Comparison of M-line and other myofibril components during reversible phorbol ester treatment.

T. C. Doetschman, H. M. Eppenberger

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


The events occurring during phorbol ester mediated destruction of myofibrils in differentiated muscle cells were followed at the fluorescence and electron microscope levels using antibodies which bind troponin-T, a newly discovered 185 000 dalton M-line protein called myomesin and muscle type creatine kinase. The following series of events is proposed. Within one day of phorbol ester treatment, Z-bands and thin filaments, including troponin-T, are absent from many myofibrils resulting in the rapid loss of longitudinal and lateral alignment. A-bands become randomly oriented and clustered into ever smaller compartments within the rounding, myosac-like, multinucleated cells until after 3 days of treatment they too disappear. The M-line proteins are always present in existing A-bands. These results suggest that the Z-band and associated structures are responsible for the maintenance of alignment and the lateral register of myofibrils, whereas the M-line is responsible for the structural integrity of the A-band. When phorbol ester is removed, the cells revert to a myotube morphology and within 2 to 3 days are filled with myofibrils. A comparison of the appearance of troponin-T and the 185 000 dalton myomesin in the recovery period to their appearance during normal myofibrillogenesis reveals that these proteins are more temporally co-ordinated during myofibrillogenesis than in the phorbol ester experimental system.

Original languageEnglish (US)
Pages (from-to)265-274
Number of pages10
JournalEuropean Journal of Cell Biology
Issue number2
StatePublished - Mar 1984

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology


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