Fath K R, Trimbur G M, Burgess D R
Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260.
J Cell Biol. 1994 Aug;126(3):661-75. doi: 10.1083/jcb.126.3.661.
Microtubules (MT) are required for the efficient transport of membranes from the trans-Golgi and for transcytosis of vesicles from the basolateral membrane to the apical cytoplasm in polarized epithelia. MTs in these cells are primarily oriented with their plus ends basally near the Golgi and their minus-ends in the apical cytoplasm. Here we report that isolated Golgi and Golgi-enriched membranes from intestinal epithelial cells possess the actin based motor myosin-I, the MT minus-end-directed motor cytoplasmic dynein and its in vitro motility activator dynactin (p150/Glued). The Golgi can be separated into stacks, possessing features of the Golgi cisternae, and small membranes enriched in the trans-Golgi network marker TGN 38/41. Whereas myosin-I is present on all membranes in the Golgi fraction, dynein is present only on the small membrane fraction. Dynein, like myosin-I, is associated with membranes as a cytoplasmic peripheral membrane protein. Dynein and myosin-I coassociate with membranes that bind to MTs and cross-link actin filaments and MTs in a nucleotide-dependent manner. We propose that cytoplasmic dynein moves Golgi membranes along MTs to the cell cortex where myosin-I provides local delivery through the actin-rich cytoskeleton to the apical membrane.
微管（MT）对于极化上皮细胞中从反式高尔基体高效运输膜以及将囊泡从基底外侧膜转运至顶端细胞质的转胞吞作用是必需的。这些细胞中的微管主要以其正端在高尔基体附近的基部、负端在顶端细胞质中的方式定向排列。在此我们报告，从肠上皮细胞分离的高尔基体和富含高尔基体的膜含有基于肌动蛋白的马达蛋白肌球蛋白-I、微管负端定向马达蛋白胞质动力蛋白及其体外运动激活剂动力蛋白激活蛋白（p150/Glued）。高尔基体可分离成具有高尔基体潴泡特征的堆叠以及富含反式高尔基体网络标志物TGN 38/41的小膜。虽然肌球蛋白-I存在于高尔基体部分的所有膜上，但动力蛋白仅存在于小膜部分。与肌球蛋白-I一样，动力蛋白作为细胞质外周膜蛋白与膜相关联。动力蛋白和肌球蛋白-I与结合微管并以核苷酸依赖方式交联肌动蛋白丝和微管的膜共缔合。我们提出，胞质动力蛋白沿着微管将高尔基体膜转运至细胞皮层处，在那里肌球蛋白-I通过富含肌动蛋白的细胞骨架向顶端膜提供局部递送。
