T-type α1H Ca2+ channels are involved in Ca2+ signaling during terminal differentiation (fusion) of human myoblasts
Abstract
Mechanisms underlying Ca2+ signaling during human myoblast terminal differentiation were studied using cell cultures. We found that T-type Ca2+ channels (T-channels) are expressed in myoblasts just before fusion. Their inhibition by amiloride or Ni2+ suppresses fusion and prevents an intracellular Ca2+ concentration increase normally observed at the onset of fusion. The use of antisense oligonucleotides indicates that the functional T-channels are formed by α1H subunits. At hyperpolarized potentials, these channels allow a window current sufficient to increase [Ca2+]i. As hyperpolarization is a prerequisite to myoblast fusion, we conclude that the Ca2+ signal required for fusion is produced when the resting potential enters the T-channel window. A similar mechanism could operate in other cell types of which differentiation implicates membrane hyperpolarization.
- Publication:
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Proceedings of the National Academy of Science
- Pub Date:
- June 2000
- DOI:
- 10.1073/pnas.97.13.7627
- Bibcode:
- 2000PNAS...97.7627B
- Keywords:
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- Physiology