Structural characterization of GABARAP–ligand interactions

Abstract

The GABA_Areceptor-associated protein (GABARAP) plays an important role in intracellular trafficking of several proteins. It undergoes a C-terminal lipidation process that enables anchoring in the cytosolic leaflet of cellular membranes. While the three-dimensional structure of GABARAP itself has been determined, structural investigation of complexes with its interaction partners has just commenced. Studies with indole derivatives revealed that GABARAP features two hydrophobic binding sites (hp1 and hp2). These also play an essential role in complex formation with the native ligand calreticulin. Furthermore, a model of hexameric N-ethylmaleimide-sensitive factor (NSF) suggests that binding of GABARAP to this molecular machine may involve a similar site. Since hp1 and hp2 are highly conserved throughout the GABARAP family, the relevance of the structural data presented here is likely to extend to GABARAP homologues.