解整合素和金属蛋白酶 17 (ADAM17) 是一种膜束缚蛋白酶，可触发多种信号通路。它释放主要炎症细胞因子肿瘤坏死因子 (TNF) 和癌症相关表皮生长因子 (EGF) 家族生长因子的活性形式。 iRhom2 是一种菱形、膜嵌入的假蛋白酶，是 ADAM17 的重要辅助因子。在这里，我们展示了人类 ADAM17/iRhom2 复合物在非活性和活性状态下的冷冻电子显微镜 (cryo-EM) 结构。这些揭示了三种调节机制。首先，利用 TMD 识别的菱形标志，iRhom2 与 ADAM17 TMD 相互作用，促进 ADAM17 运输和酶成熟。其次，独特的 iRhom2 胞外结构域出乎意料地保留了切割的 ADAM17 抑制性前结构域，防止过早激活和蛋白水解失调。最后，复合物中前结构域的丢失会动员 ADAM17 蛋白酶结构域，从而增强其与底物结合的能力。我们的结果揭示了菱形样假蛋白酶在进化过程中如何被重新利用来调节有效的膜束缚酶 ADAM17，从而确保炎症和生长因子信号传导的保真度。版权所有 © 2024 作者。由爱思唯尔公司出版。保留所有权利。

A disintegrin and metalloprotease 17 (ADAM17) is a membrane-tethered protease that triggers multiple signaling pathways. It releases active forms of the primary inflammatory cytokine tumor necrosis factor (TNF) and cancer-implicated epidermal growth factor (EGF) family growth factors. iRhom2, a rhomboid-like, membrane-embedded pseudoprotease, is an essential cofactor of ADAM17. Here, we present cryoelectron microscopy (cryo-EM) structures of the human ADAM17/iRhom2 complex in both inactive and active states. These reveal three regulatory mechanisms. First, exploiting the rhomboid-like hallmark of TMD recognition, iRhom2 interacts with the ADAM17 TMD to promote ADAM17 trafficking and enzyme maturation. Second, a unique iRhom2 extracellular domain unexpectedly retains the cleaved ADAM17 inhibitory prodomain, safeguarding against premature activation and dysregulated proteolysis. Finally, loss of the prodomain from the complex mobilizes the ADAM17 protease domain, contributing to its ability to engage substrates. Our results reveal how a rhomboid-like pseudoprotease has been repurposed during evolution to regulate a potent membrane-tethered enzyme, ADAM17, ensuring the fidelity of inflammatory and growth factor signaling.Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.