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Acceleration of human myoblast fusion by depolarization: graded Ca2+ signals involved

Liu, J. H.
Published in Development. 2003, vol. 130, no. 15, p. 3437-3446
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-a-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-a-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.
Keywords Calcium/ metabolismCation Transport ProteinsCell FusionCytoplasm/physiologyDNA-Binding ProteinsEther-A-Go-Go Potassium ChannelsHumansMembrane Potentials/physiologyMuscle Development/physiologyMyoblasts/ metabolismPotassium Channels/metabolismPotassium Channels, Voltage-GatedTrans-Activators
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Other version: http://dev.biologists.org/content/130/15/3437.full.pdf
PMID: 12810591
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