Effects of thiol protease inhibitors on myoblast fusion and myofibril assembly in vitro

Carole L. Monoman, Kuan Wang

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


To investigate the roles of thiol proteases such as cathepsins and calpains in muscle differentiation, we have treated primary cultures of pectoralis muscle with a variety of protease inhibitors and examined the effects these agents have on myoblast fusion and myofibrillogenesis. We have found that a membrane-permeable inhibitor, E64D, has dramatic effects on both events of muscle differentiation. Cells treated with this inhibitor display gross morphological changes, severe delays in myofibril assembly, and reduced ability to fuse in culture. These morphological changes are correlated with a build up of β1-integrin throughout the cytoplasm. These effects could also be produced using NH4Cl, a lysosomotrophic agent. In addition, we show that two nonpermeable inhibitors (leupeptin and E64) slightly decrease myoblast fusion, but have no effects on the ability of the cells to form mature myofibrils. These results are discussed in terms of their relevance to the inheritable disease of muscular dystrophy and I-cell disease (mucolipodosis II).

Original languageEnglish
Pages (from-to)354-367
Number of pages14
JournalCell Motility and the Cytoskeleton
Issue number4
Publication statusPublished - 1998
Externally publishedYes


  • Confocal microscopy
  • Dystrophin
  • Integrins
  • Myoblast fusion
  • Myofibril assembly

ASJC Scopus subject areas

  • Structural Biology
  • Cell Biology


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