| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.70794506 |
| Following exposure of cells to these stress agents , PACT is phosphorylated and associates with PKR with increased affinity . 0.70794506^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.5500146 |
| We found that PACT , originally identified as protein activator for dsRNA dependent protein kinase ( PKR ) and implicated in the regulation of translation , augmented IFN beta gene activation induced by Newcastle disease virus . 0.5500146^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :1.1963594 |
| Previous reports demonstrate that following stress , RAX / PACT associates with and activates PKR resulting in eIF2alpha phosphorylation , consequent translation inhibition , and cell death via apoptosis . 1.1963594^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.55234343 |
| Our results suggest that the interactions between PKR and PACT / RAX modulate the effect of ethanol on protein synthesis and cell survival in the central nervous system . . 0.55234343^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.71703327 |
| Now we report that RAX , the only known cellular activator for PKR , initiates PKR activation in response to a broad range of stresses including serum deprivation , cytotoxic cytokine or chemotherapy treatment , or viral infection . 0.71703327^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Modular structure of PACT : distinct domains for binding and activating PKR . ^^^ PACT is a 35 kDa human protein that can directly bind and activate the latent protein kinase , PKR . ^^^ Here we report that PKR activation by PACT causes cellular apoptosis in addition to PKR autophosphorylation and translation inhibition . ^^^ We analyzed the structure function relationship of PACT by measuring its ability to bind and activate PKR in vitro and in vivo . ^^^ Our studies revealed that among three domains of PACT , the presence of either domain 1 or domain 2 was sufficient for high affinity binding of PACT to PKR . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| PACT , a protein activator of the interferon induced protein kinase , PKR . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Organizations and promoter analyses of the human and the mouse genes for PACT , the protein activator of the interferon induced protein kinase , PKR . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| RAX has a high sequence homology to human PACT , which activates PKR in the absence of dsRNA . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| PACT and PKR : turning on NF kappa B in the absence of virus . ^^^ However , the notion that PKR acts solely as a sensor for viral infection has been challenged by recent findings that alteration of PKR activity has effects on cellular growth and by the discovery of a virus independent activator of PKR , a cellular protein called PACT ( PKR activating protein ) . ^^^ First , is PACT an alternative to dsRNA as a direct activator of the PKR NF kappaB pathway . ^^^ Second , how is PACT itself activated and targeted to PKR . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| The C terminal , third conserved motif of the protein activator PACT plays an essential role in the activation of double stranded RNA dependent protein kinase ( PKR ) . ^^^ We have recently identified PACT , a novel protein activator of PKR , as an important modulator of PKR activity in cells in the absence of viral infection . ^^^ PACT heterodimerizes with PKR and activates it by direct protein protein interactions . ^^^ Endogenous PACT acts as an activator of PKR in response to diverse stress signals , such as serum starvation and peroxide or arsenite treatment , and is therefore a novel , stress modulated physiological activator of PKR . ^^^ In this study , we have characterized the functional domains of PACT that are required for PKR activation . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| The protein activator of RNA activated protein kinase ( PKR ) is a proapoptotic protein called PACT . ^^^ In the absence of viral infections , PKR is activated by its activator PACT , especially in response to diverse stress signals . ^^^ PACT expression also coincides with the presence of active PKR and phosphorylated eIF2alpha . ^^^ These results suggest a possible role of PACT mediated PKR activation in the regulation of epithelial cell apoptosis in mouse colon . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Inhibition of PACT mediated activation of PKR by the herpes simplex virus type 1 Us 11 protein . ^^^ PACT , a protein activator of PKR , can cause inhibition of cellular protein synthesis and apoptosis . ^^^ Here , we report that the Us 11 protein of herpes simplex virus type 1 can block PKR activation by PACT both in vitro and in vivo . ^^^ Although Us 11 can bind to both PKR and PACT , mutational analyses revealed that the binding of Us 11 to PKR , and not to PACT , was essential for its inhibitory action . ^^^ The binding of Us 11 to PKR did not block the binding of PKR to PACT but prevented its activation . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Tumour necrosis factor alpha up regulates protein kinase R ( PKR ) activating protein ( PACT ) and increases phosphorylation of PKR and eukaryotic initiation factor 2 alpha in articular chondrocytes . ^^^ Our previous analysis of the genes regulated in cartilage at the onset of spontaneous osteoarthritis in the guinea pig knee revealed up regulation of the gene for protein kinase R ( PKR ) activating protein ( PACT ) , which encodes the cellular activator of the protein kinase , PKR . ^^^ PACT and PKR are upstream components of a number of signal transduction and gene transcription pathways used by pro inflammatory cytokines . ^^^ We have investigated the role of PACT and PKR in articular cartilage degradation using cytokine treatment of bovine primary chondrocytes and cartilage explants . ^^^ The known role of PKR in cytokine induced signalling pathways , together with our data showing cytokine regulation of PACT and PKR in chondrocytes , reveals a novel mechanism of cartilage degradation that may be important in the pathogenesis of arthritic diseases . . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| The carboxy terminal , M 3 motifs of PACT and TRBP have opposite effects on PKR activity . ^^^ The three known activators of PKR are dsRNA , heparin , and PACT . ^^^ PACT activates PKR by direct protein protein interaction in response to cellular stress . ^^^ The human TAR ( trans activating region ) binding protein ( TRBP ) , which is very homologous to PACT , also interacts with PKR , leading to an inhibition of PKR activity . ^^^ Our results indicate that TRBP and PACT interact with PKR through the same residues , and no differences were identified in these two interactions . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Such modular configurations occur in functionally diverse proteins such as myosin and a regulator of the double stranded DNA stimulated protein kinase ( PKR ) called PACT . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| These included monocyte chemoattractant protein , transmembrane protein 3 , tetratricopeptide repeat protein 1 , a ubiquitin like 17 kDa protein , ubiquitin specific protease ISG 43 , an RNA helicase DEAD box protein , GTP binding MX protein , the cytokine IP 10 , and the PKR activator PACT . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| The cellular protein , PACT , can directly activate protein kinase ( PKR ) in vitro by the interaction of PACT domain 3 with PKR . ^^^ In contrast , in vivo , PACT mediated PKR activation and concomitant inhibition of protein synthesis require additional cellular stresses . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Furthermore , the lack of PKR activation was not due to differing levels of the PKR activator , PACT nor of the PKR inhibitor , p 58 ( IPK ) . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| We report here a homomultimerization activity of a type B dsRBD and suggest possible implications that include a model for PKR activation by PACT . . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Activation of PKR can occur in the absence of dsRNA and in such case is controlled by intracellular regulators like the PKR activating protein ( PACT ) , the PKR inhibitor p 58 ( IPK ) , or heat shock proteins ( Hsp ) . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Binding of the influenza A virus NS 1 protein to PKR mediates the inhibition of its activation by either PACT or double stranded RNA . ^^^ A major component of the cellular antiviral system is the latent protein kinase PKR , which is activated by binding to either double stranded RNA ( dsRNA ) or the cellular PACT protein . ^^^ In the present study , we first carried out a series of in vitro experiments to determine whether the NS1A protein could utilize a common mechanism to inhibit PKR activation by both PACT and dsRNA , despite their different modes of activation . ^^^ First , we showed that an NS1A protein lacking RNA binding activity , like the wild type ( wt ) protein , blocked PKR activation by PACT in vivo , as well as the downstream effects of PKR activation in cells , namely , eIF 2 phosphorylation and apoptosis . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Molecular basis for PKR activation by PACT or dsRNA . ^^^ To be enzymatically active , latent PKR needs to be activated by binding to one of its activators , dsRNA or PACT protein . ^^^ These observations suggest a model for PKR activation upon binding of dsRNA or PACT . . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| Ceramide regulates protein synthesis by a novel mechanism involving the cellular PKR activator RAX . ^^^ The recently discovered cellular PKR activator , RAX , is phosphorylated in association with PKR activation ( Ito , T . , Yang , M . , and May , W . ^^^ Since ceramide potently promotes RAX and eukaryotic initiation factor 2alpha phosphorylation , a possible role for ceramide in this process may involve the activation of PKR by RAX . ^^^ Since 2 aminopurine , a serine / threonine kinase inhibitor that has previously been shown to inhibit PKR , blocks both the potentiation of ceramide killing by RAX and ceramide induced inhibition of protein synthesis , ceramide appears to promote PKR activation , at least indirectly . ^^^ |
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| Interacting proteins: O75569 and P19525 |
Pubmed |
SVM Score :0.0 |
| A novel role for RAX , the cellular activator of PKR , in synergistically stimulating SV 40 large T antigen dependent gene expression . ^^^ The double stranded ( ds ) RNA binding protein RAX was discovered as a stress induced cellular activator of the dsRNA dependent protein kinase ( PKR ) , a key regulator of protein synthesis in response to viral infection and cellular stress . ^^^ We now report a novel function of RAX , independent of PKR , to enhance SV 40 promoter ( origin ) / enhancer dependent gene expression . ^^^ Thus , in addition to stimulating PKR activity , RAX can positively regulate both SV 40 large T antigen dependent DNA replication and transcription in a mechanism that may alter the interaction of the cellular factor ( s ) with the SV 40 enhancer via the dsRNA binding domains of RAX . ^^^ |
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