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Query: UNIPROT:P14784 (IL-2 receptor)
 3,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stimulation of the interleukin-2 (IL-2) receptor results in phosphorylation and activation of cytosolic Raf-1 serine/threonine kinase. Herein, we report that enzymatically active Raf-1 is physically associated with the IL-2 receptor beta chain (p75) in T-cell blasts. Following stimulation with IL-2, Raf-1 dissociates from the IL-2 receptor complex and translocates to the cytosol. Genistein, a protein tyrosine kinase inhibitor, prevents the dissociation of enzymatically active Raf-1 from the ligand-stimulated IL-2 receptor complex. These data favor a model of IL-2 receptor activation in which an IL-2-activated protein tyrosine kinase phosphorylates the IL-2 receptor and/or receptor-bound Raf-1. Following tyrosine phosphorylation, enzymatically active Raf-1 dissociates from the IL-2 receptor and translocates into the cytosol.
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PMID:Interleukin-2 (IL-2) induces tyrosine kinase-dependent translocation of active raf-1 from the IL-2 receptor into the cytosol. 163 73

Interleukin 2 (IL-2) is a lymphokine, produced by T cells upon antigenic or mitogenic stimulation, that is a critical regulator of T-cell proliferation. Although the binding of IL-2 to its receptor has been well characterized, the molecular mechanisms by which IL-2 transmits its signal from the membrane to the interior of the cell are poorly understood. Like most other growth factors, IL-2 causes rapid phosphorylation of proteins within its target cells. Unlike many other growth factors, however, the known subunits of the IL-2 receptor lack tyrosine-specific kinase activity, and little is known about the kinases whose activities are regulated by IL-2. Here we show that IL-2 (but not IL-4) induces rapid phosphorylation of the p72-74 serine/threonine-specific kinase encoded by the c-Raf-1 protooncogene in an IL-2-dependent murine T-cell line, CTLL-2, and that this phosphorylation is associated with increased kinase activity in p72-74 Raf-1-containing immune complexes. The concentration dependence of IL-2-mediated elevations in Raf-1 kinase activity correlated well with IL-2-stimulated proliferation of CTLL-2 cells. Furthermore, much of the IL-2-stimulated phosphorylation of p72-74 Raf-1 occurred on tyrosines. To our knowledge, the Raf-1 kinase represents the first endogenous substrate of an IL-2-regulated tyrosine kinase to be identified.
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PMID:Interleukin 2 induces tyrosine phosphorylation and activation of p72-74 Raf-1 kinase in a T-cell line. 199 24

The product of the c-raf-1 proto-oncogene, Raf-1, is known to encode a 74-kDa ubiquitously expressed cytoplasmic serine/threonine kinase. Various growth factors such as epidermal growth factor, acidic fibroblast growth factor, platelet-derived growth factor, insulin, granulocyte-macrophage colony-stimulating factor, interleukin (IL)-2, IL-3 and erythropoietin have been shown to induce phosphorylation of Raf-1, thereby activating Raf-1 kinase. Raf-1 is, thus, believed to play a role in coupling growth factor receptors to proliferation. We have examined the role of Raf-1 in the mitogenic response of human peripheral blood-derived IL-2 receptor expressing T cells to human recombinant IL-2 employing c-raf antisense (AS) oligodeoxyribonucleotide. Uptake studies of oligonucleotides indicated that incorporation of oligomers was maximal at 4 h and oligodeoxynucleotides remained stable in these cells for up to 24 h. Treatment of T cells with the AS oligodeoxyribonucleotide in intracellular duplex formation followed by efficient translation blockade of c-raf-1. In contrast, sense (S) and nonsense (NS) oligodeoxynucleotides failed to form intracellular duplexes and did not interfere with translation of c-raf-1, suggesting specific elimination of c-raf-1 by the AS oligomer. Proliferation of T cells ([3H]thymidine incorporation) following exposure to IL-2 was substantially reduced when the c-raf-1 AS oligodeoxyribonucleotide was added to cultures, while the mitogenic response to this factor remained almost unaffected in the presence of S and NS oligodeoxyribonucleotides.
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PMID:The mitogenic response of T cells to interleukin-2 requires Raf-1. 825 28

Protooncogenes are the normal forms of cellular genes that when altered in their expression or coding sequences can contribute to neoplastic transformation. As these genes often are important for normal cellular growth control, we explored the possibility that protein kinases encoded by particular protooncogenes could participate in signal transduction pathways regulated by the T cell growth factor, interleukin-2 (IL-2). In this review we summarize our findings to date regarding Raf-1, a serine/threonine-specific kinase that becomes phosphorylated on tyrosine residues and enzymatically activated in response to IL-2 stimulation. In addition, we describe our investigations of Lck and Lyn, two closely related protein tyrosine kinases of the src gene family that physically associate with the IL-2 receptor complex and whose activities are regulated by IL-2 in at least some T cells and B cells, respectively.
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PMID:Protooncogene-encoded protein kinases in interleukin-2 signal transduction. 826 Jun 49

The 90-kDa heat shock protein (Hsp90) is the most abundant molecular chaperone of eukaryotic cells. Its chaperone function in folding nascent proteins seems to be restricted to a subset of proteins including major components of signal transduction pathways (eg, nuclear hormone receptors, transcription factors, and protein kinases). Improper function of these proteins can be induced by selective disruption of their complexes with Hsp90 using the benzoquinonoid ansamycin geldanamycin. In this study, we demonstrate that geldanamycin treatment blocks interleukin (IL)-2 secretion, IL-2 receptor expression, and proliferation of stimulated T-lymphocytes. Moreover, geldanamycin decreases the amount and phosphorylation of Lck and Raf-1 kinases and prevents activation of the extracellular signal regulated kinase (ERK)-2 kinase. Geldanamycin also disrupts the T-cell receptor-mediated activation of nuclear factor of activated T-cells (NF-AT). Treatment with geldanamycin, however, does not affect the activation of lysophosphatide acyltransferase, which is a plasma membrane enzyme coupled to the T-cell receptor after T-cell stimulation. Through demonstrating the selective inhibition of kinase-related T-lymphocyte responses by geldanamycin, our results emphasize the substantial role of Hsp90-kinase complexes in T-cell activation.
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PMID:The Hsp90-specific inhibitor geldanamycin selectively disrupts kinase-mediated signaling events of T-lymphocyte activation. 1070 40