Major viral protease that mediates proteolytic processing of the polyprotein. Cleaves host EIF5B, contributing to host translation shutoff. Cleaves also host PABPC1, contributing to host translation shutoff. Disassembles host cytoplasmic stress granules by cleaving host G3BP1, although this effect is less prononced than the inhibition induced by protease 2A. Cleaves host RIGI and thus contributes to the inhibition of type I interferon production. Cleaves host IRF7 and thus contributes to the inhibition of type I interferon production. Cleaves host HNRNPA1 thereby increasing the translation of apoptosis protease activating factor APAF1, leading to apoptosis of the host cell. Cleaves host NLRP1, triggers host N-glycine-mediated degradation of the autoinhibitory NLRP1 N-terminal fragment 