Myopathy-causing Q147P TPM2 mutation shifts tropomyosin strands further towards the open position and increases the proportion of strong-binding cross-bridges during the ATPase cycle

O. E. Karpicheva, A. O. Simonyan, N. V. Kuleva, C. S. Redwood, Y. S. Borovikov

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The molecular mechanisms of skeletal muscle dysfunction in congenital myopathies remain unclear. The present study examines the effect of a myopathy-causing mutation Q147P in β-tropomyosin on the position of tropomyosin on troponin-free filaments and on the actin–myosin interaction at different stages of the ATP hydrolysis cycle using the technique of polarized fluorimetry. Wild-type and Q147P recombinant tropomyosins, actin, and myosin subfragment-1 were modified by 5-IAF, 1,5-IAEDANS or FITC-phalloidin, and 1,5-IAEDANS, respectively, and incorporated into single ghost muscle fibers, containing predominantly actin filaments which were free of troponin and tropomyosin. Despite its reduced affinity for actin in co-sedimentation assay, the Q147P mutant incorporates into the muscle fiber. However, compared to wild-type tropomyosin, it locates closer to the center of the actin filament. The mutant tropomyosin increases the proportion of the strong-binding myosin heads and disrupts the co-operation of actin and my
Original languageEnglish
Pages (from-to)260-267
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1864
Issue number3
DOIs
StatePublished - 2016

Keywords

  • β-Tropomyosin
  • Actin
  • Myosin head
  • Ghost muscle fiber
  • Congenital myopathy
  • Polarized fluorescence

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