Deltex Homolog 1 (DTX1)

Expression of DTX1 partially inhibited transactivation of a CSL (RBPSUH)-dependent luciferase reporter by activated intracellular NOTCH1 (ICN1) in human and mouse cells. The N terminus of DTX1, which directly interacts with the NOTCH1 ankyrin repeats, inhibited transactivation by ICN1 possessing the ankyrin repeats, probably by inhibiting recruitment of coactivators to the C-terminal transactivation domain of NOTCH1.the 620-amino acid DTX1 protein contains an N-terminal domain predicted to associate with Notch ankyrin repeats, followed by a proline-rich region with potential SH3 domain-binding sites and a C-terminal domain that includes a classic RING-H2 finger motif. DTX1 functioned as a ubiquitin E3 ligase. It showed highest ubiquitination activity in conjunction with the E2 enzyme UBCH5A (UBE2D1).