PPP1R3A and infection: Consistently, flow cytometry analysis showed that HSV-1 infection led to extensive apoptosis (Annexin V-FITC/PI-labeled) in THP-1 cells in a time- and dose-dependent manner, while HSV-1-ΔUL10 infection could not induce a similar effect (Fig 5G and 5H), suggesting that gM protein is required for HSV-1 infection-induced apoptosis.