ANAT 262 Lecture Notes - Lecture 21: Ldl Receptor, Transferrin Receptor, Lipid Raft

• School: McGill University
• Department: Anatomy & Cell Biology
• Course: ANAT 262
• Professor: John Presley

Document Summary

Major endocytic compartments: endocytic vesicles => early endosome => multi-vesicular body => lysosome. Phagocytosis: zipper model, endocytosis of solid particles done mostly specialized cells. Macrophages have fc receptors that bind antibodies surrounding the antigen leading to formation of phagosome, and internalization. Autophagy: (1) chaperone mediated autophagy (small proteins with specific sequence at. C-term) (2) microautophagy (internal in mvb, proteins associated in membrane, end up in lumen of lysosome) and (3) macroautophagy (membrane phagophore surrounds protein aggregates forming autophagosome, changes in membrane leading to fusion with lysosome. Lc3 is found in cytoplasm, which undergo cleavage and then large fragment is attached to pe in phagophore membrane forming lc3ii. Two types of endocytosis: (1) receptor-mediated concentration (you can concentrate receptors in coated pits hence high [ligand] are endocytosed) and (2) bulk (fluid phase endocytosis) Ldl (cholesterol ester and tag) concentrated in clathrin pits, receptors are first concentrated and then ligands are concentrated.