Organization of myosin in a submembranous sheath in well-spread human fibroblasts.
Organization of myosin in a submembranous sheath in well-spread human fibroblasts.
复制标题
分布良好的人成纤维细胞膜下鞘中肌球蛋白的组织。
DOI：
10.1016/0014-4827(79)90349-5
复制
发表时间：
1979
影响因子：
3.7
通讯作者：
Joseph Bryan
中科院分区：
文献类型：
--
作者：
Sally H. Zigmond;Joann J. Otto;Joseph Bryan
Using an indirect immunofluorescence technique, antibodies against human platelet myosin stain a highly organized layer of sheath of fibers in well-spread human fibroblasts. By adjusting the focus, the sheath is seen to be continuous over the top of the cell. Myosin staining along a fiber is periodic with a mean spacing of 0.71 ± 0.1 μm. Although the sheath becomes progressively disorganized and eventually disappears upon cell rounding after trypsinization, the mean spacing in the fibers remaining at intermediate stages does not appear to change. The organization is sensitive to cytochalasin B (CB), but insensitive to colchicine. Anti-myosin staining of the sheath persists in cells lysed in 0.1–0.5% Triton X-100 at low ionic strength despite some myosin extraction. Preparation of the cytoskeleton at increasingly higher ionic strength or extraction with ATP or pyrophosphate diminishes the sheath staining with anti-myosin. A detailed analysis of the mean myosin spacing in the cytoskeleton after various treatments designed to induce contraction suggests (1) that reagents which extract myosin, i.e., ATP, high salt and pyrophosphate, all cause contraction and (2) that the mean spacing does not detectably change. Anti-alpha-actinin and anti-tropomyosin also localize and demonstrate a periodicity for their respective antigens in the sheath fibers. Double staining with anti-myosin and anti-tropomyosin gives an enhancement of the basic myosin perodicity indicating co-localization. Double staining with anti-alpha-actinin and anti-myosin gives a nearly continuous fluorescence along the sheath fiber suggesting a complementary periodicity. This finding was confirmed with a direct anti-myosin-indirect anti-alpha-actinin staining experiment. A possible chemical mechanism, based on a competition of these proteins for actin, for the generation of the observed periodicity and formation of the sheath is considered.
