Fig. 4.

Electron microscopy localization of epsin 3 at coated pits and vesicles at the base of apical canaliculi. Immunogold labeling of ultrathin frozen sections. H/K ATPase is localized, as expected, on intracellular tubulovesicles (asterisks) in cimetidine-treated samples and on the surface of microvilli (arrows) in histamine-treated cells. In both conditions, epsin 3 (polyclonal antibodies) and clathrin are found at the surface of invaginations among microvilli and on underlying coated vesicles. (Scale bars, 100 nm.)