title: Effect of Ca++ on triphosphoinositide extraction in fusing myoblasts.
abstract: Ca++-dependent degradation of triphosphoinositide has been postulated to regulate levels of membrane-bound Ca++ and to generate a 1,2-diacylglycerol fusogen in cell fusion. Triphosphoinositide metabolism was therefore studied during Ca++-induced fusion of cultured chick embryo myoblasts. Using a frequently cited extraction procedure, it was found that apparent Ca++-dependent triphosphoinositide degradation was actually due to inhibition of extraction. A new procedure using the ion-pairing reagent tetrabutylammonium sulfate was developed which was unaffected by Ca++ and gave 2- to 20-fold greater extraction of triphosphoinositide than existing procedures. With this procedure, no changes in triphosphoinositide metabolism were found during myoblast fusion.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002413:Cations, Divalent; D002459:Cell Fusion / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D009132:Muscles / Q000032:analysis / Q000166:cytology / Q000196:embryology*; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; C018803:triphosphoinositide; D002118:Calcium