Figure 4. Atg17 is associated with lysosomes and colocalizes with Atg8a, Atg5, and Ref(2)P. (A) Atg17-GFP colocalizes with endogenous Atg8a in fat cells of starved larvae. (B) No punctate Atg17 or Atg5 structures are seen in well-fed Atg8a-null mutant gastric ceca. (C) Endogenous Atg17 colocalizes with Atg5-positive PAS in starved Atg8a-null mutant gastric ceca. (D) Atg17-GFP localizes to Ref(2)P aggregates in control larvae. (E) Endogenous Atg17 colocalizes with endogenous Ref(2)P in Atg7-null mutants. (F) No cytoplasmic Atg17 dots are seen in starved atg17-null mutants, while nonspecific nuclear staining is observed. (G) Transient expression of Atg17-GFP rescues punctate LTR staining in fat body cells of starved atg17-null mutants. Note that Atg17 dots are tightly associated with LTR-positive autolysosomes. (H) Endogenous Atg17 accumulates near Cp1-positive lysosomes in Atg7-null mutant fat cells. (I) Punctate Ref(2)P-GFP structures are observed near LTR-positive autolysosomes. Scale bar in (A): 20 µm for (A, B, E, F, H, and I); in (C): 20 µm for (C, D, and G). Boxed areas are shown enlarged with merged image (top), red channel in grayscale (middle) and green channel in grayscale (bottom). FB, fat body; GC, gastric ceca.