Structural Insight into the Interaction of Sendai Virus C Protein with Alix To Stimulate Viral Budding
Structural Insight into the Interaction of Sendai Virus C Protein with Alix To Stimulate Viral Budding
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DOI：
10.1128/jvi.00815-21
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发表时间：
2021-10-01
影响因子：
5.4
通讯作者：
Sakaguchi，Takemasa
中科院分区：
文献类型：
--
作者：
Oda，Kosuke;Matoba，Yasuyuki;Sakaguchi，Takemasa
仙台病毒（Sendai virus，SeV）属于副粘病毒科呼吸道病毒属（Respirovirusgenus），具有一种辅助蛋白C蛋白。此外，已知C蛋白通过与宿主ALG-2相互作用蛋白X（阿利克斯）结合来刺激病毒样颗粒的出芽，所述蛋白X是转运（ESCRT）机制所需的内体分选复合物的组分。然而，小干扰RNA（siRNA）介导的基因敲除研究表明，无论是阿利克斯或C蛋白是与SeV出芽。在本研究中，我们确定了一个复合物的晶体结构，包括C-末端的一半的C蛋白（Y3）和Bro 1结构域的阿利克斯在2.2毫米的分辨率调查的作用，复杂的SeV出芽。结构表明，一个新的共有序列，LXXW，这是保守的呼吸道病毒C蛋白，是重要的阿利克斯结合。SeV拥有一个突变的C蛋白与减少Alix结合亲和力显示受损的病毒生产，这与结合亲和力。与未突变的病毒相比，在感染后12小时，C蛋白的亲和力降低了160倍，而C蛋白与CHMP 4竞争结合阿利克斯，CHMP 4是ESCRT-III复合物的一个亚基。总之，这些结果突出了C蛋白在SeV出芽中的关键作用。重要提示人副流感病毒I型（hPIV 1）是一种呼吸道病原体，影响幼儿，免疫功能低下的患者和老年人，没有可用的疫苗或抗病毒药物。仙台病毒（SeV）是hPIV 1的鼠对应物，已被广泛研究以确定hPIV 1的分子和生物学特性。这些病毒具有多功能的辅助蛋白C蛋白，这是刺激病毒繁殖所必需的，但其在出芽中的作用仍有争议。在本研究中，与阿利克斯，细胞膜调节机械ESCRT的组成部分的Bro 1结构域相关的SeV C蛋白的C-末端的一半的晶体结构被阐明。基于该结构，我们设计了与阿利克斯具有不同结合亲和力的突变C蛋白，并表明C和阿利克斯之间的相互作用对病毒出芽至关重要。这些发现为开发针对hPIV 1的新型抗病毒药物提供了新的见解。
Sendai virus (SeV), belonging to theRespirovirusgenus of the familyParamyxoviridae, harbors an accessory protein, named C protein, which facilitates viral pathogenicity in mice. In addition, the C protein is known to stimulate the budding of virus-like particles by binding to the host ALG-2 interacting protein X (Alix), a component of the endosomal sorting complexes required for transport (ESCRT) machinery. However, small interfering RNA (siRNA)-mediated gene knockdown studies suggested that neither Alix nor C protein is related to SeV budding. In the present study, we determined the crystal structure of a complex comprising the C-terminal half of the C protein (Y3) and the Bro1 domain of Alix at a resolution of 2.2 Å to investigate the role of the complex in SeV budding. The structure revealed that a novel consensus sequence, LXXW, which is conserved amongRespirovirusC proteins, is important for Alix binding. SeV possessing a mutated C protein with reduced Alix-binding affinity showed impaired virus production, which correlated with the binding affinity. Infectivity analysis showed a 160-fold reduction at 12 h postinfection compared with nonmutated virus, while C protein competes with CHMP4, one subunit of the ESCRT-III complex, for binding to Alix. All together, these results highlight the critical role of C protein in SeV budding.IMPORTANCEHuman parainfluenza virus type I (hPIV1) is a respiratory pathogen affecting young children, immunocompromised patients, and the elderly, with no available vaccines or antiviral drugs. Sendai virus (SeV), a murine counterpart of hPIV1, has been studied extensively to determine the molecular and biological properties of hPIV1. These viruses possess a multifunctional accessory protein, C protein, which is essential for stimulating viral reproduction, but its role in budding remains controversial. In the present study, the crystal structure of the C-terminal half of the SeV C protein associated with the Bro1 domain of Alix, a component of cell membrane modulating machinery ESCRT, was elucidated. Based on the structure, we designed mutant C proteins with different binding affinities to Alix and showed that the interaction between C and Alix is vital for viral budding. These findings provide new insights into the development of new antiviral drugs against hPIV1.