E3 ubiquitin-protein ligase that specifically binds poly-ADP-ribosylated (PARsylated) proteins and mediates their ubiquitination and subsequent degradation (PubMed:21478859, PubMed:21799911, PubMed:22267412). May regulate many important biological processes, such as cell survival and DNA damage response (PubMed:21825151, PubMed:22267412). Acts as an activator of the Wnt signaling pathway by mediating the ubiquitination of PARsylated AXIN1 and AXIN2, 2 key components of the beta-catenin destruction complex (PubMed:21478859, PubMed:21799911). Acts in cooperation with tankyrase proteins (TNKS and TNKS2), which mediate PARsylation of target proteins AXIN1, AXIN2, BLZF1, CASC3, TNKS and TNKS2 (PubMed:21799911). Recognizes and binds tankyrase-dependent PARsylated proteins via its WWE domain and mediates their ubiquitination, leading to their degradation (PubMed:21799911). Different ubiquitin linkage types have been observed: TNKS2 undergoes ubiquitination at ‘Lys-48’ and ‘Lys-63’, while AXIN1 is only ubiquitinated at ‘Lys-48’ (PubMed:21799911). May regulate TNKS and TNKS2 subcellular location, preventing aggregation at a centrosomal location (PubMed:21799911). Neuroprotective protein (PubMed:21602803). Protects the brain against N-methyl-D-aspartate (NMDA) receptor-mediated glutamate excitotoxicity and ischemia, by interfering with PAR-induced cell death, called parthanatos (By similarity). Prevents nuclear translocation of AIFM1 in a PAR-binding dependent manner (By similarity). Does not affect PARP1 activation (By similarity). Protects against cell death induced by DNA damaging agents, such as N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and rescues cells from G1 arrest (By similarity). Promotes cell survival after gamma-irradiation (PubMed:21825151). Facilitates DNA repair (PubMed:21825151).
