Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM
Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM
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冷冻电镜揭示小鼠轴丝径向辐条头的独特结构和组成
DOI：
10.1073/pnas.2021180118
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发表时间：
2021-01-26
影响因子：
11.1
通讯作者：
Cong，Yao
中科院分区：
文献类型：
--
作者：
Zheng，Wei;Li，Fan;Cong，Yao
能动纤毛和鞭毛的辐射辐头与中央对器的突起接触以协调运动，但原生动物和后生动物的形态不同。在这里，我们表明，小鼠RS头是从衣原体组成不同。我们重建的小鼠RS头部核心复合物由RCR 11，RCR 13 b，RCR 14 a和RCR 19组成，缺少RCR 16 a和RCR 10 b，其直系同源物存在于原生动物RS头部中。我们解决其冷冻电子显微镜（cryo-EM）结构在3.2- 100分辨率。我们的原子模型进一步揭示了一个双重对称的刹车片状结构，其中RST 4a和RST 9形成一个紧凑的体，其横向延伸有两个扭曲的RST 1 β-片层的长臂，并可能通过RST 3b与RS柄背侧连接。此外，我们的建模表明，核心复杂的接触周期性CP预测刚性通过其齿形R4 a区域或弹性通过优化RS-CP相互作用和mechanosignal转导的双臂。
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 ofChlamydomonas. 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.