201
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Davidsen B, Nielsen OH, Vainer B, Kirman I. Section Review: Pulmonary-Allergy, Dermatological, Gastrointestinal & Arthritis: The immunological network: Novel approaches to the treatment of Crohn's disease. Expert Opin Investig Drugs 1996. [DOI: 10.1517/13543784.5.5.555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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202
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203
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O'Neal KD, Chari MV, Mcdonald CH, Cook RG, Yu-Lee LY, Morrisett JD, Shearer WT. Multiple cis-trans conformers of the prolactin receptor proline-rich motif (PRM) peptide detected by reverse-phase HPLC, CD and NMR spectroscopy. Biochem J 1996; 315 ( Pt 3):833-44. [PMID: 8645165 PMCID: PMC1217282 DOI: 10.1042/bj3150833] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
An eight-amino-acid synthetic peptide (IIe1-Phe2-Pro3-Pro4-Val5-Pro6-Gly7-Pro8) corresponding to the conserved proline-rich motif (PRM) of the intracellular domain of the prolactin receptor (PRL-R) was studied by one- and two-dimensional (1D and 2D) proton NMR spectroscopy in water and DMSO in order to characterize its conformational dynamics. The purified PRL-R PRM peptide eluted as two partially resolved peaks in equilibrium on reverse-phase HPLC (RP-HPLC) at 20 degrees C with a ratio of 60:40. At 30 degrees C, the two peaks coalesced into a single peak The two RP-HPLC peaks correspond to two peptide conformers resulting from the slow cis-trans isomerization of one of the four proline amide bonds. Although the peptide has only three amide (NH) protons, its ID NMR spectrum in water contains approximately 15 discernible NH region peaks, providing evidence for multiple conformers. The amide resonances were assigned on the basis of 2D-COSY spectra, chemical shift values resonance splitting patterns and temperature coefficients. The cis:trans ratio for each proline in water, calculated from integrated intensities and/or peak heights of the appropriate resonances, were Phe2-Pro3 (35:65), Pro3-Pro4 (40:60), Val5-Pro6 (70:30), and Gly7-Pro8 (30:70). Temperature studies (25-70 degrees C) were used to semi-quantitatively estimate the rates of isomerization for the different prolines. In water, Pro8 undergoes rapid isomerization; Pro3 isomerizes at an intermediate rate; while Pro4 and Pro6 both appear to isomerize very slowly since no coalescence of amide resonances was observed. In DMSO, only Pro4 displayed slow isomerization. Slow kinetics combined with a similar 60:40 ratio of conformers determined by RP-HPLC and NMR suggests that isomerization of the Pro3-Pro4 bond generates the two RP-HPLC peaks. Both proximal and distal proline isomerization effects were observed in NMR experiments. All of the 16 theoretical (24 = 16) proline configurations appear to exist in equilibrium in water The predominant (19%) conformation, trans3-trans4-cis6-trans8, may reflect the configuration of the PRM prolines in the native PRL-R. Isomerization of Pro6 from cis to trans generates an interaction between the peptide N-and C-termini, suggesting an overall pseudo-cyclic conformation. This all-trans proline configuration may play an important biochemical role in the function of cytokine/haematopoietin receptors. A model is proposed which suggests that isomerization of the PRM by an immunophilin such as the FK 506-binding protein (FKBP) serves as an on-off switch for cytokine receptor activation.
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Affiliation(s)
- K D O'Neal
- Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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204
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Flores I, Casaseca T, Martinez-A C, Kanoh H, Merida I. Phosphatidic acid generation through interleukin 2 (IL-2)-induced alpha-diacylglycerol kinase activation is an essential step in IL-2-mediated lymphocyte proliferation. J Biol Chem 1996; 271:10334-40. [PMID: 8626603 DOI: 10.1074/jbc.271.17.10334] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Proliferation of T lymphocytes is triggered by the interaction of interleukin 2 (IL-2) with its high affinity specific receptor that is expressed on the cell surface following T lymphocyte activation. Significant advances have recently been made in identifying the multiple signals that follow IL-2 receptor occupancy, although the exact mechanism responsible for IL-2-induced proliferation remains an enigma. It has been shown previously that unique species of phosphatidic acid are rapidly produced in vivo following IL-2 binding. It was then suggested that, in contrast to other eukaryotic growth factor systems, phosphatidic acid was at least in part generated through IL-2-induced diacylglycerol (DG) kinase activation. In the present study we demonstrate IL-2-dependent activation of the alpha isoform of DG kinase. Confocal microscopy studies reveal that the enzyme is located in the cytosol and nuclei of resting T cells. Interleukin 2 stimulation induces translocation of the enzyme to the perinuclear region. Furthermore, our results indicate that inhibition of the alpha isoform of DG kinase has a profound effect on IL-2-induced T cell growth. Studies on cell cycle distribution demonstrate that the inhibition of IL-2-induced phosphatidic acid production induces arrest in late G1 phase of IL-2 dependent cells. Altogether, these results link previous observations of interleukin 2 and phosphatidic acid production to activation of an specific isoform of DG kinase and suggest that activation of this enzyme is part of a novel signaling cascade that utilizes phosphatidic acid as an effector molecule.
