Seems to be essential for minus-strand RNAs and subgenomic 26S mRNAs synthesis (Probable). Displays mono-ADP-ribosylhydrolase activity (Probable). ADP-ribosylation is a post-translational modification that controls various processes of the host cell and the virus probably needs to revert it for optimal viral replication (Probable). Binds proteins of G3BP family and sequesters them into the viral RNA replication complexes thereby inhibiting the formation of host stress granules on viral mRNAs (Probable). The nsp3'-G3BP complexes bind viral RNAs and probably orchestrate the assembly of viral replication complexes, thanks to the ability of G3BP family members to self-assemble and bind DNA 