Active, Recombinant Human ARIH1

Background: ARIH1 (Ariadne RBR E3 Ubiquitin Protein Ligase 1, also known as HHARI) is a member of the RBR (RING-between-RING) family of E3 ubiquitin ligases that functions in concert with Cullin-RING ligase (CRL) complexes to regulate substrate ubiquitylation. ARIH1 is activated through interactions with neddylated CRLs, which relieve its autoinhibited conformation and enable transfer of ubiquitin from an E2 ubiquitin-conjugating enzyme to substrate proteins through a catalytic cysteine intermediate. This unique mechanism positions ARIH1 as an important amplifier of CRL-mediated ubiquitylation, contributing to the regulation of protein turnover, cell cycle progression, DNA damage responses, and cellular stress pathways. Recombinant ARIH1 is well suited for in vitro ubiquitylation assays, mechanistic studies of RBR E3 ligases, CRL-dependent ubiquitylation reconstitution, inhibitor characterization, and targeted protein degradation research.