Effect of caffeine and reduced temperature (20 degrees C) on the organization of the pre-Golgi and the Golgi stack membranes

The cells were then chased for 60, 120, or 180 rain at 20~ in the absence (c, e, and g, respectively) or presence of 10 mM caffeine (d, f, and h, respectively), fixed, and labeled with antibodies to man II. Incubation of the cells in the presence of caffeine at 20~ inhibits the exit of man II from th ER after the removal of the BFA (d, f, and h). In control cells at 20~ already 60 rain after the BFA removal, man II can be seen to be located in peripheral elements and in some degree in the ER (c). After 120 min, man II is mainly in perinuclear elements (e). After a 180-rain chase in a caffeine-free medium at 20~ man II is located perinuclearly (g). Bar, 20 #m.