Recycling of Cell-surface Receptors: Observations from the LDL Receptor System
This extract was created in the absence of an abstract.
Excerpt
During receptor-mediated endocytosis, extracellular ligands bind to plasma-membrane receptors and rapidly enter cells when the membrane invaginates and pinches off to form an endocytic vesicle. In many systems the receptors cluster in discrete regions of the plasma membrane, called coated pits, that invaginate to form clathrin-coated vesicles. The internalized vesicles rapidly lose their clathrin coats and eventually fuse with lysosomes (Goldstein et al. 1979; Pearse 1980).
Ever since the earliest studies of receptor-mediated endocytosis, the importance of receptor recycling has been evident (Goldstein and Brown 1974; Brown and Goldstein 1975). Even though the internalized ligand is destroyed in lysosomes, in many cases the receptors survive and are recycled back to the plasma membrane and reutilized. Recycling appears to be the rule in those systems in which receptor-mediated endocytosis functions to transport plasma proteins other than hormones into cells. These include receptor systems for low-density lipoprotein (LDL) in fibroblasts (Goldstein et...
