The GAT domain is responsible for binding of GGA proteins to several members of the ARF family including ARF1 [1] and ARF3. The GAT domain stabilises membrane bound ARF1 in its GTP bound state, by interfering with GAP proteins [2].

1: GGAs: a family of ADP ribosylation factor-binding proteins related to adaptors and associated with the Golgi complex. Dell'Angelica EC, Puertollano R, Mullins C, Aguilar RC, Vargas JD, Hartnell LM, Bonifacino JS; J Cell Biol 2000;149:81-94. PMID:10747089

2: The GGAs promote ARF-dependent recruitment of clathrin to the TGN. Puertollano R, Randazzo PA, Presley JF, Hartnell LM, Bonifacino JS; Cell 2001;105:93-102. PMID:11301005

3: The Vps27/Hse1 complex is a GAT domain-based scaffold for ubiquitin-dependent sorting. Prag G, Watson H, Kim YC, Beach BM, Ghirlando R, Hummer G, Bonifacino JS, Hurley JH; Dev Cell. 2007;12:973-986. PMID:17543868