Flag-PP1 (α, β and γ) expression plasmids cloned in Flag-CMV4 were provided by Dr. Sherry Winter [53 (link)]. Flag-IRF7 expression plasmids and its mutants were described previously [54 , 55 (link)]. 2XMyc-IRF7 plasmids were generated by subcloning of 2XMyc-IRF7 fragment (by PCR amplification from pcDNA3-IRF7) into pCMV-Tag3B (Stratagene). TLR7 cDNA was cloned from human genome (the human B cell line BJAB) by PCR amplification. Deletion and point mutants were generated by site-directed mutation (Stratagene), and verified by sequencing. PE-conjugated IRF7(p477/479) antibody (clone K47–671) for flow cytometry was purchased from BD Biosciences. The same clone with higher concentration but without conjugation was customized for immunoblotting. Mouse anti-PP1 (clone E-9), mouse anti-PP1α (clone G-4), goat anti-PP1α (clone C19), mouse anti-IRF7 (clone G-8), rabbit anti-IRF7 (clone H-246), goat anti-mouse IgG-HRP, mouse anti-rabbit IgG-HRP, and mouse anti-goat IgG-HRP, were purchased from Santa Cruz. Flag (clone M2) and Myc (clone 9E10) antibodies were from Sigma and Roche, respectively. FITC-, PE-, APC-, and PerCP-eFluor710-conjugated antibodies for flow cytometry were purchased from eBioscience. Gardiquimod (designated as “Gardi” in figure legend) and HIV-1 ssRNA40 and controls were purchased from Invivogen. IFNα2 was purchased from Sigma. Tautomycin was purchased from EMD Millipore.