SARS-CoV-2 ORF8 reshapes the ER through forming mixed disulfides with ER oxidoreductases

• Published in: Redox biology 2022-08, Vol.54, p.102388-102388, Article 102388
• Main Authors: Liu, Ping, Wang, Xi, Sun, Yiwei, Zhao, Hongyu, Cheng, Fang, Wang, Jifeng, Yang, Fuquan, Hu, Junjie, Zhang, Hong, Wang, Chih-chen, Wang, Lei
• Format: Article
• Language: English
• Subjects: Endoplasmic reticulum; ORF8; Redox; Research Paper; SARS-CoV-2; Unfolded protein response
• ISSN: 2213-2317; 2213-2317
• DOI: 10.1016/j.redox.2022.102388

The replication machinery of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is closely associated with the endoplasmic reticulum (ER) in host cells. Activation of the unfolded protein response (UPR) is a strategy hijacked by coronavirus to facilitate its replication and suppress host innate immunity. Here, we have found that SARS-CoV-2 ORF8 protein accumulates in the ER and escapes the degradation system by forming mixed disulfide complexes with ER oxidoreductases. ORF8 induces the activation of three UPR pathways through targeting key UPR components, remodels ER morphology and accelerates protein trafficking. Moreover, small molecule reducing agents release ORF8 from the mixed disulfide complexes and facilitate its degradation, therefore mitigate ER stress. Our study reveals a unique mechanism by which SARS-CoV-2 ORF8 escapes degradation by host cells and regulates ER reshaping. Targeting ORF8-involved mixed disulfide complexes could be a new strategy to alleviate SARS-CoV-2 induced ER stress and related diseases. Image 1 • SARS-CoV-2 ORF8 protein accumulates in the ER through forming mixed disulfide complexes. • Two key protein disulfide isomerases, PDI and ERp44, are main targets of ORF8. • ORF8 induces ER stress, remodels the ER and accelerates protein trafficking. • Small molecule reducing agents facilitates the degradation of ORF8 and mitigates ER stress.