canonical GAT domain found in metazoan and fungal ADP-ribosylation factor (Arf)-binding proteins (GGAs)
GGAs, also called Golgi-localized gamma-ear-containing Arf-binding proteins, belong to a family of ubiquitously expressed, monomeric, motif-binding cargo/clathrin adaptor proteins that regulate clathrin-mediated trafficking of cargo proteins from the trans-Golgi network (TGN) to endosomes. GGAs also play important roles in ubiquitin-dependent sorting of cargo proteins both in biosynthetic and endocytic pathways. The family includes three GGAs (GGA1, GGA2, and GGA3) identified in mammals and two GGAs (Gga1p and Gga2p) identified in the budding yeast Saccharomyces cerevisiae. All these GGAs have a multidomain structure consisting of: an N-terminal VHS (Vps27/Hrs/Stam) domain that binds acidic-cluster dileucine (DxxLL)-type sorting signals (where x is any amino acid) found in the cytoplasmic tail of TGN sorting receptors; a GAT (GGA and TOM) domain that interacts with class I GTP-bound form of Arf proteins, Rabaptin-5, ubiquitin, and the tumor susceptibility gene 101 product (TSG101); a largely unstructured hinge region that contains clathrin-binding motifs; and a C-terminal GAE (gamma-adaptin ear homology) domain that binds accessory proteins. In contrast to other GGAs-like proteins, members of this family contain a GAT N-terminal region, a helix-loop-helix in the complex with Arf1-GTP.