The low density lipoprotein receptor (LDL R) is the founding member of the LDL R family of scavenger receptors.Binds LDL, the major cholesterol-carrying lipoprotein of plasma, and transports it into cells by endocytosis.LDLR is ubiquitously expressed and is a key receptor for maintaining cholesterol homeostasis in mammals. LDLR-mediated endocytosis is essential for lipoprotein and lipid metabolism.Impaired LDLR function by genetic mutations results in a condition with extremely elevated serum LDL levels and early onset atherosclerosis known as familial hypercholesterolemia (FH).