EIF3F and infection: Although we validated cleavage of several 3Cpro high-confidence candidate substrates identified by TAILS in virus-infected cells, it was not surprising that a few of the top candidate substrates were cleaved in vitro but not during virus infection (e.g., actin, eIF3F, and fascin) (data not shown; see also Table S6 in the supplemental material), indicating that an in vitro cleavage assay approach does not fully recapitulate in vivo infection, as expected.