Question

summarize the process of receptor mediated endocytosis of LDL, emphasizing the roles of key proteins. mention the key proteins involved and clearly but very briefly state the protein's role.

Answer 1

LDL particles in the blood stream are endocytosed by receptor mediated endocytosis. The apoprotein B100 present on the surface of LDL particle is recognized by the LDL receptor(on the cell surface), that is clustered in clathrin coated pits. These coated pits then pinch offs from the membrane, leading to internalization of LDL-LDL receptor into coated endocytic vesicles. This is followed by fusion of these clathrin coated vesicles with the acidic endosomes where the LDL particle dissociate from the receptor and the LDL receptor is recycled back to the cell surface. The LDL particle further fuses with the lysosomes where it is degraded by lysosomal hydrolases and the fatty acids and cholesterol are released for use in cellular processes.