TARBP2
Function
Required for formation of the RNA induced silencing complex (RISC). Component of the RISC loading complex (RLC), also known as the micro-RNA (miRNA) loading complex (miRLC), which is composed of DICER1, AGO2 and TARBP2. Within the RLC/miRLC, DICER1 and TARBP2 are required to process precursor miRNAs (pre-miRNAs) to mature miRNAs and then load them onto AGO2. AGO2 bound to the mature miRNA constitutes the minimal RISC and may subsequently dissociate from DICER1 and TARBP2. May also play a role in the production of short interfering RNAs (siRNAs) from double-stranded RNA (dsRNA) by DICER1 (By similarity) (PubMed:15973356, PubMed:16142218, PubMed:16271387, PubMed:16357216, PubMed:16424907, PubMed:17452327, PubMed:18178619). Binds in vitro to the PRM1 3'-UTR (By similarity). Seems to act as a repressor of translation (By similarity). For some pre-miRNA substrates, may also alter the choice of cleavage site by DICER1 (PubMed:23063653). Negatively regulates IRF7-mediated IFN-beta signaling triggered by viral infection by inhibiting the phosphorylation of IRF7 and promoting its 'Lys'-48-linked ubiquitination and degradation (PubMed:30927622).
(Microbial infection) Binds to the HIV-1 TAR RNA which is located in the long terminal repeat (LTR) of HIV-1, and stimulates translation of TAR-containing RNAs (PubMed:11438532, PubMed:12475984, PubMed:2011739). This is achieved in part at least by binding to and inhibiting EIF2AK2/PKR, thereby reducing phosphorylation and inhibition of EIF2S1/eIF-2-alpha (PubMed:11438532). May also promote translation of TAR-containing RNAs independently of EIF2AK2/PKR (PubMed:12475984). Mediates recruitment of FTSJ3 methyltransferase to HIV-1 RNA, leading to 2'-O-methylation of the viral genome, allowing HIV-1 to escape the innate immune system (PubMed:30626973).
Sequence Similarities
Belongs to the TARBP2 family.
Cellular localization
- Cytoplasm
- Cytoplasm
- Perinuclear region
- Nucleus
Alternative names
TRBP, TARBP2, RISC-loading complex subunit TARBP2, TAR RNA-binding protein 2, Trans-activation-responsive RNA-binding protein