Department of Biology, Texas A&M University, College Station, Texas, USA.
Int Rev Cell Mol Biol. 2012;293:149-68. doi: 10.1016/B978-0-12-394304-0.00010-5.
Cilia rely on their distinctive protein compositions to function. Proteins gain access to the privileged ciliary compartment through two major routes, membrane trafficking and intraflagellar transport (IFT). Recent advances have provided two possible models for ciliary membrane transport: lateral diffusion and retention, and targeted vesicle transport. The Rab11-Rab8 cascade, which was originally discovered in the yeast's secretion pathway for bud formation, is shown to be required for cilia membrane assembly. Small GTPases, including two IFT particle subunits, and Ran, the master regulator for nuclear-cytoplasmic transport, are implicated in various aspects of IFT, a fundamental process required for the assembly of the microtubule-based backbone of cilia. This chapter reviews the key steps of ciliogenesis and possible mechanisms of IFT regulation, with emphasis on the regulatory roles of small GTPases and their regulators.
纤毛依赖其独特的蛋白质组成发挥功能。蛋白质通过两种主要途径进入特有的纤毛隔室：膜运输和内鞭毛运输（IFT）。最近的进展为纤毛膜运输提供了两种可能的模型：侧向扩散和保留，以及靶向囊泡运输。最初在酵母芽形成的分泌途径中发现的 Rab11-Rab8 级联反应被证明是纤毛膜组装所必需的。小 GTPases，包括两个 IFT 颗粒亚基和 Ran，核质运输的主要调节剂，参与 IFT 的各个方面，IFT 是组装纤毛的微管为基础的骨干所必需的基本过程。本章综述了纤毛发生的关键步骤和 IFT 调节的可能机制，重点介绍了小 GTPases 及其调节剂的调节作用。
