Enables ubiquitin binding activity. Predicted to be involved in protein transport to vacuole involved in ubiquitin-dependent protein catabolic process via the multivesicular body sorting pathway. Predicted to act upstream of or within endosomal transport. Located in late endosome and lysosome. Orthologous to human VPS36 (vacuolar protein sorting 36 homolog). [provided by Alliance of Genome Resources, Apr 2022]