INTERACTION OF THE MICROTUBULE CYTOSKELETON WITH ENDOCYTIC VESICLES AND CYTOPLASMIC DYNEIN IN CULTURED RAT HEPATOCYTES
INTERACTION OF THE MICROTUBULE CYTOSKELETON WITH ENDOCYTIC VESICLES AND CYTOPLASMIC DYNEIN IN CULTURED RAT HEPATOCYTES
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DOI：
10.1074/jbc.270.25.15242
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发表时间：
1995-06-23
影响因子：
4.8
通讯作者：
WOLKOFF, AW
中科院分区：
文献类型：
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作者：
ODA, H;STOCKERT, RJ;WOLKOFF, AW
在最近的一项研究中(Goltz，J.S.，Wolkoff，A.W.，Novikoff，P.M.，Stockert，R.J.，and Satir，P.(1992)Proc.娜塔莉。阿卡德。SCI。美国R89,7026-7030)，我们发现，在受体介导的类黏液细胞吞噬作用60min后，含有配体和受体的内吞囊泡在体外与内源性微管结合。在三磷酸腺苷存在的情况下，含配体的内吞囊泡从微管中释放出来，而含有受体的内吞囊泡则不能。我们推测，胞质动力蛋白可能与内吞泡含配体的结构域有关，而不是与受体相关的结构域有关，并可能参与含配体的囊泡在从受体中分离的过程中沿微管的运动。本研究获得了支持这一假说的直接证据。在各种条件下，含配体的囊泡与微管的结合与动力蛋白的结合高度相关(p<；0.001)，但与动蛋白的结合无关。含有受体的囊泡与微管的结合不依赖于细胞质动力蛋白和动蛋白的结合。免疫沉淀可直接观察到胞浆动力蛋白与一群含配体的小泡紧密结合。这些结果支持这一观点，即在受体介导的内吞作用中，含配体的囊泡通过细胞质动力蛋白与微管结合。虽然内小体的受体结构域仍然以不依赖于ATP的方式附着在微管上，但含有配体的结构域可能会被这种运动分子移向内质网周围的溶酶体。
In a recent study (Goltz, J. S., Wolkoff, A. W., Novikoff, P. M., Stockert, R. J., and Satir, P. (1992) Proc. Natl. Acad. Sci. U.S. R 89, 7026-7030), we found that ligand- and receptor containing endocytic vesicles bind to endogenous microtubules in vitro after 60 min of receptor-mediated endocytosis of asialo-orosomucoid. In the presence of ATP, ligand-containing endocytic vesicles are released from microtubules, while those containing receptor are not. We hypothesized that cytoplasmic dynein may associate with ligand-containing, but not receptor-containing, domains of endocytic vesicles and might be involved in the movement of ligand-containing vesicles along microtubules during sorting of ligand from receptor. Direct evidence in support of this hypothesis has been obtained in the present study. Binding of ligand-containing vesicles to microtubules correlates highly (p < 0.001) with binding of dynein, but not kinesin, under a variety of conditions. Binding of receptor-containing vesicles to microtubules is independent of both cytoplasmic dynein and kinesin binding. Tight association of cytoplasmic dynein with a population of ligand-containing vesicles is seen directly by immunoprecipitation. These results support the view that in receptor-mediated endocytosis, ligand-containing vesicles become bound to microtubules by cytoplasmic dynein. While receptor domains of endosomes remain attached to microtubules in an ATP-independent manner, ligand-containing domains might be moved away toward pericentrosomal lysosomes by this motor molecule.