The LDL lipoprotein complexes bind to receptor cells at specialized sites called LDL receptors. The receptors are clustered in structures called coated pits, which are abundant in the protein called clathrin. After binding to the LDL receptor, the LDL is internalized into the target cell by a process called receptor mediated endocytosis (Figure 18.10).

People with the hereditary disease familial hypercholesterolemia have elevated serum cholesterol levels arising from problems with their LDL receptors.