Figure 5

The serine/threonine kinase activity of PRV US3 protein interfered with the GTPase activity of GBP1. A The actin cytoskeleton was not damaged during the early stages of PRV infection (1 MOI, 4 h). Representative immunofluorescent stain of DAPI (blue), EP0 (cherry), and F-actin (green). Scale bar, 10 μm. B–D HEK293T cells were transfected with the indicated plasmids and GTPase activity was measured by enzyme-linked inorganic phosphate assay (ELIPA). The 293T cells transfected HA-GBP1(K51A) served as a control without GTPase activity. B The GTPase activity of GBP1 was suppressed during PRV infection. At 24 h post-transfection, cells were infected with or without PRV (1 MOI) for 2 h. Relative change in amount of GTPase activity.** P < 0.01, versus the cells expressing HA-GBP1. C The GTPase activity of GBP1 was suppressed by PRV US3. Relative change in the amount of GTPase activity. ** P < 0.01, versus the HA-GBP1 and pEGFP-N1 vector-transfected cells. D The US3 serine/threonine kinase activity was required for interfering with the GTPase activity of GBP1. Relative change in amount of GTPase activity. ** P < 0.01, versus the HA-GBP1 plasmid transfected cells.