BIOL3006 Lecture Notes - Lecture 1: Transferrin, Cation-Dependent Mannose-6-Phosphate Receptor, Golgi Apparatus
Document Summary
Receptor-mediated endocytosis: best understood, clathrin coated pits (100nm, 1. 5% of pm surface, goes on at all times, clathrin and dynamin dependent, viruses use this pathway. Clathrin-independent endocytosis: cdc42 (gtpase) dependent, regulates actin cytoskeleton, tubular structures instead of vesicles, gpi-anchored protein, high capacity for fluid uptake, less well known. Important in cancer cells: allows for uptake of large proteins which can be degraded and used for energy to aid. Phagocytosis in proliferation: engulfment of large proteins, defence against pathogens, stimulated by particles, actin dependent. Nutrient uptake: example: iron bound to transferrin or cholesterol in the form of ldls. Removing proteins from cell surface in down regulation: eg. receptor binds ligands and is engulfed into cell and degraded to switch off signalling process (mutations lead to cancer) Interplay between endocytosis and recycling: recycling back to pm/golgi or degradation. Early endosome: ph 6, tubular compartment (recycling, vesicular compartment (degradation, uncoupling of receptors and ligands (major sorting compartment, low levels of lysosomal enzymes.
