardiac insults consistently regulate the expression of miR-1183 and its downstream targets in acute and chronic remodeling. Thus, elevated expression of miR-1183 might serve as a tissue biomarker for atrial remodeling and might be of potential functional significance in cardiac disease.
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Affiliation(s)
- Natasa Djalinac
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- Unit of Human Molecular Genetics and Functional Genomics, Department of Biology, University of Padua, 35121 Padua, Italy
| | - Ewald Kolesnik
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
| | - Heinrich Maechler
- Department of Cardiothoracic Surgery, Medical University of Graz, 8036 Graz, Austria;
| | - Susanne Scheruebel-Posch
- Gottfried Schatz Research Center, Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria; (S.S.-P.); (B.P.)
| | - Brigitte Pelzmann
- Gottfried Schatz Research Center, Institute of Biophysics, Medical University of Graz, 8010 Graz, Austria; (S.S.-P.); (B.P.)
| | - Peter P. Rainer
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- BioTechMed Graz, 8036 Graz, Austria
| | - Ines Foessl
- Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, 8010 Graz, Austria;
| | - Markus Wallner
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- Cardiovascular Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
- Correspondence: (M.W.); (D.v.L.); Tel.: +43-316-385-31261 (M.W.); +43-316-385-80684 (D.v.L.)
| | - Daniel Scherr
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
| | - Akos Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, 8010 Graz, Austria;
| | - Simon Sedej
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- BioTechMed Graz, 8036 Graz, Austria
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
| | - Senka Ljubojevic-Holzer
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- BioTechMed Graz, 8036 Graz, Austria
| | - Dirk von Lewinski
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
- Correspondence: (M.W.); (D.v.L.); Tel.: +43-316-385-31261 (M.W.); +43-316-385-80684 (D.v.L.)
| | - Egbert Bisping
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, 8036 Graz, Austria; (N.D.); (E.K.); (P.P.R.); (D.S.); (S.S.); (S.L.-H.); (E.B.)
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14
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van de Locht M, Borsboom TC, Winter JM, Ottenheijm CAC. Troponin Variants in Congenital Myopathies: How They Affect Skeletal Muscle Mechanics. Int J Mol Sci 2021; 22:ijms22179187. [PMID: 34502093 PMCID: PMC8430961 DOI: 10.3390/ijms22179187] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/19/2021] [Accepted: 08/23/2021] [Indexed: 02/05/2023] Open
Abstract
The troponin complex is a key regulator of muscle contraction. Multiple variants in skeletal troponin encoding genes result in congenital myopathies. TNNC2 has been implicated in a novel congenital myopathy, TNNI2 and TNNT3 in distal arthrogryposis (DA), and TNNT1 and TNNT3 in nemaline myopathy (NEM). Variants in skeletal troponin encoding genes compromise sarcomere function, e.g., by altering the Ca2+ sensitivity of force or by inducing atrophy. Several potential therapeutic strategies are available to counter the effects of variants, such as troponin activators, introduction of wild-type protein through AAV gene therapy, and myosin modulation to improve muscle contraction. The mechanisms underlying the pathophysiological effects of the variants in skeletal troponin encoding genes are incompletely understood. Furthermore, limited knowledge is available on the structure of skeletal troponin. This review focusses on the physiology of slow and fast skeletal troponin and the pathophysiology of reported variants in skeletal troponin encoding genes. A better understanding of the pathophysiological effects of these variants, together with enhanced knowledge regarding the structure of slow and fast skeletal troponin, will direct the development of treatment strategies.
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15
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New Insights into Cellular Functions of Nuclear Actin. BIOLOGY 2021; 10:biology10040304. [PMID: 33916969 PMCID: PMC8067577 DOI: 10.3390/biology10040304] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/12/2022]
Abstract
Simple Summary It is well known that actin forms a cytoplasmic network of microfilaments, the part of the cytoskeleton, in the cytoplasm of eukaryotic cells. The presence of nuclear actin was elusive for a very long time. Now, there is a very strong evidence that actin plays many important roles in the nucleus. Here, we discuss the recently discovered functions of the nuclear actin pool. Actin does not have nuclear localization signal (NLS), so its import to the nucleus is facilitated by the NLS-containing proteins. Nuclear actin plays a role in the maintenance of the nuclear structure and the nuclear envelope breakdown. It is also involved in chromatin remodeling, and chromatin and nucleosome movement necessary for DNA recombination, repair, and the initiation of transcription. It also binds RNA polymerases, promoting transcription. Because of the multifaceted role of nuclear actin, the future challenge will be to further define its functions in various cellular processes and diseases. Abstract Actin is one of the most abundant proteins in eukaryotic cells. There are different pools of nuclear actin often undetectable by conventional staining and commercial antibodies used to identify cytoplasmic actin. With the development of more sophisticated imaging and analytical techniques, it became clear that nuclear actin plays a crucial role in shaping the chromatin, genomic, and epigenetic landscape, transcriptional regulation, and DNA repair. This multifaceted role of nuclear actin is not only important for the function of the individual cell but also for the establishment of cell fate, and tissue and organ differentiation during development. Moreover, the changes in the nuclear, chromatin, and genomic architecture are preamble to various diseases. Here, we discuss some of the newly described functions of nuclear actin.
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16
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Shah M, Chacko LA, Joseph JP, Ananthanarayanan V. Mitochondrial dynamics, positioning and function mediated by cytoskeletal interactions. Cell Mol Life Sci 2021; 78:3969-3986. [PMID: 33576841 PMCID: PMC11071877 DOI: 10.1007/s00018-021-03762-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/27/2020] [Accepted: 01/15/2021] [Indexed: 12/22/2022]
Abstract
The ability of a mitochondrion to undergo fission and fusion, and to be transported and localized within a cell are central not just to proper functioning of mitochondria, but also to that of the cell. The cytoskeletal filaments, namely microtubules, F-actin and intermediate filaments, have emerged as prime movers in these dynamic mitochondrial shape and position transitions. In this review, we explore the complex relationship between the cytoskeleton and the mitochondrion, by delving into: (i) how the cytoskeleton helps shape mitochondria via fission and fusion events, (ii) how the cytoskeleton facilitates the translocation and anchoring of mitochondria with the activity of motor proteins, and (iii) how these changes in form and position of mitochondria translate into functioning of the cell.
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Affiliation(s)
- Mitali Shah
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Leeba Ann Chacko
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Joel P Joseph
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
| | - Vaishnavi Ananthanarayanan
- Centre for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India.
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia.
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17
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Jaswandkar SV, Faisal HMN, Katti KS, Katti DR. Dissociation Mechanisms of G-actin Subunits Govern Deformation Response of Actin Filament. Biomacromolecules 2021; 22:907-917. [PMID: 33481563 DOI: 10.1021/acs.biomac.0c01602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Actin molecules are essential structural components of the cellular cytoskeleton. Here, we report a comprehensive analysis of F-actin's deformation behavior and highlight underlying mechanisms using steered molecular dynamics simulations (SMD). The investigation of F-actin was done under tension, compression, bending, and torsion. We report that the dissociation pattern of conformational locks at intrastrand and interstrand G-actin interfaces regulates the deformation response of F-actin. The conformational locks at the G-actin interfaces are portrayed by a spheroidal joint, interlocking serrated plates' analogy. Further, the SMD simulation approach was utilized to evaluate Young's modulus, flexural rigidity, persistent length, and torsional rigidity of F-actin, and the values obtained were found to be consistent with available experimental data. The evaluation of the mechanical properties of actin and the insight into the fundamental mechanisms contributing to its resilience described here are necessary for developing accurate models of eukaryotic cells and for assessing cellular viability and mobility.
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Affiliation(s)
- Sharad V Jaswandkar
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58105, United States
| | - H M Nasrullah Faisal
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Kalpana S Katti
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58105, United States
| | - Dinesh R Katti
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota 58105, United States
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18
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The actin polymerization factor Diaphanous and the actin severing protein Flightless I collaborate to regulate sarcomere size. Dev Biol 2021; 469:12-25. [PMID: 32980309 DOI: 10.1016/j.ydbio.2020.09.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 09/15/2020] [Accepted: 09/19/2020] [Indexed: 12/22/2022]
Abstract
The sarcomere is the basic contractile unit of muscle, composed of repeated sets of actin thin filaments and myosin thick filaments. During muscle development, sarcomeres grow in size to accommodate the growth and function of muscle fibers. Failure in regulating sarcomere size results in muscle dysfunction; yet, it is unclear how the size and uniformity of sarcomeres are controlled. Here we show that the formin Diaphanous is critical for the growth and maintenance of sarcomere size: Dia sets sarcomere length and width through regulation of the number and length of the actin thin filaments in the Drosophila flight muscle. To regulate thin filament length and sarcomere size, Dia interacts with the Gelsolin superfamily member Flightless I (FliI). We suggest that these actin regulators, by controlling actin dynamics and turnover, generate uniformly sized sarcomeres tuned for the muscle contractions required for flight.
