Inheritance of the newly assembled flagellum in the human parasite Trypanosoma brucei depends on the faithful duplication and segregation of multiple flagellum-associated cytoskeletal structures, including the hook complex and its associated centrin arm. The biological functions of this unique hook complex–centrin arm assembly remain poorly understood. Here, we report a hook complex–associated protein named BOH2 that plays an essential role in promoting flagellum inheritance. BOH2 localizes to the hooked part of the hook complex by bridging the hook complex, the centrin arm, and the flagellum attachment zone filament. Depletion of BOH2 caused the loss of the shank part of the hook complex and its associated protein TbSmee1, disrupted the assembly of the centrin arm and the recruitment of centrin arm–associated protein CAAP1, inhibited the assembly of the flagellum attachment zone, and caused flagellum mispositioning and detachment. These results demonstrate crucial roles of BOH2 in maintaining hook complex integrity and promoting centrin arm formation and suggest that proper assembly of the hook complex–centrin arm structure facilitates flagellum inheritance.

中文翻译：

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保持钩复合体的完整性和中心蛋白臂组装有助于布氏锥虫的鞭毛遗传。

人类寄生虫布氏锥虫中新组装鞭毛的遗传取决于多个鞭毛相关细胞骨架结构的忠实复制和分离，包括钩复合物及其相关的中心蛋白臂。这种独特的钩复合物 - 中心臂组件的生物学功能仍然知之甚少。在这里，我们报告了一种名为 BOH2 的钩状复合体相关蛋白，它在促进鞭毛遗传方面发挥着重要作用。BOH2 通过桥接钩复合体、中心臂和鞭毛附着区细丝，定位于钩复合体的钩状部分。BOH2 的消耗导致钩复合体的柄部分及其相关蛋白 TbSmee1 的丢失，破坏了中心蛋白臂的组装和中心蛋白臂相关蛋白 CAAP1 的募集，抑制了鞭毛附着区的组装，并导致鞭毛错位和脱离。这些结果证明了 BOH2 在维持钩复合物完整性和促进中心蛋白臂形成方面的关键作用，并表明钩复合物 - 中心蛋白臂结构的正确组装有利于鞭毛遗传。