Tsukita S, Tsukita S, Matsumoto G
Department of Ultrastructural Research, Tokyo Metropolitan Institute of Medical Science, Japan.
J Cell Biol. 1988 Apr;106(4):1151-60. doi: 10.1083/jcb.106.4.1151.
The cytoskeleton in squid photoreceptor microvilli was studied by freeze-substitution electron microscopy combined with rapid freezing using liquid helium, under dark-adapted and light-illuminated conditions. In the dark-adapted microvilli, actin filaments were regularly associated with granular structures on their surface; these granular structures were cross-linked to the rhodopsin-bearing plasma membranes through slender strands. Upon exposure to light, the granular components detached from the actin filaments, which then appeared to be fragmented and/or depolymerized. These observations have led us to conclude that light stimulation triggers the breakdown of the microvillar actin filament complex in squid photoreceptor cells. The results are discussed with special reference to the physiological role of actin filaments in photoreception.
利用液氦快速冷冻结合冷冻置换电子显微镜技术,在暗适应和光照条件下,对鱿鱼光感受器微绒毛中的细胞骨架进行了研究。在暗适应的微绒毛中,肌动蛋白丝在其表面与颗粒结构规则地相关联;这些颗粒结构通过细链与含视紫红质的质膜交联。暴露于光下后,颗粒成分从肌动蛋白丝上分离,然后肌动蛋白丝似乎发生了断裂和/或解聚。这些观察结果使我们得出结论,光刺激触发了鱿鱼光感受器细胞中微绒毛肌动蛋白丝复合物的分解。结合肌动蛋白丝在光感受中的生理作用,对结果进行了讨论。