scholarly journals Stat5b Inhibits NFκB-Mediated Signaling

2000 ◽  
Vol 14 (1) ◽  
pp. 114-123 ◽  
Author(s):  
Guoyang Luo ◽  
Li-yuan Yu-Lee
Keyword(s):  
Protein Interactions ◽  
Nuclear Translocation ◽  
Early Response ◽  
Inhibitory Effect ◽  
Interferon Regulatory Factor ◽  
Cytokine Signaling ◽  
Regulatory Factor ◽  
Protein Protein Interactions ◽  
Interferon Regulatory Factor 1 ◽  
Target Promoters

Abstract Signal transducers and activators of transcription (Stat) are latent transcription factors that participate in cytokine signaling by regulating the expression of early response genes. Our previous studies showed that Stat5 functions not only as a transcriptional activator but also as a transcriptional inhibitor, depending on the target promoter. This report further investigates the mechanism of Stat5b-mediated inhibition and demonstrates that PRL-inducible Stat5b inhibits nuclear factorκB (NFκB) signaling to both the interferon regulatory factor-1 promoter and to the thymidine kinase promoter containing multimerized NFκB elements (NFκB-TK). Further, PRL-inducible Stat5b inhibits tumor necrosis factor-α signaling presumably by inhibiting endogenous NFκB. This Stat5b-mediated inhibitory effect on NFκB signaling is independent of Stat5b-DNA interactions but requires the carboxyl terminus of Stat5b as well as Stat5b nuclear translocation and/or accumulation, suggesting that Stat5b is competing for a nuclear factor(s) necessary for NFκB-mediated activation of target promoters. Increasing concentrations of the coactivator p300/CBP reverses Stat5b inhibition at both the interferon-regulatory factor-1 and NFκB-TK promoters, suggesting that Stat5b may be squelching limiting coactivators via protein-protein interactions as one mechanism of promoter inhibition. These results further substantiate our observation that Stat factors can function as transcriptional inhibitors. Our studies reveal cross-talk between the Stat5b and NFκB signal transduction pathways and suggest that Stat5b-mediated inhibition of target promoters occurs at the level of protein-protein interactions and involves competition for limiting coactivators.

scholarly journals Interferon regulatory factor 1 (IRF-1) directs IL-4/IL-13 induced death of neonatal Th1 cells

2017 ◽  
Author(s):  
◽  
Mindy Marie Miller
Keyword(s):  
Interferon Regulatory Factor ◽  
Th2 Cells ◽  
Cytokine Signaling ◽  
Th1 Cells ◽  
Regulatory Factor ◽  
Th1 Cell ◽  
Newborn Mice ◽  
Apoptosis Pathway ◽  
Interferon Regulatory Factor 1 ◽  
Intrinsic Apoptosis Pathway

Newborns typically have immune responses that are allergic, due to a predominance of Th2 cells, and lack the ability to respond to vaccines as well as display poor protection against microbes, due to a lack of Th1 cells. Our lab has previously discovered that the paucity of Th1 cells in the neonatal period occurs because these cells die during a second antigen encounter. This research utilizes murine neonates to demonstrate that Th1 cell death occurs from antigen and IL-4/IL-13 cytokine signaling and identifies the signaling pathway within the cell that leads to death. Interestingly, a novel role for a transcription factor, interferon regulatory factor 1 (IRF-1), has been discovered whereby it is induced upon cytokine signaling and initiates the intrinsic apoptosis pathway. Furthermore, by blocking this pathway, it is possible to rescue neonatal Th1 cells and improve vaccine efficacy in newborn mice. This is of high clinical importance as a significant number of human neonatal deaths occur from infections and vaccines remain at the forefront of infection prevention.

scholarly journals Cytomegalovirus Activates Interferon Immediate-Early Response Gene Expression and an Interferon Regulatory Factor 3-Containing Interferon-Stimulated Response Element-Binding Complex

1998 ◽  
Vol 18 (7) ◽  
pp. 3796-3802 ◽  
Author(s):  
Lorena Navarro ◽  
Kerri Mowen ◽  
Steven Rodems ◽  
Brian Weaver ◽  
Nancy Reich ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Kinase Inhibitors ◽  
Nuclear Translocation ◽  
Early Response ◽  
Interferon Regulatory Factor ◽  
Immediate Early ◽  
Creb Binding Protein ◽  
Regulatory Factor ◽  
Response Element ◽  
Interferon Regulatory Factor 3