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Affiliation(s)
- I Flores
- Department of Immunology and Oncology, Centro Nacional de Biotecnologia, Campus de Cantoblanco, Madrid 28049, Spain
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205
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Sugamura K, Asao H, Kondo M, Tanaka N, Ishii N, Ohbo K, Nakamura M, Takeshita T. The interleukin-2 receptor gamma chain: its role in the multiple cytokine receptor complexes and T cell development in XSCID. Annu Rev Immunol 1996; 14:179-205. [PMID: 8717512 DOI: 10.1146/annurev.immunol.14.1.179] [Citation(s) in RCA: 322] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Interleukin 2 (IL-2), a T cell-derived cytokine, targets a variety of cells to induce their growth, differentiation, and functional activation. IL-2 inserts signals into the cells through IL-2 receptors expressed on cell surfaces to induce such actions. In humans, the functional IL-2 receptor consists of the subunit complexes of the alpha, beta and gamma chains, or the beta and gamma chains. The third component, the gamma chain, of IL-2 receptor plays a pivotal role in formation of the full-fledged IL-2 receptor, together with the beta chain, the gamma chain participates in increasing the IL-2 binding affinity and intracellular signal transduction. Moreover, the cytokine receptors for at least IL-2, IL-4, IL-7, IL-9, and IL-15 utilize the same gamma chain as an essential subunit. Interestingly, mutations of the gamma chain gene cause human X-linked severe combined immunodeficiency (XSCID) characterized by a complete or profound T cell defect. Among the cytokines sharing the gamma chain, at least IL-7 is essentially involved in early T cell development in the mouse organ culture system. The molecular identification of the gamma chain brought a grasp of the structures and functions of the cytokine receptor and an in-depth understanding of the cause of human XSCID. To investigate the mechanism of XSCID and development of gene therapy for XSCID, knockout mice for the gamma chain gene were produced that showed similar but not exactly the same phenotypes as human XSCID.
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Affiliation(s)
- K Sugamura
- Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan
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206
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Friedmann MC, Migone TS, Russell SM, Leonard WJ. Different interleukin 2 receptor beta-chain tyrosines couple to at least two signaling pathways and synergistically mediate interleukin 2-induced proliferation. Proc Natl Acad Sci U S A 1996; 93:2077-82. [PMID: 8700888 PMCID: PMC39912 DOI: 10.1073/pnas.93.5.2077] [Citation(s) in RCA: 159] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
One of the earliest events induced by interleukin 2 (IL-2) is tyrosine phosphorylation of cellular proteins, including the IL-2 receptor beta chain (IL-2Rbeta). Simultaneous mutation of three tyrosines (Y338, Y392, and Y510) in the IL-2Rbeta cytoplasmic domain abrogated IL-2-induced proliferation, whereas mutation of only Y338 or of Y392 and Y510 inhibited proliferation only partially. While Y392 and Y510 were critical for IL-2-induced activation of signal transducers and activators of transcription (STAT proteins), Y338 was required for Shc-IL-2Rbeta association and for IL-2-induced tyrosine phosphorylation of Shc. Thus, activation of both Jak-STAT and Shc-coupled signaling pathways requires specific IL-2Rbeta tyrosines that together act in concert to mediate maximal proliferation. In COS-7 cells, overexpression of Jak1 augmented phosphorylation of Y338 as well as Y392 and Y510, suggesting that the role for this Jak kinase may extend beyond the Jak-STAT pathway.
