Cholesterol is an essential element of cell membranes and is carried around the body packaged in lipoproteins, primarily low-density lipoproteins (LDLs). The LDL receptors (LDLRs) are cell surface glycoproteins that scavenge LDL from the blood and regulate plasma LDL cholesterol. LDLRs contain five primary domains: the ligand binding domain, the homology with the EGF precursor domain, the O-linked sugars domain, the membrane-spanning region, and a cytoplasmic tail. In humans, more than 60% of the LDL R3 are found in the liver. LDLR expression is under hormonal control both in vivo and in vitro. Mutations in the LDLR gene cause disorders such as familial hypercholesterolemia and atherosclerosis. Murine LDLR is 864 amino acids in length with an estimated molecular weight of 95 kDa. The protein is highly glycosylated through N- and O-linkages and thus migrates at 100 to 160 kDa bands on SDS-PAGE. Cayman’s LDL receptor polyclonal antibody detects both glycosylated and unglycosylated proteins in tissue/cell samples such as liver, HepG2, and RAW 264.7 cells.
