Morris C E
Neurosciences, Ottawa Health Research Institute, Ottawa Hospital, 725 Parkdale Ave, Ottawa, Ontario, Canada K1Y 4K9.
Cell Mol Biol Lett. 2001;6(3):703-20.
Though the cytomechanics of spectrin have been explored only for erythrocytes, it is thought that the spectrin skeleton acts universally to support the otherwise mechanically vulnerable cell surface bilayer. Evidence for this role is beginning to accumulate and is reviewed here. Compared to that for erythrocytes, cells whose simplicity facilitates biophysical approaches, the evidence is indirect. One way that membrane skeleton/bilayer interactions have been probed is via the behavior of mechanosusceptible ion channels - channel whose gating is perturbed by abnormally high bilayer tension. These initially unresponsive channels become progressively more mechanoresponsive as stretch and chemical reagents damage the membrane skeleton. The straightforward implication is that the intact membrane skeleton is mechanoprotective. In non-erythroid cells there is continual trafficking of bilayer to and from the plasma membrane. Some of the traffic involves spectrin-lined vacuolar membrane. Several lines of evidence suggest that when neurons elongate and remodel their neurites, membrane skeleton-based mechanoprotection allows the dynamic vacuoles and the plasma membrane to participate in mechanosensitive surface area expansion and retrieval.
尽管血影蛋白的细胞力学仅在红细胞中得到研究,但人们认为血影蛋白骨架普遍发挥作用,以支撑原本在机械方面较为脆弱的细胞表面双层膜。这一作用的证据开始不断积累,本文对此进行综述。与红细胞相比,红细胞结构简单,便于采用生物物理方法研究,而对于其他细胞,相关证据是间接的。探测膜骨架/双层膜相互作用的一种方法是通过机械敏感离子通道的行为——这类通道的门控会因异常高的双层膜张力而受到干扰。随着拉伸和化学试剂对膜骨架造成损伤,这些最初无反应的通道会逐渐变得对机械刺激更敏感。直接的推断是完整的膜骨架具有机械保护作用。在非红细胞中,双层膜不断在质膜与其他部位之间运输。其中一些运输涉及由血影蛋白排列的液泡膜。几条证据表明,当神经元伸长并重塑其神经突时,基于膜骨架的机械保护作用使动态液泡和质膜能够参与机械敏感的表面积扩展和回收。