The Experts below are selected from a list of 3606 Experts worldwide ranked by ideXlab platform
Serge Y. Fuchs - One of the best experts on this subject based on the ideXlab platform.
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Cancer-associated fibroblasts downregulate type I interferon receptor to stimulate intratumoral stromagenesis
Oncogene, 2020Co-Authors: Riddhita Mukherjee, Kanstantsin V. Katlinski, Amy R. Peck, Noreen Mcbrearty, Priya K. Govindaraju, Ellen Puré, Serge Y. FuchsAbstract:Activation of cancer-associated fibroblasts (CAFs) and ensuing desmoplasia play an important role in the growth and progression of solid tumors. Here we demonstrate that, within colon and pancreatic ductal adenocarcinoma tumors, efficient stromagenesis relies on downregulation of the IFNAR1 chain of the type I interferon (IFN1) receptor. Expression of the fibroblast activation protein (FAP) and accumulation of the extracellular matrix (ECM) was notably impaired in tumors grown in the IFNAR1 ^S526A (SA) knock-in mice, which are deficient in IFNAR1 downregulation. Primary fibroblasts from these mice exhibited elevated levels of Smad7, a negative regulator of the transforming growth factor-β (TGFβ) pathway. Knockdown of Smad7 alleviated deficient ECM production in SA fibroblasts in response to TGFβ. Analysis of human colorectal cancers revealed an inverse correlation between IFNAR1 and FAP levels. Whereas growth of tumors in SA mice was stimulated by co-injection of wild type but not SA fibroblasts, genetic ablation of IFNAR1 in fibroblasts also accelerated tumor growth. We discuss how inactivation of IFNAR1 in CAFs acts to stimulate stromagenesis and tumor growth.
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Downregulation of the IFNAR1 chain of type 1 interferon receptor contributes to the maintenance of the haematopoietic stem cells
Cancer biology & therapy, 2017Co-Authors: Jun Gui, Bin Zhao, Kaosheng Lyu, Wei Tong, Serge Y. FuchsAbstract:ABSTRACTRecent studies demonstrated that prolonged exposure of haematopoietic stem cells (HSCs) to type I interferons (IFN) stimulates HSCs entrance into cell cycle, continuous proliferation and eventual exhaustion, which could be prevented by ablation of the IFNAR1 chain of IFN receptor. Given that levels IFNAR1 expression can be robustly affected by IFN-independent ubiquitination and downregulation of IFNAR1 in response to activation of protein kinases such as protein kinase R-like endoplasmic reticulum kinase (PERK) and casein kinase 1α (CK1α), we aimed to determine the role of IFNAR1 downregulation in the maintenance of HSCs. Mice harboring the ubiquitination-deficient IFNAR1S526A allele displayed greater levels of haematopoietic cell progenitors but reduced numbers of the long-term HSCs compared with wild type mice and animals lacking IFNAR1. Studies using competitive bone marrow repopulation assays showed that CK1α (but not PERK) is essential for the long-term HSCs function. Concurrent ablation of I...
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downregulation of the IFNAR1 chain of type 1 interferon receptor contributes to the maintenance of the haematopoietic stem cells
Cancer Biology & Therapy, 2017Co-Authors: Jun Gui, Bin Zhao, Kaosheng Lyu, Wei Tong, Serge Y. FuchsAbstract:Recent studies demonstrated that prolonged exposure of haematopoietic stem cells (HSCs) to type I interferons (IFN) stimulates HSCs entrance into cell cycle, continuous proliferation and eventual exhaustion, which could be prevented by ablation of the IFNAR1 chain of IFN receptor. Given that levels IFNAR1 expression can be robustly affected by IFN-independent ubiquitination and downregulation of IFNAR1 in response to activation of protein kinases such as protein kinase R-like endoplasmic reticulum kinase (PERK) and casein kinase 1α (CK1α), we aimed to determine the role of IFNAR1 downregulation in the maintenance of HSCs. Mice harboring the ubiquitination-deficient IFNAR1S526A allele displayed greater levels of haematopoietic cell progenitors but reduced numbers of the long-term HSCs compared with wild type mice and animals lacking IFNAR1. Studies using competitive bone marrow repopulation assays showed that CK1α (but not PERK) is essential for the long-term HSCs function. Concurrent ablation of IFNAR1 led to a modest attenuation of the CK1α-null phenotype indicating that, although other CK1α targets are likely to be important, IFNAR1 downregulation can contribute to the maintenance of the HSCs function.
