GARP Complex in Golgi Physiology

The Golgi Associated Retrograde Protein (GARP) complex, a member of the Complexes Associated with Tethering Containing Helical Rods (CATCHR) family, is proposed to tether vesicles arriving from endosomes to the trans-Golgi network (TGN). Discovered nearly 25 years ago, this protein complex is important for sorting vacuolar hydrolases and recycling membrane proteins from the endosomal/prevacuolar compartment to the TGN; however, its exact function, molecular partners, and the nature of GARP-dependent trafficking intermediates remain understudied. GARP-dependent transport route is utilized by various plasma membrane recycling proteins, lysosomal hydrolase receptors, and pathogens, including toxins. Mutations in GARP subunits have been associated with multiple neurological disorders, although the precise mechanisms by which these mutations lead to these conditions remain unclear. This chapter reviews the current understanding of GARP's structure, function, interacting partners, mutations, and associated pathologies in both humans and model organisms.