The GAT (GGA and Tom1) domains are known to interact with GTP-bound ARF and are crucial for membrane recruitment of GGAs to the trans-Golgi network. Results have found the GAT domain of GGAs to possess dual functions. The N-terminal subdomain of GAT is bound to GTP-ARF as the C-terminal subdomain is bound to ubiquitin. The GAT domain is found in 25 proteins from various species and contains a three-helix bundle with a hydrophobic core. Both GGAs and Tom1 are capable of binding ubiquitin via their GAT domains suggesting roles for these proteins in mediating intracellular trafficking and sorting(1).

1. http://www.ebi.ac.uk/interpro/entry/IPR004152