A. The ypt1-1 mutation is epistatic to vps21∆ in ER-phagy. yDsRed-Snc1-PEM was overexpressed in WT, vps21∆, ypt1-1 and ypt1-1vps21∆ double mutant cells that also expressed the autophagosomal marker yEGFP-Atg8. Cells were analyzed by live-cell microscopy. Shown from left to right: DIC, DsRed, GFP, merge, % cells Atg8 dots, number of Atg8 dots per cell, and % cells in which the Atg8 dots co-localize with Snc1-PEM. About 50% of WT and 85% of vps21∆ mutant cells contain ~1 dot of Atg8 representing the AP. Importantly, in ~70% of the vps21∆ mutant cells Snc1-PEM co-localizes with the APs, as compared to ~4% in WT cells. In contrast, ~90% ypt1-1 and ypt1-1vps21∆ mutant cells contain three APs per cell, and Snc1-PEM does not co-localize with them. Arrows point to co-localization; arrowheads point to either Atg8 dots or GFP-Snc1-PEM that do not co-localize. 