TRIM22
Description
The TRIM22 (tripartite motif containing 22) is a protein-coding gene located on chromosome 11.
Tripartite motif-containing 22, also known as TRIM22, is a protein which in humans is encoded by the TRIM22 gene.
== Function == The protein encoded by this gene is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains, a RING, a B-box type 1 and a B-box type 2, and a coiled-coil region. This protein localizes to the cytoplasm and its expression is induced by interferon. TRIM22 is also a target gene of the tumor suppressor protein p53. 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.
== Clinical significance == The protein down-regulates transcription from the HIV-1 long 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.
Interferon-induced E3 ubiquitin ligase that plays important roles in innate and adaptive immunity. Restricts the replication of many viruses including HIV-1, encephalomyocarditis virus (EMCV), hepatitis B virus (HBV), hepatitis C virus (HCV) or Zika virus (ZIKV). Mechanistically, negatively regulates HCV replication by promoting ubiquitination and subsequent degradation of viral NS5A. Acts also by promoting the degradation of Zika virus NS1 and NS3 proteins through proteasomal degradation. Acts as a suppressor of basal HIV-1 LTR-driven transcription by preventing Sp1 binding to the HIV-1 promoter. Plays also a role in antiviral immunity by co-regulating together with NT5C2 the RIGI/NF-kappa-B pathway by promoting 'Lys-63'-linked ubiquitination of RIGI, while NT5C2 is responsible for 'Lys-48'-linked ubiquitination of RIGI. Participates in adaptive immunity by suppressing the amount of MHC class II protein in a negative feedback manner in order to limit the extent of MHC class II induction.
TRIM22 is also known as GPSTAF50, RNF94, STAF50.