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19
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Shakiba D, Alisafaei F, Savadipour A, Rowe RA, Liu Z, Pryse KM, Shenoy VB, Elson EL, Genin GM. The Balance between Actomyosin Contractility and Microtubule Polymerization Regulates Hierarchical Protrusions That Govern Efficient Fibroblast-Collagen Interactions. ACS NANO 2020; 14:7868-7879. [PMID: 32286054 DOI: 10.1021/acsnano.9b09941] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Fibroblasts undergo a critical transformation from an initially inactive state to a morphologically different and contractile state after several hours of being embedded within a physiologically relevant three-dimensional (3D) fibrous collagen-based extracellular matrix (ECM). However, little is known about the critical mechanisms by which fibroblasts adapt themselves and their microenvironment in the earliest stage of cell-matrix interaction. Here, we identified the mechanisms by which fibroblasts interact with their 3D collagen fibrous matrices in the early stages of cell-matrix interaction and showed that fibroblasts use energetically efficient hierarchical micro/nano-scaled protrusions in these stages as the primary means for the transformation and adaptation. We found that actomyosin contractility in these protrusions in the early stages of cell-matrix interaction restricts the growth of microtubules by applying compressive forces on them. Our results show that actomyosin contractility and microtubules work in concert in the early stages of cell-matrix interaction to adapt fibroblasts and their microenvironment to one another. These early stage interactions result in responses to disruption of the microtubule network and/or actomyosin contractility that are opposite to well-known responses to late-stage disruption and reveal insight into the ways that cells adapt themselves and their ECM recursively.
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Affiliation(s)
- Delaram Shakiba
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
| | - Farid Alisafaei
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Alireza Savadipour
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
| | - Roger A Rowe
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
| | - Zhangao Liu
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
| | - Kenneth M Pryse
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
| | - Vivek B Shenoy
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Elliot L Elson
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Guy M Genin
- NSF Science and Technology Center for Engineering Mechanobiology and Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri 63130 United States
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20
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Saito Y, Nishikawa A, Iida A, Mori-Yoshimura M, Oya Y, Ishiyama A, Komaki H, Nakamura S, Fujikawa S, Kanda T, Yamadera M, Sakiyama H, Hayashi S, Nonaka I, Noguchi S, Nishino I. ADSSL1 myopathy is the most common nemaline myopathy in Japan with variable clinical features. Neurology 2020; 95:e1500-e1511. [DOI: 10.1212/wnl.0000000000010237] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 03/17/2020] [Indexed: 11/15/2022] Open
Abstract
ObjectiveTo elucidate the prevalence of Japanese ADSSL1 myopathy and determine the clinicopathologic features of the disease.MethodsWe searched forADSSL1variants in myopathic patients from January 1978 to March 2019 in our repository and assessed the clinicopathologic features of patients with variants.ResultsWe identified 63 patients from 59 families with biallelic variants ofADSSL1. Among the 7 distinct variants identified, c.781G>A and c.919delA accounted for 53.2% and 40.5% of alleles, respectively, suggesting the presence of common founders, while the other 5 were novel. Most of the identified patients displayed more variable muscle symptoms, including symptoms in the proximal and/or distal leg muscles, tongue, masseter, diaphragm, and paraspinal muscles, in adolescence than previously reported patients. Dysphagia with masticatory dysfunction developed in 26 out of 63 patients; hypertrophic cardiomyopathy developed in 12 out of 48 patients; and restrictive ventilatory insufficiency developed in 26 out of 34 patients in later stages. Radiologically, fat infiltration into the periphery of vastus lateralis, gastrocnemius, and soleus muscles was observed in all patients. Pathologically, nemaline bodies in addition to increased lipid droplets and myofibrillar disorganization were commonly observed in all patients, suggesting that the disease may be classified as nemaline myopathy. This finding revealed thatADSSL1myopathy is the most frequent among all genetically diagnosable nemaline myopathies in our center.ConclusionsADSSL1 myopathy is characterized by more variable manifestations than previously reported. It is the most common among all genetically diagnosable nemaline myopathies in our center, although mildly increased lipid droplets are also constantly observed features.
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21
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Djalinac N, Ljubojevic-Holzer S, Matzer I, Kolesnik E, Jandl K, Lohberger B, Rainer P, Heinemann A, Sedej S, von Lewinski D, Bisping E. The role of stretch, tachycardia and sodium-calcium exchanger in induction of early cardiac remodelling. J Cell Mol Med 2020; 24:8732-8743. [PMID: 32573098 PMCID: PMC7412684 DOI: 10.1111/jcmm.15504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 05/20/2020] [Accepted: 05/24/2020] [Indexed: 12/14/2022] Open
Abstract
Stretch and tachycardia are common triggers for cardiac remodelling in various conditions, but a comparative characterization of their role in the excitation‐transcription coupling (ETC) and early regulation of gene expression and structural changes is lacking. Here, we show that stretch and tachycardia directly induced hypertrophy of neonatal rat cardiac myocytes and also of non‐myocytes. Both triggers induced similar patterns of hypertrophy but had largely distinct gene expression profiles. ACTA1 served as good hypertrophy marker upon stretch, while RCAN1 was found increased in response to tachycardia in a rate‐dependent fashion. Mechanistically, several calcium‐handling proteins, including the sodium‐calcium exchanger (NCX), contributed to ETC. Phosphorylation of the calcium/calmodulin‐dependent protein kinase II (CaMKII) was elevated and occurred downstream of NCX activation upon tachycardia, but not stretch. Microarray profiling revealed that stretch and tachycardia regulated around 33% and 20% genes in a NCX‐dependent manner, respectively. In conclusion, our data show that hypertrophy induction by stretch and tachycardia is associated with different gene expression profiles with a significant contribution of the NCX.
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Affiliation(s)
- Natasa Djalinac
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | | | - Ingrid Matzer
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Ewald Kolesnik
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Katharina Jandl
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria.,Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - Birgit Lohberger
- Department of Orthopedics and Trauma, Medical University of Graz, Graz, Austria
| | - Peter Rainer
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | - Akos Heinemann
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz, Austria
| | - Simon Sedej
- Department of Cardiology, Medical University of Graz, Graz, Austria
| | | | - Egbert Bisping
- Department of Cardiology, Medical University of Graz, Graz, Austria
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22
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Regulation of Actin Filament Length by Muscle Isoforms of Tropomyosin and Cofilin. Int J Mol Sci 2020; 21:ijms21124285. [PMID: 32560136 PMCID: PMC7352323 DOI: 10.3390/ijms21124285] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/11/2020] [Accepted: 06/13/2020] [Indexed: 12/17/2022] Open
Abstract
In striated muscle the extent of the overlap between actin and myosin filaments contributes to the development of force. In slow twitch muscle fibers actin filaments are longer than in fast twitch fibers, but the mechanism which determines this difference is not well understood. We hypothesized that tropomyosin isoforms Tpm1.1 and Tpm3.12, the actin regulatory proteins, which are specific respectively for fast and slow muscle fibers, differently stabilize actin filaments and regulate severing of the filaments by cofilin-2. Using in vitro assays, we showed that Tpm3.12 bound to F-actin with almost 2-fold higher apparent binding constant (Kapp) than Tpm1.1. Cofilin2 reduced Kapp of both tropomyosin isoforms. In the presence of Tpm1.1 and Tpm3.12 the filaments were longer than unregulated F-actin by 25% and 40%, respectively. None of the tropomyosins affected the affinity of cofilin-2 for F-actin, but according to the linear lattice model both isoforms increased cofilin-2 binding to an isolated site and reduced binding cooperativity. The filaments decorated with Tpm1.1 and Tpm3.12 were severed by cofilin-2 more often than unregulated filaments, but depolymerization of the severed filaments was inhibited. The stabilization of the filaments by Tpm3.12 was more efficient, which can be attributed to lower dynamics of Tpm3.12 binding to actin.
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23
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Yin Y, Zou YF, Xiao Y, Wang TX, Wang YN, Dong ZC, Huo YH, Yao BC, Meng LB, Du SX. Identification of Potential Hub Genes of Atherosclerosis Through Bioinformatic Analysis. J Comput Biol 2020; 28:60-78. [PMID: 32286084 DOI: 10.1089/cmb.2019.0334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cardiovascular and cerebrovascular diseases, which mainly consist of atherosclerosis (AS), are major causes of death. A great deal of research has been carried out to clarify the molecular mechanisms of AS. However, the etiology of AS remains poorly understood. To screen the potential genes of AS occurrence and development, GSE43292 and GSE57691 were obtained from the Gene Expression Omnibus (GEO) database in this study for bioinformatic analysis. First, GEO2R was used to identify differentially expressed genes (DEGs) and the functional annotation of DEGs was performed by gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The Search Tool for the Retrieval of Interacting Genes (STRING) tool was used to construct the protein-protein interaction network and the most important modules and core genes were mined. The results show that a total of 211 DEGs are identified. The functional changes of DEGs are mainly associated with the cellular process, catalytic activity, and protein binding. Eighteen genes were identified as core genes. Bioinformatic analysis showed that the core genes are mainly enriched in numerous processes related to actin. In conclusion, the DEGs and hub genes identified in this study may help us understand the potential etiology of the occurrence and development of AS.
