SERCA2 tethers the ER with the isolation membrane through interaction with the ULK1/FIP200 complex and LC3B. (A) Co-IP of FLAG-SERCA2 with the ULK1/FIP200 complex members in transfected SUM1315 cells. (B) Co-localization of DFCP1 with SERCA2 in SUM1315 cells treated with or without EBSS for 1 h. Left panel, Representative images. Scale bar, 5 μm. Right panel, quantification of co-localization. n = 200 puncta. (C) Co-IP of LC3B with the ULK1/FIP200 complex members in SUM1315 cells transiently transfected with the indicated plasmids. (D) Western blot analysis of indicated proteins in SUM1315 cells transfected with the indicated siRNA or plasmids, which were then treated with EBSS for 12 h. (E) Co-localization of FIP200 with LC3 in SUM1315 cells transfected with the indicated siRNA or plasmids, which were then treated with EBSS for 1 h. Upper panel, representative images. Scale bars, 5 μm; insets, 2 μm. Lower panel, quantification of co-localization. n = 200 puncta. (F) Co-localization of DFCP1 with LC3 in SUM1315 cells transfected with the indicated plasmids, which were then treated with EBSS for 4 h in the absence or presence of 100 nmol/L thapsigargin (TG). Upper panel, representative images. Scale bars, 5 μm; insets, 2 μm. Lower panel, quantification of co-localization. n = 200 puncta. Data are shown as the mean ± SD of at least three independent experiments. ∗P < 0.05, ∗∗∗P < 0.001.