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Expression of the IFNAR1 chain of type 1 interferon receptor in benign cells protects against progression of acute leukemia
Leukemia & lymphoma, 2017Co-Authors: Bin Zhao, Sabyasachi Bhattacharya, Serge Y. FuchsAbstract:Type I interferons (IFN) were widely used for leukemia treatment. These cytokines act on cell surface receptor consisting of the IFNAR1/2 chains to induce anti-tumorigenic effects. Given that levels of IFNAR1 can be regulated by phosphorylation-driven ubiquitination and degradation that undermines IFN signaling and anti-tumorigenic effects, we sought to determine the importance of IFNAR1 downregulation in progression of acute leukemia. Using knock-in mice deficient in downregulation of IFNAR1, we uncovered that IFNAR1 expression in stromal benign cells functions to protect against progression of leukemia. We discuss putative mechanisms of this regulation and potential of therapeutic targeting of IFNAR1 downregulation to treat leukemia.
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endocytosis of the IFNAR1 chain of type 1 interferon receptoris regulated by diverse e2 ubiquitin conjugation enzymes 50
Успехи молекулярной онкологии, 2014Co-Authors: Christopher J. Carbone, Hui Zheng, Serge Y. FuchsAbstract:Ubiquitination of signaling receptors triggers their endocytosis to restrict the extent of cell signaling. Type 1 interferon (IFN1) eliminates its receptor from cell surface via stimulating the ubiquitination of its IFNAR1 chain. While it was suggested that this ubiquitination aids IFNAR1 internalization via relieving a steric hindrance of a linear motif within IFNAR1 from the endocytic machinery, the mechanisms involved remain poorly understood. Here we describe a specific role for two disparate ubiquitin acceptor sites within this receptor. These sites, Lys501 and Lys525 / 526, exhibit a preference for polyubiquitination via either Lys63- or Lys48‑linked chains (K63‑Ub and K48‑Ub, respectively). Whereas the SCFβTrcp E3 ubiquitin ligase controls either type of ubiquitination-dependent IFNAR1 endocytosis, the specificity of these processes is determined by two different E2 ubiquitin conjugating enzymes, Ubc13 and Cdc34. These enzymes can be directly used by SCFβTrcp E3 ubiquitin ligase to generate either K63‑Ub or K48‑Ub in vitro. Ubc13 is involved in IFNAR1 endocytosis driven by the K63‑Ub modification of Lys501, whereas the K48‑Ub-specific Cdc34 affects receptor endocytosis via ubiquitin conjugation that occurs on Lys525 / 526. Both types of linkages combine to maximize IFNAR1 endocytosis otherwise suppressed by unfavorable conformation dependent on the presence of a conserved Pro470 within the intracellular domain of IFNAR1. We propose a model where alternate utilization of both E2s to assemble diverse polyubiquitin linkages cooperates to achieve IFNAR1 intracellular domain conformations and spatial arrangements that favor a maximal rate of receptor endocytosis.
Sandra Pellegrini - One of the best experts on this subject based on the ideXlab platform.
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Hepatitis B virus X protein inhibits extracellular IFN-α-mediated signal transduction by downregulation of type I IFN receptor
International journal of molecular medicine, 2012Co-Authors: Il-rae Cho, Sandra Pellegrini, Serge Y. Fuchs, Sang Seok Koh, Waraporn Malilas, Ratakorn Srisuttee, Byung Hak Jhun, Young-hwa ChungAbstract:We have previously shown that hepatitis B virus (HBV) protein X (HBX), a regulatory protein of HBV, activates Stat1, leading to type I interferon (IFN) production. Type I IFN secreted from HBX-expressing hepatic cells enforces antiviral signals through its binding to the cognate type I IFN receptor. We therefore investigated how cells handle this detrimental situation. Interestingly, compared to Chang cells stably expressing an empty vector (Chang-Vec), Chang cells stably expressing HBX (Chang-HBX) showed lower levels of IFN-α receptor 1 (IFNAR1) protein, a subunit of type I IFN receptor. The levels of IFNAR1 transcripts detected in Chang-HBX cells were lower than the levels in Chang-Vec cells, indicating that HBX regulates IFNAR1 at the transcriptional level. Moreover, we observed that HBX induced the translocation of IFNAR1 to the cytoplasm. Consistent with these observations, HBX also downregulated Tyk2, which is required for the stable expression of IFNAR1 on the cell surface. Eventually, Chang-HBX cells consistently maintained a lower level of IFNAR1 expression and displayed no proper response to IFN-α, while Chang-Vec cells exhibited a proper response to IFN-α treatment. Taken together, we propose that HBX downregulates IFNAR1, leading to the avoidance of extracellular IFN-α signal transduction.
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Ligand-independent pathway that controls stability of interferon alpha receptor.
