Abstract:
Receptor-interacting protein kinase 1 (RIPK1) is a therapeutic target in treating neurodegenerative diseases and cancers. RIPK1 has three distinct functional domains, with the center domain containing a receptor-interacting protein homotypic interaction motif (RHIM), which mediates amyloid formation. The functional amyloid formed by RIPK1 and/or RIPK3 is a crucial intermediate in regulating cell necroptosis. In this study, the amyloid structure of mouse RIPK1, formed by an 82-residue sequence centered at RHIM, is presented. It reveals the \"N\"-shaped folding of the protein subunit in the fibril with four β-strands. The folding pattern is shared by several amyloid structures formed by proteins with RHIM, with the central β-strand formed by the most conserved tetrad sequence I/VQI/VG. However, the solid-state NMR results indicate a structural difference between mouse RIPK1 and mouse RIPK3. A change in the structural rigidity is also suggested by the observation of weakened signals for mouse RIPK3 upon mixing with RIPK1 to form the RIPK1/RIPK3 complex fibrils. Our results provide vital information to understand the interactions between different proteins with RHIM, which will help us further comprehend the regulation mechanism in cell necroptosis.
摘要:
受体相互作用蛋白激酶1(RIPK1)是治疗神经退行性疾病和癌症的治疗靶点。RIPK1有三个不同的功能结构域,中心域包含受体相互作用蛋白同型相互作用基序(RHIM),介导淀粉样蛋白的形成。由RIPK1和/或RIPK3形成的功能性淀粉样蛋白是调节细胞坏死性凋亡的关键中间体。在这项研究中,小鼠RIPK1的淀粉样蛋白结构,由一个以RHIM为中心的82个残基的序列形成,是presented。它揭示了原纤维中蛋白质亚基的“N”形折叠,具有四个β链。折叠模式由蛋白质与RHIM形成的几种淀粉样结构共享,由最保守的四聚体序列I/VQI/VG形成的中央β链。然而,固态NMR结果表明小鼠RIPK1和小鼠RIPK3之间的结构差异。通过与RIPK1混合形成RIPK1/RIPK3复合原纤维后观察到小鼠RIPK3的减弱信号,也表明了结构刚度的变化。我们的结果为了解不同蛋白质与RHIM之间的相互作用提供了重要信息,这将有助于我们进一步理解细胞坏死性凋亡的调控机制。