Second Clinical Medical College of Jinan University, Shenzhen Peoples Hospital, Shenzhen 518000, China; Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun 130122, China.
Second Clinical Medical College of Jinan University, Shenzhen Peoples Hospital, Shenzhen 518000, China.
Int J Biochem Cell Biol. 2022 Dec;153:106325. doi: 10.1016/j.biocel.2022.106325. Epub 2022 Oct 28.
IFITM proteins are a host restriction factor with broad-spectrum antiviral activity, but the role in the paramyxovirus entry remains unclear. Nipah virus (NiV) is a zoonotic virus of the paramyxoviridae with extremely high lethality. Here, we assessed the role of IFITM3 on NiV G and F glycoprotein-mediated virus entry. Using NiV pseudovirus bearing NiV G and F proteins to infect IFITM3-induced MDCK cells, we found that overexpression of IFITM3 promotes NiV G and F proteins-mediated virus entry. Mechanistically, the subcellular distribution showed that F protein completely co-localized with IFITM3, but G protein does not. Immunoprecipitation further indicated that IFITM3 strongly captures F protein rather than G protein. F protein truncation found that the F1 subunit completely co-localized and captures with IFITM3, but not the F2 subunit. Furthermore, IFITM3 strongly binds to F1 truncations containing fusion peptide (FP), and F1 strongly captures IFITM3 truncation with the intramembrane domain (IMD). Together, the results suggest that IFITM3 can promote NiV G and F proteins-mediated virus entry into MDCK cells, and IFITM3 directly interacts with the F1 subunit of NiV F protein dependent on the former's IMD and the latter's FP, which may occur after incorporation of fusion peptides into the cell membrane following virus fusion activation.
IFITM 蛋白是一种具有广谱抗病毒活性的宿主限制因子，但在副粘病毒进入细胞过程中的作用尚不清楚。尼帕病毒（NiV）是副粘病毒科的一种人畜共患病病毒，具有极高的致死率。在这里，我们评估了 IFITM3 在尼帕病毒 G 和 F 糖蛋白介导的病毒进入中的作用。我们使用携带 NiV G 和 F 蛋白的 NiV 假病毒感染 IFITM3 诱导的 MDCK 细胞，发现 IFITM3 的过表达促进了 NiV G 和 F 蛋白介导的病毒进入。从机制上讲，亚细胞分布显示 F 蛋白完全与 IFITM3 共定位，但 G 蛋白不与 IFITM3 共定位。免疫沉淀进一步表明，IFITM3 强烈捕获 F 蛋白而不是 G 蛋白。F 蛋白截短发现 F1 亚基完全与 IFITM3 共定位并捕获，但 F2 亚基不与 IFITM3 共定位。此外，IFITM3 与包含融合肽（FP）的 F1 截短强烈结合，而 F1 则强烈捕获含有跨膜域（IMD）的 IFITM3 截短。总之，这些结果表明，IFITM3 可以促进 NiV G 和 F 蛋白介导的病毒进入 MDCK 细胞，并且 IFITM3 直接与 NiV F 蛋白的 F1 亚基相互作用，这依赖于前者的 IMD 和后者的 FP，这可能发生在病毒融合激活后融合肽被整合到细胞膜中之后。
