Identification of a Karyopherin β1/β2 Proline-Tyrosine Nuclear Localization Signal in Huntingtin Protein*

Among the known pathways of protein nuclear import, the karyopherin β2/transportin pathway is only the second to have a defined nuclear localization signal (NLS) consensus. Huntingtin, a 350-kDa protein, has defined roles in the nucleus, as well as a CRM1/exportin-dependent nuclear export signal; however, the NLS and exact pathway of import have remained elusive. Here, using a live cell assay and affinity chromatography, we show that huntingtin …