Jorgensen A O, Shen A C, Daly P, MacLennan D H
J Cell Biol. 1982 Jun;93(3):883-92. doi: 10.1083/jcb.93.3.883.
Localization of the Ca2+ + Mg2+-ATPase of the sarcoplasmic reticulum in rat papillary muscle was determined by indirect immunofluorescence and immunoferritin labeling of cryostat and ultracryotomy sections, respectively. The Ca2+ + Mg2+-ATPase was found to be rather uniformly distributed in the free sarcoplasmic reticulum membrane but to be absent from both peripheral and interior junctional sarcoplasmic reticulum membrane, transverse tubules, sarcolemma, and mitochondria. This suggests that the Ca2+ + Mg2+-ATPase of the sarcoplasmic reticulum is antigenically unrelated to the Ca2+ + Mg2+-ATPase of the sarcolemma. These results are in agreement with the idea that the sites of interior and peripheral coupling between sarcoplasmic reticulum membrane and transverse tubules and between sarcoplasmic reticulum and sarcolemmal membranes play the same functional role in the excitation-contraction coupling in cardiac muscle.
分别通过对冰冻切片和超薄冰冻切片进行间接免疫荧光和免疫铁蛋白标记，来确定大鼠乳头肌肌浆网Ca2+ + Mg2+-ATP酶的定位。结果发现，Ca2+ + Mg2+-ATP酶相当均匀地分布于游离的肌浆网膜中，但在周边和内部连接肌浆网膜、横小管、肌膜及线粒体中均未发现。这表明肌浆网的Ca2+ + Mg2+-ATP酶与肌膜的Ca2+ + Mg2+-ATP酶在抗原性上无关。这些结果与以下观点一致，即肌浆网膜与横小管之间以及肌浆网与肌膜之间的内部和周边偶联位点在心肌兴奋-收缩偶联中发挥相同的功能作用。
