Discerning the mechanisms of cell membrane budding by coronavirus non-structural proteins nsp3, nsp4, and nsp6

人类中病毒感染的发生可以追溯到20世纪初，此后出现了各种各样的病毒病原体。具体来说，冠状病毒导致了严重急性呼吸系统综合征（SARS）、中东呼吸综合征（MERS）和SARS- cov -2大流行。在宿主细胞的冠状病毒感染过程中，一组非结构蛋白（nsps）对促进病毒复制至关重要——nsp3、nsp4和nsp6。这些跨膜蛋白被确定在内质网（ER）膜变形中发挥积极作用，与其他宿主蛋白结合形成双膜泡（DMV）。dmv是一种重要的复制结构，它通过为细胞和病毒成分提供理想的环境，同时为宿主细胞防御机制提供保护，从而有助于病毒RNA的合成。尽管由nsp蛋白诱导的DMV结构的形成在冠状病毒和十年前的SARS流行中是保守的，但控制nsp诱导的DMV形成的基本生化和生物物理机制仍然知之甚少。因此，我们建议使用重组仿生膜系统和sars - cov -2衍生的nsp蛋白和肽来研究DMV形成背后的生化和生物力学方面。这可以通过广泛的生物物理和成像方法来确定脂质膜在与nsps结合时如何改变生物物理特性和相互作用动力学来实现。该项目的研究结果将极大地促进我们对nsp驱动的冠状病毒复制的分子机制的理解。

The occurrence of viral infections in human populations dates to the early 20th century and a large variety of viral pathogens have emerged since. Specifically, Coronaviridae have caused the severe acute respiratory syndrome (SARS) epidemic, the Middle-East respiratory syndrome (MERS), and the SARS-CoV-2 pandemic. Throughout coronaviral infections in host cells, a set of non-structural proteins (nsps) is crucial for facilitating viral replication - nsp3, nsp4, and nsp6. These membrane-spanning proteins were determined to play an active role in deforming the endoplasmic reticulum (ER) membrane in conjunction with other host proteins to form double-membrane vesicles (DMV). DMVs are important replicative structures, which contribute to viral RNA synthesis by providing an ideal environment of cellular and viral constituents while offering protection from host cell defence mechanisms. Despite the formation of DMV structures induced by nsp proteins being conserved in coronaviruses and the SARS epidemic dating back a decade, essential biochemical and biophysical mechanisms governing nsp-induced DMV formation remain poorly understood. Thus, we propose the use of reconstituted biomimetic membrane systems and SARS-CoV-2-derived nsp proteins and peptides to study the biochemical and biomechanical aspects underlying DMV formation. This can be achieved by determining how biophysical properties and interaction dynamics of lipid membranes are altered when bound to nsps, by means of a wide range of biophysical and imaging methods. The results of this project will greatly further our understanding of the molecular mechanisms in nsp-driven coronaviral replication.