Biology 2382B Lecture Notes - Lecture 6: Ldl Receptor, Transferrin Receptor, Cholesteryl Ester
Document Summary
Low-density lipoprotein and its properties: major steps of receptor-mediated endocytosis, transferrin cycle, delivery of membrane and cytosolic proteins for degradation in lysosomes. Recap: endocytosis: process of getting stuff from outside the cell to inside the cell. Invagination of the plasma membrane: vesicles pinch off, vesicles go through maturation steps to become early/late endosomes and lysosomes, or are recycled back to the plasma membrane. Ldl (low-density lipoprotein: transferrin, many more: hormones (e. g. insulin), certain glycoproteins, etc. Low-density lipoprotein (ldl: a way of transporting lipid and fat in the blood stream. Lipids are transported in large well-defined water-soluble complexes/particles called lipoproteins. Structure: outside: composed of a phospholipid monolayer, and the large protein apolipoprotein b, polar, hydrophilic. Inside: contains cholesterol apolar core, hydrophobic: has hydrophobic and hydrophilic properties - amphipathic. Ldl receptors on plasma membrane (localized in clathrin-coated pits: apolipoprotein b helps acts as a belt that contains the structure and helps guide the ldl to its receptors.