Associates with IFNAR1 to form the type I interferon receptor. Receptor for interferons alpha and beta. Involved in IFN-mediated STAT1, STAT2 and STAT3 activation.
J. Biol. Chem. 270, 21606-21611 (1995)[PubMed:7665574]
The interferon alpha beta receptor (IFN alpha R) or type I IFN-R is formed by a 110-kDa alpha subunit or IFNAR and by a beta subunit, which has short and long forms (molecular masses of 55 and 95-100 kDa, respectively). In this report, we demonstrate that the IFN alpha/beta R cDNA recently cloned corresponds to the 55-kDa or short form of the beta subunit, while the 95-100-kDa species reported here corresponds to a longer form of the IFN alpha/beta R cDNA that is probably produced by alternative splicing of the same gene. Stable transfection of the alpha subunit with either form of the beta subunit results in the expression of low and high affinity receptors, while expression of either form of the beta subunit alone only produces low affinity receptors. More important, only expression of the alpha and long form of the human beta subunits in mouse L-929 cells reconstitutes the activation of the Jak kinases and the Stat factors, as well as the antiviral response to human type I IFNs.
Human type I interferons (IFNs) play an important role in the regulation of antiviral defense mechanisms, immunomodulatory activities, and growth control. Recent efforts have demonstrated the importance of IFNs in the activation of signal transducers and activators of transcription (STATs). The role of STAT1 and STAT2 in IFN-dependent JAK-STAT signaling is well established; however, the role of STAT3 and its activation by IFNs remains unclear. Understanding the IFN-dependent regulation of STAT3 is of increasing interest because recent studies have demonstrated that STAT3 may play a role in cancer. Studies have revealed that STAT3 is constitutively active in a number of cancer cell lines and that overexpression of an active form of STAT3 transforms normal fibroblasts. Therefore, STAT3 exhibits properties indicative of known oncogenes. In this report, we define the role of the type I IFN receptor in STAT3 activation and identify for the first time tyrosine residues present in the cytoplasmic domain of IFNAR2c that are critical for STAT3 activation. The regulation of STAT3 activation by IFNs was measured in a human lung fibrosarcoma cell line lacking IFNAR2c but stably expressing various IFNAR2c tyrosine mutants. We show here that in addition to IFN-dependent tyrosine phosphorylation of STAT3, activation using a STAT3-dependent electrophoretic mobility shift assay and a STAT3-specific reporter can also be demonstrated. Furthermore, we demonstrate that type I IFN-dependent activation of STAT3 proceeds through a novel mechanism that is dependent on two tyrosines, Tyr(337) and Tyr(512), present in IFNAR2c and contained within a conserved six-amino acid residue motif, GxGYxM. Surprisingly, both tyrosines were previously shown to be required for type I IFN-dependent STAT1 and STAT2 activation. Our results reveal that type I IFNs activate multiple STATs via the overlapping usage of two tyrosine residues located in the cytoplasmic domain of IFNAR2c.
We describe a universal ligand-binding receptor for human interferons alpha and interferon beta (type I IFNs). A soluble 40 kDa IFN-alpha/beta receptor (p40) that blocks the activity of type I IFNs was purified from urine and sequenced. Antibodies raised against p40 completely block the activity of several type I IFNs and immuno-precipitate both a cellular 102 kDa IFN-alpha/beta receptor and its cross-linked complexes with IFN-alpha 2. The receptor is a disulfide-linked dimer, consisting of 51 kDa subunits. We isolated and expressed a 1.5 kb cDNA, coding for the IFN-alpha/beta receptor. Its 331 amino acid sequence includes a leader and a transmembrane region, while its ectodomain corresponds to p40. IFN-alpha/beta receptor is physically associated with the cytoplasmic Tyr kinase JAK1, hence, in addition to ligand binding, it is directly involved in signal transduction.
