Table 2.
Selected metazoan Rab GTPases and their regulators in autophagy.
| RAB GTPase (metazoan) | GEF | GAP | Function | Literature |
|---|---|---|---|---|
| RAB1 | TRAPPIII | RAB1 mediates the recruitment of the ULK1 complex from the cytosol and controls ATG9 cycling. ATG9 vesicles are positive for RAB1. | [18,[50], [51], [52]] | |
| RAB2 | OATL1 (also known as TBC1D25) | RAB2 interacts with ULK1 and mediates the association between ULK1 and ATG9. ATG9 vesicles are positive for RAB2. RAB2 stimulates ULK1 activity. RAB2 mediates autophagosome-lysosome fusion. |
[24,238] | |
| RAB5 | RAB5 stimulates the activity of PIK3C-CI as well as of PI(4)- and PI(5)-phosphatases. RAB5 activity stimulates ATG12-ATG5 conjugation. |
[[109], [110], [111], [112]] | ||
| RAB7 | MON1/CCZ1/C18orf8 |
Armusa (also known as TBC1D2A), TBC1D5a, TBC1D15a |
RAB7 mediates intracellular autophagosome trafficking and autophagosome-lysosome fusion. Further roles of RAB7 include regulation of membrane expansion during mitophagy. RAB7B regulates Atg4 activity. RAB7 GAPs are involved in ATG9 trafficking. The GEF MON1/CCZ1/C18orf8 mediates autophagosome-lysosome fusion. |
[17,22,56,57,197,201,[[203], [204], [205],237] |
| RAB9 | RAB9 mediates unconventional autophagy (independent of Atg8 conjugation machinery). | [87] | ||
| RAB11 |
TBC1D9Ba, TBC1D15a |
RAB11 acts on recycling endosomes which are ULK1 positive and function in ATG9 trafficking and further provide a phagophore assembly platform. RAB11A binds WIPI2 and enhances WIPI2 association with membranes. |
[20,51,55,58,206] | |
| RAB18 | RAB18 acts on lipid droplets and influences ATG9 trafficking. | [25] | ||
| RAB33B | OATL1a (also known as TBC1D25) | OATL1 is implicated in autophagosome-lysosome fusion. RAB33B binds ATG16L and enhances ATG16L association with membranes. |
[138,139,209] |
a
Direct interaction with Atg8 proteins.