PAK6 and infection: Conversely, when we performed luciferase assays using a plasmid harboring a mutant version of the PAK6 mRNA 3′-UTR (the miR-23a binding sites were inactivated by site-directed mutagenesis), the luciferase activity of the mutant reporter was unaffected by the simultaneous infection with miR-23a (Figure 4C).