Skeletal muscle cells express different isoforms of the calcium channel alpha2/delta subunit.
We examined developmental changes in calcium channel alpha2/delta subunit mRNA in skeletal muscle and their possible influence on L-type calcium currents (ICa-L). Several isoforms of alpha2/delta-1 mRNA were found in myotubes and muscle fibers, and their relative levels changed with time in culture or age of the animal. Levels of alpha2/delta-1a were largest in older myotubes and was the only alpha2/delta-1 isoform present in adult muscle. Both myotubes and muscle fibers also expressed low levels of alpha2/delta-2 and alpha2/delta-3 mRNA at all ages. alpha2/delta-4 mRNA could not be detected in either myotubes or muscle fibers. Changes in amplitude and voltage-dependent inactivation of the ICa-L concurred with the shift in alpha2/delta-1 isoform message, suggesting that alternative splicing of this subunit might be important for modulation of ICa-L.
Nabhani
Thomas
T
Department of Physiology and Biophysics, University of Illinois at Chicago College of Medicine, 835 South Wolcott Avenue, Chicago, IL 60612, USA.
Shah
Tanvi
T
García
Jesús
J
D000818:Animals; D001483:Base Sequence; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D015870:Gene Expression; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology* / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
C486058:Cacna2d2 protein, mouse; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020033:Protein Isoforms; D012333:RNA, Messenger