据研究人员介绍，纤毛是一种类似于天线的细胞器，发挥着许多细胞功能，包括运动、感知和信号。纤毛虫的基部包含一个选择性屏障，它调节大型纤毛内运输（IFT）列车的进入，这些列车携带纤毛组装和维护所需的货物蛋白。然而，纤毛基部的原生结构和IFT列车的组装过程仍未得到解决。
研究人员使用原位低温电子断层扫描技术来揭示了过渡区的局部结构和在衣藻类的纤毛基部组装IFT列车。研究人员将这种直接的细胞可视化与超微结构扩展显微镜相结合，描述了IFT列车的前后阶梯式组装。IFT-B形成骨架，在其上结合IFT-A、dynein-1b，最后是kinesin-2，然后进入纤毛内。
附：英文原文
Title: In situ architecture of the ciliary base reveals the stepwise assembly of intraflagellar transport trains
Author: Hugo van den Hoek, Nikolai Klena, Mareike A. Jordan, Gonzalo Alvarez Viar, Ricardo D. Righetto, Miroslava Schaffer, Philipp S. Erdmann, William Wan, Stefan Geimer, Jürgen M. Plitzko, Wolfgang Baumeister, Gaia Pigino, Virginie Hamel, Paul Guichard, Benjamin D. Engel
Issue&Volume: 2022-07-29
Abstract: The cilium is an antenna-like organelle that performs numerous cellular functions, including motility, sensing, and signaling. The base of the cilium contains a selective barrier that regulates the entry of large intraflagellar transport (IFT) trains, which carry cargo proteins required for ciliary assembly and maintenance. However, the native architecture of the ciliary base and the process of IFT train assembly remain unresolved. In this work, we used in situ cryo–electron tomography to reveal native structures of the transition zone region and assembling IFT trains at the ciliary base in Chlamydomonas. We combined this direct cellular visualization with ultrastructure expansion microscopy to describe the front-to-back stepwise assembly of IFT trains: IFT-B forms the backbone, onto which bind IFT-A, dynein-1b, and finally kinesin-2 before entry into the cilium.
DOI: abm6704
Source: https://www.science.org/doi/10.1126/science.abm6704