Biochemical and Biophysical Research Communications, 2008Co-Authors: Jianghuai Liu, Alexander Plotnikov, Anamika Banerjee, K. G. Suresh Kumar, Josiane Ragimbeau, Zrinka Marijanovic, Darren P. Baker, Sandra Pellegrini, Serge Y. FuchsAbstract:Ligand-specific negative regulation of cytokine-induced signaling relies on down regulation of the cytokine receptors. Down regulation of the IFNAR1 sub-unit of the Type I interferon (IFN) receptor proceeds via lysosomal receptor proteolysis, which is triggered by ubiquitination that depends on IFNAR1 serine phosphorylation. While IFN-inducible phosphorylation, ubiquitination, and degradation requires the catalytic activity of the Tyk2 Janus kinase, here we found the ligand- and Tyk2-independent pathway that promotes IFNAR1 phosphorylation, ubiquitination, and degradation when IFNAR1 is expressed at high levels. A major cellular kinase activity that is responsible for IFNAR1 phosphorylation in vitro does not depend on either ligand or Tyk2 activity. Inhibition of ligand-independent IFNAR1 degradation suppresses cell proliferation. We discuss the signaling events that might lead to ubiquitination and degradation of IFNAR1 via ligand-dependent and independent pathways and their potential physiologic significance.
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Comparable potency of IFN{alpha}2 and IFN{beta} on immediate JAK/STAT activation but differential down-regulation of IFNAR2
Biochemical Journal, 2007Co-Authors: Zrinka Marijanovic, Josiane Ragimbeau, Gilles Uzé, José Van Der Heyden, Sandra PellegriniAbstract:Type I interferons (IFNα/β) form a family of related cytokines that control a variety of cellular functions through binding to a receptor composed of IFNAR1 and IFNAR2. Among type I IFN, the α2 and β subtypes exhibit a large difference in their binding affinities to IFNAR1 and it was suggested that high concentration of IFNAR1 may compensate for its low intrinsic binding affinity to IFNα2. We tested whether receptor-proximal signaling events are sensitive to IFNAR1 surface concentration by investigating the relationship between relative IFNAR1/IFNAR2 surface levels and IFNα2 vs IFNβ signaling potencies in several cell lines. For this, we monitored the activation profile of Jak/Stat proteins, measured basal and ligand-induced surface decay of each receptor subunit and tested the effect of variable IFNAR1 levels on IFNα2 signaling potency. Our data show that the cell surface IFNAR1 level is indeed a limiting factor for assembly of the functional complex, but an increased concentration of it does not translate into an IFNα/β differential Jak/Stat signaling nor it changes the dynamics of the engaged receptor. Importantly, however, our data highlight a differential effect upon routing of IFNAR2. Following binding of IFNα2, IFNAR2 is internalized but, instead of being routed towards degradation as it is when complexed to IFNβ, it recycles back to the cell surface. These observations strongly suggest that stability and intracellular lifetime of the ternary complex account for the differential control of IFNAR2. Moreover, this work opens up the attractive possibility that endosomal-initiated signaling may contribute to IFNα/β differential bioactivities.
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TYK2 activity promotes ligand-induced IFNAR1 proteolysis.
The Biochemical journal, 2006Co-Authors: Zrinka Marijanovic, Josiane Ragimbeau, Serge Y. Fuchs, K.g. Suresh Kumar, Sandra PellegriniAbstract:The type I IFNR (interferon receptor) is a heterodimer composed of two transmembrane chains, IFNAR1 (interferon-alpha receptor 1 subunit) and IFNAR2, which are associated with the tyrosine kinases Tyk2 and Jak1 (Janus kinase 1) respectively. Ligand-induced down-regulation of the type I IFNR is a major mechanism of negative regulation of cellular signalling and involves the internalization and lysosomal degradation of IFNAR1. IFNalpha promotes the phosphorylation of IFNAR1 on Ser535, followed by recruitment of the E3 ubiquitin ligase, beta-TrCP2 (beta-transducin repeats-containing protein 2), ubiquitination of IFNAR1 and proteolysis. The non-catalytic role of Tyk2 in sustaining the steady-state IFNAR1 level at the plasma membrane is well documented; however, little is known about the function of Tyk2 in the steps that precede and succeed serine phosphorylation and ubiquitination of IFNAR1 in response to ligand binding. In the present study, we show that catalytic activation of Tyk2 is not essential for IFNAR1 internalization, but is required for ligand-induced IFNAR1 serine phosphorylation, ubiquitination and efficient lysosomal proteolysis.
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Differential responsiveness to IFN-alpha and IFN-beta of human mature DC through modulation of IFNAR expression.
Journal of Leukocyte Biology, 2006Co-Authors: M. Severa, Josiane Ragimbeau, Sandra Pellegrini, Gilles Uzé, M.e. Remoli, E. Giacomini, R. Lande, E.m. CocciaAbstract:In human monocyte-derived dendritic cells (DC), infection with Mycobacterium tuberculosis and viruses or stimulation with Toll-like receptor type 3 and 4 agonists causes the release of type I interferon (IFN). Here, we describe that the IFN-beta released upon stimulation with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C) is responsible for a rapid and sustained signal transducer and activator of transcription 1 and 2 activation and expression of IFN-stimulated genes, such as the transcription factor IFN regulatory factor 7 and the chemokine CXC chemokine ligand 10. The autocrine production of IFN-beta from LPS and poly I:C-matured DC (mDC) induced a temporary saturation of the response to type I IFN and a marked decline in the level of the two IFN receptor (IFNAR) subunits. It is interesting that we found that upon clearing of the released cytokines, LPS-stimulated DC reacquired full responsiveness to IFN-beta but only partial responsiveness to IFN-alpha, and their maturation process was unaffected. Monitoring of surface and total levels of the receptor subunits showed that maximal expression of IFNAR2 resumed within 24 h of clearing, and IFNAR1 expression remained low. Thus, mDC can modulate their sensitivity to two IFN subtypes through a differential regulation of the IFNAR subunits.