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Affiliation(s)
- Yang Yin
- Department of Cardiac Surgery, Tianjin Chest Hospital, Tianjin, P.R. China
| | - Yang-Fan Zou
- Department of Neurosurgery, Chinese People's Liberation Army General Hospital-Sixth Medical Center, Beijing, P.R. China
| | - Yu Xiao
- Department of Basic Medicine, Peking University, Beijing, P.R. China
| | - Tian-Xi Wang
- Department of Artificial Intelligence, Hebei University of Technology, Tianjin, P.R. China
| | - Ya-Ni Wang
- Department of Basic Medical Sciences, Hebei Medical University, Shijiazhuang, P.R. China
| | - Zhi-Cheng Dong
- Neurology Department, The Second Central Hospital of Baoding, Zhuozhou, P.R. China
| | - Yu-Hu Huo
- Department of Breast and Thyroid Surgery, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, P.R. China
| | - Bo-Chen Yao
- Department of Cardiac Surgery, Tianjin Chest Hospital, Tianjin, P.R. China
| | - Ling-Bing Meng
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing, P.R. China
| | - Shuang-Xia Du
- Neurology Department, The Second Central Hospital of Baoding, Zhuozhou, P.R. China
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24
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TPM2 as a potential predictive biomarker for atherosclerosis. Aging (Albany NY) 2019; 11:6960-6982. [PMID: 31487691 PMCID: PMC6756910 DOI: 10.18632/aging.102231] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 08/18/2019] [Indexed: 12/28/2022]
Abstract
Cardiac-cerebral vascular disease (CCVD), is primarily induced by atherosclerosis, and is a leading cause of mortality. Numerous studies have investigated and attempted to clarify the molecular mechanisms of atherosclerosis; however, its pathogenesis has yet to be completely elucidated. Two expression profiling datasets, GSE43292 and GSE57691, were obtained from the Gene Expression Omnibus (GEO) database. The present study then identified the differentially expressed genes (DEGs), and functional annotation of the DEGs was performed. Finally, an atherosclerosis animal model and neural network prediction model was constructed to verify the relationship between hub gene and atherosclerosis. The results identified a total of 234 DEGs between the normal and atherosclerosis samples. The DEGs were mainly enriched in actin filament, actin binding, smooth muscle cells, and cytokine-cytokine receptor interactions. A total of 13 genes were identified as hub genes. Following verification of animal model, the common DEG, Tropomyosin 2 (TPM2), was found, which were displayed at lower levels in the atherosclerosis models and samples. In summary, DEGs identified in the present study may assist clinicians in understanding the pathogenesis governing the occurrence and development of atherosclerosis, and TPM2 exhibits potential as a promising diagnostic and therapeutic biomarker for atherosclerosis.
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MELEKOĞLU A, KARAHAN O. Hücre İskeleti Yapıları ve Hastalıklarla Etkileşimleri. ACTA MEDICA ALANYA 2019. [DOI: 10.30565/medalanya.528070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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26
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Hayashi Y, Ono K, Ono S. Mutations in Caenorhabditis elegans actin, which are equivalent to human cardiomyopathy mutations, cause abnormal actin aggregation in nematode striated muscle. F1000Res 2019; 8:279. [PMID: 30984387 PMCID: PMC6446495 DOI: 10.12688/f1000research.18476.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/08/2019] [Indexed: 01/19/2023] Open
Abstract
Actin is a central component of muscle contractile apparatuses, and a number of actin mutations cause diseases in skeletal, cardiac, and smooth muscles. However, many pathogenic actin mutations have not been characterized at cell biological and physiological levels. In this study, we tested whether the nematode Caenorhabditis elegans could be used to characterize properties of actin mutants in muscle cells in vivo. Two representative actin mutations, E99K and P164A, which cause hypertrophic cardiomyopathy in humans, are introduced in a muscle-specific C. elegans actin ACT-4 as E100K and P165A, respectively. When green fluorescent protein-tagged wild-type ACT-4 (GFP-ACT-4), is transgenically expressed in muscle at low levels as compared with endogenous actin, it is incorporated into sarcomeres without disturbing normal structures. GFP-ACT-4 variants with E100K and P165A are incorporated into sarcomeres, but also accumulated in abnormal aggregates, which have not been reported for equivalent actin mutations in previous studies. Muscle contractility, as determined by worm motility, is not apparently affected by expression of ACT-4 mutants. Our results suggest that C. elegans muscle is a useful model system to characterize abnormalities caused by actin mutations.
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Affiliation(s)
- Yuriko Hayashi
- Department of Pathology, Emory University, Atlanta, Georgia, 30322, USA
- Department of Cell Biology, Emory University, Atlanta, Georgia, 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, Georgia, 30322, USA
| | - Kanako Ono
- Department of Pathology, Emory University, Atlanta, Georgia, 30322, USA
- Department of Cell Biology, Emory University, Atlanta, Georgia, 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, Georgia, 30322, USA
| | - Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia, 30322, USA
- Department of Cell Biology, Emory University, Atlanta, Georgia, 30322, USA
- Winship Cancer Institute, Emory University, Atlanta, Georgia, 30322, USA
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27
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Kelpsch DJ, Tootle TL. Nuclear Actin: From Discovery to Function. Anat Rec (Hoboken) 2018; 301:1999-2013. [PMID: 30312531 PMCID: PMC6289869 DOI: 10.1002/ar.23959] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/20/2018] [Accepted: 05/14/2018] [Indexed: 01/02/2023]
Abstract
While actin was discovered in the nucleus over 50 years ago, research lagged for decades due to strong skepticism. The revitalization of research into nuclear actin occurred after it was found that cellular stresses induce the nuclear localization and alter the structure of actin. These studies provided the first hints that actin has a nuclear function. Subsequently, it was established that the nuclear import and export of actin is highly regulated. While the structures of nuclear actin remain unclear, it can function as monomers, polymers, and even rods. Furthermore, even within a given structure, distinct pools of nuclear actin that can be differentially labeled have been identified. Numerous mechanistic studies have uncovered an array of functions for nuclear actin. It regulates the activity of RNA polymerases, as well as specific transcription factors. Actin also modulates the activity of several chromatin remodeling complexes and histone deacetylases, to ultimately impinge on transcriptional programing and DNA damage repair. Further, nuclear actin mediates chromatin movement and organization. It has roles in meiosis and mitosis, and these functions may be functionally conserved from ancient bacterial actin homologs. The structure and integrity of the nuclear envelope and sub-nuclear compartments are also regulated by nuclear actin. Furthermore, nuclear actin contributes to human diseases like cancer, neurodegeneration, and myopathies. Here, we explore the early discovery of actin in the nucleus and discuss the forms and functions of nuclear actin in both normal and disease contexts. Anat Rec, 301:1999-2013, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Daniel J. Kelpsch
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, 51 Newton Rd, 1-500 BSB, Iowa City, IA 52242
| | - Tina L. Tootle
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, 51 Newton Rd, 1-500 BSB, Iowa City, IA 52242
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28
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Park B, Oh S, Jo S, Kang D, Lim J, Jung Y, Lee H, Jun SC. Determination of the molecular assembly of actin and actin-binding proteins using photoluminescence. Colloids Surf B Biointerfaces 2018; 169:462-469. [DOI: 10.1016/j.colsurfb.2018.05.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 04/26/2018] [Accepted: 05/19/2018] [Indexed: 11/27/2022]
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29
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Cencioni C, Spallotta F, Savoia M, Kuenne C, Guenther S, Re A, Wingert S, Rehage M, Sürün D, Siragusa M, Smith JG, Schnütgen F, von Melchner H, Rieger MA, Martelli F, Riccio A, Fleming I, Braun T, Zeiher AM, Farsetti A, Gaetano C. Zeb1-Hdac2-eNOS circuitry identifies early cardiovascular precursors in naive mouse embryonic stem cells. Nat Commun 2018; 9:1281. [PMID: 29599503 PMCID: PMC5876398 DOI: 10.1038/s41467-018-03668-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 03/02/2018] [Indexed: 01/04/2023] Open
Abstract
Nitric oxide (NO) synthesis is a late event during differentiation of mouse embryonic stem cells (mESC) and occurs after release from serum and leukemia inhibitory factor (LIF). Here we show that after release from pluripotency, a subpopulation of mESC, kept in the naive state by 2i/LIF, expresses endothelial nitric oxide synthase (eNOS) and endogenously synthesizes NO. This eNOS/NO-positive subpopulation (ESNO+) expresses mesendodermal markers and is more efficient in the generation of cardiovascular precursors than eNOS/NO-negative cells. Mechanistically, production of endogenous NO triggers rapid Hdac2 S-nitrosylation, which reduces association of Hdac2 with the transcriptional repression factor Zeb1, allowing mesendodermal gene expression. In conclusion, our results suggest that the interaction between Zeb1, Hdac2, and eNOS is required for early mesendodermal differentiation of naive mESC.
