Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM.

Wei Zheng, Fan Li, Zhanyu Ding, Hao Liu, Lei Zhu, Cong Xu, Jiawei Li, Qi Gao, Yanxing Wang, Zhenglin Fu, Chao Peng, Xiumin Yan, Xueliang Zhu, Yao Cong

Proceedings of the National Academy of Sciences of the United States of America 2021 Jan 26

filter terms:

The radial spoke (RS) heads of motile cilia and flagella contact projections of the central pair (CP) apparatus to coordinate motility, but the morphology is distinct for protozoa and metazoa. Here we show the murine RS head is compositionally distinct from that of Chlamydomonas Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a and Rsph10b, whose orthologs exist in the protozoan RS head. We resolve its cryo-electron microscopy (cryo-EM) structure at 3.2-Å resolution. Our atomic model further reveals a twofold symmetric brake pad-shaped structure, in which Rsph4a and Rsph9 form a compact body extended laterally with two long arms of twisted Rsph1 β-sheets and potentially connected dorsally via Rsph3b to the RS stalk. Furthermore, our modeling suggests that the core complex contacts the periodic CP projections either rigidly through its tooth-shaped Rsph4a regions or elastically through both arms for optimized RS-CP interactions and mechanosignal transduction.

Citation

Wei Zheng, Fan Li, Zhanyu Ding, Hao Liu, Lei Zhu, Cong Xu, Jiawei Li, Qi Gao, Yanxing Wang, Zhenglin Fu, Chao Peng, Xiumin Yan, Xueliang Zhu, Yao Cong. Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM. Proceedings of the National Academy of Sciences of the United States of America. 2021 Jan 26;118(4)