Phosphatidylinositol 4,5-biphosphate stimulates parotid endoplasmic reticulum (Ca2+ + Mg2+)-ATP'ase.
The effect of various phospholipids on the (Ca2+ + Mg2+)-ATP'ase of rat parotid endoplasmic reticulum was investigated. At a concentration of 20 micrograms/ml, phosphatidylinositol 4,5-biphosphate stimulated the Ca2+-activated ATP'ase by 69%. None of the other phospholipids tested or 10 microM inositol 1,4,5-triphosphate had any significant effect on the ATP'ase. Stimulation by phosphatidylinositol 4,5-biphosphate was concentration dependent and half maximal stimulation required 8 micrograms/ml of the phospholipid. The results suggest that changes in the cellular concentration of phosphatidylinositol 4,5-biphosphate may be of importance in regulating Ca2+ transport by the endoplasmic reticulum.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004789:Enzyme Activation / Q000187:drug effects; D010306:Parotid Gland / Q000201:enzymology*; D010716:Phosphatidylinositols / Q000494:pharmacology*; D010743:Phospholipids / Q000494:pharmacology; D051381:Rats
D010716:Phosphatidylinositols; D010743:Phospholipids; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium