This entry includes ADP-ribosylation factor-like protein 8A/8B (Arl8a/Arl8b) and related proteins. In animals, Arl8a and Arl8b are small GTPases that regulate axonal transport of synaptic vesicle proteins and lysosome motility [, ]. Human Arl8a/Arl8b (also known as GIE2/GIE1) are required for chromosome segregation [].