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Affiliation(s)
- Chiara Cencioni
- Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany. .,National Research Council, Institute of Cell Biology and Neurobiology (IBCN), Via del Fosso di Fiorano 64, 00143, Rome, Italy.
| | - Francesco Spallotta
- Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Matteo Savoia
- Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.,Institute of Medical Pathology, Università Cattolica di Roma, Largo Francesco Vito 1, 00168, Rome, Italy
| | - Carsten Kuenne
- ECCPS Bioinformatics and deep sequencing platform, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231, Bad Nauheim, Germany
| | - Stefan Guenther
- ECCPS Bioinformatics and deep sequencing platform, Max Planck Institute for Heart and Lung Research, Ludwigstrasse 43, 61231, Bad Nauheim, Germany
| | - Agnese Re
- National Research Council, Institute of Cell Biology and Neurobiology (IBCN), Via del Fosso di Fiorano 64, 00143, Rome, Italy
| | - Susanne Wingert
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Maike Rehage
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Duran Sürün
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Mauro Siragusa
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Jacob G Smith
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, Kings Cross, London, WC1E 6BT, UK
| | - Frank Schnütgen
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Harald von Melchner
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Michael A Rieger
- LOEWE Center for Cell and Gene Therapy and Department of Medicine, Hematology/Oncology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Fabio Martelli
- Molecular Cardiology Laboratory, IRCCS-Policlinico San Donato, Via Morandi 30 San Donato Milanese, 20097, Milan, Italy
| | - Antonella Riccio
- MRC Laboratory for Molecular Cell Biology, University College London, Gower St, Kings Cross, London, WC1E 6BT, UK
| | - Ingrid Fleming
- Institute for Vascular Signalling, Centre for Molecular Medicine, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max-Planck-Institute for Heart and Lung Research, Ludwigstrasse 43, 61231, Bad Nauheim, Germany
| | - Andreas M Zeiher
- Internal Medicine Clinic III, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Antonella Farsetti
- National Research Council, Institute of Cell Biology and Neurobiology (IBCN), Via del Fosso di Fiorano 64, 00143, Rome, Italy. .,Internal Medicine Clinic III, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany.
| | - Carlo Gaetano
- Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Germany. .,Laboratorio di Epigenetica, Istituti Clinici Scientifici Maugeri, Via Maugeri 4, 27100, Pavia, Italy.
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Zalewski JK, Mo JH, Heber S, Heroux A, Gardner RG, Hildebrand JD, VanDemark AP. Structure of the Shroom-Rho Kinase Complex Reveals a Binding Interface with Monomeric Shroom That Regulates Cell Morphology and Stimulates Kinase Activity. J Biol Chem 2016; 291:25364-25374. [PMID: 27758857 DOI: 10.1074/jbc.m116.738559] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/27/2016] [Indexed: 12/21/2022] Open
Abstract
Shroom-mediated remodeling of the actomyosin cytoskeleton is a critical driver of cellular shape and tissue morphology that underlies the development of many tissues including the neural tube, eye, intestines, and vasculature. Shroom uses a conserved SD2 domain to direct the subcellular localization of Rho-associated kinase (Rock), which in turn drives changes in the cytoskeleton and cellular morphology through its ability to phosphorylate and activate non-muscle myosin II. Here, we present the structure of the human Shroom-Rock binding module, revealing an unexpected stoichiometry for Shroom in which two Shroom SD2 domains bind independent surfaces on Rock. Mutation of interfacial residues impaired Shroom-Rock binding in vitro and resulted in altered remodeling of the cytoskeleton and loss of Shroom-mediated changes in cellular morphology. Additionally, we provide the first direct evidence that Shroom can function as a Rock activator. These data provide molecular insight into the Shroom-Rock interface and demonstrate that Shroom directly participates in regulating cytoskeletal dynamics, adding to its known role in Rock localization.
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Affiliation(s)
- Jenna K Zalewski
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Joshua H Mo
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Simone Heber
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Annie Heroux
- the Department of Biology, Brookhaven National Laboratory, Upton, New York 11973, and
| | - Richard G Gardner
- the Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Jeffrey D Hildebrand
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Andrew P VanDemark
- From the Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260,
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31
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Zukosky K, Meilleur K, Traynor BJ, Dastgir J, Medne L, Devoto M, Collins J, Rooney J, Zou Y, Yang ML, Gibbs JR, Meier M, Stetefeld J, Finkel RS, Schessl J, Elman L, Felice K, Ferguson TA, Ceyhan-Birsoy O, Beggs AH, Tennekoon G, Johnson JO, Bönnemann CG. Association of a Novel ACTA1 Mutation With a Dominant Progressive Scapuloperoneal Myopathy in an Extended Family. JAMA Neurol 2015; 72:689-98. [PMID: 25938801 DOI: 10.1001/jamaneurol.2015.37] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
IMPORTANCE New genomic strategies can now be applied to identify a diagnosis in patients and families with previously undiagnosed rare genetic conditions. The large family evaluated in the present study was described in 1966 and now expands the phenotype of a known neuromuscular gene. OBJECTIVE To determine the genetic cause of a slowly progressive, autosomal dominant, scapuloperoneal neuromuscular disorder by using linkage and exome sequencing. DESIGN, SETTING, AND PARTICIPANTS Fourteen affected individuals in a 6-generation family with a progressive scapuloperoneal disorder were evaluated. Participants were examined at pediatric, neuromuscular, and research clinics from March 1, 2005, to May 31, 2014. Exome and linkage were performed in genetics laboratories of research institutions. MAIN OUTCOMES AND MEASURES Examination and evaluation by magnetic resonance imaging, ultrasonography, electrodiagnostic studies, and muscle biopsies (n = 3). Genetic analysis included linkage analysis (n = 17) with exome sequencing (n = 7). RESULTS Clinical findings included progressive muscle weakness in an initially scapuloperoneal and distal distribution, including wrist extensor weakness, finger and foot drop, scapular winging, mild facial weakness, Achilles tendon contractures, and diminished or absent deep tendon reflexes. Both age at onset and progression of the disease showed clinical variability within the family. Muscle biopsy specimens demonstrated type I fiber atrophy and trabeculated fibers without nemaline rods. Analysis of exome sequences within the linkage region (4.8 megabases) revealed missense mutation c.591C>A p.Glu197Asp in a highly conserved residue in exon 4 of ACTA1. The mutation cosegregated with disease in all tested individuals and was not present in unaffected individuals. CONCLUSIONS AND RELEVANCE This family defines a new scapuloperoneal phenotype associated with an ACTA1 mutation. A highly conserved protein, ACTA1 is implicated in multiple muscle diseases, including nemaline myopathy, actin aggregate myopathy, fiber-type disproportion, and rod-core myopathy. To our knowledge, mutations in Glu197 have not been reported previously. This residue is highly conserved and located in an exposed position in the protein; the mutation affects the intermolecular and intramolecular electrostatic interactions as shown by structural modeling. The mutation in this residue does not appear to lead to rod formation or actin accumulation in vitro or in vivo, suggesting a different molecular mechanism from that of other ACTA1 diseases.
