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PROSITE documentation PDOC50909 [for PROSITE entry PS50909]

GAT domain profile





Description

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 ubiquitin [1,2,3,4,5].

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 [3]. It has been proposed that this interaction might stabilize the hook subdomain [4]. The C-terminal three-helix bundle is involved in the binding with Rabaptin5 and ubiquitin [5].

The profile we developed covers the entire GAT domain.

Last update:

November 2004 / First entry.

Technical section

PROSITE method (with tools and information) covered by this documentation:

GAT, PS50909; GAT domain profile  (MATRIX)


References

1AuthorsDell'Angelica E.C. Puertollano R. Mullins C. Aguilar R.C. Vargas J.D. Hartnell L.M. Bonifacino J.S.
SourceJ. Cell Biol. 149:81-94(2000).

2AuthorsPuertollano R. Randazzo P.A. Presley J.F. Hartnell L.M. Bonifacino J.S.
TitleThe GGAs promote ARF-dependent recruitment of clathrin to the TGN.
SourceCell 105:93-102(2001).
PubMed ID11301005

3AuthorsCollins B.M. Watson P.J. Owen D.J.
TitleThe structure of the GGA1-GAT domain reveals the molecular basis for ARF binding and membrane association of GGAs.
SourceDev. Cell 4:321-332(2003).
PubMed ID12636914

4AuthorsShiba T. Kawasaki M. Takatsu H. Nogi T. Matsugaki N. Igarashi N. Suzuki M. Kato R. Nakayama K. Wakatsuki S.
TitleMolecular mechanism of membrane recruitment of GGA by ARF in lysosomal protein transport.
SourceNat. Struct. Biol. 10:386-393(2003).
PubMed ID12679809
DOI10.1038/nsb920

5AuthorsZhu G. Zhai P. He X. Wakeham N. Rodgers K. Li G. Tang J. Zhang X.C.
TitleCrystal structure of human GGA1 GAT domain complexed with the GAT-binding domain of Rabaptin5.
SourceEMBO J. 23:3909-3917(2004).
PubMed ID15457209
DOI10.1038/sj.emboj.7600411



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