Type I interferons (IFNs) are cytokines that play a central role in mediating antiviral, antiproliferative, and immunomodulatory activities in virtually all cells. These activities are entirely dependent on the interaction of IFNs with their particular cell surface receptor. In this report, we identify two specific tyrosine residues located within the cytoplasmic domain of IFNAR2c that are obligatory for IFN-dependent signaling. Various IFNAR2c tyrosine mutants were expressed in a human lung fibroscarcoma cell line lacking IFNAR2c (U5A). Stable clones expressing these mutants were analyzed for their ability to induce STAT1 and STAT2 activation, ISGF3 transcriptional complex formation, gene expression, and cell growth regulation in response to stimulation with type I IFNs. The replacement of all seven cytoplasmic tyrosine residues of IFNAR2c with phenylalanine resulted in a receptor unable to respond to IFN stimulation. Substitution of single tyrosines at amino acid residue 269, 316, 318, 337, or 512 with phenylalanine had no effect on IFN-dependent signaling, suggesting that no single tyrosine is essential for IFN receptor-mediated signaling. In addition, IFNAR2c retaining five proximal tyrosines residues (269, 306, 316, 318, and 337) or either two distal tyrosine residues (411 or 512) continued to be responsive to IFN stimulation. Surprisingly, the presence of only a single tyrosine at either position 337 or 512 was sufficient to restore a complete IFN response. These results indicate that IFN-dependent signaling proceeds through the redundant usage of two tyrosine residues in the cytoplasmic domain of IFNAR2c.
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Type I interferons (IFNs) are cytokines that play a central role in mediating antiviral, antiproliferative, and immunomodulatory activities in virtually all cells. These activities are entirely dependent on the interaction of IFNs with their particular cell surface receptor. In this report, we identify two specific tyrosine residues located within the cytoplasmic domain of IFNAR2c that are obligatory for IFN-dependent signaling. Various IFNAR2c tyrosine mutants were expressed in a human lung fibroscarcoma cell line lacking IFNAR2c (U5A). Stable clones expressing these mutants were analyzed for their ability to induce STAT1 and STAT2 activation, ISGF3 transcriptional complex formation, gene expression, and cell growth regulation in response to stimulation with type I IFNs. The replacement of all seven cytoplasmic tyrosine residues of IFNAR2c with phenylalanine resulted in a receptor unable to respond to IFN stimulation. Substitution of single tyrosines at amino acid residue 269, 316, 318, 337, or 512 with phenylalanine had no effect on IFN-dependent signaling, suggesting that no single tyrosine is essential for IFN receptor-mediated signaling. In addition, IFNAR2c retaining five proximal tyrosines residues (269, 306, 316, 318, and 337) or either two distal tyrosine residues (411 or 512) continued to be responsive to IFN stimulation. Surprisingly, the presence of only a single tyrosine at either position 337 or 512 was sufficient to restore a complete IFN response. These results indicate that IFN-dependent signaling proceeds through the redundant usage of two tyrosine residues in the cytoplasmic domain of IFNAR2c.
We describe a universal ligand-binding receptor for human interferons alpha and interferon beta (type I IFNs). A soluble 40 kDa IFN-alpha/beta receptor (p40) that blocks the activity of type I IFNs was purified from urine and sequenced. Antibodies raised against p40 completely block the activity of several type I IFNs and immuno-precipitate both a cellular 102 kDa IFN-alpha/beta receptor and its cross-linked complexes with IFN-alpha 2. The receptor is a disulfide-linked dimer, consisting of 51 kDa subunits. We isolated and expressed a 1.5 kb cDNA, coding for the IFN-alpha/beta receptor. Its 331 amino acid sequence includes a leader and a transmembrane region, while its ectodomain corresponds to p40. IFN-alpha/beta receptor is physically associated with the cytoplasmic Tyr kinase JAK1, hence, in addition to ligand binding, it is directly involved in signal transduction.
