Interferon-induced antiviral protein involved in cell innate immunity. The antiviral activity could in part be mediated by TRIM22-dependent ubiquitination of viral proteins. Plays a role in restricting the replication of HIV-1, encephalomyocarditis virus (EMCV) and hepatitis B virus (HBV). Acts as a transcriptional repressor of HBV core promoter. May have E3 ubiquitin-protein ligase activity. 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. Homotrimer (PubMed:17156811). (Microbial infection) Interacts with HIV-1 Gag polyprotein; this interaction seems to reduce gag production or virus budding. (Microbial infection) Interacts with EMCV protease 3C; this interaction leads to viral protease ubiquitination. Localizes predominantly to the nucleus, found in cytoplasm to some extent. Forms distinct nuclear bodies that undergo dynamic changes during cell cycle progression. Nuclear bodies start to form in the early G0/G1 phase but become speckle-like in the S-phase and completely dispersed in mitosis. 35% of TRIM22 nuclear bodies overlap or are found adjacent to Cajal bodies. Strongly expressed in peripheral blood leukocytes, spleen, thymus, and ovary. Expressed at basal levels in other tissues. By interferons alpha and beta. Up-regulated by p53/TP53. Dramatically induced by progesterone in MDA-MB-231-derived ABC28 cells and T47D cells. The C-terminal SPRY domain is required for the transcriptional suppressor activity, probably by mediating correct nuclear localization. Residues 491-494 are essential for nuclear localization and nuclear bodies formation. The RING domain is essential for antiviral activity and for TRIM22 nuclear bodies (NB) formation but is not necessary for nuclear localization. Auto-ubiquitinated. Belongs to the TRIM/RBCC family.