Stidwill R P, Wysolmerski T, Burgess D R
J Cell Biol. 1984 Feb;98(2):641-5. doi: 10.1083/jcb.98.2.641.
The shape and stability of intestinal epithelial cell microvilli are maintained by a cytoskeletal core composed of a bundle of actin filaments with several associated proteins. The core filaments are intimately associated with the overlying plasma membrane, in which there occur rapid turnover of proteins and constant incorporation of new membrane. Previous work has shown that starvation or inhibition of protein synthesis results in modulation of microvillar length, which indicates that there may be cytoskeletal protein turnover. We demonstrate herein, by means of in vivo pulse labeling with radioactive amino acids, that turnover of brush border cytoskeletal proteins occurs in mature absorptive cells. Turnover of cytoskeletal proteins appears to be quite slow relative to membrane protein turnover, which suggests that the turnover of these two microvillar compartments is not coupled. We thus conclude that cytoskeletal protein turnover may be a factor used to maintain normal length and stability of microvilli and that the cytoskeleton cannot be considered a static structure.
肠道上皮细胞微绒毛的形状和稳定性由一个细胞骨架核心维持，该核心由一束肌动蛋白丝及几种相关蛋白组成。核心丝与覆盖其上的质膜紧密相连，质膜中蛋白质快速周转且不断有新膜整合。先前的研究表明，饥饿或蛋白质合成抑制会导致微绒毛长度的调节，这表明可能存在细胞骨架蛋白周转。我们在此通过用放射性氨基酸进行体内脉冲标记证明，成熟吸收细胞中刷状缘细胞骨架蛋白会发生周转。相对于膜蛋白周转，细胞骨架蛋白周转似乎相当缓慢，这表明这两个微绒毛区室的周转并不耦合。因此，我们得出结论，细胞骨架蛋白周转可能是用于维持微绒毛正常长度和稳定性的一个因素，并且细胞骨架不能被视为一个静态结构。
