Grin Peter M, Baid Kaushal, de Jesus Hugo C R, Kozarac Nedim, Bell Peter A, Jiang Steven Z, Kappelhoff Reinhild, Butler Georgina S, Leborgne Nathan G F, Pan Christina, Pablos Isabel, Machado Yoan, Vederas John C, Kim Hugh, Benarafa Charaf, Banerjee Arinjay, Overall Christopher M
Department of Biochemistry and Molecular Biology, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada; Centre for Blood Research, University of British Columbia, Life Sciences Centre, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
Vaccine and Infectious Diseases Organization, Department of Veterinary Microbiology, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada.
Cell Rep. 2024 Dec 24;43(12):115080. doi: 10.1016/j.celrep.2024.115080. Epub 2024 Dec 12.
SARS-CoV-2 3C-like protease (3CL or M) cleaves the SARS-CoV-2 polyprotein and >300 intracellular host proteins to enhance viral replication. By lytic cell death following gasdermin (GSDM) pore formation in cell membranes, antiviral pyroptosis decreases 3CL expression and viral replication. Unexpectedly, 3CL and nucleocapsid proteins undergo unconventional secretion from infected cells via caspase-activated GSDMD/E pores in the absence of cell lysis. Bronchoalveolar lavage fluid of wild-type SARS-CoV-2-infected mice contains 3CL, which decreases in GsdmdGsdme mice. We identify new 3CL cut-sites in GSDMD at LQ↓SS, which blocks pore formation by 3CL cleavage at LH↓N lying adjacent to the caspase activation site (NFLTD↓G). Cleavage inactivation of GSDMD prevents excessive pore formation, thus countering antiviral pyroptosis and increasing 3CL secretion. Extracellular 3CL retains activity in serum, dampens platelet activation and aggregation, and inactivates antiviral interferon-λ1. Thus, in countering gasdermin pore formation and pyroptosis in SARS-CoV-2 infection, 3CL is secreted with extracellular pathological sequelae.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）的3C样蛋白酶（3CL或M）可切割SARS-CoV-2多蛋白和300多种细胞内宿主蛋白，以增强病毒复制。抗病毒细胞焦亡通过细胞膜上gasdermin（GSDM）孔形成后的溶细胞性细胞死亡来降低3CL表达和病毒复制。出乎意料的是，在没有细胞裂解的情况下，3CL和核衣壳蛋白通过半胱天冬酶激活的GSDMD/E孔从受感染细胞中进行非常规分泌。野生型SARS-CoV-2感染小鼠的支气管肺泡灌洗液中含有3CL，在GsdmdGsdme小鼠中其含量会降低。我们在GSDMD的LQ↓SS处鉴定出了新的3CL切割位点，该位点可通过在与半胱天冬酶激活位点（NFLTD↓G）相邻的LH↓N处进行3CL切割来阻断孔的形成。GSDMD的切割失活可防止过度的孔形成，从而对抗抗病毒细胞焦亡并增加3CL分泌。细胞外的3CL在血清中保持活性，抑制血小板活化和聚集，并使抗病毒干扰素-λ1失活。因此，在对抗SARS-CoV-2感染中的gasdermin孔形成和细胞焦亡时，3CL会与细胞外病理后遗症一起分泌。
