a, Live blebbishields internalized labelled surface membranes (arrowheads), but fixed blebbishields did not. Note the labelling is restricted to the surface (arrows). DIC, differential interference contrast. b, Nocodazole-arrested mitotic cells did not internalize surface membranes. c, Genetic labelling of Golgi membranes using Golgi-CFP revealed that they were exposed to the cell surface (arrows) during metaphase and telophase in untreated 293T mitotic cells and underwent fusion during telophase. CF, mitotic cleavage furrow; FF, fusion furrow. DIC, differential interference contrast. d, 293T mitotic cells were capable of fusion with blebbishields derived from RT4P cells. n, number of colonies.