Coated pits in interphase and mitotic A431 cells.

Endocytosis is inhibited during mitosis in A431 cells (Warren et al., 1984) but the site of inhibition is unknown. A quantitative method measuring the extent of budding was used to compare coated pits in interphase and mitotic cells. Every stage of budding found in interphase cells was also found in cells at every stage of mitosis. Flatter coated pits appeared more frequent in mitotic cells but this can be partly, if not entirely, explained by their greater size. We conclude that, if budding is inhibited, inhibition must occur at all stages of the budding process.