J. Biol. Chem. 270, 21606-21611 (1995)[PubMed:7665574]
The interferon alpha beta receptor (IFN alpha R) or type I IFN-R is formed by a 110-kDa alpha subunit or IFNAR and by a beta subunit, which has short and long forms (molecular masses of 55 and 95-100 kDa, respectively). In this report, we demonstrate that the IFN alpha/beta R cDNA recently cloned corresponds to the 55-kDa or short form of the beta subunit, while the 95-100-kDa species reported here corresponds to a longer form of the IFN alpha/beta R cDNA that is probably produced by alternative splicing of the same gene. Stable transfection of the alpha subunit with either form of the beta subunit results in the expression of low and high affinity receptors, while expression of either form of the beta subunit alone only produces low affinity receptors. More important, only expression of the alpha and long form of the human beta subunits in mouse L-929 cells reconstitutes the activation of the Jak kinases and the Stat factors, as well as the antiviral response to human type I IFNs.
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Human type I interferons (IFNs) play an important role in the regulation of antiviral defense mechanisms, immunomodulatory activities, and growth control. Recent efforts have demonstrated the importance of IFNs in the activation of signal transducers and activators of transcription (STATs). The role of STAT1 and STAT2 in IFN-dependent JAK-STAT signaling is well established; however, the role of STAT3 and its activation by IFNs remains unclear. Understanding the IFN-dependent regulation of STAT3 is of increasing interest because recent studies have demonstrated that STAT3 may play a role in cancer. Studies have revealed that STAT3 is constitutively active in a number of cancer cell lines and that overexpression of an active form of STAT3 transforms normal fibroblasts. Therefore, STAT3 exhibits properties indicative of known oncogenes. In this report, we define the role of the type I IFN receptor in STAT3 activation and identify for the first time tyrosine residues present in the cytoplasmic domain of IFNAR2c that are critical for STAT3 activation. The regulation of STAT3 activation by IFNs was measured in a human lung fibrosarcoma cell line lacking IFNAR2c but stably expressing various IFNAR2c tyrosine mutants. We show here that in addition to IFN-dependent tyrosine phosphorylation of STAT3, activation using a STAT3-dependent electrophoretic mobility shift assay and a STAT3-specific reporter can also be demonstrated. Furthermore, we demonstrate that type I IFN-dependent activation of STAT3 proceeds through a novel mechanism that is dependent on two tyrosines, Tyr(337) and Tyr(512), present in IFNAR2c and contained within a conserved six-amino acid residue motif, GxGYxM. Surprisingly, both tyrosines were previously shown to be required for type I IFN-dependent STAT1 and STAT2 activation. Our results reveal that type I IFNs activate multiple STATs via the overlapping usage of two tyrosine residues located in the cytoplasmic domain of IFNAR2c.
J. Biol. Chem. 270, 21606-21611 (1995)[PubMed:7665574]
The interferon alpha beta receptor (IFN alpha R) or type I IFN-R is formed by a 110-kDa alpha subunit or IFNAR and by a beta subunit, which has short and long forms (molecular masses of 55 and 95-100 kDa, respectively). In this report, we demonstrate that the IFN alpha/beta R cDNA recently cloned corresponds to the 55-kDa or short form of the beta subunit, while the 95-100-kDa species reported here corresponds to a longer form of the IFN alpha/beta R cDNA that is probably produced by alternative splicing of the same gene. Stable transfection of the alpha subunit with either form of the beta subunit results in the expression of low and high affinity receptors, while expression of either form of the beta subunit alone only produces low affinity receptors. More important, only expression of the alpha and long form of the human beta subunits in mouse L-929 cells reconstitutes the activation of the Jak kinases and the Stat factors, as well as the antiviral response to human type I IFNs.