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Affiliation(s)
- Kristen Zukosky
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Katherine Meilleur
- National Institute of Nursing Research, National Institutes of Health, Bethesda, Maryland
| | - Bryan J Traynor
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, Porter Neuroscience Research Center, National Institute on Aging, National Institutes of Health, Bethesda, Maryland
| | - Jahannaz Dastgir
- Division of Child Neurology, Columbia University Medical Center, New York, New York
| | - Livija Medne
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Marcella Devoto
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia7Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia8Department of Molecular Medicine, Universit
| | - James Collins
- Department of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Jachinta Rooney
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland11Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC
| | - Yaqun Zou
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Michele L Yang
- Department of Pediatrics and Neurology, Children's Hospital Colorado, Aurora
| | - J Raphael Gibbs
- Computational Biology Core, Laboratory of Neurogenetics, Porter Neuroscience Research Center, National Institute on Aging, National Institutes of Health, Bethesda, Maryland
| | - Markus Meier
- Department of Chemistry, Microbiology, Biochemistry, and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Joerg Stetefeld
- Department of Chemistry, Microbiology, Biochemistry, and Medical Genetics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Richard S Finkel
- Department of Pediatrics, Nemours Children's Hospital, Orlando, Florida
| | - Joachim Schessl
- Department of Neurology, Friedrich-Baur Institute, Ludwig-Maximillans University of Munich, Munich, Germany
| | - Lauren Elman
- Department of Neurology, University of Pennsylvania, Philadelphia
| | - Kevin Felice
- Department of Neuromuscular Medicine, Hospital for Special Care, New Britain, Connecticut
| | - Toby A Ferguson
- Shriners Pediatric Research Center, Department of Neurology, Temple University, Philadelphia, Pennsylvania
| | - Ozge Ceyhan-Birsoy
- The Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Alan H Beggs
- The Manton Center for Orphan Disease Research, Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Gihan Tennekoon
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Janel O Johnson
- Neuromuscular Diseases Research Section, Laboratory of Neurogenetics, Porter Neuroscience Research Center, National Institute on Aging, National Institutes of Health, Bethesda, Maryland
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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SMIFH2 has effects on Formins and p53 that perturb the cell cytoskeleton. Sci Rep 2015; 5:9802. [PMID: 25925024 PMCID: PMC5386218 DOI: 10.1038/srep09802] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 03/19/2015] [Indexed: 01/08/2023] Open
Abstract
Formin proteins are key regulators of the cytoskeleton involved in developmental and homeostatic programs, and human disease. For these reasons, small molecules interfering with Formins' activity have gained increasing attention. Among them, small molecule inhibitor of Formin Homology 2 domains (SMIFH2) is often used as a pharmacological Formin blocker. Although SMIFH2 inhibits actin polymerization by Formins and affects the actin cytoskeleton, its cellular mechanism of action and target specificity remain unclear. Here we show that SMIFH2 induces remodelling of actin filaments, microtubules and the Golgi complex as a result of its effects on Formins and p53. We found that SMIFH2 triggers alternated depolymerization-repolymerization cycles of actin and tubulin, increases cell migration, causes scattering of the Golgi complex, and also cytotoxicity at high dose. Moreover, SMIFH2 reduces expression and activity of p53 through a post-transcriptional, proteasome-independent mechanism that influences remodelling of the cytoskeleton. As the action of SMIFH2 may go beyond Formin inhibition, only short-term and low-dose SMIFH2 treatments minimize confounding effects induced by loss of p53 and cytotoxicity.
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Liu Z, Li W, Ma X, Ding N, Spallotta F, Southon E, Tessarollo L, Gaetano C, Mukouyama YS, Thiele CJ. Essential role of the zinc finger transcription factor Casz1 for mammalian cardiac morphogenesis and development. J Biol Chem 2014; 289:29801-16. [PMID: 25190801 DOI: 10.1074/jbc.m114.570416] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chromosome 1p36 deletion syndrome is one of the most common terminal deletions observed in humans and is related to congenital heart disease (CHD). However, the 1p36 genes that contribute to heart disease have not been clearly delineated. Human CASZ1 gene localizes to 1p36 and encodes a zinc finger transcription factor. Casz1 is required for Xenopus heart ventral midline progenitor cell differentiation. Whether Casz1 plays a role during mammalian heart development is unknown. Our aim is to determine 1p36 gene CASZ1 function at regulating heart development in mammals. We generated a Casz1 knock-out mouse using Casz1-trapped embryonic stem cells. Casz1 deletion in mice resulted in abnormal heart development including hypoplasia of myocardium, ventricular septal defect, and disorganized morphology. Hypoplasia of myocardium was caused by decreased cardiomyocyte proliferation. Comparative genome-wide RNA transcriptome analysis of Casz1 depleted embryonic hearts identifies abnormal expression of genes that are critical for muscular system development and function, such as muscle contraction genes TNNI2, TNNT1, and CKM; contractile fiber gene ACTA1; and cardiac arrhythmia associated ion channel coding genes ABCC9 and CACNA1D. The transcriptional regulation of some of these genes by Casz1 was also found in cellular models. Our results showed that loss of Casz1 during mouse development led to heart defect including cardiac noncompaction and ventricular septal defect, which phenocopies 1p36 deletion syndrome related CHD. This suggests that CASZ1 is a novel 1p36 CHD gene and that the abnormal expression of cardiac morphogenesis and contraction genes induced by loss of Casz1 contributes to the heart defect.
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Affiliation(s)
| | - Wenling Li
- the Laboratories of Stem Cell and Neuro-vascular Biology and
| | - Xuefei Ma
- the Molecular Cardiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892, and
| | | | - Francesco Spallotta
- the Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Frankfurt am Main 60596, Germany
| | - Eileen Southon
- the Mouse Cancer Genetics Program, Neural Development Section, National Cancer Institute, Bethesda, Maryland 20892
| | - Lino Tessarollo
- the Mouse Cancer Genetics Program, Neural Development Section, National Cancer Institute, Bethesda, Maryland 20892
| | - Carlo Gaetano
- the Division of Cardiovascular Epigenetics, Department of Cardiology, Goethe University, Frankfurt am Main 60596, Germany
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Artificial neural network inference (ANNI): a study on gene-gene interaction for biomarkers in childhood sarcomas. PLoS One 2014; 9:e102483. [PMID: 25025207 PMCID: PMC4099183 DOI: 10.1371/journal.pone.0102483] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/19/2014] [Indexed: 01/31/2023] Open
Abstract
Objective To model the potential interaction between previously identified biomarkers in children sarcomas using artificial neural network inference (ANNI). Method To concisely demonstrate the biological interactions between correlated genes in an interaction network map, only 2 types of sarcomas in the children small round blue cell tumors (SRBCTs) dataset are discussed in this paper. A backpropagation neural network was used to model the potential interaction between genes. The prediction weights and signal directions were used to model the strengths of the interaction signals and the direction of the interaction link between genes. The ANN model was validated using Monte Carlo cross-validation to minimize the risk of over-fitting and to optimize generalization ability of the model. Results Strong connection links on certain genes (TNNT1 and FNDC5 in rhabdomyosarcoma (RMS); FCGRT and OLFM1 in Ewing’s sarcoma (EWS)) suggested their potency as central hubs in the interconnection of genes with different functionalities. The results showed that the RMS patients in this dataset are likely to be congenital and at low risk of cardiomyopathy development. The EWS patients are likely to be complicated by EWS-FLI fusion and deficiency in various signaling pathways, including Wnt, Fas/Rho and intracellular oxygen. Conclusions The ANN network inference approach and the examination of identified genes in the published literature within the context of the disease highlights the substantial influence of certain genes in sarcomas.
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Perkins AD, Tanentzapf G. An ongoing role for structural sarcomeric components in maintaining Drosophila melanogaster muscle function and structure. PLoS One 2014; 9:e99362. [PMID: 24915196 PMCID: PMC4051695 DOI: 10.1371/journal.pone.0099362] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 05/14/2014] [Indexed: 11/29/2022] Open
Abstract
Animal muscles must maintain their function while bearing substantial mechanical loads. How muscles withstand persistent mechanical strain is presently not well understood. The basic unit of muscle is the sarcomere, which is primarily composed of cytoskeletal proteins. We hypothesized that cytoskeletal protein turnover is required to maintain muscle function. Using the flight muscles of Drosophila melanogaster, we confirmed that the sarcomeric cytoskeleton undergoes turnover throughout adult life. To uncover which cytoskeletal components are required to maintain adult muscle function, we performed an RNAi-mediated knockdown screen targeting the entire fly cytoskeleton and associated proteins. Gene knockdown was restricted to adult flies and muscle function was analyzed with behavioural assays. Here we analyze the results of that screen and characterize the specific muscle maintenance role for several hits. The screen identified 46 genes required for muscle maintenance: 40 of which had no previously known role in this process. Bioinformatic analysis highlighted the structural sarcomeric proteins as a candidate group for further analysis. Detailed confocal and electron microscopic analysis showed that while muscle architecture was maintained after candidate gene knockdown, sarcomere length was disrupted. Specifically, we found that ongoing synthesis and turnover of the key sarcomere structural components Projectin, Myosin and Actin are required to maintain correct sarcomere length and thin filament length. Our results provide in vivo evidence of adult muscle protein turnover and uncover specific functional defects associated with reduced expression of a subset of cytoskeletal proteins in the adult animal.
