State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China.
Autophagy. 2021 Feb;17(2):496-511. doi: 10.1080/15548627.2020.1725375. Epub 2020 Feb 11.
Influenza A virus (IAV) infection induces mitophagy, which is essential for the clearance of damaged mitochondria. Dysfunctional mitochondria can be selectively targeted by PINK1, which recruits PRKN/PARK2 and leads to subsequent mitochondrial sequestration within autophagosomes. The IAV PB1-F2 protein translocates to mitochondria, accelerates the mitochondrial fragmentation and impairs the innate immunity. However, whether PB1-F2 mediates IAV-induced mitophagy and the relation between mitophagy and PB1-F2-attenuated innate immunity remain obscure. Here, we showed that PB1-F2 translocated to mitochondria by interacting and colocalizing with TUFM (Tu translation elongation factor, mitochondrial). Further studies revealed that PB1-F2 induced complete mitophagy, which required the interactions of PB1-F2 with both TUFM and MAP1LC3B/LC3B that mediated the autophagosome formation. PB1-F2-induced mitophagy was critical for the MAVS (mitochondrial antiviral signaling protein) degradation and led to its suppression of the type I IFN production. Importantly, the C-terminal LIR motif of PB1-F2 protein was demonstrated to be essential for its mitophagy induction and attenuated innate immunity. In conclusion, PB1-F2-induced mitophagy strongly correlates with impaired cellular innate immunity, revealing it is a potential therapeutic target. BCL2L13: BCL2 like 13; BECN1: beclin 1; BNIP3L/Nix: BCL2 interacting protein 3 like; CQ: chloroquine; DDX58: DExD/H-box helicase 58; eGFP: enhanced green fluorescent protein; hpi: hours post infection; IAV: influenza A virus; IFN: interferon; IP: immunoprecipitation; LIR: LC3-interacting region; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MAVS: mitochondrial antiviral signaling protein; MMP: mitochondrial membrane potential; MOI, multiplicity of infection; mRFP: monomeric red fluorescent protein; NBR1: NBR1 autophagy cargo receptor; NC: negative control; NLRP3: NLR family pyrin domain containing 3; PINK1: PTEN induced kinase 1; PRKN/PARK2: parkin RBR E3 ubiquitin protein ligase; RLR: RIG-I-like-receptor; ROS: reactive oxygen species; SEV: sendai virus; SQSTM1/p62: sequestosome 1; TAX1BP1: Tax1 binding protein 1; TM: transmembrane; TOMM20/40: translocase of outer mitochondrial membrane 20/40; TUFM: Tu translation elongation factor, mitochondrial.
甲型流感病毒（IAV）感染诱导细胞自噬，这对于清除受损的线粒体是必不可少的。功能失调的线粒体可以被 PINK1 选择性靶向，PINK1 招募 PRKN/PARK2 并导致随后的线粒体被自噬体隔离。IAV 的 PB1-F2 蛋白易位到线粒体，加速线粒体碎片化，并损害先天免疫。然而，PB1-F2 是否介导 IAV 诱导的细胞自噬以及自噬与 PB1-F2 减弱的先天免疫之间的关系仍不清楚。在这里，我们表明 PB1-F2 通过与 TUFM（Tu 翻译延伸因子，线粒体）相互作用和共定位而转移到线粒体。进一步的研究表明，PB1-F2 诱导完全的细胞自噬，这需要 PB1-F2 与 TUFM 和 MAP1LC3B/LC3B 的相互作用，介导自噬体的形成。PB1-F2 诱导的细胞自噬对于 MAVS（线粒体抗病毒信号蛋白）的降解至关重要，并导致其抑制 I 型 IFN 的产生。重要的是，PB1-F2 蛋白的 C 端 LIR 基序对于其诱导的细胞自噬和减弱的先天免疫是必需的。总之，PB1-F2 诱导的细胞自噬与细胞先天免疫受损密切相关，表明它是一个有潜力的治疗靶点。BCL2L13：BCL2 样 13；BECN1：自噬相关蛋白 1；BNIP3L/Nix：BCL2 相互作用蛋白 3 样；CQ：氯喹；DDX58：DExD/H 盒解旋酶 58；eGFP：增强型绿色荧光蛋白；hpi：感染后小时数；IAV：甲型流感病毒；IFN：干扰素；IP：免疫沉淀；LIR：LC3 相互作用区域；MAP1LC3B/LC3B：微管相关蛋白 1 轻链 3β；MAVS：线粒体抗病毒信号蛋白；MMP：线粒体膜电位；MOI，感染复数；mRFP：单体红色荧光蛋白；NBR1：NBR1 自噬货物受体；NC：阴性对照；NLRP3：NLR 家族包含pyrin 结构域的 3；PINK1：PTEN 诱导激酶 1；PRKN/PARK2：parkin RBR E3 泛素蛋白连接酶；RLR：RIG-I 样受体；ROS：活性氧；SEV：仙台病毒；SQSTM1/p62：自噬体相关蛋白 1；TAX1BP1：Tax1 结合蛋白 1；TM：跨膜；TOMM20/40：外线粒体膜转位酶 20/40；TUFM：Tu 翻译延伸因子，线粒体。