Human type I interferons (IFNs) play an important role in the regulation of antiviral defense mechanisms, immunomodulatory activities, and growth control. Recent efforts have demonstrated the importance of IFNs in the activation of signal transducers and activators of transcription (STATs). The role of STAT1 and STAT2 in IFN-dependent JAK-STAT signaling is well established; however, the role of STAT3 and its activation by IFNs remains unclear. Understanding the IFN-dependent regulation of STAT3 is of increasing interest because recent studies have demonstrated that STAT3 may play a role in cancer. Studies have revealed that STAT3 is constitutively active in a number of cancer cell lines and that overexpression of an active form of STAT3 transforms normal fibroblasts. Therefore, STAT3 exhibits properties indicative of known oncogenes. In this report, we define the role of the type I IFN receptor in STAT3 activation and identify for the first time tyrosine residues present in the cytoplasmic domain of IFNAR2c that are critical for STAT3 activation. The regulation of STAT3 activation by IFNs was measured in a human lung fibrosarcoma cell line lacking IFNAR2c but stably expressing various IFNAR2c tyrosine mutants. We show here that in addition to IFN-dependent tyrosine phosphorylation of STAT3, activation using a STAT3-dependent electrophoretic mobility shift assay and a STAT3-specific reporter can also be demonstrated. Furthermore, we demonstrate that type I IFN-dependent activation of STAT3 proceeds through a novel mechanism that is dependent on two tyrosines, Tyr(337) and Tyr(512), present in IFNAR2c and contained within a conserved six-amino acid residue motif, GxGYxM. Surprisingly, both tyrosines were previously shown to be required for type I IFN-dependent STAT1 and STAT2 activation. Our results reveal that type I IFNs activate multiple STATs via the overlapping usage of two tyrosine residues located in the cytoplasmic domain of IFNAR2c.
Type I interferons (IFNs) are cytokines that play a central role in mediating antiviral, antiproliferative, and immunomodulatory activities in virtually all cells. These activities are entirely dependent on the interaction of IFNs with their particular cell surface receptor. In this report, we identify two specific tyrosine residues located within the cytoplasmic domain of IFNAR2c that are obligatory for IFN-dependent signaling. Various IFNAR2c tyrosine mutants were expressed in a human lung fibroscarcoma cell line lacking IFNAR2c (U5A). Stable clones expressing these mutants were analyzed for their ability to induce STAT1 and STAT2 activation, ISGF3 transcriptional complex formation, gene expression, and cell growth regulation in response to stimulation with type I IFNs. The replacement of all seven cytoplasmic tyrosine residues of IFNAR2c with phenylalanine resulted in a receptor unable to respond to IFN stimulation. Substitution of single tyrosines at amino acid residue 269, 316, 318, 337, or 512 with phenylalanine had no effect on IFN-dependent signaling, suggesting that no single tyrosine is essential for IFN receptor-mediated signaling. In addition, IFNAR2c retaining five proximal tyrosines residues (269, 306, 316, 318, and 337) or either two distal tyrosine residues (411 or 512) continued to be responsive to IFN stimulation. Surprisingly, the presence of only a single tyrosine at either position 337 or 512 was sufficient to restore a complete IFN response. These results indicate that IFN-dependent signaling proceeds through the redundant usage of two tyrosine residues in the cytoplasmic domain of IFNAR2c.
We describe a universal ligand-binding receptor for human interferons alpha and interferon beta (type I IFNs). A soluble 40 kDa IFN-alpha/beta receptor (p40) that blocks the activity of type I IFNs was purified from urine and sequenced. Antibodies raised against p40 completely block the activity of several type I IFNs and immuno-precipitate both a cellular 102 kDa IFN-alpha/beta receptor and its cross-linked complexes with IFN-alpha 2. The receptor is a disulfide-linked dimer, consisting of 51 kDa subunits. We isolated and expressed a 1.5 kb cDNA, coding for the IFN-alpha/beta receptor. Its 331 amino acid sequence includes a leader and a transmembrane region, while its ectodomain corresponds to p40. IFN-alpha/beta receptor is physically associated with the cytoplasmic Tyr kinase JAK1, hence, in addition to ligand binding, it is directly involved in signal transduction.
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Interacting selectively and non-covalently with any protein or protein complex (a complex of two or more proteins that may include other nonprotein molecules).
