What causes endocytosis?

Endocytosis is a type of active transport that enables cells to take up macromolecules and particles from their surrounding extracellular environment. While different variations of endocytosis have been identified (e.g. phagocytosis, pinocytosis and receptor-mediated endocytosis) each mode is activated in a similar manner and follows the same basic process. First, a particle binds to the cell membrane either in a non-specific manner or via binding to specific receptors on the cell surface. This interaction activates endocytosis triggering the invagination of the plasma membrane, which then pinches off to form an internalized vesicle containing the targeted material.