ABSTRACTInterferon establishes an antiviral state in numerous cell types through the induction of a set of immediate-early response genes. Activation of these genes is mediated by phosphorylation of latent transcription factors of the STAT family. We found that infection of primary foreskin fibroblasts with human cytomegalovirus (HCMV) causes selective transcriptional activation of the alpha/beta-interferon-responsive ISG54 gene. However, no activation or nuclear translocation of STAT proteins was detected. Activation of ISG54 occurs independent of protein synthesis but is prevented by protein tyrosine kinase inhibitors. Further analysis revealed that HCMV infection induced the DNA binding of a novel complex, tentatively called cytomegalovirus-induced interferon-stimulated response element binding factor (CIF). CIF is composed, at least in part, of the recently identified interferon regulatory factor 3 (IRF3), but it does not contain the STAT1 and STAT2 proteins that participate in the formation of interferon-stimulated gene factor 3. IRF3, which has previously been shown to possess no intrinsic transcriptional activation potential, interacts with the transcriptional coactivator CREB binding protein, but not with p300, to form CIF. Activating interferon-stimulated genes without the need for prior synthesis of interferons might provide the host cell with a potential shortcut in the activation of its antiviral defense.

Target-Templated de novo Design of Macrocyclic D-/L-Peptides: Inhibitors of the PD-1/PD-L1 Interaction

2020 ◽  
Author(s):  
Salvador Guardiola ◽  
Monica Varese ◽  
Xavier Roig ◽  
Jesús Garcia ◽  
Ernest Giralt
Keyword(s):  
Protein Interactions ◽  
Cyclic Peptides ◽  
General Framework ◽  
Large Scale ◽  
De Novo ◽  
Inhibitory Effect ◽  
Original Text ◽  
Protein Protein Interactions ◽  
Retraction Notice ◽  
Pharmaceutical Properties

<p>NOTE: This preprint has been retracted by consensus from all authors. See the retraction notice in place above; the original text can be found under "Version 1", accessible from the version selector above.</p><p><br></p><p>------------------------------------------------------------------------</p><p><br></p><p>Peptides, together with antibodies, are among the most potent biochemical tools to modulate challenging protein-protein interactions. However, current structure-based methods are largely limited to natural peptides and are not suitable for designing target-specific binders with improved pharmaceutical properties, such as macrocyclic peptides. Here we report a general framework that leverages the computational power of Rosetta for large-scale backbone sampling and energy scoring, followed by side-chain composition, to design heterochiral cyclic peptides that bind to a protein surface of interest. To showcase the applicability of our approach, we identified two peptides (PD-<i>i</i>3 and PD-<i>i</i>6) that target PD-1, a key immune checkpoint, and work as protein ligand decoys. A comprehensive biophysical evaluation confirmed their binding mechanism to PD-1 and their inhibitory effect on the PD-1/PD-L1 interaction. Finally, elucidation of their solution structures by NMR served as validation of our <i>de novo </i>design approach. We anticipate that our results will provide a general framework for designing target-specific drug-like peptides.<i></i></p>

Target-Templated de novo Design of Macrocyclic D-/L-Peptides: Inhibitors of the PD-1/PD-L1 Interaction

2020 ◽  
Author(s):  
Salvador Guardiola ◽  
Monica Varese ◽  
Xavier Roig ◽  
Jesús Garcia ◽  
Ernest Giralt
Keyword(s):  
Protein Interactions ◽  
Cyclic Peptides ◽  
General Framework ◽  
Large Scale ◽  
De Novo ◽  
Inhibitory Effect ◽  
Original Text ◽  
Protein Protein Interactions ◽  
Retraction Notice ◽  
Pharmaceutical Properties

<p>NOTE: This preprint has been retracted by consensus from all authors. See the retraction notice in place above; the original text can be found under "Version 1", accessible from the version selector above.</p><p><br></p><p>------------------------------------------------------------------------</p><p><br></p><p>Peptides, together with antibodies, are among the most potent biochemical tools to modulate challenging protein-protein interactions. However, current structure-based methods are largely limited to natural peptides and are not suitable for designing target-specific binders with improved pharmaceutical properties, such as macrocyclic peptides. Here we report a general framework that leverages the computational power of Rosetta for large-scale backbone sampling and energy scoring, followed by side-chain composition, to design heterochiral cyclic peptides that bind to a protein surface of interest. To showcase the applicability of our approach, we identified two peptides (PD-<i>i</i>3 and PD-<i>i</i>6) that target PD-1, a key immune checkpoint, and work as protein ligand decoys. A comprehensive biophysical evaluation confirmed their binding mechanism to PD-1 and their inhibitory effect on the PD-1/PD-L1 interaction. Finally, elucidation of their solution structures by NMR served as validation of our <i>de novo </i>design approach. We anticipate that our results will provide a general framework for designing target-specific drug-like peptides.<i></i></p>

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