Calsequestrin is a major binding protein of myotoxin alpha and an endogenous Ca2+ releaser in sarcoplasmic reticulum.
Myotoxin alpha from prairie rattlesnakes induced Ca2+ release from the heavy fraction of sarcoplasmic reticulum at submicromolar concentrations. 125I-Labeled myotoxin alpha (125I-myotoxin alpha) specifically bound to the heavy fraction. Fractionation of the solubilized heavy fraction with a spermine-agarose column gave purified calsequestrin as a major binding protein of 125I-myotoxin alpha. We have first indicated that calsequestrin is a target protein for Ca(2+)-releasing action of myotoxin alpha. Calsequestrin probably plays a key role in physiological Ca2+ release from sarcoplasmic reticulum.
Ohkura
M
M
Department of Pharmaceutical Molecular Biology, Tohoku University, Sendai, Japan.
Furukawa
K
K
Tu
A T
AT
Ohizumi
Y
Y
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002155:Calsequestrin / Q000378:metabolism*; D003435:Crotalid Venoms / Q000378:metabolism*; D017839:Crotalus; D011485:Protein Binding; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
D002155:Calsequestrin; D003435:Crotalid Venoms; C018932:myotoxin A; D002118:Calcium