Microinjection of calpastatin inhibits fusion in myoblasts

Constance J. Temm-Grove, David Wert, V. F. Thompson, R. E. Allen, Darrel E. Goll

Research output: Contribution to journalArticle

60 Scopus citations

Abstract

Rat satellite cells (RSC) were microinjected with purified calpastatin or m-calpain, and myoblasts from a C2C12 mouse line were microinjected with purified calpastatin. Microinjection with calpastatin completely prevented fusion of myoblasts from both sources, whereas microinjection with m-calpain significantly increased the rate of fusion of cultured RSC; 44% of the nuclei of RSC cultures were in multinucleated myotubes within 48 h after microinjection with m-calpain plus labeled dextran, whereas only 15% of the nuclei were in multinucleated myotubes after microinjection with dextran alone. Western analyses indicated that neither RSC nor C2C12 myoblasts contained detectable amounts of μ-calpain before fusion. The levels of calpastatin in C2C12 myoblasts increased as cells passed from the proliferative stage to the onset of fusion, and these levels increased substantially in both the C2C12 and the RSC cells as they progressed to the late or postfusion stage. Both RSC and C2C12 myoblasts contained an 80-kDa polypeptide that was labeled with an anti-m-calpain antibody in Western blots. The results are consistent with a role of the calpain system (m-calpain in these myoblast lines) in remodeling of the cytoskeletal/plasma membrane interactions during cell fusion.

Original languageEnglish (US)
Pages (from-to)293-303
Number of pages11
JournalExperimental Cell Research
Volume247
Issue number1
DOIs
StatePublished - Feb 25 1999

Keywords

  • Calpain
  • Calpastatin
  • Microinjection
  • Myoblast fusion
  • Satellite cells

ASJC Scopus subject areas

  • Cell Biology

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