Formation of a complex involving NOTCH, Deltex (DTX) and non-visual beta-arrestin (ARRB) has not been directly studied in mammalian cells. The mammalian non-visual beta-arrestins ARRB1 and ARRB2 play a major role in desensitization and endocytosis of G-protein-coupled receptors (GPCRs), and their interaction with GPCRs involves N-terminal beta-arrestin sequences that are homologous to the Deltex-binding N-terminus of Drosophila Kurtz (Mukherjee et al. 2005). Shrub, a core component of the ESCRT-III complex, was recently identified as an important modulator of non-visual beta-arrestin-mediated downregulation of Notch in Drosophila (Hori et al. 2011).