Dstac Regulates Excitation-Contraction Coupling Indrosophilabody Wall Muscles

Stac3 regulates excitation-contraction coupling (EC coupling) in vertebrate skeletal muscles by regulating the L-type voltage-gated calcium channel (Ca(v)channel). Recently astac-like gene,Dstac, was identified inDrosophilaand found to be expressed by both a subset of neurons and muscles. Here, we show that Dstac and Dmca1D, theDrosophilaL-type Ca(v)channel, are necessary for normal locomotion by larvae. Immunolabeling with specific antibodies against Dstac and Dmca1D found that Dstac and Dmca1D are expressed by larval body-wall muscles. Furthermore, Ca(2+)imaging of muscles of Dstac and Dmca1D deficient larvae found that Dstac and Dmca1D are required for excitation-contraction coupling. Finally, Dstac appears to be required for normal expression levels of Dmca1D in body-wall muscles. These results suggest that Dstac regulates Dmca1D during EC coupling and thus muscle contraction.