Huntingtin Associated Protein 1 (HAP1)

Huntingtin-associated protein 1 (HAP1) was found to bind to the mutant huntingtin protein (mHtt) in proportion to the number of glutamines present in the glutamine repeat region.Huntington"""s disease (HD), a neurodegenerative disorder characterized by loss of striatal neurons, is caused by an expansion of a polyglutamine tract in the HD protein huntingtin. This gene encodes a protein that interacts with huntingtin, with two cytoskeletal proteins (dynactin and pericentriolar autoantigen protein 1), and with a hepatocyte growth factor-regulated tyrosine kinase substrate (HGS). The interactions with cytoskeletal proteins and a kinase substrate suggest a role for this protein in vesicular trafficking or organelle transport.