Morphodynamics of the secretory pathway.

A careful scrutiny of the dynamics of secretory compartments in the entire eukaryotic world reveals many common themes. The most fundamental theme is that the Golgi apparatus and related structures appear as compartments formed by the act of transporting cargo. The second common theme is the pivotal importance for endomembrane dynamics of shifting back and forth the equilibrium between full and perforated cisternae along the pathway.

Soi3p/Rav1p functions at the early endosome to regulate endocytic trafficking to the vacuole and localization of trans-Golgi network transmembrane proteins.

SOI3 was identified by a mutation, soi3-1, that suppressed a mutant trans-Golgi network (TGN) localization signal in the Kex2p cytosolic tail. SOI3, identical to RAV1, encodes a protein important for regulated assembly of vacuolar ATPase. Here, we show that Soi3/Rav1p is required for transport between the early endosome and the late endosome/prevacuolar compartment (PVC).

Golgi inheritance under a block of anterograde and retrograde traffic.

In mitosis, the Golgi complex is inherited following its dispersion, equal partitioning and reformation in each daughter cell. The state of Golgi membranes during mitosis is controversial, and the role of Golgi-intersecting traffic in Golgi inheritance is unclear. We have used brefeldin A (BFA) to perturb Golgi-intersecting membrane traffic at different stages of the cell cycle and followed by live cell imaging the fate of Golgi membranes in those conditions.

The Arf activator Gea2p and the P-type ATPase Drs2p interact at the Golgi in Saccharomyces cerevisiae.

Arf GTPases regulate both the morphological and protein sorting events that are essential for membrane trafficking. Guanine nucleotide exchange factors (GEFs) specific for Arf proteins determine when and where Arf GTPases will be activated in cells. The yeast Gea2p Arf GEF is a member of an evolutionarily conserved family of high molecular mass Arf GEFs that are peripherally associated with membranes.