MCB 2050 Lecture Notes - Lecture 11: Dynamin, Clathrin, Endosome

• School: University of Guelph
• Department: Molecular and Cellular Biology
• Course: MCB 2050
• Professor: Peter Krell

Document Summary

Key role in autophagy (degradation of cell organelles/components) Contain acid hydrolase enzymes that are active at ph 4. 6 in lysosome. Lysosome proteins shielded from degradation by the attached lumen-facing carbohydrate groups (added in er and golgi) Low ph maintained by atpase proton pump (pumps h+ from cytosol) In tgn, m6p-bearing proteins recognized by m6p receptor. Cytosolic domain of m6p receptor binds gga adaptor coat proteins (proteins with multiple binding domains) Gga proteins are linkers during clathrin-coated vesicle assembly. Gga = golgi-localizing, gamma adaptin ear domain homology, arf- binding proteins. Release/pinching off of the clathrin-coated vesicle from the tgn mediated by dynamin (a. M6p receptors from their proteins (the tgn & vesicle has ph 6. 4: m6p receptors recycled back to the tgn for another round of trafficking. Late"endosome" (late endosome fragment) fuses with lysosome: mvb lumenal contents released into lysosome, lysosomal proteins (acid hydrolases) are activated in low lysosome ph (4. 6, intraluminal vesicles with pm materials are degraded.