Biozentrum, University of Basel, 4056 Basel, Switzerland.
Helmholtz Pioneer Campus, Helmholtz Munich, 85764 Neuherberg, Germany.
Science. 2022 Jul 29;377(6605):543-548. doi: 10.1126/science.abm6704. Epub 2022 Jul 28.
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 . 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.
纤毛是一种类似天线的细胞器，执行许多细胞功能，包括运动、感应和信号传递。纤毛的基部包含一个选择性的屏障，调节大型内鞭毛运输 (IFT) 列车的进入，IFT 列车携带组装和维持纤毛所需的货物蛋白。然而，纤毛基部的天然结构和 IFT 列车组装的过程仍然没有得到解决。在这项工作中，我们使用原位冷冻电子断层扫描来揭示. 中过渡区区域和组装 IFT 列车的天然结构。我们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 列车从前到后的逐步组装：IFT-B 形成骨干，然后 IFT-A、动力蛋白-1b 和最后是驱动蛋白-2结合，然后进入纤毛。
