Nucleocapsid proteins from human coronaviruses possess phase separation capabilities and promote FUS pathological aggregation

• Published in: Protein science Vol. 32; no. 12; pp. e4826 - n/a
• Main Authors: Dong, Hui, Zhang, Hong, Jalin, Julie, He, Ziqi, Wang, Runhan, Huang, Leqi, Liu, Zibo, Zhang, Shenqing, Dai, Bin, Li, Dan
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.12.2023; Wiley Subscription Services, Inc
• Subjects: Amyloid; Amyotrophic lateral sclerosis; Coronaviridae; Coronaviruses; COVID-19; FUS protein; Homeostasis; Homology; human coronaviruses; Liquid phases; N protein; nucleocapsid proteins; Nucleocapsids; Packaging; Phase separation; Phase transitions; Proteins; Replication; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Solid phases; Viral diseases
• ISSN: 0961-8368; 1469-896X
• DOI: 10.1002/pro.4826

The nucleocapsid (N) protein is an essential structural component necessary for genomic packaging and replication in various human coronaviruses (HCoVs), such as SARS‐CoV‐2 and MERS‐CoV. Recent studies have revealed that the SARS‐CoV‐2 N protein exhibits a high capacity for liquid–liquid phase separation (LLPS), which plays multiple roles in viral infection and replication. In this study, we systematically investigate the LLPS capabilities of seven homologous N proteins from different HCoVs using a high‐throughput protein phase separation assay. We found that LLPS is a shared intrinsic property among these N proteins. However, the phase separation profiles of the various N protein homologs differ, and they undergo phase separation under distinct in vitro conditions. Moreover, we demonstrate that N protein homologs can co‐phase separate with FUS, a SG‐containing protein, and accelerate its liquid‐to‐solid phase transition and amyloid aggregation, which is closely related to amyotrophic lateral sclerosis. Further study shows that N protein homologs can directly bind to the low complexity domain of FUS. Together, our work demonstrates that N proteins of different HCoVs possess phase separation capabilities, which may contribute to promoting pathological aggregation of host proteins and disrupting SG homeostasis during the infection and replication of various HCoVs.