Define the endomembrane system and introduce the general concepts of vesicle-mediated traffic
– Understand the temporal sequence of events beginning with ER and ending at PM
– Explore details of Golgi function
– Understand Golgi to PM pathway
– The role of the endosome in sorting
– The significance of the lysosome
The endomembrane system is a network of organelles in eukaryotic cells
Membrane-bound compartments called vesicles shuttle between organelles in the endomembrane system and are responsible for carrying material from one organelle to another.
– The creation, transport, targeting, and fusion of vesicles occurs in nine steps.
Endocytosis begins at the plasma membrane
Key Concepts:
– The onset of endocytosis is most often indicated by the clustering of cargo receptors on the plasma membrane, accompanied by the assembly of a clathrin coat on the cytosolic face of the cluster. In micrographs, this structure resembles a pit in the membrane, so it is often called a coated pit.
– Coated pits complete the nine steps of vesicle transport and deliver the vesicle to an organelle called the endosome.
- Clathrin stabilizes the formation of endocytic vesicles
- Endogenous proteins destined for lysosome are tagged and sorted by Golgi
