1yd8
COMPLEX OF HUMAN GGA3 GAT DOMAIN AND UBIQUITINCOMPLEX OF HUMAN GGA3 GAT DOMAIN AND UBIQUITIN
Structural highlights
Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe Golgi-localized, gamma-ear-containing, Arf (ADP-ribosylation factor)-binding (GGA) proteins are clathrin adaptors that mediate the sorting of transmembrane-cargo molecules at the trans-Golgi network and endosomes. Cargo proteins can be directed into the GGA pathway by at least two different types of sorting signals: acidic cluster-dileucine motifs and covalent modification by ubiquitin. The latter modification is recognized by the GGAs through binding to their GAT [GGA and TOM (target of Myb)] domain. Here we report the crystal structure of the GAT domain of human GGA3 in a 1:1 complex with ubiquitin at 2.8-A resolution. Ubiquitin binds to a hydrophobic and acidic patch on helices alpha1 and alpha2 of the GAT three-helix bundle that includes Asn-223, Leu-227, Glu-230, Met-231, Asp-244, Glu-246, Leu-247, Glu-250, and Leu-251. The GAT-binding surface on ubiquitin is a hydrophobic patch centered on Ile-44 that is also responsible for binding most other ubiquitin effectors. The ubiquitin-binding site observed in the crystal is distinct from the Rabaptin-5-binding site on helices alpha2 and alpha3 of the GAT domain. Mutational analysis and modeling of the ubiquitin-Rabaptin-5-GAT ternary complex indicates that ubiquitin and Rabaptin-5 can bind to the GAT domain at two different sites without any steric conflict. This ability highlights the GAT domain as a hub for interactions with multiple partners in trafficking. Structural mechanism for ubiquitinated-cargo recognition by the Golgi-localized, gamma-ear-containing, ADP-ribosylation-factor-binding proteins.,Prag G, Lee S, Mattera R, Arighi CN, Beach BM, Bonifacino JS, Hurley JH Proc Natl Acad Sci U S A. 2005 Feb 15;102(7):2334-9. Epub 2005 Feb 8. PMID:15701688[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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