Inositol phospholipid metabolism and myoblast fusion.
The fusion of chick embryonic myoblasts has been studied in tissue culture. Myoblasts are maintained at 0.1 microM-Ca2+ for 50 h. During this time they achieve fusion competence. Fusion is initiated by raising the medium Ca2+ concentration to 1.4 mM. A rapid breakdown of the polyphosphoinositides was detected within 3 min of Ca2+ addition. Rapid synthesis of phosphatidic acid was also detected at this time. Breakdown of phosphatidylinositol and synthesis of 1,2-diacylglycerol were also detected. Other phospholipids were unaffected. Sr2+ could replace Ca2+ in this process but Mg2+ could not and also inhibited the Ca2+ effect. The Ca2+-ionophore A23187 stimulated further apparent polyphosphoinositide breakdown in the presence of Ca2+. 6. The results are discussed with respect to myoblast fusion.
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D002459:Cell Fusion; D002478:Cells, Cultured; D002642:Chick Embryo; D050356:Lipid Metabolism; D009132:Muscles / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism*
D002413:Cations, Divalent; D010716:Phosphatidylinositols; D000001:Calcimycin; D002118:Calcium