Uptake of fluorescent nano beads into BY2‐cells involves clathrin‐dependent and clathrin‐independent endocytosis

To follow endocytosis in BY‐2 cells we made use of fluorescent nano beads. Beads with 20 nm in diameter were internalised rapidly and accumulated partially in compartments also labelled by the endocytic marker FM4‐64. Studies in BY‐2 cells and protoplasts revealed that larger beads (100 nm) were excluded from uptake into turgescent and plasmolysed cells while protoplasts were able to internalise beads with a diameter of up to 1000 nm. Endocytosis of beads was only partially inhibited by the clathrin‐specific inhibitor Ikarugamycin and strongly blocked by wortmannin. These results imply that uptake of beads involves clathrin‐dependent and clathrin‐independent endocytic mechanisms and supports the hypothesis that clathrin‐independent endocytosis plays a general role in plants.

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