Interaction of human tRNA-dihydrouridine synthase-2 with interferon-induced protein kinase PKR

Mittelstadt, Megan L.; Frump, Andrea L.; Khuu, TuAnh; Fowlkes, Vennece; Handy, Indhira; Patel, Chandrashekhar V.; Patel, Rekha C.

doi:10.1093/nar/gkm1129

Cited by 51 publications

(41 citation statements)

References 78 publications

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“…More work is required to determine if G3BP1 plays only scaffolding/ recruitment roles, can activate PKR alone, or requires a third factor or several other cofactors to activate PKR. Other PKR-interacting proteins have been described that either activate PKR (PACT, IPS1, and NFAR1/2) or inhibit PKR (MDA7, hDUS2, and p58 IPK ) (46)(47)(48)(49)(50)(51)(52). It would be of interest to investigate whether these proteins also interact with G3BP1-induced SGs and modulate SG assembly.…”

Section: Discussionmentioning

confidence: 99%

The Stress Granule Protein G3BP1 Recruits Protein Kinase R To Promote Multiple Innate Immune Antiviral Responses

Reineke

Lloyd

2015

J Virol

181

189

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Stress granules (SGs) are cytoplasmic storage sites containing translationally silenced mRNPs that can be released to resume translation after stress subsides. We previously showed that poliovirus 3C proteinase cleaves the SG-nucleating protein G3BP1, blocking the ability of cells to form SGs late in infection. Many other viruses also target G3BP1 and inhibit SG formation, but the reasons why these functions evolved are unclear. Previously, we also showed a link between G3BP1-induced SGs and protein kinase R (PKR)-mediated translational control, but the mechanism of PKR interplay with SG and the antiviral consequences are unknown. Here, we show that G3BP1 exhibits antiviral activity against several enteroviruses, whereas truncated G3BP1 that cannot form SGs does not. G3BP1-induced SGs are linked to activation of innate immune transcriptional responses through NF-B and JNK. The G3BP1-induced SGs also recruit PKR and other antiviral proteins. We show that the PXXP domain within G3BP1 is essential for the recruitment of PKR to SGs, for eIF2␣ phosphorylation driven by PKR, and for nucleating SGs of normal composition. We also show that deletion of the PXXP domain in G3BP1 compromises its antiviral activity. These findings tie PKR activation to its recruitment to SGs by G3BP1 and indicate that G3BP1 promotes innate immune responses at both the transcriptional and translational levels and integrates cellular stress responses and innate immunity. IMPORTANCEStress granules appear during virus infection, and their importance is not well understood. Previously, it was assumed that they were nonfunctional artifacts associated with cellular stress. PKR is a well-known antiviral protein; however, its regulation in cells is not well understood. Our work links cellular stress granules with activation of PKR and other innate immune pathways through the activity of G3BP1, a critical stress granule component. The ability of stress granules and G3BP1 to activate PKR and other innate immune transcriptional responses indicates that G3BP1 is an antiviral protein. This work helps to refine a longstanding paradigm indicating stress granules are inert structures and explains why G3BP1 is subverted by many viruses to promote a productive infection. Stress granules (SGs) are macromolecular triage centers for mRNAs that contain translationally silenced messenger RNPs (mRNPs). Stress granules contain many translation initiation factors, 40S ribosomal subunits, mRNAs, and RNA-binding proteins, which form in response to cellular stresses that inhibit protein synthesis (1, 2). Stress responses are induced during virus infection and are countered by viruses to maximize replication efficiency. Indeed, several examples of viral SG disruption and viral subversion of SG proteins have been described (3-6), indicating stress granules may play antiviral roles against these viruses. Ras-GTPase-activating protein (SH3 domain) binding protein 1 (G3BP1) is a stress granule-resident protein that nucleates stress granule assembly and is also inactiv...