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Affiliation(s)
- M C Friedmann
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1674, USA
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207
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Abstract
Hematopoiesis is largely regulated by the binding of cytokines to receptors of the cytokine receptor superfamily. Although lacking catalytic domains, members of the cytokine receptor superfamily mediate ligand dependent activation of tyrosine phosphorylation which is critical for all receptor functions. Recent studies have demonstrated that this is mediated through the association and activation of members of the Janus kinase (Jak) family of protein tyrosine kinases. The activated Jaks phosphorylate the receptors, creating docking sites for SH2 containing signalling proteins which are tyrosine phosphorylated following their association with the receptor complex. Among the substrates of tyrosine phosphorylation are members of the signal transducers and activators of transcription family of proteins (Stats). Various cytokines induce the tyrosine phosphorylation and activation of one or more of the six family members. The pattern of Stat activation provides a level of cytokine individuality that is not observed in the activation of other signalling pathways. Although not required for mitogenic responses, it is speculated that the Stats may mediate many of the cytokine specific functional responses of hematopoietic cells.
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Affiliation(s)
- J N Ihle
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38101, USA
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208
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Leonard WJ. The molecular basis of X-linked severe combined immunodeficiency: defective cytokine receptor signaling. Annu Rev Med 1996; 47:229-39. [PMID: 8712778 DOI: 10.1146/annurev.med.47.1.229] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
X-linked severe combined immunodeficiency (XSCID) is an inherited disease characterized by profoundly diminished cell-mediated and humoral immunity. XSCID was found to result from mutations in the interleukin-2 (IL-2) receptor gamma chain. Knowledge of the genetic defect has important implications for prenatal and postnatal diagnosis, carrier female identification, and the possibility of gene therapy. The fact that the phenotype and clinical manifestations in XSCID are more severe than the abnormalities found in humans or mice deficient in IL-2 led to the speculation and subsequent confirmation that the IL-2 receptor is not the only receptor to contain the gamma chain. Instead, the gamma chain is also a component of the receptors for IL-4, IL-7, IL-9, and IL-15 and is now denoted as the common cytokine receptor gamma chain, gamma c. The role of gamma c in signaling and lymphoid development and the implications of a shared receptor component are discussed.
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Affiliation(s)
- W J Leonard
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-1674, USA
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209
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Lai SY, Xu W, Gaffen SL, Liu KD, Longmore GD, Greene WC, Goldsmith MA. The molecular role of the common gamma c subunit in signal transduction reveals functional asymmetry within multimeric cytokine receptor complexes. Proc Natl Acad Sci U S A 1996; 93:231-5. [PMID: 8552611 PMCID: PMC40212 DOI: 10.1073/pnas.93.1.231] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The specific signal transduction function of the gamma c subunit in the interleukin (IL) 2, IL-4, IL-7, IL-9, and IL-15 receptor complexes remains undefined. The present structure-function analyses demonstrated that the entire cytoplasmic tail of gamma c could be functionally replaced in the IL-2 receptor (IL-2R) signaling complex by a severely truncated erythropoietin receptor cytoplasmic domain lacking tyrosine residues. Heterodimerization of IL-2R beta with either gamma c or the truncated erythropoietin receptor chain led to an array of specific signals normally derived from the native IL-2R despite the substitution of Janus kinase JAK2 for JAK3 in the receptor complex. These findings thus suggest a model in which the gamma c subunit serves as a common and generic "trigger" chain by providing a nonspecific Janus kinase for signaling program initiation, while signal specificity is determined by the unique "driver" subunit in each of the gamma c- containing receptor complexes. Furthermore, these results may have important functional implications for the asymmetric design of many cytokine receptor complexes and the evolutionary design of receptor subfamilies that share common trigger or driver subunits.