Darren P. Baker - One of the best experts on this subject based on the ideXlab platform.
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Therapeutic Elimination of the Type 1 Interferon Receptor for Treating Psoriatic Skin Inflammation
The Journal of investigative dermatology, 2016Co-Authors: Jun Gui, Darren P. Baker, Kanstantsin V. Katlinski, Michael D. Gober, Xiaoping Yang, Christine Marshall, Meena R. Sharma, Victoria P. Werth, Hallgeir Rui, John T. SeykoraAbstract:Phototherapy with UV light is a standard treatment for psoriasis, yet the mechanisms underlying the therapeutic effects are not well understood. Studies in human and mouse keratinocytes and in the skin tissues from human patients and mice showed that UV treatment triggers ubiquitination and downregulation of the type I IFN receptor chain IFNAR1, leading to suppression of IFN signaling and an ensuing decrease in the expression of inflammatory cytokines and chemokines. The severity of imiquimod-induced psoriasiform inflammation was greatly exacerbated in skin of mice deficient in IFNAR1 ubiquitination (IFNAR1SA). Furthermore, these mice did not benefit from UV phototherapy. Pharmacologic induction of IFNAR1 ubiquitination and degradation by an antiprotozoal agent halofuginone also relieved psoriasiform inflammation in wild-type but not in IFNAR1SA mice. These data identify downregulation of IFNAR1 by UV as a major mechanism of the UV therapeutic effects against the psoriatic inflammation and provide a proof of principle for future development of agents capable of inducing IFNAR1 ubiquitination and downregulation for the treatment of psoriasis.
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Protein tyrosine phosphatase 1B is a key regulator of IFNAR1 endocytosis and a target for antiviral therapies
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Christopher J. Carbone, Darren P. Baker, Hui Zheng, Sabyasachi Bhattacharya, John R. Lewis, Alexander M. Reiter, Paula S. Henthorn, Zhong Yin Zhang, Radha Ukkiramapandian, Kendra K. BenceAbstract:Type 1 interferons (IFN1) elicit antiviral defenses by activating the cognate receptor composed of IFN-α/β receptor chain 1 (IFNAR1) and IFNAR2. Down-regulation of this receptor occurs through IFN1-stimulated IFNAR1 ubiquitination, which exposes a Y466-based linear endocytic motif within IFNAR1 to recruitment of the adaptin protein-2 complex (AP2) and ensuing receptor endocytosis. Paradoxically, IFN1-induced Janus kinase-mediated phosphorylation of Y466 is expected to decrease its affinity for AP2 and to inhibit the endocytic rate. To explain how IFN1 promotes Y466 phosphorylation yet stimulates IFNAR1 internalization, we proposed that the activity of a protein tyrosine phosphatase (PTP) is required to enable both events by dephosphorylating Y466. An RNAi-based screen identified PTP1B as a specific regulator of IFNAR1 endocytosis stimulated by IFN1, but not by ligand-independent inducers of IFNAR1 ubiquitination. PTP1B is a promising target for treatment of obesity and diabetes; numerous research programs are aimed at identification and characterization of clinically relevant inhibitors of PTP1B. PTP1B is capable of binding and dephosphorylating IFNAR1. Genetic or pharmacologic modulation of PTP1B activity regulated IFN1 signaling in a manner dependent on the integrity of Y466 within IFNAR1 in human cells. These effects were less evident in mouse cells whose IFNAR1 lacks an analogous motif. PTP1B inhibitors robustly augmented the antiviral effects of IFN1 against vesicular stomatitis and hepatitis C viruses in human cells and proved beneficial in feline stomatitis patients. The clinical significance of these findings in the context of using PTP1B inhibitors to increase the therapeutic efficacy of IFN against viral infections is discussed.
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Anti-tumorigenic effects of Type 1 interferon are subdued by integrated stress responses.