Evidence
1:
Inferred from Physical InteractionIntAct
Cytokine-activated receptors initiate intracellular signaling by recruiting protein kinases that phosphorylate the receptors on tyrosine residues, thus enabling docking of SH2 domain-bearing activating factors. Here we report that in response to type 1 interferon (IFNalpha), IFNalpha receptors recruit cytoplasmic CREB-binding protein (CBP). By binding to IFNalphaR2 within the region where two adjacent proline boxes bear phospho-Ser364 and phospho-Ser384, CBP acetylates IFNalphaR2 on Lys399, which in turn serves as the docking site for interferon regulatory factor 9 (IRF9). IRF9 interacts with the acetyl-Lys399 motif by means of its IRF homology2 (IH2) domain, leading to formation of the ISGF3 complex that includes IRF9, STAT1, and STAT2. All three components are acetylated by CBP. Remarkably, acetylation within the DNA-binding domain (DBD) of both IRF9 and STAT2 is critical for the ISGF3 complex activation and its associated antiviral gene regulation. These results have significant implications concerning the central role of acetylation in cytokine receptor signal transduction.
Evidence
2:
Inferred from Physical InteractionIntAct
J. Immunol. 165, 5127-5132 (2000)[PubMed:11046044]
The cytoplasmic domain of the human type I IFN receptor chain 2 (IFNAR2c or IFN-alphaRbetaL) was used as bait in a yeast two-hybrid system to identify novel proteins interacting with this region of the receptor. We report here a specific interaction between the cytoplasmic domain of IFN-alphaRbetaL and a previously identified protein, RACK-1 (receptor for activated C kinase). Using GST fusion proteins encoding different regions of the cytoplasmic domain of IFN-alphaRbetaL, the minimum site for RACK-1 binding was mapped to aa 300-346. RACK-1 binding to IFN-alphaRbetaL did not require the first 91 aa of RACK-1, which includes two WD domains, WD1 and WD2. The interaction between RACK-1 and IFN-alphaRbetaL, but not the human IFN receptor chain 1 (IFNAR1 or IFN-alphaRalpha), was also detected in human Daudi cells by coimmunoprecipitation. RACK-1 was shown to be constitutively associated with IFN-alphaRbetaL, and this association was not effected by stimulation of Daudi cells with type I IFNs (IFN-beta1b). RACK-1 itself did not become tyrosine phosphorylated upon stimulation of Daudi cells with IFN-beta1b. However, stimulation of cells with either IFN-beta1b or PMA did result in an increase in detectable immunofluorescence and intracellular redistribution of RACK-1.
Interacting selectively and non-covalently with a protein kinase, any enzyme that catalyzes the transfer of a phosphate group, usually from ATP, to a protein substrate.
Evidence
1:
Inferred from Physical InteractionUniProtKB
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Interacting selectively and non-covalently with a type I interferon. Type I interferons include the interferon-alpha, beta, delta, epsilon, zeta, kappa, tau, and omega gene families.
Evidence
1:
Inferred from Physical InteractionUniProtKB
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Combining with a type I interferon and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity. Type I interferons include the interferon-alpha, beta, delta, epsilon, zeta, kappa, tau, and omega gene families.
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
A series of molecular signals initiated by activation of a receptor on the surface of a cell. The pathway begins with binding of an extracellular ligand to a cell surface receptor, or for receptors that signal in the absence of a ligand, by ligand-withdrawal or the activity of a constitutively active receptor. The pathway ends with regulation of a downstream cellular process, e.g. transcription.
J. Biol. Chem. 271, 23630-23633 (1996)[PubMed:8798579]
All Type I interferons (IFNalpha, IFNbeta, IFNomega) bind to the Type I IFN receptor (IFNR) and elicit a common set of signaling events, including activation of the Jak/Stat and IRS pathways. However, IFNbeta selectively induces the association of the alpha subunit of the Type I IFNR with p100, a tyrosyl phosphoprotein, to transduce IFNbeta-specific signals. Using antibodies raised against the different components of the Type I IFNR, we identified p100 as the long form of the beta subunit (betaL subunit) of the Type I IFNR. This was also confirmed in experiments with mouse L-929 cells transfected with truncated forms of betaL. Thus, IFNbeta stimulation of human cells or mouse L-929 transfectants expressing the human alpha and betaL subunits, selectively induces the formation of a signaling complex containing the alpha and betaL subunits of the receptor. The IFNbeta-regulated interaction of the alpha and betaL chains is rapid and transient and follows a similar time course with the tyrosine phosphorylation of these receptor components. These data demonstrate that the signaling specificity for different Type I IFNs is established early in the signaling cascade, at the receptor level, and results from distinct interactions between components of the Type I IFNR.
