Huntingtin-associated protein 1 (HAP1) is a novel protein of unknown function with a higher
binding affinity for the mutant form of Huntington's disease protein huntingtin. Here we report
that HAP1 interacts with hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs),
a mammalian homologue of yeast vacuolar protein sorting protein Vps27p involved in the
endosome-to-lysosome trafficking. This novel interaction was identified in a yeast two-hybrid
screen using full-length Hrs as bait, and confirmed byin vitro binding assays and co …