Dubreuil R R, Bouck G B
J Cell Biol. 1985 Nov;101(5 Pt 1):1884-96. doi: 10.1083/jcb.101.5.1884.
In this paper we show that a membrane skeleton associated with the plasma membrane of the unicellular organism Euglena consists of approximately 40 individual S-shaped strips that overlap along their lateral margins. The region of strip overlap is occupied by a set of microtubule-associated bridges and microtubule-independent bridges. Both cell form and plasma membrane organization are dependent on the integrity of this membrane skeleton. Removal of the membrane skeleton with a low-molar base results in loss of membrane form and randomization of the paracrystalline membrane interior characteristic of untreated cells. Conversely, removal of the plasma membrane and residual cytoplasm with lithium 3,5-diiodosalicylate/Nonidet P-40 yields cell ghosts that retain the form of the original cell but consist only of the membrane skeleton. Two major polypeptides of 86 and 80 KD persist in the skeleton and two other major proteins of 68 and 39 kD are associated with the plasma membrane fraction. None of these components appears to be the same as the major polypeptides (spectrins, band 3) of the erythrocyte ghost, the other cell system in which a well-defined peripheral membrane skeleton has been identified. We suggest that the articulating strips of euglenoids are not only the basic unit of cell and surface form, but that they are also positioned to mediate or accommodate surface movements by sliding, and to permit surface replication by intussusception.
在本文中，我们表明，与单细胞生物眼虫的质膜相关的膜骨架由大约40条单独的S形条带组成，这些条带沿其侧缘重叠。条带重叠区域被一组微管相关桥和微管非依赖桥占据。细胞形态和质膜组织都依赖于这种膜骨架的完整性。用低摩尔碱去除膜骨架会导致膜形态丧失以及未处理细胞中典型的准晶体膜内部的随机化。相反，用3,5 - 二碘水杨酸锂/聚山梨醇酯 - 40去除质膜和残留细胞质会产生细胞空壳，其保留了原始细胞的形态，但仅由膜骨架组成。86和80 KD的两种主要多肽在骨架中持续存在，另外两种68和39 kD的主要蛋白质与质膜部分相关。这些成分似乎都与红细胞空壳的主要多肽（血影蛋白、带3）不同，红细胞空壳是另一种已鉴定出明确外周膜骨架的细胞系统。我们认为，眼虫类的连接条带不仅是细胞和表面形态的基本单位，而且它们的位置还能通过滑动介导或适应表面运动，并通过套叠允许表面复制。