Oncogene, 2012Co-Authors: Sabyasachi Bhattacharya, Darren P. Baker, Juan Qian, Wei Chun Huangfu, Guangyu Dong, Jayashree Karar, Constantinos Koumenis, J A Diehl, Serge Y. FuchsAbstract:Viral and pharmacological inducers of protein kinase RNA-activated (PKR)-like ER kinase (PERK) were shown to accelerate the phosphorylation-dependent degradation of the IFNAR1 chain of the Type 1 interferon (IFN) receptor and to limit cell sensitivity to IFN. Here we report that hypoxia can elicit these effects in a PERK-dependent manner. The altered fate of IFNAR1 affected by signaling downstream of PERK depends on phosphorylation of eIF2α (eukaryotic translational initiation factor 2-α) and ensuing activation of p38α kinase. Activators of other eIF2α kinases such as PKR or GCN2 (general control nonrepressed-2) are also capable of eliminating IFNAR1 and blunting IFN responses. Modulation of constitutive PKR activity in human breast cancer cells stabilizes IFNAR1 and sensitizes these cells to IFNAR1-dependent anti-tumorigenic effects. Although downregulation of IFNAR1 and impaired IFNAR1 signaling can be elicited in response to amino-acid deficit, the knockdown of GCN2 in melanoma cells reverses these phenotypes. We propose that, in cancer cells and the tumor microenvironment, activation of diverse eIF2α kinases followed by IFNAR1 downregulation enables multiple cellular components of tumor tissue to evade the direct and indirect anti-tumorigenic effects of Type 1 IFN.
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Vascular endothelial growth factor–induced elimination of the type 1 interferon receptor is required for efficient angiogenesis
Blood, 2011Co-Authors: Hui Zheng, Darren P. Baker, Juan Qian, Christopher J. Carbone, N. Adrian Leu, Serge Y. FuchsAbstract:Angiogenesis is stimulated by vascular endothelial growth factor (VEGF) and antagonized by type 1 interferons, including IFN-α/β. On engaging their respective receptors (VEGFR2 and IFNAR), both stimuli activate protein kinase D2 (PKD2) and type 1 IFNs require PKD2 activation and recruitment to IFNAR1 to promote the phosphorylation-dependent ubiquitination, down-regulation, and degradation of the cognate receptor chain, IFNAR1. Data reveal that PKD2 activity is dispensable for VEGF-stimulated down-regulation of VEGFR2. Remarkably, VEGF treatment promotes the recruitment of PKD2 to IFNAR1 as well as ensuing phosphorylation, ubiquitination, and degradation of IFNAR1. In cells exposed to VEGF, phosphorylation-dependent degradation of IFNAR1 leads to an inhibition of type 1 IFN signaling and is required for efficient VEGF-stimulated angiogenesis. Importance of this mechanism for proangiogenic or antiangiogenic responses in cells exposed to counteracting stimuli and the potential medical significance of this regulation are discussed.
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Pathogen recognition receptor signaling accelerates phosphorylation-dependent degradation of IFNAR1
PLoS pathogens, 2011Co-Authors: Juan Qian, Jianghuai Liu, Darren P. Baker, Hui Zheng, Christopher J. Carbone, N. Adrian Leu, Wei Chun Huangfu, Serge Y. FuchsAbstract:An ability to sense pathogens by a number of specialized cell types including the dendritic cells plays a central role in host's defenses. Activation of these cells through the stimulation of the pathogen-recognition receptors induces the production of a number of cytokines including Type I interferons (IFNs) that mediate the diverse mechanisms of innate immunity. Type I IFNs interact with the Type I IFN receptor, composed of IFNAR1 and IFNAR2 chains, to mount the host defense responses. However, at the same time, Type I IFNs elicit potent anti-proliferative and pro-apoptotic effects that could be detrimental for IFN-producing cells. Here, we report that the activation of p38 kinase in response to pathogen-recognition receptors stimulation results in a series of phosphorylation events within the IFNAR1 chain of the Type I IFN receptor. This phosphorylation promotes IFNAR1 ubiquitination and accelerates the proteolytic turnover of this receptor leading to an attenuation of Type I IFN signaling and the protection of activated dendritic cells from the cytotoxic effects of autocrine or paracrine Type I IFN. In this paper we discuss a potential role of this mechanism in regulating the processes of innate immunity.
Nicole A De Weerd - One of the best experts on this subject based on the ideXlab platform.
