Aut7p, a soluble autophagic factor, participates in multiple membrane trafficking processes

Aut7p, a protein recently implicated in autophagic events in the yeast Sacc haromyces cerevisiae, exhibits significant homology to a mammalian protein, p16, herein termed GATE-16 (Golgi-associated ATPase Enhancer of 16 kDa), a novel intra-Golgi transport factor. Here we provide evidence for the invol vement of Aut7p in different membrane trafficking processes. Aut7p largely substitutes for the activity of GATE-16 in mammalian intra-Golgi transport in vitro. In vivo, AUT7 interacts genetically with endoplasmic reticulum to Golgi SNAREs, specifically with BET1 and SEC22. Aut7p interacts physically with the following two v-SNAREs: Bet1p, which is involved in endoplasmic r eticulum to Golgi vesicular transport, and Nyv1p, implicated in vacuolar in heritance. We suggest that, in addition to its role in autophagocytosis, Au t7p has pleiotropic effects and participates in at least two membrane traff ic events.