Dyn2 knockdown results in the formation of enlarged autophagic structures. (A–D) Transmission electron micrographs (TEMs) of oleate-loaded Hep3B hepatocytes treated with nontargeting control (siNT) or Dyn2 (siDyn2) siRNA for 72 h. Bars: (A and B) 2 µm; (A′ and B′) 1 µm; (C and D) 0.5 µm. Insets in A and B show fluorescent micrographs of LAMP1-stained cells (bars, 10 µM). Control cells (A) contain an abundance of small (<1 µm) electron-dense lysosomes and autolysosomes (arrowheads). Under conditions in which Dyn2 expression is suppressed (B–D), far fewer small lysosomes are observed. Instead, the cells are populated by larger autolysosomes (≥1 µm) with aberrant morphologies and containing putative LDs (*). (E) Quantitative measure of autolysosomal size from cells in which Dyn2 was knocked down as compared with control cells. Values represent the fold-increase in the number of autophagic structures of a given diameter (measured in microns) observed over siNT-treated control cells. Data were obtained from a single experiment with n = 6 cells examined by electron microscopy from each condition.