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a hot spot on interferon α β receptor subunit 1 IFNAR1 underpins its interaction with interferon β and dictates signaling
Journal of Biological Chemistry, 2017Co-Authors: Nicole A De Weerd, Antony Yaron Matthews, Phillip R. Pattie, Nollaig M. Bourke, San Sui Lim, Julian P VivianAbstract:The interaction of IFN-β with its receptor IFNAR1 (interferon α/β receptor subunit 1) is vital for host-protective anti-viral and anti-proliferative responses, but signaling via this interaction can be detrimental if dysregulated. Whereas it is established that IFNAR1 is an essential component of the IFNAR signaling complex, the key residues underpinning the IFN-β-IFNAR1 interaction are unknown. Guided by the crystal structure of the IFN-β-IFNAR1 complex, we used truncation variants and site-directed mutagenesis to investigate domains and residues enabling complexation of IFN-β to IFNAR1. We have identified an interface on IFNAR1-subdomain-3 that is differentially utilized by IFN-β and IFN-α for signal transduction. We used surface plasmon resonance and cell-based assays to investigate this important IFN-β binding interface that is centered on IFNAR1 residues Tyr240 and Tyr274 binding the C and N termini of the B and C helices of IFN-β, respectively. Using IFNAR1 and IFN-β variants, we show that this interface contributes significantly to the affinity of IFN-β for IFNAR1, its ability to activate STAT1, the expression of interferon stimulated genes, and ultimately to the anti-viral and anti-proliferative properties of IFN-β. These results identify a key interface created by IFNAR1 residues Tyr240 and Tyr274 interacting with IFN-β residues Phe63, Leu64, Glu77, Thr78, Val81, and Arg82 that underlie IFN-β-IFNAR1-mediated signaling and biological processes.
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A hot spot on interferon α/β receptor subunit 1 (IFNAR1) underpins its interaction with interferon-β and dictates signaling
The Journal of biological chemistry, 2017Co-Authors: Nicole A De Weerd, Julian P Vivian, Jamie Rossjohn, Antony Yaron Matthews, Phillip R. Pattie, Nollaig M. Bourke, San Sui Lim, Paul J. HertzogAbstract:The interaction of IFN-β with its receptor IFNAR1 (interferon α/β receptor subunit 1) is vital for host-protective anti-viral and anti-proliferative responses, but signaling via this interaction can be detrimental if dysregulated. Whereas it is established that IFNAR1 is an essential component of the IFNAR signaling complex, the key residues underpinning the IFN-β-IFNAR1 interaction are unknown. Guided by the crystal structure of the IFN-β-IFNAR1 complex, we used truncation variants and site-directed mutagenesis to investigate domains and residues enabling complexation of IFN-β to IFNAR1. We have identified an interface on IFNAR1-subdomain-3 that is differentially utilized by IFN-β and IFN-α for signal transduction. We used surface plasmon resonance and cell-based assays to investigate this important IFN-β binding interface that is centered on IFNAR1 residues Tyr240 and Tyr274 binding the C and N termini of the B and C helices of IFN-β, respectively. Using IFNAR1 and IFN-β variants, we show that this interface contributes significantly to the affinity of IFN-β for IFNAR1, its ability to activate STAT1, the expression of interferon stimulated genes, and ultimately to the anti-viral and anti-proliferative properties of IFN-β. These results identify a key interface created by IFNAR1 residues Tyr240 and Tyr274 interacting with IFN-β residues Phe63, Leu64, Glu77, Thr78, Val81, and Arg82 that underlie IFN-β-IFNAR1-mediated signaling and biological processes.
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Structural basis of a unique interferon-β signaling axis mediated via the receptor IFNAR1
Nature Immunology, 2013Co-Authors: Nicole A De Weerd, Julian P Vivian, Thao K Nguyen, Niamh E Mangan, Jodee A Gould, Susie-jane Braniff, Leyla Zaker-tabrizi, Ka Yee Fung, Samuel C Forster, Travis BeddoeAbstract:Type I interferons regulate immune responses by signaling via heterodimeric IFNAR1-IFNAR2 complexes. Hertzog and colleagues reveal a unique IFN-β–IFNAR1 signaling complex that is IFNAR2-independent and modulates expression of a distinct set of interferon-inducible genes. Type I interferons are important in regulating immune responses to pathogens and tumors. All interferons are considered to signal via the heterodimeric IFNAR1-IFNAR2 complex, yet some subtypes such as interferon-β (IFN-β) can exhibit distinct functional properties, although the molecular basis of this is unclear. Here we demonstrate IFN-β can uniquely and specifically ligate to IFNAR1 in an IFNAR2-independent manner, and we provide the structural basis of the IFNAR1–IFN-β interaction. The IFNAR1–IFN-β complex transduced signals that modulated expression of a distinct set of genes independently of Jak-STAT pathways. Lipopolysaccharide-induced sepsis was ameliorated in IFNAR1 ^−/− mice but not Ifnar2 ^−/− mice, suggesting that IFNAR1–IFN-β signaling is pathologically relevant. Thus, we provide a molecular basis for understanding specific functions of IFN-β.
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structural basis of a unique interferon beta signaling axis mediated via the receptor IFNAR1
Nature Immunology, 2013Co-Authors: Nicole A De Weerd, Julian P Vivian, Niamh E Mangan, Jodee A Gould, Thao Kim Thi Nguyen, Susie-jane BraniffAbstract:Type I interferons regulate immune responses by signaling via heterodimeric IFNAR1-IFNAR2 complexes. Hertzog and colleagues reveal a unique IFN-β–IFNAR1 signaling complex that is IFNAR2-independent and modulates expression of a distinct set of interferon-inducible genes.
