The mechanism by which the conserved Ypt1/Rab1 #GTPases mediate the beginning of #secretion and #autophagy is unknown. In @jcb.org, Gyurkovska, Segev et al. use in vivo analysis to show that distinct TRAPP complexes activate the yeast Ypt1 in secretion and autophagy rupress.org/jcb/article/...