What is the Origin of Receptor-Mediated Endocytosis?

The term is a descriptive compound of its components: 'receptor-mediated' (dependent on specific receptor binding) and 'endocytosis' (the process of taking materials into the cell). This fundamental cellular mechanism was elucidated through the work of Brown and Goldstein on cholesterol metabolism, demonstrating a precise, controlled method for cellular uptake distinct from non-specific pinocytosis.

What is the Mechanism of Receptor-Mediated Endocytosis?

The mechanism begins with the binding of the ligand, such as a peptide hormone, to its specific receptor, which is often clustered in specialized regions of the cell membrane called clathrin-coated pits. This binding triggers the invagination of the membrane, forming a coated vesicle that pinches off and enters the cytoplasm as an endosome. Once internalized, the receptor-ligand complex is sorted; the ligand is often routed to the lysosome for degradation, and the receptor is either degraded or recycled back to the cell surface, thus controlling the duration of the hormonal signal.

Receptor-Mediated Endocytosis ∞ Area

Receptor-Mediated Endocytosis

Meaning

Receptor-Mediated Endocytosis is a highly specific cellular process by which cells internalize macromolecules from the extracellular fluid by binding them to specific receptors located on the cell surface. This process is crucial in endocrinology for the uptake of various hormones, growth factors, and nutrients, as well as for the down-regulation of receptor sensitivity. It allows the cell to concentrate and selectively internalize specific molecules with high efficiency.