Role of troponin I isoform switching in determining the pH sensitivity of Ca2+ regulation in developing rabbit cardiac muscle

Sachio Morimoto, Takako Goto

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

Skinned muscle fibers prepared from fetal rabbit heart (28 days of gestation) showed a marked resistance to acidic pH in the Ca2+ regulation of force generation, compared to the fibers prepared from adult heart. SDS-PAGE and immunoblot analysis showed that the slow skeletal troponin I was predominantly expressed in the fetal cardiac muscle, while the cardiac isoform was predominantly expressed in the adult cardiac muscle. Direct exchange of purified slow skeletal and cardiac troponin I isoforms into these skinned muscle fibers revealed that cardiac troponin I made the Ca2+ regulation of contraction sensitive to acidic pH just as in the adult fibers, whereas slow skeletal troponin I made the Ca2+ regulation of contraction resistant to acidic pH just as in the fetal fibers. These results demonstrate that the troponin I isoform switching accounts fully for the change in the pH dependence of Ca2+ regulation of contraction in developmental cardiac muscle. (C) 2000 Academic Press.

Original languageEnglish
Pages (from-to)912-917
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume267
Issue number3
DOIs
Publication statusPublished - Jan 27 2000

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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