小柯机器人

美国哈佛医学院Stephen C. Blacklow团队近期取得重要工作进展，他们研究发现了ADAM10对膜近端底物进行蛋白水解的结构基础。相关研究工作2023年7月28日在线发表于《细胞》杂志上。

据介绍，内多肽酶ADAM10是哺乳动物发育、生理和APP非淀粉样蛋白裂解的关键驱动因素的重要催化剂，是主要的α-分泌酶。ADAM10的功能需要与C8-四聚乙二醇蛋白形成复合物，但四聚乙二醇蛋白如何结合使酶活性位点定位以进行膜近端切割，目前扔不清楚。

研究人员展示了vFab-ADAM10-Tspan15复合物的冷冻电镜结构，表明Tspan15的结合减轻了ADAM10的自动抑制，并作为分子测量棒将酶活性位点定位在离质膜约20Å的位置，用于膜近端底物切割。N-钙粘蛋白脱落的基于细胞的测定表明，通过ADAM10催化结构域和结合的四聚乙二醇蛋白之间的界面定位活性位点影响优选切割位点的选择。

总之，这些研究揭示了膜近端ADAM10蛋白水解的分子机制，并为其在疾病中的调节提供了路线图。

附：英文原文

Title: Structural basis for membrane-proximal proteolysis of substrates by ADAM10

Author: Colin H. Lipper, Emily D. Egan, Khal-Hentz Gabriel, Stephen C. Blacklow

Issue&Volume: 2023-07-28

Abstract: The endopeptidase ADAM10 is a critical catalyst for the regulated proteolysis of keydrivers of mammalian development, physiology, and non-amyloidogenic cleavage of APPas the primary α-secretase. ADAM10 function requires the formation of a complex witha C8-tetraspanin protein, but how tetraspanin binding enables positioning of the enzymeactive site for membrane-proximal cleavage remains unknown. We present here a cryo-EMstructure of a vFab-ADAM10-Tspan15 complex, which shows that Tspan15 binding relievesADAM10 autoinhibition and acts as a molecular measuring stick to position the enzymeactive site about 20 from the plasma membrane for membrane-proximal substrate cleavage.Cell-based assays of N-cadherin shedding establish that the positioning of the activesite by the interface between the ADAM10 catalytic domain and the bound tetraspanininfluences selection of the preferred cleavage site. Together, these studies revealthe molecular mechanism underlying ADAM10 proteolysis at membrane-proximal sites andoffer a roadmap for its modulation in disease.

DOI: 10.1016/j.cell.2023.06.026

Source: https://www.cell.com/cell/fulltext/S0092-8674(23)00733-X