RT Journal Article SR Electronic T1 Interaction of Huntingtin-Associated Protein with Dynactin P150Glued JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 1261 OP 1269 DO 10.1523/JNEUROSCI.18-04-01261.1998 VO 18 IS 4 A1 Shi-Hua Li A1 Claire-Anne Gutekunst A1 Steven M. Hersch A1 Xiao-Jiang Li YR 1998 UL http://www.jneurosci.org/content/18/4/1261.abstract AB Huntingtin is the protein product of the gene for Huntington’s disease (HD) and carries a polyglutamine repeat that is expanded in HD (>36 units). Huntingtin-associated protein (HAP1) is a neuronal protein and binds to huntingtin in association with the polyglutamine repeat. Like huntingtin, HAP1 has been found to be a cytoplasmic protein associated with membranous organelles, suggesting the existence of a protein complex including HAP1, huntingtin, and other proteins. Using the yeast two-hybrid system, we found that HAP1 also binds to dynactin P150Glued (P150), an accessory protein for cytoplasmic dynein that participates in microtubule-dependent retrograde transport of membranous organelles. An in vitro binding assay showed that both huntingtin and P150 selectively bound to a glutathione transferase (GST)–HAP1 fusion protein. An immunoprecipitation assay demonstrated that P150 and huntingtin coprecipitated with HAP1 from rat brain cytosol. Western blot analysis revealed that HAP1 was enriched in rat brain microtubules and comigrated with P150 and huntingtin in sucrose gradients. Immunofluorescence showed that transfected HAP1 colocalized with P150 and huntingtin in human embryonic kidney (HEK) 293 cells. We propose that HAP1, P150, and huntingtin are present in a protein complex that may participate in dynein–dynactin-associated intracellular transport.