M Papadaki1, J M de Winter2, M B Neu3, S Donkervoort3, J Kirschner4, V Bolduc3, M L Yang5, M A Gibbons6, Y Hu3, J Dastgir3, M E Leach3,7, A Rutkowski8, A R Foley3, M Krüger9, E P Wartchow10, E McNamara11, R Ong11, K J Nowak3, N G Laing12, N F Clarke13, Cac Ottenheijm2, S B Marston1, C G Bönnemann3. 1. National Heart and Lung Institute, Imperial College London, London, UK. 2. Department of Physiology, VU University Medical Center, Amsterdam, The Netherlands. 3. National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA. 4. Department of Neuropediatrics and Muscle Disorders, University Medical Center Freiburg, Freiburg, Germany. 5. University of Colorado School of Medicine, Department of Pediatrics and Neurology, Section of Child Neurology, Aurora, CO, USA. 6. University of Colorado Denver School of Medicine, Aurora, CO, USA. 7. Children's National Health System, Washington DC, USA. 8. Kaiser SCPMG, Cure CMD, P.O. Box 701, Olathe, KS 66051, USA. 9. Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Center Freiburg, Freiburg, Germany. 10. Department of Pathology, Children's Hospital Colorado, Aurora, Colorado, USA. 11. Neuromuscular Diseases Laboratory, Centre for Medical Research, Faculty of Medicine, Dentistry and Health Sciences, The University of Western Australia Crawley, WA, Australia. 12. Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Perth, Western Australia, Australia. 13. Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, University of Sydney, Sydney, Australia.
Abstract
OBJECTIVE: Mutations in TPM3, encoding Tpm3.12, cause a clinically and histopathologically diverse group of myopathies characterized by muscle weakness. We report two patients with novel de novo Tpm3.12 single glutamic acid deletions at positions ΔE218 and ΔE224, resulting in a significant hypercontractile phenotype with congenital muscle stiffness, rather than weakness, and respiratory failure in one patient. METHODS: The effect of the Tpm3.12 deletions on the contractile properties in dissected patient myofibers was measured. We used quantitative in vitro motility assay to measure Ca(2+) sensitivity of thin filaments reconstituted with recombinant Tpm3.12 ΔE218 and ΔE224. RESULTS: Contractility studies on permeabilized myofibers demonstrated reduced maximal active tension from both patients with increased Ca(2+) sensitivity and altered cross-bridge cycling kinetics in ΔE224 fibers. In vitro motility studies showed a two-fold increase in Ca(2+) sensitivity of the fraction of filaments motile and the filament sliding velocity concentrations for both mutations. INTERPRETATION: These data indicate that Tpm3.12 deletions ΔE218 and ΔE224 result in increased Ca(2+) sensitivity of the troponin-tropomyosin complex, resulting in abnormally active interaction of the actin and myosin complex. Both mutations are located in the charged motifs of the actin-binding residues of tropomyosin 3, thus disrupting the electrostatic interactions that facilitate accurate tropomyosin binding with actin necessary to prevent the on-state. The mutations destabilize the off-state and result in excessively sensitized excitation-contraction coupling of the contractile apparatus. This work expands the phenotypic spectrum of TPM3-related disease and provides insights into the pathophysiological mechanisms of the actin-tropomyosin complex.
OBJECTIVE: Mutations in TPM3, encoding Tpm3.12, cause a clinically and histopathologically diverse group of myopathies characterized by muscle weakness. We report two patients with novel de novo Tpm3.12 single glutamic acid deletions at positions ΔE218 and ΔE224, resulting in a significant hypercontractile phenotype with congenital muscle stiffness, rather than weakness, and respiratory failure in one patient. METHODS: The effect of the Tpm3.12 deletions on the contractile properties in dissected patient myofibers was measured. We used quantitative in vitro motility assay to measure Ca(2+) sensitivity of thin filaments reconstituted with recombinant Tpm3.12 ΔE218 and ΔE224. RESULTS: Contractility studies on permeabilized myofibers demonstrated reduced maximal active tension from both patients with increased Ca(2+) sensitivity and altered cross-bridge cycling kinetics in ΔE224 fibers. In vitro motility studies showed a two-fold increase in Ca(2+) sensitivity of the fraction of filaments motile and the filament sliding velocity concentrations for both mutations. INTERPRETATION: These data indicate that Tpm3.12 deletions ΔE218 and ΔE224 result in increased Ca(2+) sensitivity of the troponin-tropomyosin complex, resulting in abnormally active interaction of the actin and myosin complex. Both mutations are located in the charged motifs of the actin-binding residues of tropomyosin 3, thus disrupting the electrostatic interactions that facilitate accurate tropomyosin binding with actin necessary to prevent the on-state. The mutations destabilize the off-state and result in excessively sensitized excitation-contraction coupling of the contractile apparatus. This work expands the phenotypic spectrum of TPM3-related disease and provides insights into the pathophysiological mechanisms of the actin-tropomyosin complex.
Authors: Elmar Behrmann; Mirco Müller; Pawel A Penczek; Hans Georg Mannherz; Dietmar J Manstein; Stefan Raunser Journal: Cell Date: 2012-07-20 Impact factor: 41.582
Authors: Coen A C Ottenheijm; Pleuni Hooijman; Elizabeth T DeChene; Ger J Stienen; Alan H Beggs; Henk Granzier Journal: J Struct Biol Date: 2009-11-26 Impact factor: 2.867
Authors: Coen A C Ottenheijm; Christian C Witt; Ger J Stienen; Siegfried Labeit; Alan H Beggs; Henk Granzier Journal: Hum Mol Genet Date: 2009-04-04 Impact factor: 6.150
Authors: D Wattanasirichaigoon; K J Swoboda; F Takada; H-Q Tong; V Lip; S T Iannaccone; C Wallgren-Pettersson; N G Laing; A H Beggs Journal: Neurology Date: 2002-08-27 Impact factor: 9.910
Authors: Gerrie P Farman; Michael J Rynkiewicz; Marek Orzechowski; William Lehman; Jeffrey R Moore Journal: Arch Biochem Biophys Date: 2018-04-05 Impact factor: 4.013
Authors: Barbara Joureau; Josine Marieke de Winter; Stefan Conijn; Sylvia J P Bogaards; Igor Kovacevic; Albert Kalganov; Malin Persson; Johan Lindqvist; Ger J M Stienen; Thomas C Irving; Weikang Ma; Michaela Yuen; Nigel F Clarke; Dilson E Rassier; Edoardo Malfatti; Norma B Romero; Alan H Beggs; Coen A C Ottenheijm Journal: Ann Neurol Date: 2018-02-06 Impact factor: 10.422
Authors: Ingrid Bader; M Freilinger; F Landauer; S Waldmüller; W Mueller-Felber; C Rauscher; W Sperl; R E Bittner; W M Schmidt; J A Mayr Journal: Orphanet J Rare Dis Date: 2022-07-19 Impact factor: 4.303