RALBP1 plays a role in receptor-mediated endocytosis and is a downstream effector of the small GTP-binding protein RAL (see RALA; MIM 179550). Small G proteins, such as RAL, have GDP-bound inactive and GTP-bound active forms, which shift from the inactive to the active state through the action of RALGDS (MIM 601619), which in turn is activated by RAS (see HRAS; MIM 190020) (summary by Feig, 2003 [PubMed 12888294]).[supplied by OMIM, Nov 2010].