Solubilization and separation of Ca2+-ATPase from the Ca2+-ryanodine receptor complex.
Heavy sarcoplasmic reticulum (SR) preparations of rabbit skeletal muscle, which are enriched in Ca2+-release vesicles from the terminal cisternae (TC) and [3H]ryanodine receptor density, exhibit 60% of the Ca2+-ATPase activity, 58% of the EP level, and 30% of the steady state Ca2+ loading compared to membrane vesicles from the longitudinal SR. The Ca2+-ATPase of TC SR is solubilized and separated from the Ca2+-ryanodine receptor complex in the insoluble fraction on treatment with the detergent C12E9. However, a 50% decrease in receptor density is observed upon removal of the Ca2+-ATPase, suggesting a significant contribution of this protein to maintaining optimal receptor complex density.
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000032:analysis; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000032:analysis / Q000302:isolation & purification*; D011817:Rabbits; D011950:Receptors, Cholinergic / Q000032:analysis*; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D012995:Solubility
D011950:Receptors, Cholinergic; D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium