Dyn2 knockdown disrupts autophagic lysosomal reformation (ALR) and lysosomal tubule scission. Hep3B cells treated with either a nontargeting control siRNA (A and B, siNT) or an siRNA targeting human Dyn2 (C and D, siDyn2) were fixed and stained with an antibody specific for LAMP1 after a 24-h starvation period in media containing 0.1% FBS. Control cells displayed normal lysosomal compartments, with LAMP1-stained structures dispersed throughout the cytosol, some containing short reformation tubules (B′). After Dyn2 knockdown, many cells contained enlarged autolysosomes with a noticeable increase in persistent and lengthy reformation tubules emanating from LAMP1-positive compartments (C′ and D′). Bars: (A–D) 20 µM; (A′ and B′) 5 µM; (C′ and D′) 10 µM. (E and F) Measurements of the length (E) and distribution (F) of LAMP1-stained ALR tubules in control (siNT) and siDyn2-treated cells. Data represent the mean derived from measurements of tubules in a minimum of 40 cells for each experimental group over 6 independent experiments. Error bars represent SE; *, P ≤ 0.05; **, P ≤ 0.01. (G) TEM of siDyn2-treated Hep3B hepatocyte exhibiting enlarged autolysosomal structures with extensive tubulation (arrows). Bar, 2 µm. (G′) Inset showing enlargement of autolysosomal tubule (arrows). Bar, 1 µm. (H) Tubulating autolysosome with engulfed lipid droplet. Bar, 0.5 µm.