Figure 8.

A model for the coordination of entry into and exit from the yeast Golgi by a GEF complex common to Ypt1 and Ypt31/32 GTPases. Ypt1 GTPase is required for ER-to-Golgi transport Golgi (Segev et al., 1988; Baker et al., 1990; Jedd et al., 1995), while the Ypt31/32 functional pair is essential for exit from the trans-Golgi (Jedd et al., 1997). A common GEF complex, TRAPP, might coordinate these steps through the regulation of the Ypt GTPases activation. The importance of such a coordination is discussed in the text.