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Affiliation(s)
- Alexander D. Perkins
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Institute, Vancouver, British Columbia, Canada
| | - Guy Tanentzapf
- Department of Cellular and Physiological Sciences, University of British Columbia, Life Sciences Institute, Vancouver, British Columbia, Canada
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Yuan B, Wan P, Chu D, Nie J, Cao Y, Luo W, Lu S, Chen J, Yang Z. A cardiomyocyte-specific Wdr1 knockout demonstrates essential functional roles for actin disassembly during myocardial growth and maintenance in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1967-80. [PMID: 24840128 DOI: 10.1016/j.ajpath.2014.04.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 03/26/2014] [Accepted: 04/07/2014] [Indexed: 11/25/2022]
Abstract
Actin dynamics are critical for muscle development and function, and mutations leading to deregulation of actin dynamics cause various forms of heritable muscle diseases. AIP1 is a major cofactor of the actin depolymerizing factor/cofilin in eukaryotes, promoting actin depolymerizing factor/cofilin-mediated actin disassembly. Its function in vertebrate muscle has been unknown. To investigate functional roles of AIP1 in myocardium, we generated conditional knockout (cKO) mice with cardiomyocyte-specific deletion of Wdr1, the mammalian homolog of yeast AIP1. Wdr1 cKO mice began to die at postnatal day 13 (P13), and none survived past P24. At P12, cKO mice exhibited cardiac hypertrophy and impaired contraction of the left ventricle. Electrocardiography revealed reduced heart rate, abnormal P wave, and abnormal T wave at P10 and prolonged QT interval at P12. Actin filament (F-actin) accumulations began at P10 and became prominent at P12 in the myocardium of cKO mice. Within regions of F-actin accumulation in myofibrils, the sarcomeric components α-actinin and tropomodulin-1 exhibited disrupted patterns, indicating that F-actin accumulations caused by Wdr1 deletion result in disruption of sarcomeric structure. Ectopic cofilin colocalized with F-actin aggregates. In adult mice, Wdr1 deletion resulted in similar but much milder phenotypes of heart hypertrophy, F-actin accumulations within myofibrils, and lethality. Taken together, these results demonstrate that AIP1-regulated actin dynamics play essential roles in heart function in mice.
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Affiliation(s)
- Baiyin Yuan
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Ping Wan
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Dandan Chu
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China; Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China
| | - Junwei Nie
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Yunshan Cao
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Wen Luo
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Shuangshuang Lu
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China
| | - Jiong Chen
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China.
| | - Zhongzhou Yang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China; State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China.
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Rubenstein PA, Wen KK. Insights into the effects of disease-causing mutations in human actins. Cytoskeleton (Hoboken) 2014; 71:211-29. [PMID: 24574087 DOI: 10.1002/cm.21169] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 02/13/2013] [Accepted: 02/19/2014] [Indexed: 01/04/2023]
Abstract
Mutations in all six actins in humans have now been shown to cause diseases. However, a number of factors have made it difficult to gain insight into how the changes in actin functions brought about by these pathogenic mutations result in the disease phenotype. These include the presence of multiple actins in the same cell, limited accessibility to pure mutant material, and complexities associated with the structures and their component cells that manifest the diseases. To try to circumvent these difficulties, investigators have turned to the use of model systems. This review describes these various approaches, the initial results obtained using them, and the insight they have provided into allosteric mechanisms that govern actin function. Although results so far have not explained a particular disease phenotype at the molecular level, they have provided valuable insight into actin function at the mechanistic level which can be utilized in the future to delineate the molecular bases of these different actinopathies.
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Affiliation(s)
- Peter A Rubenstein
- Department of Biochemistry, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Rouède D, Coumailleau P, Schaub E, Bellanger JJ, Blanchard-Desce M, Tiaho F. Myofibrillar misalignment correlated to triad disappearance of mdx mouse gastrocnemius muscle probed by SHG microscopy. BIOMEDICAL OPTICS EXPRESS 2014; 5:858-875. [PMID: 24688819 PMCID: PMC3959848 DOI: 10.1364/boe.5.000858] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/15/2014] [Accepted: 01/19/2014] [Indexed: 06/03/2023]
Abstract
We show that the canonical single frequency sarcomeric SHG intensity pattern (SHG-IP) of control muscles is converted to double frequency sarcomeric SHG-IP in preserved mdx mouse gastrocnemius muscles in the vicinity of necrotic fibers. These double frequency sarcomeric SHG-IPs are often spatially correlated to double frequency sarcomeric two-photon excitation fluorescence (TPEF) emitted from Z-line and I-bands and to one centered spot SHG angular intensity pattern (SHG-AIP) suggesting that these patterns are signature of myofibrillar misalignement. This latter is confirmed with transmission electron microscopy (TEM). Moreover, a good spatial correlation between SHG signature of myofibrillar misalignment and triad reduction is established. Theoretical simulation of sarcomeric SHG-IP is used to demonstrate the correlation between change of SHG-IP and -AIP and myofibrillar misalignment. The extreme sensitivity of SHG microscopy to reveal the submicrometric organization of A-band thick filaments is highlighted. This report is a first step toward future studies aimed at establishing live SHG signature of myofibrillar misalignment involving excitation contraction defects due to muscle damage and disease.
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Affiliation(s)
- Denis Rouède
- IPR, CNRS, UMR-CNRS UR1- 6251, Université de Rennes1, Campus de Beaulieu, Rennes, F-35000, France
| | - Pascal Coumailleau
- IRSET, INSERM, U1085, Université de Rennes1, Campus de Beaulieu, Rennes, F-35000, France
| | - Emmanuel Schaub
- IPR, CNRS, UMR-CNRS UR1- 6251, Université de Rennes1, Campus de Beaulieu, Rennes, F-35000, France
| | | | | | - François Tiaho
- IRSET, INSERM, U1085, Université de Rennes1, Campus de Beaulieu, Rennes, F-35000, France
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Gurniak CB, Chevessier F, Jokwitz M, Jönsson F, Perlas E, Richter H, Matern G, Boyl PP, Chaponnier C, Fürst D, Schröder R, Witke W. Severe protein aggregate myopathy in a knockout mouse model points to an essential role of cofilin2 in sarcomeric actin exchange and muscle maintenance. Eur J Cell Biol 2014; 93:252-66. [PMID: 24598388 DOI: 10.1016/j.ejcb.2014.01.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 01/19/2023] Open
Abstract
Mutations in the human actin depolymerizing factor cofilin2 result in an autosomal dominant form of nemaline myopathy. Here, we report on the targeted ablation of murine cofilin2, which leads to a severe skeletal muscle specific phenotype within the first two weeks after birth. Apart from skeletal muscle, cofilin2 is also expressed in heart and CNS, however the pathology was restricted to skeletal muscle. The two close family members of cofilin2 - ADF and cofilin1 - were co-expressed in muscle, but unable to compensate for the loss of cofilin2. While primary myofibril assembly and muscle development were unaffected in cofilin2 mutant mice, progressive muscle degeneration was observed between postnatal days 3 and 7. Muscle pathology was characterized by sarcoplasmic protein aggregates, fiber size disproportion, mitochondrial abnormalities and internal nuclei. The observed muscle pathology differed from nemaline myopathy, but showed combined features of actin-associated myopathy and myofibrillar myopathy. In cofilin2 mutant mice, the postnatal expression pattern and turnover of sarcomeric α-actin isoforms were altered. Levels of smooth muscle α-actin were increased and remained high in developing muscles, suggesting that cofilin2 plays a crucial role during the exchange of α-actin isoforms during the early postnatal remodeling of the sarcomere.
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Affiliation(s)
| | | | - Melanie Jokwitz
- University of Bonn, Institute of Genetics, Cell Migration Unit, Germany
| | - Friederike Jönsson
- Institut Pasteur, Département d'Immunologie, Laboratoire Anticorps en Thérapie et Pathologie, Inserm, U.760, 75015 Paris, France
| | | | - Hendrik Richter
- University of Bonn, Institute of Cellular and Molecular Botany, Germany
| | - Gabi Matern
- University of Bonn, Institute of Genetics, Cell Migration Unit, Germany
| | - Pietro Pilo Boyl
- University of Bonn, Institute of Genetics, Cell Migration Unit, Germany
| | | | - Dieter Fürst
- University of Bonn, Institute of Cell Biology, Germany
| | - Rolf Schröder
- University of Erlangen, Institute of Neuropathology, Germany
| | - Walter Witke
- University of Bonn, Institute of Genetics, Cell Migration Unit, Germany.
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Wang LL, Peng ZH, Fan Y, Li LY, Wu D, Zhang Y, Miao JN, Bai YZ, Yuan ZW, Wang WL, Sun KL. Dynamic expression of molecules that control limb muscle development including Fhl1 in hind limbs of different gestational age. APMIS 2014; 122:766-71. [PMID: 24475781 DOI: 10.1111/apm.12217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 10/21/2013] [Indexed: 01/07/2023]
Abstract
Muscle abnormality could be a key reason for congenital clubfoot (CCF) deformity, which manifests itself during fetal development. FHL1 down-regulated expression is involved in the formation of skeletal muscle abnormalities in CCF and FHL1 gene mutations contribute to the development of some kinds of myopathies. Therefore, detecting dynamic expression of Fhl1 and other molecules (Hgf, MyoD1, Myogenin, and Myh4) that control limb muscle development in hind limbs of different gestational age will provide a foundation for further research on the molecular mechanism involves in the myopathies or CCF. The dynamic gene expression levels of Fhl1, Hgf, MyoD1, Myogenin, and Myh4 in the lower limbs of E16, E17, E19, and E20 rat embryos were examined by real-time RT-PCR. Immunofluorescence was used to detect formation of specific muscle fibers (fast or slow fibers) in distal E17 hind limbs. The expression levels of Fhl1, Hgf, MyoD1, Myogenin, and Myh4 were varying in hind limbs of different gestational age. Real-time PCR results showed that all the genes that control skeletal muscle development except for Fhl1 exhibited a peak in E17 lower limbs. Immunofluorescence results showed obviously positive fast-myosin in the distal E17 lower limbs and meanwhile slow-myosin had no apparently signals. E17 was a critical time point for terminal skeletal muscle differentiation in the lower limbs of rat embryos.
