canonical GAT domain found in target of Myb-like protein 1 (Tom1L1)
Tom1L1, also called Src-activating and signaling molecule protein (Srcasm), was identified as a substrate of the Src family of protein kinases. It is tyrosine-phosphorylated by Src family kinases and modulates growth factor and Src-mediated signaling pathways. It also plays a potential role in endosomal sorting and ligand-stimulated endocytosis of EGF receptors (EGFR). Tom1L1 is predominantly present in the cytosol and can interact with Toll-interacting protein (Tollip), Hrs or TSG101, clathrin, and ubiquitinated proteins. It contains an N-terminal VHS (Vps27p/Hrs/STAM)-domain, a GAT (GGA and TOM1) domain, and a C-terminal clathrin-binding region, both of which are conserved in Golgi-localized gamma ear-containing Arf-binding proteins (GGAs). It interacts with Tollip through their GAT domain and recuits clathrin onto endosomes through their C-terminal region. However, in the C-terminal clathrin-binding region, Tom1 and Tom1L2 are similar to each other, but distinguishable from Tom1L1. The canonical GAT domain is a monomeric three-helix bundle that binds ubiquitin.