Liu Xi, Li Yang, Castro Lennice, Yu Zanlin, Cheng Yifan, Daugherty Matthew D, Gross John D
bioRxiv. 2024 Jun 24:2024.06.24.600508. doi: 10.1101/2024.06.24.600508.
ZYG11B is a substrate specificity factor for Cullin-RING ubiquitin ligase (CRL2) involved in many biological processes, including Gly/N-degron pathways. Yet how the binding of ZYG11B with CRL2 is coupled to substrate recognition and ubiquitination is unknown. We present the Cryo-EM structures of the CRL2-ZYG11B holoenzyme alone and in complex with a Gly/N-peptide from the inflammasome-forming pathogen sensor NLRP1. The structures indicate ZYG11B folds into a Leucine-Rich Repeat followed by two armadillo repeat domains that promote assembly with CRL2 and recognition of NLRP1 Gly/N-degron. ZYG11B promotes activation of the NLRP1 inflammasome through recognition and subsequent ubiquitination of the NLRP1 Gly/N-degron revealed by viral protease cleavage. Our structural and functional data indicate that blocking ZYG11B recognition of the NLRP1 Gly/N-degron inhibits NLRP1 inflammasome activation by a viral protease. Overall, we show how the CRL2-ZYG11B E3 ligase complex recognizes Gly/N-degron substrates, including those that are involved in viral protease-mediated activation of the NLRP1 inflammasome.
ZYG11B是一种参与包括Gly/N-降解途径在内的许多生物过程的Cullin-RING泛素连接酶（CRL2）的底物特异性因子。然而，ZYG11B与CRL2的结合如何与底物识别和泛素化偶联尚不清楚。我们展示了单独的CRL2-ZYG11B全酶以及与来自形成炎性小体的病原体传感器NLRP1的Gly/N-肽形成复合物的冷冻电镜结构。这些结构表明，ZYG11B折叠成富含亮氨酸重复序列，随后是两个犰狳重复结构域，它们促进与CRL2的组装以及对NLRP1 Gly/N-降解子的识别。ZYG11B通过识别病毒蛋白酶切割所揭示的NLRP1 Gly/N-降解子并随后对其进行泛素化，促进NLRP1炎性小体的激活。我们的结构和功能数据表明，阻断ZYG11B对NLRP1 Gly/N-降解子的识别可抑制病毒蛋白酶对NLRP1炎性小体的激活。总体而言，我们展示了CRL2-ZYG11B E3连接酶复合物如何识别Gly/N-降解子底物，包括那些参与病毒蛋白酶介导的NLRP1炎性小体激活的底物。
