FIG. 4.

Protection of viral gB from proteinase K correlates with endocytic entry. After virus attachment for 45 min at 4°C, cells were either held at 4°C (lanes 1 and 3) or incubated at 37°C for 10 min (lanes 2 and 4) and then chilled on ice. Cells were then digested (lanes 3 and 4) or mock treated (lanes 1 and 2) with proteinase K and lysed in the presence of PMSF. gB was immunoprecipitated from the lysates and detected by Western blotting.