E3 ubiquitin-protein ligase, which catalyzes ubiquitination of target proteins together with ubiquitin-conjugating enzyme E2 ube2l3. Acts as an atypical E3 ubiquitin-protein ligase by working together with cullin-RING ubiquitin ligase (CRL) complexes and initiating ubiquitination of CRL substrates: associates with CRL complexes and specifically mediates addition of the first ubiquitin on CRLs targets. The initial ubiquitin is then elongated. E3 ubiquitin-protein ligase activity is activated upon binding to neddylated cullin-RING ubiquitin ligase complexes. [E2 ubiquitin-conjugating enzyme]-S-ubiquitinyl-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-N(6)-ubiquitinyl-L-lysine. Autoinhibited by the ariadne domain, which masks the second RING-type zinc finger that contains the active site and inhibits the E3 activity. Inhibition is relieved upon binding to neddylated cullin-RING ubiquitin ligase complexes, which activate the E3 ligase activity of ARIH1. Protein modification; protein ubiquitination. Interacts (via the first RING-type zinc finger) with ube2l3. Associates with cullin-RING ubiquitin ligase (CRL) complexes containing neddylated cullin. Members of the RBR family are atypical E3 ligases. They interact with the E2 conjugating enzyme UBE2L3 and function like HECT-type E3 enzymes: they bind E2s via the first RING-type zinc finger, but require an obligate trans-thiolation step during the ubiquitin transfer, requiring a conserved active site Cys residue in the second RING-type zinc finger. The active site probably forms a thioester intermediate with ubiquitin taken from the active-site cysteine of the E2 before ultimately transferring it to a Lys residue on the substrate. The Ariadne domain inhibits activity by masking the second RING-type zinc finger that contains the active site. Belongs to the RBR family. Ariadne subfamily.