| Primary Identifier | IPR041198 | Type | Domain |
| Short Name | GGA_N-GAT |
| description | This domain is found in the N-terminal region of the GGA and Tom1 (GAT) domain in Golgi-localizing gamma-adaptin ARF-binding protein 1 (GGA1). This domain can also be found in GGA2 and GGA3. The GAT domains is the key region in GGA that interacts with ARF. ARF plays a crucial role in docking adaptor proteins to membranes. This domain is referred to as N-GAT and it interacts extensively with ARF [].The GAT domain is a region of homology of ~130 residues, which is found in eukaryotic GGAs (for Golgi-localized, gamma ear-containing ADP ribosylation factor (ARF)-binding proteins) and vertebrate TOMs (for target of myb). The GAT domain is found in its entirety only in GGAs, although, at the C terminus it shares partial sequence similarity with a short region of TOMs. The GAT domain is found in association with other domains, such as VHS and GAE. The GAT domain of GGAs serves as a molecular anchor of GGA to trans-Golgi network (TGN) membranes via its interaction with the GTP-bound form of a member of the ARFfamily of small GTPases and can bind specifically to the Rab GTPase effector rabaptin5 and to ubiquitin [, , , ].The GGA-GAT domain possesses an all α-helical structure, composed of four helices arranged in a somewhat unusual topology, which has been called the helical paper clip. The overall structure shows that the GAT domain has an elongated shape, in which the longest helix participates in two small independent subdomains: an N-terminal helix-loop-helix hook and a C-terminal three-helix bundle. The hook subdomain has been shown to be both necessary and sufficient for ARF-GTP binding and Golgi targeting of GGAs. The N-terminal hook subdomain contains a hydrophobic patch, which is found to interact directly with ARF []. It has been proposed that this interaction might stabilise the hook subdomain []. The C-terminal three-helix bundle is involved in the binding with Rabaptin5 and ubiquitin []. |