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Affiliation(s)
- Li-Li Wang
- Key laboratory of health ministry for congenital malformation, Shengjing Hospital, China Medical University, Shenyang, China
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Blache U, Silván U, Plodinec M, Suetterlin R, Jakob R, Klebba I, Bentires-Alj M, Aebi U, Schoenenberger CA. A tumorigenic actin mutant alters fibroblast morphology and multicellular assembly properties. Cytoskeleton (Hoboken) 2013; 70:635-50. [DOI: 10.1002/cm.21120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 06/07/2013] [Accepted: 06/17/2013] [Indexed: 01/19/2023]
Affiliation(s)
- Ulrich Blache
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Unai Silván
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Marija Plodinec
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Rosmarie Suetterlin
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Roman Jakob
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Ina Klebba
- Mechanisms of Cancer; Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
| | - Mohamed Bentires-Alj
- Mechanisms of Cancer; Friedrich Miescher Institute for Biomedical Research; Basel Switzerland
| | - Ueli Aebi
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
| | - Cora-Ann Schoenenberger
- Focal Area Structural Biology and Biophysics; Biozentrum; University of Basel; Basel Switzerland
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Gineste C, Le Fur Y, Vilmen C, Le Troter A, Pecchi E, Cozzone PJ, Hardeman EC, Bendahan D, Gondin J. Combined MRI and ³¹P-MRS investigations of the ACTA1(H40Y) mouse model of nemaline myopathy show impaired muscle function and altered energy metabolism. PLoS One 2013; 8:e61517. [PMID: 23613869 PMCID: PMC3629063 DOI: 10.1371/journal.pone.0061517] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 03/11/2013] [Indexed: 11/19/2022] Open
Abstract
Nemaline myopathy (NM) is the most common disease entity among non-dystrophic skeletal muscle congenital diseases. Mutations in the skeletal muscle α-actin gene (ACTA1) account for ∼25% of all NM cases and are the most frequent cause of severe forms of NM. So far, the mechanisms underlying muscle weakness in NM patients remain unclear. Additionally, recent Magnetic Resonance Imaging (MRI) studies reported a progressive fatty infiltration of skeletal muscle with a specific muscle involvement in patients with ACTA1 mutations. We investigated strictly noninvasively the gastrocnemius muscle function of a mouse model carrying a mutation in the ACTA1 gene (H40Y). Skeletal muscle anatomy (hindlimb muscles and fat volumes) and energy metabolism were studied using MRI and 31Phosphorus magnetic resonance spectroscopy. Skeletal muscle contractile performance was investigated while applying a force-frequency protocol (from 1–150 Hz) and a fatigue protocol (80 stimuli at 40 Hz). H40Y mice showed a reduction of both absolute (−40%) and specific (−25%) maximal force production as compared to controls. Interestingly, muscle weakness was associated with an improved resistance to fatigue (+40%) and an increased energy cost. On the contrary, the force frequency relationship was not modified in H40Y mice and the extent of fatty infiltration was minor and not different from the WT group. We concluded that the H40Y mouse model does not reproduce human MRI findings but shows a severe muscle weakness which might be related to an alteration of intrinsic muscular properties. The increased energy cost in H40Y mice might be related to either an impaired mitochondrial function or an alteration at the cross-bridges level. Overall, we provided a unique set of anatomic, metabolic and functional biomarkers that might be relevant for monitoring the progression of NM disease but also for assessing the efficacy of potential therapeutic interventions at a preclinical level.
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Affiliation(s)
- Charlotte Gineste
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Yann Le Fur
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Christophe Vilmen
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Arnaud Le Troter
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Emilie Pecchi
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Patrick J. Cozzone
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Edna C. Hardeman
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - David Bendahan
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
| | - Julien Gondin
- Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), Centre de Résonance Magnétique Biologique et Médicale (CRMBM) Unité Mixte de Recherche (UMR), Marseille, France
- * E-mail:
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Noorman M, Groeneweg JA, Asimaki A, Rizzo S, Papegaaij M, van Stuijvenberg L, de Jonge N, Dooijes D, Basso C, Saffitz JE, van Veen TA, Vink A, Hauer RN. End stage of arrhythmogenic cardiomyopathy with severe involvement of the interventricular septum. Heart Rhythm 2013; 10:283-9. [DOI: 10.1016/j.hrthm.2012.10.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Indexed: 10/27/2022]
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Gineste C, De Winter JM, Kohl C, Witt CC, Giannesini B, Brohm K, Le Fur Y, Gretz N, Vilmen C, Pecchi E, Jubeau M, Cozzone PJ, Stienen GJM, Granzier H, Labeit S, Ottenheijm CAC, Bendahan D, Gondin J. In vivo and in vitro investigations of heterozygous nebulin knock-out mice disclose a mild skeletal muscle phenotype. Neuromuscul Disord 2013; 23:357-69. [PMID: 23375831 DOI: 10.1016/j.nmd.2012.12.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 12/07/2012] [Accepted: 12/29/2012] [Indexed: 01/30/2023]
Abstract
Nemaline myopathy is the most common congenital skeletal muscle disease, and mutations in the nebulin gene account for 50% of all cases. Recent studies suggest that the disease severity might be related to the nebulin expression levels. Considering that mutations in the nebulin gene are typically recessive, one would expect that a single functional nebulin allele would maintain nebulin protein expression which would result in preserved skeletal muscle function. We investigated skeletal muscle function of heterozygous nebulin knock-out (i.e., nebulin(+/-)) mice using a multidisciplinary approach including protein and gene expression analysis and combined in vivo and in vitro force measurements. Skeletal muscle anatomy and energy metabolism were studied strictly non-invasively using magnetic resonance imaging and 31P-magnetic resonance spectroscopy. Maximal force production was reduced by around 16% in isolated muscle of nebulin(+/-) mice while in vivo force generating capacity was preserved. Muscle weakness was associated with a shift toward a slower proteomic phenotype, but was not related to nebulin protein deficiency or to an impaired energy metabolism. Further studies would be warranted in order to determine the mechanisms leading to a mild skeletal muscle phenotype resulting from the expression of a single nebulin allele.
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Affiliation(s)
- C Gineste
- Aix-Marseille Université, CRMBM, 13005 Marseille, France
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Identification of cytoskeleton-associated proteins essential for lysosomal stability and survival of human cancer cells. PLoS One 2012; 7:e45381. [PMID: 23071517 PMCID: PMC3469574 DOI: 10.1371/journal.pone.0045381] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 08/17/2012] [Indexed: 11/19/2022] Open
Abstract
Microtubule-disturbing drugs inhibit lysosomal trafficking and induce lysosomal membrane permeabilization followed by cathepsin-dependent cell death. To identify specific trafficking-related proteins that control cell survival and lysosomal stability, we screened a molecular motor siRNA library in human MCF7 breast cancer cells. SiRNAs targeting four kinesins (KIF11/Eg5, KIF20A, KIF21A, KIF25), myosin 1G (MYO1G), myosin heavy chain 1 (MYH1) and tropomyosin 2 (TPM2) were identified as effective inducers of non-apoptotic cell death. The cell death induced by KIF11, KIF21A, KIF25, MYH1 or TPM2 siRNAs was preceded by lysosomal membrane permeabilization, and all identified siRNAs induced several changes in the endo-lysosomal compartment, i.e. increased lysosomal volume (KIF11, KIF20A, KIF25, MYO1G, MYH1), increased cysteine cathepsin activity (KIF20A, KIF25), altered lysosomal localization (KIF25, MYH1, TPM2), increased dextran accumulation (KIF20A), or reduced autophagic flux (MYO1G, MYH1). Importantly, all seven siRNAs also killed human cervix cancer (HeLa) and osteosarcoma (U-2-OS) cells and sensitized cancer cells to other lysosome-destabilizing treatments, i.e. photo-oxidation, siramesine, etoposide or cisplatin. Similarly to KIF11 siRNA, the KIF11 inhibitor monastrol induced lysosomal membrane permeabilization and sensitized several cancer cell lines to siramesine. While KIF11 inhibitors are under clinical development as mitotic blockers, our data reveal a new function for KIF11 in controlling lysosomal stability and introduce six other molecular motors as putative cancer drug targets.
