Biology 2382B Lecture Notes - Lecture 6: Cholesteryl Ester, Golgi Apparatus, Ldl Receptor
4 Mar 2020
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Document Summary
Receptor-mediated endocytosis - a method of selective internalization of specific extracellular molecules (usage of ligands) Lipids are transported in large well-defined water-soluble complexes/particles called lipoproteins. Ldl contain approximately 88% cholesteryl esters and mediates cholesterol transport. Ldl receptors on plasma membrane (localized in clathrin-coated pits). Amphipathic shell, composed of a phospholipid monolayer and apolipoprotein. Apolar core - hydrophobic mostly cholesteryl esters. Inside are cholesteryl esters and outside is phospholipids which makes it polar. The belt of apolipoprotein b helps it target receptors. Incorporated into the cell via the plasma membrane. Receptors in plasma membrane recognizes a unique ligand (ldl) Two layer coat: clathrin and adapter protein (ap) complexes: Ap complexes recognize sorting signals of cargo proteins or receptors. Clathrin-coated vesicles pinch off using dlamini and gtp hydrolysis (dynamin forms rings around vesicle neck, polymerizes) A protein called dynamin causes the merging of the membrane - the energy is from gtp hydrolysis. ph-dependent binding of ldl particles to ldl receptor.
