Molecule of the Month: Aminopeptidase 1 and Autophagy
Aminopeptidase 1 is delivered inside the cell using the machinery of autophagy
Autophagy in Action
Cytoplasm to Vacuole
Exploring the Structure
Interaction of Atg8 with Atg7 and Atg3
Dozens of proteins orchestrate the building of the phagophore and its fusion with lysosomes or yeast vacuoles. The proteins shown here are involved with activating one of the receptor proteins that tether aminopeptidase 1 to the phagophore membrane (PDB entries 4gsl and 3rui). In yeast, these proteins are given the name “Atg” for “Autophagy-related proteins”. In these structures, Atg8 is the protein found in the phagophore membrane, and Atg7 and Atg3 are part of the machinery that activates it by attaching a lipid to it. To explore this complex in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Many other autophagy-related proteins are available in the PDB. For instance, an unusual S-shaped complex of several Atg proteins, PDB entry 4p1w, is involved in getting the whole process started. Try searching for “autophagy” to see some of these proteins.
- A 2016 Nobel Prize was awarded to Yoshinori Ohsumi for his discoveries of mechanisms for autophagy. You can search on his name to see some of the structures determined in his laboratory.
- The enzyme alpha-mannosidase is also delivered along with aminopeptidase 1 in the phagophore—you can see its structure in PDB entry 5jm0.
November 2016, David Goodselldoi:10.2210/rcsb_pdb/mom_2016_11