How do receptor mediated endocytosis and LDL receptors help reduce our serum levels of cholesterol?
The above cartoon shows a figure from your text in which the LDL receptors are collecting with their ligand (LDL) in a clathrin coated pit. LDL has been called the “bad cholesterol”. High serum LDL’s go along with high serum cholesterol However, we can reduce serum cholesterol by taking it up into cells that need it (for membranes, steroid hormone production, etc.) This requires a specific LDL receptor and a working receptor mediated endocytosis process. Some families have a defect in the Adaptin-2 binding site on the LDL receptor. Recall that this site helped concentrate the LDL receptor in the coated pit. In fact, binding to the Adaptor protein actually helped recruit the clathrin to the site. The defect is shown in the above cartoon from your text. This genetic deficiency prevents LDL and its receptor from entering the coated pit or from being taken up. The result very high serum levels of cholesterol and all the problems resulting from that. This cartoon was taken from Alberts et a
