The GAT domain is a region of homology of ~130 residues, which is found in
eukaryotic GGAs (for Golgi-localized, γ 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 (see
<PDOC50179>) and GAE (see <PDOC50180>). 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 ARF family of small
GTPases and can bind specifically to the Rab GTPase effector rabaptin5 and to
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 (see <PDB:1NAF>). 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 stabilize the hook subdomain . The C-terminal three-helix bundle is
involved in the binding with Rabaptin5 and ubiquitin .
The profile we developed covers the entire GAT domain.
November 2004 / First entry.
PROSITE method (with tools and information) covered by this documentation:
Dell'Angelica E.C. Puertollano R. Mullins C. Aguilar R.C. Vargas J.D. Hartnell L.M. Bonifacino J.S.
J. Cell Biol. 149:81-94(2000).
Puertollano R. Randazzo P.A. Presley J.F. Hartnell L.M. Bonifacino J.S.
The GGAs promote ARF-dependent recruitment of clathrin to the TGN.
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