Myosin cooperates with microtubule motors during organelle transport in melanophores
Myosin cooperates with microtubule motors during organelle transport in melanophores
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DOI：
10.1016/s0960-9822(98)70063-6
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发表时间：
1998-01-29
期刊：
影响因子：
9.2
通讯作者：
Gelfand, VI
中科院分区：
文献类型：
--
作者：
Rogers, SL;Gelfand, VI
黑素细胞为研究细胞内运动提供了一个出色的系统。这些细胞将其色素填充的黑素体聚集到细胞中心或将其分散在整个细胞质中，以响应细胞内环AMP水平的激素调节，从而影响低等脊椎动物的颜色变化[1]。我们实验室以前的工作证明了基于微管的马达在黑素体运输中的作用，我们成功地在体外重建了它们沿沿着的调节运动性[2，3]。在这里，我们证明，除了微管介导的运动，黑素体纯化爪蟾黑素细胞表现出单向运动沿着肌动蛋白丝在体外。免疫印迹分析表明，这些细胞器具有肌动蛋白为基础的细胞器电机，肌球蛋白-V。在体内，黑素体能够在没有微管的情况下缓慢分散，这种缓慢的分散需要肌动蛋白细胞骨架的完整性。此外，在分散色素的细胞中，丝状肌动蛋白的破坏诱导黑素体快速的、微管依赖性的聚集到细胞中心。我们的研究结果，以及Rodionov等人的相关论文[4]，证明了基于微管和基于肌动蛋白的马达的协同努力是黑色素细胞中适当的黑素体分布所必需的。这是第一个例子的生化定义的细胞器拥有正端和负端定向微管电机和肌球蛋白;协调活动的所有三个电机是必不可少的细胞器的运动在体内。(C)当前生物有限公司
Melanophores offer an outstanding system for the study of intracellular motility. These cells aggregate their pigment-filled melanosomes to the cell center or disperse them throughout the cytoplasm in response to hormonal modulation of intracellular cyclic AMP levels in order to effect color changes in lower vertebrates [1]. Previous work from our laboratory demonstrated a role for microtubule-based motors in melanosome transport and we succeeded in reconstituting their regulated motility along microtubules in vitro [2,3]. Here we demonstrate that, in addition to microtubule-mediated motility, melanosomes purified from Xenopus melanophores exhibit unidirectional movement along actin filaments in vitro as well. Immunoblotting analysis shows that these organelles possess the actin-based organelle motor, myosin-V. In vivo, melanosomes are able to slowly disperse in the absence of microtubules, and this slow dispersion requires the integrity of the actin cytoskeleton. Furthermore, in cells with dispersed pigment, disruption of filamentous actin induces a rapid, microtubule-dependent aggregation of melanosomes to the cell center. Our results, together with the accompanying paper by Rodionov et al. [4], demonstrate that the concerted efforts of both microtubule-based and actin-based motors are required for proper melanosome distribution in melanophores. This is the first example of a biochemically defined organelle in possession of both plus-end and minus-end directed microtubule motors and a myosin; coordinated activity of all three motors is essential for organelle motility in vivo. (C) Current Biology Ltd.