Fig. 5

Phosphorylation of SAMHD1 at threonine 603 negatively correlates with infectivity in primary mouse cells. Cycling murine embryonic fibroblasts (MEFs) from SAMHD1 KO and SAMHD1 WT mice were infected with a VSV-G/HIV-GFP or b VSV-G/MLV-GFP reporter virus at a MOI of 1. Three days postinfection, viral infectivity was quantified by flow cytometry. Viral infectivity is shown as percent infection relative to the infection of cells from a WT mouse. c Phosphorylation of murine SAMHD1 at T603 in primary murine cells. MEFs and BMDCs from SAMHD1 KO and WT mice were lysed and analyzed by SDS-PAGE and immunoblot. Lysates from cycling (−PMA) and noncycling human THP-1 cells served as positive and negative control for SAMHD1 phosphorylation. Membranes were incubated with antibodies detecting SAMHD1 (MAb 3F5) and phosphorylated SAMHD1 (anti-pSAMHD1-T592)