Itin C, Ulitzur N, Mühlbauer B, Pfeffer S R
Department of Biochemistry, Stanford University School of Medicine, Stanford, California 94305-5307, USA.
Mol Biol Cell. 1999 Jul;10(7):2191-7. doi: 10.1091/mbc.10.7.2191.
Late endosomes and the Golgi complex maintain their cellular localizations by virtue of interactions with the microtubule-based cytoskeleton. We study the transport of mannose 6-phosphate receptors from late endosomes to the trans-Golgi network in vitro. We show here that this process is facilitated by microtubules and the microtubule-based motor cytoplasmic dynein; transport is inhibited by excess recombinant dynamitin or purified microtubule-associated proteins. Mapmodulin, a protein that interacts with the microtubule-associated proteins MAP2, MAP4, and tau, stimulates the microtubule- and dynein-dependent localization of Golgi complexes in semi-intact Chinese hamster ovary cells. The present study shows that mapmodulin also stimulates the initial rate with which mannose 6-phosphate receptors are transported from late endosomes to the trans-Golgi network in vitro. These findings represent the first indication that mapmodulin can stimulate a vesicle transport process, and they support a model in which the microtubule-based cytoskeleton enhances the efficiency of vesicle transport between membrane-bound compartments in mammalian cells.
晚期内体和高尔基体复合体通过与基于微管的细胞骨架相互作用来维持其细胞定位。我们在体外研究了甘露糖6-磷酸受体从晚期内体到反式高尔基体网络的运输。我们在此表明，这个过程由微管和基于微管的动力蛋白胞质动力蛋白促进；运输受到过量重组动力蛋白或纯化的微管相关蛋白的抑制。Mapmodulin是一种与微管相关蛋白MAP2、MAP4和tau相互作用的蛋白质，它能刺激半完整中国仓鼠卵巢细胞中高尔基体复合体基于微管和动力蛋白的定位。本研究表明，Mapmodulin还能刺激体外甘露糖6-磷酸受体从晚期内体运输到反式高尔基体网络的初始速率。这些发现首次表明Mapmodulin可以刺激囊泡运输过程，并且支持了一种模型，即基于微管的细胞骨架提高了哺乳动物细胞膜结合区室之间囊泡运输的效率。
