Biology Department, Cell Biology Department, Institute for Morphogenesis and Regenerative Medicine, University of Virginia, Charlottesville, VA 22903, USA.
Development. 2012 Mar;139(5):906-16. doi: 10.1242/dev.074252. Epub 2012 Jan 25.
The morphogenesis of Drosophila sensory bristles is dependent on the function of their actin and microtubule cytoskeleton. Actin filaments are important for bristle shape and elongation, while microtubules are thought to mediate protein and membrane trafficking to promote growth. We have identified an essential role for the bristle cuticle in the maintenance of bristle structure and shape at late stages of bristle development. We show that the small GTPase Rab11 mediates the organized deposition of chitin, a major cuticle component in bristles, and disrupting Rab11 function leads to phenotypes that result from bristle collapse rather than a failure to elongate. We further establish that Rab11 is required for the plasma membrane localization of the ZP domain-containing Dusky-like (Dyl) protein and that Dyl is also required for cuticle formation in bristles. Our data argue that Dyl functions as a Rab11 effector for mediating the attachment of the bristle cell membrane to chitin to establish a stable cuticle. Our studies also implicate the exocyst as a Rab11 effector in this process and that Rab11 trafficking along the bristle shaft is mediated by microtubules.
果蝇感觉刚毛的形态发生依赖于其肌动蛋白和微管细胞骨架的功能。肌动蛋白丝对于刚毛的形状和伸长很重要，而微管被认为介导蛋白质和膜运输以促进生长。我们已经确定了刚毛外角质层在刚毛发育后期维持刚毛结构和形状方面的重要作用。我们表明，小 GTPase Rab11 介导几丁质的有组织沉积，几丁质是刚毛中的主要外角质层成分，破坏 Rab11 功能会导致刚毛塌陷而不是伸长失败的表型。我们进一步确定 Rab11 对于 ZP 结构域包含的 Dusky-like (Dyl) 蛋白的质膜定位是必需的，并且 Dyl 对于刚毛中的外角质层形成也是必需的。我们的数据表明，Dyl 作为 Rab11 的效应物发挥作用，将刚毛细胞膜附着到几丁质上以建立稳定的外角质层。我们的研究还表明，外核蛋白复合物作为该过程中的 Rab11 效应物，并且 Rab11 沿着刚毛轴的运输是由微管介导的。
