E3 ubiquitin ligase that plays a role in various biological processes including neural stem cell differentiation, innate immunity, inflammatory resonse and autophagy (PubMed:19349376, PubMed:31123703). Plays a role in virus-triggered induction of IFN-beta and TNF-alpha by mediating the ubiquitination of STING1. Mechanistically, targets STING1 for ‘Lys-63’-linked ubiquitination which promotes the interaction of STING1 with TBK1 (PubMed:22745133). Regulates bacterial clearance and promotes autophagy in Mycobacterium tuberculosis-infected macrophages (PubMed:37543647). Negatively regulates TLR3/4-mediated innate immune and inflammatory response by triggering the autophagic degradation of TICAM1 in an E3 activity-independent manner (PubMed:28898289). Plays an essential role in oxidative stress induced cell death by inducing loss of transmembrane potential and enhancing mitochondrial reactive oxygen species (ROS) production during oxidative stress conditions (PubMed:32918979). Ubiquitinates XIAP and targets it for proteasomal degradation (PubMed:21628460). Ubiquitinates DTNBP1 (dysbindin) and promotes its degradation (PubMed:19349376). May ubiquitinate BBS2 (PubMed:22500027). Ubiquitinates PIAS4/PIASY and promotes its degradation in keratinocytes treated with UVB and TNF-alpha (By similarity). Also acts as a regulator of autophagy by mediating formation of unanchored ‘Lys-63’-linked polyubiquitin chains that activate ULK1: interaction with AMBRA1 is required for ULK1 activation (PubMed:31123703). Positively regulates dendritic branching by promoting ubiquitination and subsequent degradation of the epigenetic factor CDYL (PubMed:34888944). Under metabolic stress and phosphorylation by CHK2, mediates ‘Lys-63’-linked ubiquitination of ATG7 at ‘Lys-45’ to initiate autophagy (PubMed:37943659). ; (Microbial infection) May play a significant role in mediating the biological activity of the HIV-1 Tat protein in vivo (PubMed:7778269). Binds specifically to the activation domain of HIV-1 Tat and can also interact with the HIV-2 and EIAV Tat proteins in vivo (PubMed:7778269).
