Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
Science. 2013 Aug 30;341(6149):1009-12. doi: 10.1126/science.1240985.
Intraflagellar transport (IFT) of ciliary precursors such as tubulin from the cytoplasm to the ciliary tip is involved in the construction of the cilium, a hairlike organelle found on most eukaryotic cells. However, the molecular mechanisms of IFT are poorly understood. Here, we found that the two core IFT proteins IFT74 and IFT81 form a tubulin-binding module and mapped the interaction to a calponin homology domain of IFT81 and a highly basic domain in IFT74. Knockdown of IFT81 and rescue experiments with point mutants showed that tubulin binding by IFT81 was required for ciliogenesis in human cells.
纤毛前体(如微管蛋白)从细胞质到纤毛尖端的鞭毛内运输(IFT)参与了纤毛的构建,纤毛是大多数真核细胞上的毛发状细胞器。然而,IFT 的分子机制还不清楚。在这里,我们发现两个核心 IFT 蛋白 IFT74 和 IFT81 形成一个微管蛋白结合模块,并将相互作用定位到 IFT81 的钙调蛋白同源结构域和 IFT74 的高度碱性结构域。IFT81 的敲低和点突变的挽救实验表明,IFT81 的微管蛋白结合对于人细胞中的纤毛发生是必需的。