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o009 fine structural and functional characterization of a unique ifnβ IFNAR1 signaling axis
Cytokine, 2012Co-Authors: Nicole A De Weerd, Julian P Vivian, Niamh E Mangan, Travis Beddoe, Thao Kim Thi Nguyen, S. Noppert, Hugh H. Reid, Jodee Gould, Leyla Zakertabrizi, Jamie RossjohnAbstract:Introduction Type I interferons (IFNs) are an important family of cytokines which enable the immune system to fight viral infections and cancer, and modulate the immune response. The type I IFNs are unique amongst cytokines since multiple ligands all bind to and signal through the same heterodimeric receptor. Despite a shared receptor complex, discernible differences result from receptor engagement by the different IFN subtypes. Conventionally, activation of IFN signaling complex formation is initiated by ligand binding to the high affinity receptor (Ifnar2) with the subsequent recruitment of the low affinity receptor component (IFNAR1). Ligand-induced cross-linking in this manner results in activation of the canonical Jak/STAT signaling pathway and up-regulation of numerous interferon responsive genes. Methods In the current study, we have used protein crystallography to determine the fine structure of IFN β bound to the extracellular domain (ECD) of IFNAR1. We have also used microarray analysis, RT-PCR and an animal model of sepsis to investigate the consequences of the IFN β /IFNAR1 interaction. Results In the current study we demonstrate that a different functional capability and property of IFN β is dictated by its ability to interact directly via IFNAR1, independently of Ifnar2. We thus report the crystal structure of IFN β in complex with the full length, extracellular domain of IFNAR1 and demonstrate unique interaction interfaces between these proteins not previously defined by earlier structural studies of other type I IFN complexes. We also demonstrate that this complex not only occurs in vivo but participates in the transduction of IFN β signals in mice. Using microarray analysis we have identified a novel IFN β signaling axis that occurs in the absence of Ifnar2 and that induces the expression of genes encoding chemokines, cytokines and other known interferon stimulated genes. Using a mouse model of sepsis we also show that it is the unique mode of IFNAR1 engagement by IFN β that leads to lethality in this disease model. Conclusion Our results reveal for the first time the unique mechanism of Ifnar receptor engagement by IFN β and may help to explain the unique functional attributes that IFN β possesses.
Josiane Ragimbeau - One of the best experts on this subject based on the ideXlab platform.
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Ligand-independent pathway that controls stability of interferon alpha receptor.
Biochemical and Biophysical Research Communications, 2008Co-Authors: Jianghuai Liu, Alexander Plotnikov, Anamika Banerjee, K. G. Suresh Kumar, Josiane Ragimbeau, Zrinka Marijanovic, Darren P. Baker, Sandra Pellegrini, Serge Y. FuchsAbstract:Ligand-specific negative regulation of cytokine-induced signaling relies on down regulation of the cytokine receptors. Down regulation of the IFNAR1 sub-unit of the Type I interferon (IFN) receptor proceeds via lysosomal receptor proteolysis, which is triggered by ubiquitination that depends on IFNAR1 serine phosphorylation. While IFN-inducible phosphorylation, ubiquitination, and degradation requires the catalytic activity of the Tyk2 Janus kinase, here we found the ligand- and Tyk2-independent pathway that promotes IFNAR1 phosphorylation, ubiquitination, and degradation when IFNAR1 is expressed at high levels. A major cellular kinase activity that is responsible for IFNAR1 phosphorylation in vitro does not depend on either ligand or Tyk2 activity. Inhibition of ligand-independent IFNAR1 degradation suppresses cell proliferation. We discuss the signaling events that might lead to ubiquitination and degradation of IFNAR1 via ligand-dependent and independent pathways and their potential physiologic significance.
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Comparable potency of IFN{alpha}2 and IFN{beta} on immediate JAK/STAT activation but differential down-regulation of IFNAR2
Biochemical Journal, 2007Co-Authors: Zrinka Marijanovic, Josiane Ragimbeau, Gilles Uzé, José Van Der Heyden, Sandra PellegriniAbstract:Type I interferons (IFNα/β) form a family of related cytokines that control a variety of cellular functions through binding to a receptor composed of IFNAR1 and IFNAR2. Among type I IFN, the α2 and β subtypes exhibit a large difference in their binding affinities to IFNAR1 and it was suggested that high concentration of IFNAR1 may compensate for its low intrinsic binding affinity to IFNα2. We tested whether receptor-proximal signaling events are sensitive to IFNAR1 surface concentration by investigating the relationship between relative IFNAR1/IFNAR2 surface levels and IFNα2 vs IFNβ signaling potencies in several cell lines. For this, we monitored the activation profile of Jak/Stat proteins, measured basal and ligand-induced surface decay of each receptor subunit and tested the effect of variable IFNAR1 levels on IFNα2 signaling potency. Our data show that the cell surface IFNAR1 level is indeed a limiting factor for assembly of the functional complex, but an increased concentration of it does not translate into an IFNα/β differential Jak/Stat signaling nor it changes the dynamics of the engaged receptor. Importantly, however, our data highlight a differential effect upon routing of IFNAR2. Following binding of IFNα2, IFNAR2 is internalized but, instead of being routed towards degradation as it is when complexed to IFNβ, it recycles back to the cell surface. These observations strongly suggest that stability and intracellular lifetime of the ternary complex account for the differential control of IFNAR2. Moreover, this work opens up the attractive possibility that endosomal-initiated signaling may contribute to IFNα/β differential bioactivities.
