tetano
Editor, Senior Moderator
Dev Cell
. 2021 Oct 11;S1534-5807(21)00807-8.
doi: 10.1016/j.devcel.2021.10.006. Online ahead of print.
ORF3a of SARS-CoV-2 promotes lysosomal exocytosis-mediated viral egress
Di Chen[SUP] 1 [/SUP], Qiaoxia Zheng[SUP] 1 [/SUP], Long Sun[SUP] 2 [/SUP], Mingming Ji[SUP] 1 [/SUP], Yan Li[SUP] 3 [/SUP], Hongyu Deng[SUP] 2 [/SUP], Hong Zhang[SUP] 4 [/SUP]
Affiliations
Abstract
Viral entry and egress are important determinants of virus infectivity and pathogenicity. β-coronaviruses, including the COVID-19 virus SARS-CoV-2 and mouse hepatitis virus (MHV), exploit the lysosomal exocytosis pathway for egress. Here, we show that SARS-CoV-2 ORF3a, but not SARS-CoV ORF3a, promotes lysosomal exocytosis. SARS-CoV-2 ORF3a facilitates lysosomal targeting of the BORC-ARL8b complex, which mediates trafficking of lysosomes to the vicinity of the plasma membrane, and exocytosis-related SNARE proteins. The Ca[SUP]2+[/SUP] channel TRPML3 is required for SARS-CoV-2 ORF3a-mediated lysosomal exocytosis. Expression of SARS-CoV-2 ORF3a greatly elevates extracellular viral release in cells infected with the coronavirus MHV-A59, which itself lacks ORF3a. In SARS-CoV-2 ORF3a, Ser171 and Trp193 are critical for promoting lysosomal exocytosis and blocking autophagy. When these residues are introduced into SARS-CoV ORF3a, it acquires the ability to promote lysosomal exocytosis and inhibit autophagy. Our results reveal a mechanism by which SARS-CoV-2 interacts with host factors to promote its extracellular egress.
Keywords: COVID-19; ORF3a; SARS-CoV; SARS-CoV-2; lysosomal exocytosis.
. 2021 Oct 11;S1534-5807(21)00807-8.
doi: 10.1016/j.devcel.2021.10.006. Online ahead of print.
ORF3a of SARS-CoV-2 promotes lysosomal exocytosis-mediated viral egress
Di Chen[SUP] 1 [/SUP], Qiaoxia Zheng[SUP] 1 [/SUP], Long Sun[SUP] 2 [/SUP], Mingming Ji[SUP] 1 [/SUP], Yan Li[SUP] 3 [/SUP], Hongyu Deng[SUP] 2 [/SUP], Hong Zhang[SUP] 4 [/SUP]
Affiliations
- PMID: 34706264
- DOI: 10.1016/j.devcel.2021.10.006
Abstract
Viral entry and egress are important determinants of virus infectivity and pathogenicity. β-coronaviruses, including the COVID-19 virus SARS-CoV-2 and mouse hepatitis virus (MHV), exploit the lysosomal exocytosis pathway for egress. Here, we show that SARS-CoV-2 ORF3a, but not SARS-CoV ORF3a, promotes lysosomal exocytosis. SARS-CoV-2 ORF3a facilitates lysosomal targeting of the BORC-ARL8b complex, which mediates trafficking of lysosomes to the vicinity of the plasma membrane, and exocytosis-related SNARE proteins. The Ca[SUP]2+[/SUP] channel TRPML3 is required for SARS-CoV-2 ORF3a-mediated lysosomal exocytosis. Expression of SARS-CoV-2 ORF3a greatly elevates extracellular viral release in cells infected with the coronavirus MHV-A59, which itself lacks ORF3a. In SARS-CoV-2 ORF3a, Ser171 and Trp193 are critical for promoting lysosomal exocytosis and blocking autophagy. When these residues are introduced into SARS-CoV ORF3a, it acquires the ability to promote lysosomal exocytosis and inhibit autophagy. Our results reveal a mechanism by which SARS-CoV-2 interacts with host factors to promote its extracellular egress.
Keywords: COVID-19; ORF3a; SARS-CoV; SARS-CoV-2; lysosomal exocytosis.