Chandler Francesca, Reddy Poli Adi Narayana, Bhutda Smita, Ross Rebecca L, Datta Arindam, Walden Miriam, Walker Kieran, Di Donato Stefano, Cassel Joel A, Prakesch Michael A, Aman Ahmed, Datti Alessandro, Campbell Lisa J, Foglizzo Martina, Bell Lillie, Stein Daniel N, Ault James R, Al-Awar Rima S, Calabrese Antonio N, Sicheri Frank, Del Galdo Francesco, Salvino Joseph M, Greenberg Roger A, Zeqiraj Elton
Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
Medicinal Chemistry, Molecular and Cellular Oncogenesis (MCO) Program and The Wistar Cancer Center Molecular Screening, The Wistar Institute, Philadelphia, PA, USA.
Nat Struct Mol Biol. 2025 Mar 17. doi: 10.1038/s41594-025-01517-5.
Deubiquitylases (DUBs) are crucial in cell signaling and are often regulated by interactions within protein complexes. The BRCC36 isopeptidase complex (BRISC) regulates inflammatory signaling by cleaving K63-linked polyubiquitin chains on type I interferon receptors (IFNAR1). As a Zn-dependent JAMM/MPN (JAB1, MOV34, MPR1, Pad1 N-terminal) DUB, BRCC36 is challenging to target with selective inhibitors. Here, we discover first-in-class inhibitors, termed BRISC molecular glues (BLUEs), which stabilize a 16-subunit human BRISC dimer in an autoinhibited conformation, blocking active sites and interactions with the targeting subunit, serine hydroxymethyltransferase 2. This unique mode of action results in selective inhibition of BRISC over related complexes with the same catalytic subunit, splice variants and other JAMM/MPN DUBs. BLUE treatment reduced interferon-stimulated gene expression in cells containing wild-type BRISC and this effect was abolished when using structure-guided, inhibitor-resistant BRISC mutants. Additionally, BLUEs increase IFNAR1 ubiquitylation and decrease IFNAR1 surface levels, offering a potential strategy to mitigate type I interferon-mediated diseases. Our approach also provides a template for designing selective inhibitors of large protein complexes by promoting rather than blocking protein-protein interactions.
去泛素化酶（DUBs）在细胞信号传导中至关重要，并且常常受到蛋白质复合物内部相互作用的调控。BRCC36异肽酶复合物（BRISC）通过切割I型干扰素受体（IFNAR1）上K63连接的多聚泛素链来调节炎症信号传导。作为一种锌依赖性JAMM/MPN（JAB1、MOV34、MPR1、Pad1 N端）DUB，BRCC36很难用选择性抑制剂进行靶向作用。在此，我们发现了一类名为BRISC分子胶（BLUEs）的首创抑制剂，它们能将一个16亚基的人源BRISC二聚体稳定在自抑制构象中，封闭活性位点并阻断其与靶向亚基丝氨酸羟甲基转移酶2的相互作用。这种独特的作用方式导致BRISC相对于具有相同催化亚基、剪接变体和其他JAMM/MPN DUB的相关复合物受到选择性抑制。BLUE处理降低了含有野生型BRISC的细胞中干扰素刺激基因的表达，而当使用结构导向的、对抑制剂耐药的BRISC突变体时，这种效应就会消失。此外，BLUEs增加了IFNAR1的泛素化并降低了IFNAR1的表面水平，为减轻I型干扰素介导的疾病提供了一种潜在策略。我们的方法还为通过促进而非阻断蛋白质-蛋白质相互作用来设计大型蛋白质复合物的选择性抑制剂提供了一个模板。
