Figure EV3. Early autophagic structures form at ER‐PM and ER–mitochondria contact sites.

• A, B
  Confocal microscope images of HeLa cells co‐transfected with GFP‐DFCP1 (an omegasome marker), RFP‐Sec61β (an ER marker) and myc‐E‐Syt2 (an ER‐PM contact sites marker) or immunostained for TOM20 (a mitochondria marker) under starved conditions (15 min). Arrowheads denote omegasome formation at (A) ER‐PM or (B) ER–mitochondria contact sites. Scale bars, 10 μm.
• C
  Quantification of percent DFCP1‐positive structures at ER‐PM (Sec61β/E‐Syt2 interface) and ER–mitochondria (Sec61β/TOM20 interface) contact sites. Plotted are mean ± s.e.m., n = 80.
• D
  Electron microscopy images of HeLa cells transfected with the ER luminal marker ssHRP‐myc‐KDEL and starved for 1 h showing autophagic structures adjacent (within 1 μm) to ER‐PM contact sites (ER‐PM), ER‐mitochondria contact sites (ER‐mito) and to neither organelle (cytoplasm). The quantification of these autophagic structures is shown as well. Plotted are means ± s.e.m., n = 80 cells.