E3 ubiquitin ligase that harbors GTPase activity encoded by the C-terminal ARF domain. Plays an essential role in autophagy activation during viral infection (PubMed:31189704, PubMed:40360474). Mechanistically, activates TANK-binding kinase 1/TBK1 by facilitating its dimerization and ability to phosphorylate the selective autophagy receptor SQSTM1 (PubMed:28871090, PubMed:31189704). 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). Catalyzes 'Lys-63'-linked polyubiquitination of HAX1 that triggers its liquid- liquid phase separation (LLPS) and contributes to P-bodies assembly induced by energy stress (PubMed:38769438). {ECO:0000269|PubMed:15684077, ECO:0000269|PubMed:28871090, ECO:0000269|PubMed:31189704, ECO:0000269|PubMed:38769438, ECO:0000269|PubMed:40360474}. (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. . This is the function of TRIM23 (tripartite motif containing 23, Ensembl gene identifier ENSG00000113595).