A mechanism for transcellular transport in which a cell encloses extracellular material in an invagination of the cell membrane to form a vesicle (endocytosis), then moves the vesicle across the cell to eject the material through the opposite cell membrane by the reverse process (exocytosis). The transport mechanism by which most proteins reach the Golgi apparatus or the plasma membrane; the vesicles targeted toward lysosomes and secretory storage granules appear to be coated with clathrin. SYN: cytopempsis, vesicular transport.
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trans·cy·to·sis (trans″si-toґsis) a means of transporting a substance across a cell, occurring mainly in sheets of polarized epithelial cells: the substance is taken up by endocytosis, sorted in the endosomal compartment, and delivered to the opposite side of the cell where it is released by exocytosis.Medical dictionary. 2011.