Figure 5

dNTPase activity of SAMHD1 oligomerization variants immunoprecipitated from mammalian cells. The indicated FLAG-tagged SAMHD1 variants were immunoprecipitated (A), and tested for their ability to hydrolyze α - ³²P-TTP to dT and α - ³²PPP, in the presence of the allosteric activator dGTP. Reactions products were separated using thin-layer chromatography using polyethyleneimine cellulose in order to determine the amount of hydrolyzed α - ³²PPP (B). As a control, we have included the mutant HD206AA, which is a SAMHD1 protein defective in the active site of the HD domain. The results of three independent enzymatic reactions per treatment are shown. WT, wild type; CIP, calf intestine phosphatase.