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Affiliation(s)
- S Y Lai
- Gladstone Institute of Virology and Immunology, San Francisco, CA 94141, USA
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210
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211
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François C, Dantal J, Sorel M, Cherel M, Miyasaka M, Soulillou JP, Jacques Y. Antibodies directed at mouse IL-2-R α and β chains act in synergy to abolish T-cell proliferation in vitro and delayed type hypersensitivity reaction in vivo. Transpl Int 1996. [DOI: 10.1111/j.1432-2277.1996.tb00851.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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212
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François C, Dantal J, Sorel M, Cherel M, Miyasaka M, Soulillou JP, Jacques Y. Antibodies directed at mouse IL-2-R alpha and beta chains act in synergy to abolish T-cell proliferation in vitro and delayed type hypersensitivity reaction in vivo. Transpl Int 1996; 9:46-50. [PMID: 8748410 DOI: 10.1007/bf00336811] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The anti-mouse IL-2-R beta chain mAb TM-beta 1 which, by itself, does not affect IL-2-dependent proliferation through the high affinity mouse IL-2 receptor, was shown to cooperate in a synergistic way with a set of anti-IL-2-R alpha chain mAbs both in vitro and in vivo. In vitro, when associated at equimolar concentrations, the TM-beta 1/anti-alpha mAb association was four to ten times more efficient at inhibiting the proliferation of the CTL-L2 cell line than was a similar concentration of anti-alpha mAb alone. In addition, a bispecific antibody in which a Fab' fragment of TM-beta 1 was covalently linked to a Fab' fragment of one of the anti-alpha mAb (5A2) was shown to be as efficient as the TM-beta 1/5A2 association. The association of TM-beta 1 with 5A2 was also tested in vivo in a sheep red blood cell-induced delayed type hypersensitivity (DTH) model. TM-beta 1 which, by itself, had no effect on DTH, induced a two- to threefold decrease in the doses of 5A2 required to suppress this cell-mediated immune reaction.
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Affiliation(s)
- C François
- INSERM U-211, Institut de Biologie, Nantes, France
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213
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Nelson BH, Lord JD, Greenberg PD. A membrane-proximal region of the interleukin-2 receptor gamma c chain sufficient for Jak kinase activation and induction of proliferation in T cells. Mol Cell Biol 1996; 16:309-17. [PMID: 8524310 PMCID: PMC231005 DOI: 10.1128/mcb.16.1.309] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The interleukin-2 (IL-2) receptor (IL-2R) consists of three distinct subunits (alpha, beta, and gamma c) and regulates proliferation of T lymphocytes. Intracellular signalling results from ligand-mediated heterodimerization of the cytoplasmic domains of the beta and gamma c chains. To identify the residues of gamma c critical to this process, mutations were introduced into the cytoplasmic domain, and the effects on signalling were analyzed in the IL-2-dependent T-cell line CTLL2 and T-helper clone D10, using chimeric IL-2R chains that bind and are activated by granulocyte-macrophage colony-stimulating factor. Whereas previous studies of fibroblasts and transformed T cells have suggested that signalling by gamma c requires both membrane-proximal and C-terminal subdomains, our results for IL-2-dependent T cells demonstrate that the membrane-proximal 52 amino acids are sufficient to mediate a normal proliferative response, including induction of the proto-oncogenes c-myc and c-fos. Although gamma c is phosphorylated on tyrosine upon receptor activation and could potentially interact with downstream molecules containing SH2 domains, cytoplasmic tyrosine residues were dispensable for mitogenic signalling. However, deletion of a membrane-proximal region conserved among other cytokine receptors (cytoplasmic residues 5 to 37) or an adjacent region unique to gamma c (residues 40 to 52) abrogated functional interaction of the receptor chain with the tyrosine kinase Jak3. This correlated with a loss of all signalling events analyzed, including phosphorylation of the IL-2R beta-associated kinase Jak1, expression of c-myc and c-fos, and induction of the proliferative response. Thus, it appears in T cells that Jak3 is a critical mediator of mitogenic signaling by the gamma c chain.
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Affiliation(s)
- B H Nelson
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98104, USA
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214
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Ihle JN. Signaling by the cytokine receptor superfamily in normal and transformed hematopoietic cells. Adv Cancer Res 1996; 68:23-65. [PMID: 8712070 DOI: 10.1016/s0065-230x(08)60351-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- J N Ihle
- Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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215
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Cereseto A, Mulloy JC, Franchini G. Insights on the pathogenicity of human T-lymphotropic/leukemia virus types I and II. JOURNAL OF ACQUIRED IMMUNE DEFICIENCY SYNDROMES AND HUMAN RETROVIROLOGY : OFFICIAL PUBLICATION OF THE INTERNATIONAL RETROVIROLOGY ASSOCIATION 1996; 13 Suppl 1:S69-75. [PMID: 8797707 DOI: 10.1097/00042560-199600001-00013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Human T-lymphotropic/leukemia virus types I and II (HTLV-I and HTLV-II) are phylogenetically and immunologically related viruses that differ in their pathogenicity in vivo. HTLV-I is the etiologic agent of adult T-cell leukemia/lymphoma, as well as a chronic progressive myelopathy, HTLV-I-associated myelopathy/tropical spastic paraparesis. In contrast, HTLV-II has not been conclusively associated with specific diseases. Both HTLV-I and HTLV-II transform CD4+ T-cells in vitro, but their in vivo target cells appear to differ. HTLV-I is found mainly in CD4+ cells, whereas HTLV-II has been demonstrated mainly in CD8+ cells. Clearly the definition of the viral genetic determinants responsible for the different tropism and pathogenicity in vivo may provide the basis of our understanding of the HTLV-I oncogenicity. In this short review we emphasize two aspects of viral infection of T cells: (1) the influence of viral infection on the major proteins involved in the G0-G1 phase of the cell cycle and (2) the effect of viral infection on the S phase of the cell cycle, i.e., the interleukin-2 receptor pathway.
