Post-translational modifications of coronavirus proteins: roles and function

Fung, To Sing; Liu, Ding Xiang

N-linked glycosylation may also contribute to the activation of innate immune response in coronavirus-infected cells. Pretreatment of TGEV-infected cells with the plant lectin concanavalin A before exposure to porcine peripheral blood mononuclear cells led to a dose-dependent reduction in the induction of IFN-α. Also, inhibition of Nlinked glycosylation by tunicamycin or removal of N-linked glycans by PNGase F reduced TGEV-induced IFN-α production [64] . Therefore, N-linked glycans on coronavirus S protein may be a pathogen-associated molecular pattern recognized by host pattern recognition receptors, which in turn activate downstream antiviral innate immune response. However, compared with the parental PEDV strain, the more effective host immune response against the cell attenuated Zhejiang08 strain was associated with the lack of a potential glycosylation site in its S protein [65] . Thus, the effect of S protein glycosylation on the immune response is complex, which may vary depending on the specific coronavirus and host system in question.