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TYK2 activity promotes ligand-induced IFNAR1 proteolysis.
The Biochemical journal, 2006Co-Authors: Zrinka Marijanovic, Josiane Ragimbeau, Serge Y. Fuchs, K.g. Suresh Kumar, Sandra PellegriniAbstract:The type I IFNR (interferon receptor) is a heterodimer composed of two transmembrane chains, IFNAR1 (interferon-alpha receptor 1 subunit) and IFNAR2, which are associated with the tyrosine kinases Tyk2 and Jak1 (Janus kinase 1) respectively. Ligand-induced down-regulation of the type I IFNR is a major mechanism of negative regulation of cellular signalling and involves the internalization and lysosomal degradation of IFNAR1. IFNalpha promotes the phosphorylation of IFNAR1 on Ser535, followed by recruitment of the E3 ubiquitin ligase, beta-TrCP2 (beta-transducin repeats-containing protein 2), ubiquitination of IFNAR1 and proteolysis. The non-catalytic role of Tyk2 in sustaining the steady-state IFNAR1 level at the plasma membrane is well documented; however, little is known about the function of Tyk2 in the steps that precede and succeed serine phosphorylation and ubiquitination of IFNAR1 in response to ligand binding. In the present study, we show that catalytic activation of Tyk2 is not essential for IFNAR1 internalization, but is required for ligand-induced IFNAR1 serine phosphorylation, ubiquitination and efficient lysosomal proteolysis.
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Differential responsiveness to IFN-alpha and IFN-beta of human mature DC through modulation of IFNAR expression.
Journal of Leukocyte Biology, 2006Co-Authors: M. Severa, Josiane Ragimbeau, Sandra Pellegrini, Gilles Uzé, M.e. Remoli, E. Giacomini, R. Lande, E.m. CocciaAbstract:In human monocyte-derived dendritic cells (DC), infection with Mycobacterium tuberculosis and viruses or stimulation with Toll-like receptor type 3 and 4 agonists causes the release of type I interferon (IFN). Here, we describe that the IFN-beta released upon stimulation with lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (poly I:C) is responsible for a rapid and sustained signal transducer and activator of transcription 1 and 2 activation and expression of IFN-stimulated genes, such as the transcription factor IFN regulatory factor 7 and the chemokine CXC chemokine ligand 10. The autocrine production of IFN-beta from LPS and poly I:C-matured DC (mDC) induced a temporary saturation of the response to type I IFN and a marked decline in the level of the two IFN receptor (IFNAR) subunits. It is interesting that we found that upon clearing of the released cytokines, LPS-stimulated DC reacquired full responsiveness to IFN-beta but only partial responsiveness to IFN-alpha, and their maturation process was unaffected. Monitoring of surface and total levels of the receptor subunits showed that maximal expression of IFNAR2 resumed within 24 h of clearing, and IFNAR1 expression remained low. Thus, mDC can modulate their sensitivity to two IFN subtypes through a differential regulation of the IFNAR subunits.
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TYK2 activity promotes the ligand-induced IFNAR1 proteolysis
Biochemical Journal, 2006Co-Authors: Zrinka Marijanovic, Josiane Ragimbeau, Serge Y. Fuchs, K.g. Suresh Kumar, Sandra PellegriniAbstract:The type I interferon receptor is a heterodimer of two transmembrane chains, IFNAR1 and IFNAR2, which are associated to the tyrosine kinases Tyk2 and Jak1 respectively. Ligand-induced down-regulation of the type I interferon receptor represents a major mechanism of negative regulation of signaling and involves internalization and lysosomal degradation of IFNAR1. Interferon {alpha} promotes phosphorylation of IFNAR1 on serine 535, followed by recruitment of the {beta}-TrCP2 E3 ubiquitin ligase, ubiquitination of IFNAR1 and proteolysis. The non-catalytic role of Tyk2 in sustaining the steady-state IFNAR1 level at the plasma membrane is well documented, however little is known about Tyk2 function in steps that precede and succeed serine phosphorylation and ubiquitination of IFNAR1 in response to the ligand. Here we show that catalytic activation of Tyk2 is not essential for IFNAR1 internalization, but is required for the ligand-induced IFNAR1 serine phosphorylation, ubiquitination and efficient lysosomal proteolysis.
