Ring finger protein 146/Iduna is a poly(ADP-ribose) polymer binding and PARsylation dependent E3 ubiquitin ligase.

Recent findings suggest that Ring finger protein 146 (RNF146), also called iduna, have neuroprotective property due to its inhibition of Parthanatos via binding with Poly(ADP-ribose) (PAR). The Parthanatos is a PAR dependent cell death that has been implicated in many human diseases. RNF146/Iduna acts as a PARsylation-directed E3 ubquitin ligase to mediate tankyrase-dependent degradation of axin, thereby positively regulates Wnt signaling. RNF146/Iduna can also facilitate DNA repair and protect against cell death induced by DNA damaging agents or γ-irradiation. It can translocate to the nucleus after cellular injury and promote the ubiquitination and degradation of various nuclear proteins involved in DNA damage repair. The PARsylation-directed ubquitination mediated by RNF146/Iduna is analogous to the phosphorylation-directed ubquitination catalyzed by Skp1-Cul1-F-box (SCF) E3 ubiquitin complex. RNF146/Iduna has been found to be implicated in neurodegenerative disease and cancer development. Therefore modulation of the PAR-binding and PARsylation dependent E3 ligase activity of RNF146/Iduna could have therapeutic significance for diseases, in which PAR and PAR-binding proteins play key pathophysiologic roles.