The process begins when the target molecule, often called a ligand, binds to a specific receptor on the cell surface. These receptors are typically concentrated in regions known as coated pits. After ligand binding, the pits invaginate to form a vesicle known as an endosome. The vesicle then pinches off from the membrane and moves into the cell, where it fuses with other vesicles or organelles, such as lysosomes, for further processing.