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Section: Discussionmentioning

confidence: 99%

The Stress Granule Protein G3BP1 Recruits Protein Kinase R To Promote Multiple Innate Immune Antiviral Responses

Reineke

Lloyd

2015

J Virol

181

189

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“…Inhibition by proteinprotein interactions also occurs with TRBP, tRNA-dihydrouridine synthase A, and ADAR1, which bind PKR through their dsRBDs (16,34,35). In contrast, dsRNA, heparin, and cellular proteins MDA7, PKR activator (PACT), and E2F-1 activate PKR (26,(37)(38)(39)(40)49).…”

Section: Rna Binding Protein (Trbp) and P58mentioning

confidence: 99%

ADAR1 Interacts with PKR during Human Immunodeficiency Virus Infection of Lymphocytes and Contributes to Viral Replication

Clerzius

Gélinas

Daher

et al. 2009

J Virol

127

179

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The interferon-induced protein kinase RNA activated (PKR) is activated after virus infection. This activation is transient during the human immunodeficiency virus type 1 (HIV-1) infection of lymphocytes, and the protein is not activated at the peak of infection. We observed that interferon-induced adenosine deaminase acting on RNA 1-p150 (ADAR1-p150) and ADAR1-p110 expression increases while the virus replicates actively. Furthermore, both forms of ADAR1 show enhanced interactions with PKR at the peak of HIV infection, suggesting a role for this protein in the regulation of PKR activation. We observed that ADAR1-p150, as previously shown for the TAR RNA binding protein (TRBP), reverses the PKR inhibition of HIV expression and production in HEK 293T cells. This activity requires the Z-DNA binding motif and the three double-stranded RNA binding domains but not the catalytic domain. In astrocytic cells, ADAR1-p150 increased HIV expression and production to an extent similar to that of TRBP. Small interfering RNAs against ADAR1-p150 moderately decreased HIV production. These results indicate that two interferoninduced proteins, ADAR1 and PKR, have antagonistic functions on HIV production. They suggest that ADAR1 and TRBP belong to a multiprotein complex that inhibits PKR during the HIV infection of lymphocytes.

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“…In addition to this, the two dsRBMs can mediate dsRNA-independent protein-protein interactions with other proteins that carry similar domains (19-24). Among these are proteins inhibitory for PKR activity such as TRBP (23), Dus2L (24) and also activator protein PACT (25,26). PACT’s association with PKR leads to the activation of PKR in the absence of dsRNA (25,26).…”

Section: Introductionmentioning

confidence: 99%

Essential Role of PACT-Mediated PKR Activation in Tunicamycin-Induced Apoptosis

Singh

Fowlkes

Handy

et al. 2009

Journal of Molecular Biology

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Summary Cellular stresses such as disruption of calcium homeostasis, inhibition of protein glycosylation, and reduction of disulfide bonds result in accumulation of misfolded proteins in the endoplasmic reticulum (ER) and lead to cell death by apoptosis. Tunicamycin, which is an inhibitor of protein glycosylation, induces ER stress and apoptosis. In this study, we examined the involvement of double stranded (ds) RNA-activated protein kinase PKR and its protein activator PACT in tunicamycin-induced apoptosis. We demonstrate for the first time that PACT is phosphorylated in response to tunicamycin and is responsible for PKR activation by direct interaction. Furthermore, PACT-induced PKR activation is essential for tunicamycin-induced apoptosis since PACT as well as PKR null cells are markedly resistant to tunicamycin and show defective eIF2α phosphorylation and C/EBP homologous protein (CHOP, also known as GADD153) induction especially at low concentrations of tunicamycin. Reconstitution of PKR and PACT expression in the null cells renders them sensitive to tunicamycin, thus demonstrating that PACT-induced PKR activation plays an essential function in induction of apoptosis.

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Interaction of human tRNA-dihydrouridine synthase-2 with interferon-induced protein kinase PKR

Cited by 51 publications

References 78 publications

The Stress Granule Protein G3BP1 Recruits Protein Kinase R To Promote Multiple Innate Immune Antiviral Responses

The Stress Granule Protein G3BP1 Recruits Protein Kinase R To Promote Multiple Innate Immune Antiviral Responses

ADAR1 Interacts with PKR during Human Immunodeficiency Virus Infection of Lymphocytes and Contributes to Viral Replication

Essential Role of PACT-Mediated PKR Activation in Tunicamycin-Induced Apoptosis

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