This domain is present in several proteins that are linked to the functions of GTPases in the Rap and Rab families.
They could hence play important roles in multiple Ras-like GTPase signaling pathways.
The domain comprises six conserved regions, which in some proteins have considerable insertions between them.
The domain core is thought to take up a predominantly alpha fold, with basic amino acids in regions A and D possibly playing a functional role in interactions with Ras GTPases.
[1] Human genes encoding proteins containing this domain include: