Acts as an E3 ubiquitin-protein ligase. Plays an essential role in autophagy activation during viral infection. Mechanistically, activates TANK-binding kinase 1/TBK1 by facilitating its dimerization and ability to phosphorylate the selective autophagy receptor SQSTM1. In order to achieve this function, TRIM23 mediates 'Lys-27'-linked auto-ubiquitination of its ADP-ribosylation factor (ARF) domain to induce its GTPase activity and its recruitment to autophagosomes (PubMed:28871090). (Microbial infection) Mediates TRAF6 auto-ubiquitination in the presence of human cytomegalovirus protein UL144, resulting in the virally controlled activation of NF-kappa-B stimulation at early times of HCMV infection. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Homodimer. Interacts with PSCD1. Interacts with UBE2D2 (PubMed:28681414). Interacts with TBK1 (via N-terminal kinase domain) and p62/SQSTM1. (Microbial infection) Interacts with human cytomegalovirus protein UL144; this interaction might cause autoubiquitination of TRAF6, leading to NF-kappa-B activation. Membrane-associated with the Golgi complex and lysosomal structures. The RING-type zinc finger domain is responsible for E3 ubiquitin ligase activity. This domain is catalytically active as a dimer. In the C-terminal section; belongs to the small GTPase superfamily. Arf family.