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46
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Robaszkiewicz K, Dudek E, Kasprzak AA, Moraczewska J. Functional effects of congenital myopathy-related mutations in gamma-tropomyosin gene. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1562-9. [PMID: 22749829 DOI: 10.1016/j.bbadis.2012.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 12/25/2022]
Abstract
Missense mutations in human TPM3 gene encoding γ-tropomyosin expressed in slow muscle type 1 fibers, were associated with three types of congenital myopathies-nemaline myopathy, cap disease and congenital fiber type disproportion. Functional effects of the following substitutions: Leu100Met, Ala156Thr, Arg168His, Arg168Cys, Arg168Gly, Lys169Glu, and Arg245Gly, were examined in biochemical assays using recombinant tropomyosin mutants and native proteins isolated from skeletal muscle. Most, but not all, mutations decreased the affinity of tropomyosin for actin alone and in complex with troponin (±Ca(2+)). All studied tropomyosin mutants reduced Ca-induced activation but had no effect on the inhibition of actomyosin cross-bridges. Ca(2+)-sensitivity of the actomyosin interactions, as well as cooperativity of myosin-induced activation of the thin filament was affected by individual tropomyosin mutants with various degrees. Decreased motility of the reconstructed thin filaments was a result of combined functional defects caused by myopathy-related tropomyosin mutants. We conclude that muscle weakness and structural abnormalities observed in TPM3-related congenital myopathies result from reduced capability of the thin filament to fully activate actin-myosin cross-bridges.
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Affiliation(s)
- Katarzyna Robaszkiewicz
- Kazimierz Wielki University in Bydgoszcz, Department of Biochemistry and Cell Biology, Chodkiewicza , Bydgoszcz, Poland
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Yonath H, Reznik-Wolf H, Berkenstadt M, Eisenberg-Barzilai S, Lehtokari VL, Wallgren-Pettersson C, Mehta L, Achiron R, Gilboa Y, Polak-Charcon S, Winder T, Frydman M, Pras E. Carrier state for the nebulin exon 55 deletion and abnormal prenatal ultrasound findings as potential signs of nemaline myopathy. Prenat Diagn 2012; 32:70-4. [DOI: 10.1002/pd.2905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hagith Yonath
- Danek Gertner Institute of Human Genetics; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
| | - Haike Reznik-Wolf
- Danek Gertner Institute of Human Genetics; Sheba Medical Center; Ramat Gan Israel
| | - Michal Berkenstadt
- Danek Gertner Institute of Human Genetics; Sheba Medical Center; Ramat Gan Israel
| | | | - Vilma-Lotta Lehtokari
- Folkhälsan Insitute of Genetics and Department of Medical Genetics, Haartman Institute; University of Helsinki; Helsinki Finland
| | - Carina Wallgren-Pettersson
- Folkhälsan Insitute of Genetics and Department of Medical Genetics, Haartman Institute; University of Helsinki; Helsinki Finland
| | - Lakshmi Mehta
- Department of Genetics & Genomic Sciences; Mount Sinai School of Medicine; New York NY USA
| | - Reuven Achiron
- Department of Obstetrics and Gynecology; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
| | - Yinon Gilboa
- Department of Obstetrics and Gynecology; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
| | - Sylvie Polak-Charcon
- Department of Pathology; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
| | | | - Moshe Frydman
- Danek Gertner Institute of Human Genetics; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
| | - Elon Pras
- Danek Gertner Institute of Human Genetics; Sheba Medical Center; Ramat Gan Israel
- Sackler School of Medicine; Tel Aviv University; Tel Aviv Israel
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48
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Holman SK, Daniel P, Jenkins ZA, Herron RL, Morgan T, Savarirayan R, Chow CW, Bohring A, Mosel A, Lacombe D, Steiner B, Schmitt-Mechelke T, Schroter B, Raas-Rothschild A, Miñaur SG, Porteous M, Parker M, Quarrell O, Tapon D, Cormier-Daire V, Mansour S, Nash R, Bindoff LA, Fiskerstrand T, Robertson SP. The male phenotype in osteopathia striata congenita with cranial sclerosis. Am J Med Genet A 2012; 155A:2397-408. [PMID: 22043478 DOI: 10.1002/ajmg.a.34178] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Osteopathia striata with cranial sclerosis (OSCS) is an X-linked disease caused by truncating mutations in WTX. Females exhibit sclerotic striations on the long bones, cranial sclerosis, and craniofacial dysmorphism. Males with OSCS have significant skeletal sclerosis, do not have striations but do display a more severe phenotype commonly associated with gross structural malformations, patterning defects, and significant pre- and postnatal lethality. The recent description of mutations in WTX underlying OSCS has led to the identification of a milder, survivable phenotype in males. Individuals with this presentation can have, in addition to skeletal sclerosis, Hirschsprung disease, joint contractures, cardiomyopathy, and neuromuscular anomalies. A diagnosis of OSCS should be considered in males with macrocephaly, skeletal sclerosis that is most marked in the cranium and the absence of metaphyseal striations. The observation of striations in males may be indicative of a WTX mutation in a mosaic state supporting the contention that this sign in females is indicative of the differential lyonization of cells in the osteoblastic lineage.
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Affiliation(s)
- Sarah K Holman
- Department of Paediatrics, Dunedin School of Medicine, Otago University, New Zealand
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49
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Dwyer J, Iskratsch T, Ehler E. Actin in striated muscle: recent insights into assembly and maintenance. Biophys Rev 2011; 4:17-25. [PMID: 28510000 DOI: 10.1007/s12551-011-0062-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 11/17/2011] [Indexed: 01/28/2023] Open
Abstract
Striated muscle cells are characterised by a para-crystalline arrangement of their contractile proteins actin and myosin in sarcomeres, the basic unit of the myofibrils. A multitude of proteins is required to build and maintain the structure of this regular arrangement as well as to ensure regulation of contraction and to respond to alterations in demand. This review focuses on the actin filaments (also called thin filaments) of the sarcomere and will discuss how they are assembled during myofibrillogenesis and in hypertrophy and how their integrity is maintained in the working myocardium.
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Affiliation(s)
- Joseph Dwyer
- The Randall Division of Cell and Molecular Biophysics and The Cardiovascular Division, King's College London, British Heart Foundation Centre of Research Excellence, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
| | - Thomas Iskratsch
- The Randall Division of Cell and Molecular Biophysics and The Cardiovascular Division, King's College London, British Heart Foundation Centre of Research Excellence, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.,Biological Sciences, Columbia University, 713 Fairchild Center, New York, NY, 10027, USA
| | - Elisabeth Ehler
- The Randall Division of Cell and Molecular Biophysics and The Cardiovascular Division, King's College London, British Heart Foundation Centre of Research Excellence, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
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50
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Rao JN, Rivera-Santiago R, Li XE, Lehman W, Dominguez R. Structural analysis of smooth muscle tropomyosin α and β isoforms. J Biol Chem 2011; 287:3165-74. [PMID: 22119916 DOI: 10.1074/jbc.m111.307330] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A large number of tropomyosin (Tm) isoforms function as gatekeepers of the actin filament, controlling the spatiotemporal access of actin-binding proteins to specialized actin networks. Residues ∼40-80 vary significantly among Tm isoforms, but the impact of sequence variation on Tm structure and interactions with actin is poorly understood, because structural studies have focused on skeletal muscle Tmα. We describe structures of N-terminal fragments of smooth muscle Tmα and Tmβ (sm-Tmα and sm-Tmβ). The 2.0-Å structure of sm-Tmα81 (81-aa) resembles that of skeletal Tmα, displaying a similar super-helical twist matching the contours of the actin filament. The 1.8-Å structure of sm-Tmα98 (98-aa) unexpectedly reveals an antiparallel coiled coil, with the two chains staggered by only 4 amino acids and displaying hydrophobic core interactions similar to those of the parallel dimer. In contrast, the 2.5-Å structure of sm-Tmβ98, containing Gly-Ala-Ser at the N terminus to mimic acetylation, reveals a parallel coiled coil. None of the structures contains coiled-coil stabilizing elements, favoring the formation of head-to-tail overlap complexes in four of five crystallographically independent parallel dimers. These complexes show similarly arranged 4-helix bundles stabilized by hydrophobic interactions, but the extent of the overlap varies between sm-Tmβ98 and sm-Tmα81 from 2 to 3 helical turns. The formation of overlap complexes thus appears to be an intrinsic property of the Tm coiled coil, with the specific nature of hydrophobic contacts determining the extent of the overlap. Overall, the results suggest that sequence variation among Tm isoforms has a limited effect on actin binding but could determine its gatekeeper function.
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Affiliation(s)
- Jampani Nageswara Rao
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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