Subdistal appendages (sDAPs) are centriolar elements observed proximal to the distal appendages (DAPs) in vertebrates. Despite their obvious presence, structural and functional understanding of sDAPs remains elusive. Here, by combining super-resolved localization analysis and CRISPR-Cas9 genetic perturbation, we find that, although DAPs and sDAPs are primarily responsible for distinct functions in ciliogenesis and microtubule anchoring respectively, the presence of one element actually affects the positioning of the other. Specifically, we find dual layers of both ODF2 and CEP89, where their localizations are differentially regulated by DAP and sDAP integrity. DAP depletion relaxes longitudinal occupancy of sDAP protein ninein to cover the DAP region, implying a role of DAPs in sDAP positioning. Removing sDAPs alter the distal border of centrosomal γ-tubulins, illustrating a new role of sDAPs. Together, our results provide an architectural framework of sDAPs to shed light on functional understanding, surprisingly revealing the coupling between DAPs and sDAPs.

中文翻译：

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超高分辨率显微镜显示哺乳动物中央rio下附属物和远端附属物之间的耦合

dist下附肢（sDAPs）是在脊椎动物中靠近远端附肢（DAPs）的中心粒状元件。尽管它们明显存在，但对sDAP的结构和功能的理解仍然难以捉摸。在这里，通过结合超分辨定位分析和CRISPR-Cas9遗传扰动，我们发现，尽管DAP和sDAP分别主要负责纤毛生成和微管锚定中的不同功能，但一个元件的存在实际上会影响另一个的定位。具体来说，我们发现ODF2和CEP89的双层结构，它们的定位受DAP和sDAP完整性的差异调节。DAP耗竭放松了sDAP蛋白ninein的纵向占有，从而覆盖了DAP区域，这暗示了DAP在sDAP定位中的作用。去除sDAP会改变中心体γ-微管蛋白的远端边界，这说明了sDAP的新作用。总之，我们的结果提供了sDAP的体系结构框架，以阐明功能理解，令人惊讶地揭示了DAP和sDAP之间的耦合。