Freeze-fracture evidence for the presence of cholesterol in particle-free patches of basal disks and the plasma membrane of retinal rod outer segments of mice and frogs.
Freeze-fracture evidence for the presence of cholesterol in particle-free patches of basal disks and the plasma membrane of retinal rod outer segments of mice and frogs.
复制标题
冻结裂纹证据证明了基底盘的无颗粒斑块以及小鼠和青蛙的视网膜外部片段的质膜中存在胆固醇。
DOI：
10.1083/jcb.81.1.215
复制
发表时间：
1979-04
影响因子：
7.8
通讯作者：
Cohen, A I
中科院分区：
文献类型：
--
作者：
Andrews, L D;Cohen, A I
冷冻断裂技术被用来检查小鼠和青蛙的光感受器的膜。在室温下饲养的小鼠和青蛙的外节的质膜和基底盘膜中发现无颗粒斑块，但在冷藏室中饲养的青蛙中没有。这些补丁被证明不是文物的冷冻保护或固定，他们坚持新鲜分离的外段冷冻时，通过超快速方法。当视网膜被孵育并随后在高达80摄氏度的温度下固定时，它们也被发现存在于小鼠视杆中。通过观察发现，胆固醇是贴剂的重要组分，在外节段中，由固醇特异性多烯抗生素filipin处理诱导的凹陷存在于并局限于无颗粒贴剂中。这些病变并不固有地局限于无颗粒膜区域，这在感光器内节的顶端质膜中是明显的，其中颗粒和凹坑混合在一起。用皂苷（一种专门与胆固醇复合的表面活性剂）治疗，导致无颗粒斑块消失。补丁被发现在基底盘的小鼠和青蛙杆，但不是在较老的磁盘更接近色素上皮，这表明发生的变化，在组成的磁盘膜和/或在其蛋白质和脂质成分的分子排序的早期阶段，他们从基地向顶点的外段。
The freeze-fracture technique was used to examine the membranes of the photoreceptors of mice and frogs. Particle-free patches were found in the plasma membrane and basal disk membranes of the outer segments of both mice and frogs housed at room temperature, but not in frogs kept in a cold room. These patches were shown not to be artifacts of cryoprotection or fixation, and they persisted when fresh isolated outer segments were frozen by an ultrarapid method. They were also found to persist in mouse rods when retinas were incubated and subsequently fixed at temperatures up to 80 degrees C. Cholesterol was implicated as a significant component of the patches by the observation that, in the outer segments, pits, induced by treatment with the sterol- specific polyene antibiotic filipin, were present in and confined to the particle-free patches. That these lesions are not inherently limited to particle-free membrane areas was evident in the apical plasma membrane of the photoreceptor inner segments, where particles and pits were intermixed. Treatment with saponin, a surface-active agent which specifically complexes cholesterol, resulted in the disappearance of the particle-free patches. Patches were found in basal disks of both mouse and frog rods but not in older disks nearer the pigment epithelium, which indicates that changes occur in the composition of disk membranes and/or in the molecular ordering of their protein and lipid components during the early phase of their transit from the base towards the apex of the outer segment.