Delanoue Renald, Davis Ilan
Wellcome Trust Centre for Cell Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom.
Cell. 2005 Jul 15;122(1):97-106. doi: 10.1016/j.cell.2005.04.033.
Molecular motors actively transport many types of cargo along the cytoskeleton in a wide range of organisms. One class of cargo is localized mRNAs, which are transported by myosin on actin filaments or by kinesin and dynein on microtubules. How the cargo is kept at its final intracellular destination and whether the motors are recycled after completion of transport are poorly understood. Here, we use a new RNA anchoring assay in living Drosophila blastoderm embryos to show that apical anchoring of mRNA after completion of dynein transport does not depend on actin or on continuous active transport by the motor. Instead, apical anchoring of RNA requires microtubules and involves dynein as a static anchor that remains with the cargo at its final destination. We propose a general principle that could also apply to other dynein cargo and to some other molecular motors, whereby cargo transport and anchoring reside in the same molecule.
分子马达在多种生物体中沿着细胞骨架主动运输多种类型的货物。一类货物是定位的信使核糖核酸（mRNA），它们由肌球蛋白在肌动蛋白丝上运输，或者由驱动蛋白和动力蛋白在微管上运输。货物如何被保持在其最终的细胞内目的地，以及运输完成后马达是否被循环利用，目前还知之甚少。在这里，我们在活体果蝇胚盘胚胎中使用一种新的RNA锚定检测方法，以表明动力蛋白运输完成后mRNA的顶端锚定不依赖于肌动蛋白或马达的持续主动运输。相反，RNA的顶端锚定需要微管，并涉及动力蛋白作为一个静态锚定物，它会与货物一起留在其最终目的地。我们提出了一个也可能适用于其他动力蛋白货物和一些其他分子马达的一般原则，即货物运输和锚定存在于同一个分子中。
