Biology 2382B Lecture Notes - Lecture 6: Cholesteryl Ester, Transferrin Receptor, Clathrin
Document Summary
Secretory pathway brings things in from the cell surface. Phagocytosis specialized cells can engulf something large. Pinocytosis specialized cells can bring in small vesicles containing liquid. Receptor-mediated endocytosis cells bring in specific surface ligands (ldl, transferrin, hormones and glycoproteins) Clathrin/ap-coated vesicles: mechanism for bringing in specific ligands. 2 layer coat: adaptor protein (ap) and clathrin. V-class proton pumps use atp hydrolysis to pump h+ across membrane into the endosome. Cl- channels allow anions to passively follow the pumped protons. Once clathrin/ap coat is removed, v-class pump is activated and cl- ions follow acidification of lumen (with neutral charge) Late endosome multiple fused endosomes with acidic ph. Lipoproteins are large, water-soluble complexes that transport lipids (in blood, into cells) Ldl mediates cholesterol transport (from liver to other tissues) Amphipathic shell phospholipid monolayer and polar apolipoprotein b surface. Short c-terminal cytosolic domain (npxy sorting signal) binds ap2. Long n-terminal exoplasmic segment ligand binding domain (for.