Figure 3.

Ultrastructural changes in the Golgi region during reversal from a H89 block. Cells were incubated at 20°C for 2 h. 50 μM H89 was added during the last 30 min of incubation at this temperature. They were transferred to 37°C and additionally incubated with H89 for 30 min. (A) Cells were directly fixed and processed for electron microscopy. (B) Alternatively, they were additionally incubated in H89-free medium for 8 min prior to fixation. Vesicles and buds located at the trans Golgi face are indicated with arrowheads and arrows, respectively. (C) Number of free coated vesicles in the Golgi area determined as described in Materials and Methods. Data (mean ± SD) are the average of at least five different Golgi areas. (Bars = 0.25 μm.)