Any process in which STAT proteins (Signal Transducers and Activators of Transcription) and JAK (Janus Activated Kinase) proteins convey a signal to trigger a change in the activity or state of a cell. The JAK-STAT cascade begins with activation of STAT proteins by members of the JAK family of tyrosine kinases, proceeds through dimerization and subsequent nuclear translocation of STAT proteins, and ends with regulation of target gene expression by STAT proteins.
The cellular receptor for the alpha/beta interferons contains at least two components that interact with interferon. The ifnar1 component is well characterized and a putative ifnar2 cDNA has recently been identified. We have cloned the gene for ifnar2 and show that it produces four different transcripts encoding three different polypeptides that are generated by exon skipping, alternative splicing and differential use of polyadenylation sites. One polypeptide is likely to be secreted and two are transmembrane proteins with identical extracellular and transmembrane domains but divergent cytoplasmic tails of 67 and 251 amino acids. A mutant cell line U5A, completely defective in IFN-alpha beta binding and response, has been isolated and characterized. Expression in U5A cells of the polypeptide with the long cytoplasmic domain reconstitutes a functional receptor that restores normal interferon binding, activation of the JAK/STAT signal transduction pathway, interferon-inducible gene expression and antiviral response. The IFNAR2 gene maps at 0.5 kb from the CRFB4 gene, establishing that together IFNAR2, CRFB4, IFNAR1 and AF1 form a cluster of class II cytokine receptor genes on human chromosome 21.
Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of an interferon-alpha stimulus. Interferon-alpha is a type I interferon.
J. Leukoc. Biol. 57, 712-718 (1995)[PubMed:7759950]
The recently cloned ligand binding component of the type I human interferon-alpha/beta receptor (IFN-alpha/beta R) and its soluble analogue (p40) were characterized. p40 is a potent inhibitor of type I IFNs and antibodies directed against p40 completely block the activity of type I IFNs in human cells. These antibodies immunoprecipitate cellular 102-kDa (major) and 51-kDa (minor) forms of IFN-alpha/beta R. We find that the 51-kDa IFN-alpha/beta R. Two types of cDNA clones were isolated and sequenced, a 1.5-kb cDNA coding for the transmembrane 51-kDa IFN-alpha/beta R and a 4.5-kb cDNA coding for p40. In addition to ligand binding, IFN-alpha/beta R is directly involved in signaling, because it becomes phosphorylated at Tyr residues on ligand binding and it is physically associated with the cytoplasmic tyrosine kinase JAK1.
Any process that results in a change in state or activity of a cell or an organism (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a stimulus from a virus.
The cellular receptor for the alpha/beta interferons contains at least two components that interact with interferon. The ifnar1 component is well characterized and a putative ifnar2 cDNA has recently been identified. We have cloned the gene for ifnar2 and show that it produces four different transcripts encoding three different polypeptides that are generated by exon skipping, alternative splicing and differential use of polyadenylation sites. One polypeptide is likely to be secreted and two are transmembrane proteins with identical extracellular and transmembrane domains but divergent cytoplasmic tails of 67 and 251 amino acids. A mutant cell line U5A, completely defective in IFN-alpha beta binding and response, has been isolated and characterized. Expression in U5A cells of the polypeptide with the long cytoplasmic domain reconstitutes a functional receptor that restores normal interferon binding, activation of the JAK/STAT signal transduction pathway, interferon-inducible gene expression and antiviral response. The IFNAR2 gene maps at 0.5 kb from the CRFB4 gene, establishing that together IFNAR2, CRFB4, IFNAR1 and AF1 form a cluster of class II cytokine receptor genes on human chromosome 21.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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