ADP Ribosylation Factor Like Protein 8A (ARL8A)

Arl8a and Arl8b , localise to lysosomes in mammalian cells, with the single homologue in Drosophila cells having a similar location. Conventionally, membrane binding of Arf and Arl proteins is mediated by both an N-terminal myristoyl group and an N-terminal amphipathic helix that is inserted into the lipid bilayer upon activation of the GTPase. Arl8a and Arl8b do not have N-terminal myristoylation sites, Arl8b is instead N-terminally acetylated, and an acetylated methionine is necessary for its lysosomal localization. Overexpression of Arl8a or Arl8b results in a microtubule-dependent redistribution of lysosomes towards the cell periphery. Live cell imaging shows that lysosomes move more frequently both toward and away from the cell periphery, suggesting a role for Arl8a and Arl8b as positive regulators of lysosomal transport.