d-cer-C6 treatment alters Golgi membrane morphology. (A) HeLa cells were treated with ethanol, 20 µM l-cer-C6, or 20 µM d-cer-C6 for 4 h and fixed, and the morphology of the Golgi membranes was observed by electron microscopy. (B) HeLa cells expressing ST-GFP were treated with ethanol, 20 µM l-cer-C6, or 20 µM d-cer-C6 for 4 h and fixed, and the localization of ST-GFP was visualized by cryoimmunoelectron microscopy. Bars, 200 nm.