TRIM22 possesses E3 ubiquitin ligase activity and is able to ubiquitinate itself with the assistance of the E2 enzyme UbcH5B. Furthermore TRIM22 is located in the nucleus and therefore may function as a nuclear E3 ubiquitin ligase.
The protein down-regulates transcription from the HIV-1long terminal repeat promoter region, suggesting that function of this protein may be to mediate interferon's antiviral effects. Other proteins that function to restrict HIV replication include TRIM5alpha and APOBEC3G.
It has been demonstrated that treatment of cells with interferon type I inhibits HIV replication and TRIM22 is strongly up-regulated by interferon treatment. Furthermore HIV particle release from cells depleted of TRIM22 with RNA interference is enhanced. TRIM22 appears to prevent the movement of the HIV Gag protein to the plasma membrane and hence TRIM22 can block HIV replication in cell cultures by preventing the assembly of the virus.
^Gongora C, Tissot C, Cerdan C, Mechti N (November 2000). "The interferon-inducible Staf50 gene is downregulated during T cell costimulation by CD2 and CD28". J. Interferon Cytokine Res. 20 (11): 955–61. doi:10.1089/10799900050198390. PMID11096452.