Protein N-glycosylation is essential for SARS-CoV-2 infection

Casas-Sanchez, Aitor; Romero-Ramirez, Alessandra; Hargreaves, Eleanor; Ellis, Cameron C.; Grajeda, Brian I.; Estevao, Igor; Patterson, Edward I.; Hughes, Grant L.; Almeida, Igor C.; Zech, Tobias; Acosta-Serrano, Álvaro

SARS-CoV-2 extensively N-glycosylates its spike proteins, which are necessary for host cell invasion and the target of both vaccines and immunotherapies. These sugars are predicted to help mediate spike binding to the host receptor by stabilizing its ‘open’ conformation and evading host immunity. Here, we investigated both the essentiality of the host N-glycosylation pathway and SARS-CoV-2 N-glycans for infection. Inhibition of host N-glycosylation using RNAi or FDA-approved drugs reduced virus infectivity, including that of several variants. Under these conditions, cells produced less virions and some completely lost their infectivity. Furthermore, partial deglycosylation of intact virions showed that surface-exposed N-glycans are critical for cell invasion. Altogether, spike N-glycosylation is a targetable pathway with clinical potential for treatment or prevention of COVID-19.