Acts as a component of endosomal retrieval machinery that is involved in protein transport from early endosomes to either recycling endosomes or the trans-Golgi network (By similarity). Mediates the recruitment of Golgi-associated retrograde protein (GARP) complex to the trans-Golgi network and controls early endosome-to-Golgi transport of internalized protein (By similarity). Promotes the recycling of internalized transferrin receptor (TFRC) to the plasma membrane through interaction with endosome-associated recycling protein (EARP) complex (By similarity). Controls proper insulin distribution and secretion, and retention of cargo in mature dense core vesicles (By similarity). Required for the stability of the endosome-associated retrograde protein (EARP) complex subunits and for proper localization and association of EARP with membranes (By similarity). Interacts with two multisubunit tethering complexes: EARP composed of VPS50, VPS51, VPS52 and VPS53 subunits and GARP complex composed of VPS51, VPS52, VPS53 and VPS54 subunits. Interacts with SNAP29. Belongs to the WD repeat EIPR1 family.