Figure 4.

Effects of wortmannin (Wm) treatment on the localization of the OSBP or FAPP1-PH-GFP fusion proteins in COS-7 cells. COS-7 cells were transfected with the indicated PH-GFP construct for 24 h and studied as live cells by confocal microscopy. (A) Cells were treated with 10 μM Wm for 30 min (at 37°C) to fully inhibit the type-III PI4Ks. There was a decrease in the Golgi localization of both PH domains after Wm treatment, but there was still a significant localization in vesicular compartments, often associated with the Golgi area. In most cases these vesicles were more dispersed than those in untreated cells. (B) The difference between pre- and post-Wm treatment is illustrated in a cell that was recorded both before and after the Wm treatment. The bottom panel shows a cell that rapidly loses some of its OSBP-PH domain localization after Wm treatment. Figure 7 shows additional examples of the effects of Wm treatment on the Golgi localization.