From the Department of Microbiology & Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322.
From the Department of Microbiology & Immunology, Emory Vaccine Center, Emory University School of Medicine, Atlanta, Georgia 30322
J Biol Chem. 2019 Jan 18;294(3):991-1004. doi: 10.1074/jbc.RA118.004651. Epub 2018 Nov 30.
Receptor-interacting protein (RIP) kinase 3 (RIPK3)-dependent necroptosis directs inflammation and tissue injury, as well as anti-viral host defense. In human cells, herpes simplex virus 1 (HSV1) UL39-encoded ICP6 blocks RIP homotypic interacting motif (RHIM) signal transduction, preventing this leakage form of cell death and sustaining viral infection. TNF receptor 1 (TNFR1)-induced necroptosis is known to require the formation of a RIPK1-RIPK3-mixed lineage kinase domain-like pseudokinase (MLKL) signaling complex (necrosome) that we find compartmentalizes exclusively to caveolin-1-associated detergent-resistant membrane (DRM) vesicles in HT-29 cells. Translocation proceeds in the presence of RIPK3 kinase inhibitor GSK'840 or MLKL inhibitor necrosulfonomide but requires the kinase activity, as well as RHIM signaling of RIPK1. ICP6 impedes the translocation of RIPK1, RIPK3, and MLKL to caveolin-1-containing DRM vesicles without fully blocking the activation of RIPK3 or phosphorylation of MLKL. Consistent with the important contribution of RIPK1 RHIM-dependent recruitment of RIPK3, overexpression of RHIM-deficient RIPK3 results in phosphorylation of MLKL, but this does not lead to either translocation or necroptosis. Combined, these data reveal a critical role of RHIM signaling in the recruitment of the MLKL-containing necrosome to membrane vesicle-associated sites of aggregation. A similar mechanism is predicted for other RHIM-containing signaling adaptors, Z-nucleic acid-binding protein 1 (ZBP1) (also called DAI and DLM1), and TIR domain-containing adapter-inducing interferon-β (TRIF).
受体相互作用蛋白 (RIP) 激酶 3 (RIPK3)-依赖性坏死导致炎症和组织损伤，以及抗病毒宿主防御。在人类细胞中，单纯疱疹病毒 1 (HSV1) UL39 编码的 ICP6 阻断 RIP 同源相互作用基序 (RHIM) 信号转导，防止这种细胞死亡的渗漏形式，并维持病毒感染。已知 TNF 受体 1 (TNFR1) 诱导的坏死需要形成 RIPK1-RIPK3-混合谱系激酶结构域样伪激酶 (MLKL) 信号复合物 (坏死体)，我们发现该复合物仅在 HT-29 细胞中局限于窖蛋白-1 相关去污剂抗性膜 (DRM) 囊泡。在存在 RIPK3 激酶抑制剂 GSK'840 或 MLKL 抑制剂 necrosulfonomide 的情况下，易位进行，但需要激酶活性以及 RIPK1 的 RHIM 信号。ICP6 阻止 RIPK1、RIPK3 和 MLKL 易位到含有窖蛋白-1 的 DRM 囊泡，但不完全阻断 RIPK3 的激活或 MLKL 的磷酸化。与 RIPK1 RHIM 依赖性募集 RIPK3 的重要贡献一致，过表达 RHIM 缺陷型 RIPK3 导致 MLKL 的磷酸化，但这不会导致易位或坏死。综合这些数据表明，RHIM 信号在将含有 MLKL 的坏死体募集到膜囊泡相关聚集部位中起着关键作用。预测其他含有 RHIM 的信号衔接子，Z-核酸结合蛋白 1 (ZBP1)（也称为 DAI 和 DLM1）和 TIR 结构域包含的衔接子诱导干扰素-β (TRIF)，也存在类似的机制。
