LDLRAP1: Adapter protein (clathrin-associated sorting protein (CLASP)) required for efficient endocytosis of the LDL receptor (LDLR) in polarized cells such as hepatocytes and lymphocytes, but not in non-polarized cells (fibroblasts). May be required for LDL binding and internalization but not for receptor clustering in coated pits. May facilitate the endocytocis of LDLR and LDLR-LDL complexes from coated pits by stabilizing the interaction between the receptor and the structural components of the pits. May also be involved in the internalization of other LDLR family members. Binds to phosphoinositides, which regulate clathrin bud assembly at the cell surface. Defects in LDLRAP1 are the cause of autosomal recessive hypercholesterolemia (ARH). ARH is a disorder caused by defective internalization of LDL receptors (LDLR) in the liver. ARH has the clinical features of familial hypercholesterolemia (FH) homozygotes, including severely elevated plasma LDL cholesterol, tuberous and tendon xanthomata, and premature atherosclerosis. LDL receptor (LDLR) activity measured in skin fibroblasts is normal, as the LDL binding ability.
Chromosomal Location of Human Ortholog: 1p36.11
Cellular Component: AP-1 adaptor complex; AP-2 adaptor complex; axon; basal plasma membrane; cytosol; early endosome; internal side of plasma membrane; neurofilament; recycling endosome
Molecular Function: beta-amyloid binding; clathrin binding; low-density lipoprotein receptor binding; phosphatidylinositol-4,5-bisphosphate binding; phosphotyrosine binding; protein binding; receptor signaling complex scaffold activity
Biological Process: amyloid precursor protein metabolic process; cholesterol homeostasis; positive regulation of receptor-mediated endocytosis; receptor internalization; receptor-mediated endocytosis; regulation of protein binding
Disease: Hypercholesterolemia, Autosomal Recessive
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