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Updated: Sep 25, 2026

Isolation of Human Myoblasts, Assessment of Myogenic Differentiation, and Store-operated Calcium Entry Measurement
Published on: July 26, 2017
Acceleration of human myoblast fusion by depolarization: graded Ca2+ signals involved
Jian-Hui Liu1, Stéphane König, Marlène Michel
1Département de Physiologie, Centre Médical Universitaire, Hôpital Cantonal Universitaire, CH-1211 Geneva 4, Switzerland.
Abstract:
We have previously shown that human myoblasts do not fuse when their voltage fails to reach the domain of a window T-type Ca(2+) current. We demonstrate, by changing the voltage in the window domain, that the Ca(2+) signal initiating fusion is not of the all-or-none type, but can be graded and is interpreted as such by the differentiation program. This was carried out by exploiting the properties of human ether-à-go-go related gene K(+) channels that we found to be expressed in human myoblasts. Methanesulfonanilide class III antiarrhythmic agents or antisense-RNA vectors were used to suppress completely ether-à-go-go related gene current. Both procedures induced a reproducible depolarization from -74 to -64 mV, precisely in the window domain where the T-type Ca(2+) current increases with voltage. This 10 mV depolarization raised the cytoplasmic free Ca(2+) concentration, and triggered a tenfold acceleration of myoblast fusion. Our results suggest that any mechanism able to modulate intracellular Ca(2+) concentration could affect the rate of myoblast fusion.
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