Figure 2. Sec bodies are non-membrane bound structures.
(A) Immuno-electron microscopy (IEM) visualization of Sec16 (10 nm colloidal gold) in Sec bodies in ultrathin sections of S2 cells incubated in KRB for 4 hr. Arrows point to membrane in close proximity of Sec bodies. E, endosomes; n, nucleus; m, mitochondria. (B) Visualization of Sec bodies (Sec16, green) and lipid droplets (marked by oil-red-O, red). Note that 95% of Sec bodies do not co-localize with lipid droplets. (C–C′) Visualization of Sec bodies (Sec16, red) and Atg5-GFP punctae (C) and GFP-Atg8 (C′) after 4 hr starvation. Note that 82% of Sec bodies do not co-localize with Atg5 or Atg8 punctae. Scale bars: 500 nm (A); 10 μm (B, C).