小柯机器人

美国加州大学旧金山分校David A. Agard等研究人员，合作利用原位冷冻电子断层扫描和AlphaFold2对接技术重新鉴定哺乳动物精子中的蛋白质。2023年10月20日，《细胞》杂志在线发表了这项成果。

研究人员表示，要了解细胞通路的分子机制，当代的工作流程通常需要多种技术来识别蛋白质、跟踪其定位并确定其体外结构。

研究人员结合了细胞冷冻电子断层扫描（cryo-ET）和AlphaFold2建模来解决这些问题，并了解哺乳动物精子是如何在原位构建的。细胞cryo-ET和子图平均法提供了轴丝微管结构的6.0埃重建。解析度很高的三级结构使其能够无偏见地将精子特异性密度，与21615个AlphaFold2预测的小鼠蛋白质组蛋白质模型相匹配。研究人员发现Tektin 5、CCDC105和SPACA9是新型微管相关蛋白。

这些蛋白形成了一个广泛的相互作用网络，交联轴突双微管的管腔，表明它们在调节微管丝的机械特性方面发挥作用。事实上，Tekt5^-/-精子的鞭毛变形更大，弯曲度达180°。总之，这项研究提出了细胞视觉蛋白质组学工作流程，并揭示了Tektin 5的体内功能。

附：英文原文

Title: De novo protein identification in mammalian sperm using in situ cryoelectron tomography and AlphaFold2 docking

Author: Zhen Chen, Momoko Shiozaki, Kelsey M. Haas, Will M. Skinner, Shumei Zhao, Caiying Guo, Benjamin J. Polacco, Zhiheng Yu, Nevan J. Krogan, Polina V. Lishko, Robyn M. Kaake, Ronald D. Vale, David A. Agard

Issue&Volume: 2023-10-20

Abstract: To understand the molecular mechanisms of cellular pathways, contemporary workflows typically require multiple techniques to identify proteins, track their localization, and determine their structures in vitro. Here, we combined cellular cryoelectron tomography (cryo-ET) and AlphaFold2 modeling to address these questions and understand how mammalian sperm are built in situ. Our cellular cryo-ET and subtomogram averaging provided 6.0- reconstructions of axonemal microtubule structures. The well-resolved tertiary structures allowed us to unbiasedly match sperm-specific densities with 21,615 AlphaFold2-predicted protein models of the mouse proteome. We identified Tektin 5, CCDC105, and SPACA9 as novel microtubule-associated proteins. These proteins form an extensive interaction network crosslinking the lumen of axonemal doublet microtubules, suggesting their roles in modulating the mechanical properties of the filaments. Indeed, Tekt5 / sperm possess more deformed flagella with 180° bends. Together, our studies presented a cellular visual proteomics workflow and shed light on the in vivo functions of Tektin 5.

DOI: 10.1016/j.cell.2023.09.017

Source: https://www.cell.com/cell/fulltext/S0092-8674(23)01038-3