Abstract
Nemaline myopathy (NM) is the most common congenital myopathy and is caused by mutations in various genes including NEB (nebulin), TPM2 (beta-tropomyosin), TPM3 (gamma-tropomyosin), and ACTA1 (skeletal alpha-actin). 20–25% of NM cases carry ACTA1 defects and these particular mutations usually induce substitutions of single residues in the actin protein. Despite increasing clinical and scientific interest, the contractile consequences of these subtle amino acid substitutions remain obscure. To decipher them, in the present study, we originally recorded and analysed the mechanics as well as the X-ray diffraction patterns of human membrane-permeabilized single muscle fibres with a particular peptide substitution in actin, i.e. p.Phe352Ser. Results unravelled an unexpected cascade of molecular and cellular events. During contraction, p.Phe352Ser greatly enhances the strain of individual cross-bridges. Paradoxically, p.Phe352Ser also slightly lowers the number of cross-bridges by altering the rate of myosin head attachment to actin monomers. Overall, at the cell level, these divergent mechanisms conduct to an improved steady-state force production. Such results provide new surprising scientific insights and crucial information for future therapeutic strategies.
References
Brenner B (1988) Effect of Ca2 + on cross-bridge turnover kinetics in skinned single rabbit psoas fibers: implications for regulation of muscle contraction. Proc Natl Acad Sci USA 85(9):3265–3269
Brenner B, Eisenberg E (1986) Rate of force generation in muscle: correlation with actomyosin ATPase activity in solution. Proc Natl Acad Sci USA 83(10):3542–3546
Cooke R, Franks K (1980) All myosin heads form bonds with actin in rigor rabbit skeletal muscle. Biochemistry 19(10):2265–2269
Edman KA (1979) The velocity of unloaded shortening and its relation to sarcomere length and isometric force in vertebrate muscle fibres. J Physiol 291:143–159
Feng JJ, Marston S (2009) Genotype-phenotype correlations in ACTA1 mutations that cause congenital myopathies. Neuromuscul Disord 19(1):6–16
Frontera WR, Larsson L (1997) Contractile studies of single human skeletal muscle fibers: a comparison of different muscles, permeabilization procedures, and storage techniques. Muscle Nerve 20(8):948–952
Huxley AF (1957) Muscle structure and theories of contraction. Prog Biophys Biophys Chem 7:255–318
Laing NG, Dye DE, Wallgren-Pettersson C, Richard G, Monnier N, Lillis S, Winder TL, Lochmuller H, Graziano C, Mitrani-Rosenbaum S, Twomey D, Sparrow JC, Beggs AH, Nowak KJ (2009) Mutations and polymorphisms of the skeletal muscle alpha-actin gene (ACTA1). Hum Mutat 30(9):1267–1277
Li M, Larsson L (2011) Force-generating capacity of human myosin isoforms extracted from single muscle fibre segments. J Physiol 588:5105–5114
Li XE, Tobacman LS, Mun JY, Craig R, Fischer S, Lehman W (2011) Tropomyosin position on F-actin revealed by EM reconstruction and computational chemistry. Biophys J 100(4):1005–1013
Lorenz M, Holmes KC (2011) The actin-myosin interface. Proc Natl Acad Sci USA 107(28):12529–12534
Marston S, Mirza M, Abdulrazzak H, Sewry C (2004) Functional characterisation of a mutant actin (Met132Val) from a patient with nemaline myopathy. Neuromuscul Disord 14(2):167–174
Moss RL, Razumova M, Fitzsimons DP (2004) Myosin crossbridge activation of cardiac thin filaments: implications for myocardial function in health and disease. Circ Res 94(10):1290–1300
Ochala J, Iwamoto H, Larsson L, Yagi N (2010) A myopathy-linked tropomyosin mutation severely alters thin filament conformational changes during activation. Proc Natl Acad Sci USA 107(21):9807–9812
Ochala J, Lehtokari VL, Iwamoto H, Li M, Feng HZ, Jin JP, Yagi N, Wallgren-Pettersson C, Penisson-Besnier I, Larsson L (2011) Disrupted myosin cross-bridge cycling kinetics triggers muscle weakness in nebulin-related myopathy. FASEB J 25(6):1903–1913
Ochala J, Li M, Ohlsson M, Oldfors A, Larsson L (2008) Defective regulation of contractile function in muscle fibres carrying an E41 K beta-tropomyosin mutation. J Physiol 586:2993–3004
Ottenheijm CA, Lawlor MW, Stienen GJ, Granzier H, Beggs AH (2011) Changes in cross-bridge cycling underlie muscle weakness in patients with tropomyosin 3-based myopathy. Hum Mol Genet 20(10):2015–2025
Ottenheijm CA, Witt CC, Stienen GJ, Labeit S, Beggs AH, Granzier H (2009) Thin filament length dysregulation contributes to muscle weakness in nemaline myopathy patients with nebulin deficiency. Hum Mol Genet 18(13):2359–2369
Pardee JD, Spudich JA (1982) Purification of muscle actin. Methods Cell Biol 24:271–289
Penisson-Besnier I, Monnier N, Toutain A, Dubas F, Laing N (2007) A second pedigree with autosomal dominant nemaline myopathy caused by TPM3 mutation: a clinical and pathological study. Neuromuscul Disord 17(4):330–337
Pettersen EF, Goddard TD, Huang CC, Couch GS, Greenblatt DM, Meng EC, Ferrin TE (2004) UCSF Chimera: a visualization system for exploratory research and analysis. J Comput Chem 25(13):1605–1612
Ravenscroft G, Jackaman C, Bringans S, Papadimitriou JM, Griffiths LM, McNamara E, Bakker AJ, Davies KE, Laing NG, Nowak KJ (2011) Mouse models of dominant ACTA1 disease recapitulate human disease and provide insight into therapies. Brain 134:1101–1115
Sambuughin N, Yau KS, Olive M, Duff RM, Bayarsaikhan M, Lu S, Gonzalez-Mera L, Sivadorai P, Nowak KJ, Ravenscroft G, Mastaglia FL, North KN, Ilkovski B, Kremer H, Lammens M, van Engelen BG, Fabian V, Lamont P, Davis MR, Laing NG, Goldfarb LG (2010) Dominant mutations in KBTBD13, a member of the BTB/Kelch family, cause nemaline myopathy with cores. Am J Hum Genet 87(6):842–847
Sanoudou D, Beggs AH (2001) Clinical and genetic heterogeneity in nemaline myopathy–a disease of skeletal muscle thin filaments. Trends Mol Med 7(8):362–368
Acknowledgments
The authors are grateful to Dr P. Marcorelles for the electron microscopy study; Y. Hedström, C. Dumez and I. Viau for excellent technical assistance. The authors also would like to thank Prof. N.G. Laing and Dr. K. Nowak for the genetic analysis, Dr. M. Lorenz for providing the Actomyosin model. This study was supported by grants from the Swedish Research Council and from and Harald och Greta Jeanssons Stiftelse to J.O and was performed under approval of the SPring-8 Proposal Review Committee (2011A1042).
Conflict of interest
The authors declare no conflict of interest.
Author information
Authors and Affiliations
Corresponding author
Additional information
The authors J. Lindqvist, I. Pénisson-Besnier and H. Iwamoto contributed equally to the present manuscript.
Electronic supplementary material
Below is the link to the electronic supplementary material.
Rights and permissions
About this article
Cite this article
Lindqvist, J., Pénisson-Besnier, I., Iwamoto, H. et al. A myopathy-related actin mutation increases contractile function. Acta Neuropathol 123, 739–746 (2012). https://doi.org/10.1007/s00401-012-0962-z
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00401-012-0962-z