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Affiliation(s)
- A Cereseto
- Laboratory of Tumor Cell Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4255, USA
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216
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Rebollo A, Gómez J, Martínez-A C. Lessons from immunological, biochemical, and molecular pathways of the activation mediated by IL-2 and IL-4. Adv Immunol 1996; 63:127-96. [PMID: 8787631 DOI: 10.1016/s0065-2776(08)60856-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A Rebollo
- Department of Immunology and Oncology, Centro Nacional de Biotecnología, Universidad Autónoma de Madrid, Spain
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217
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Edelbaum D, Mohamadzadeh M, Bergstresser PR, Sugamura K, Takashima A. Interleukin (IL)-15 promotes the growth of murine epidermal gamma delta T cells by a mechanism involving the beta- and gamma c-chains of the IL-2 receptor. J Invest Dermatol 1995; 105:837-43. [PMID: 7490480 DOI: 10.1111/1523-1747.ep12326630] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Dendritic epidermal T cells (DETC) are skin-specific members of the epithelial gamma delta T-cell family in mice. We have reported previously that the growth of DETC is promoted by interleukin (IL)-2 in an autocrine fashion, or by IL-7, which is secreted by neighboring keratinocytes. Here we report that DETC growth is promoted by IL-15, a newly discovered T-cell growth factor that is produced in lymphoid as well as nonlymphoid tissues. Recombinant IL-15 promoted the growth of the 7-17 DETC line in a time- and dose-dependent fashion. Using monoclonal antibodies against alpha-, beta-, or gamma c-chains of the IL-2 receptor complex, we observed that the combination of anti-beta chain and anti-gamma c chain antibodies blocked IL-15 responsiveness completely, whereas anti-alpha chain had no effect. These results indicate that this gamma delta T-cell line uses the beta/gamma c heterodimer for proliferative responses to IL-15. Antibodies against IL-2 or IL-7 did not block IL-15-driven proliferation of 7-17 DETC, indicating that IL-15 promotes their growth in an IL-2- and IL-7-independent manner. Both the surface expression of beta/gamma c heterodimers and the IL-15 responsiveness of 7-17 DETC were highest 1 to 8 days after concanavalin A stimulation, and both declined substantially 21 days after stimulation, illustrating regulation by the state of cell activation. Working with epidermal cells that were freshly procured from CBA mice, we noted that IL-15 promoted conavalin-A-triggered growth of Thy-1+ cells (i.e., DETC), but not of the Thy-1- cells. The gamma c-chain was not expressed by freshly procured DETC, becoming detectable within 48 h after concanavalin A stimulation. We propose that IL-15 facilitates the growth of epithelial gamma delta T cells by a beta/gamma c receptor-dependent mechanism.
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Affiliation(s)
- D Edelbaum
- Department of Dermatology, University of Texas Southwestern Medical Center, Dallas 75235-9069, USA
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218
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Leonard WJ, Shores EW, Love PE. Role of the common cytokine receptor gamma chain in cytokine signaling and lymphoid development. Immunol Rev 1995; 148:97-114. [PMID: 8825284 DOI: 10.1111/j.1600-065x.1995.tb00095.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To examine the role of gamma c in lymphoid development, we have analyzed mice in which the gamma c gene was specifically inactivated by homologous recombination. These mice also serve as an animal model of human X-linked severe combined immunodeficiency (XSCID). Interestingly, gamma c knockout mice exhibited a somewhat different phenotype than humans with XSCID. Absolute T-cell numbers are greatly diminished in young gamma c-/Y mice, but accumulate with age. gamma delta T cells and NK cells are absent in gamma c-/Y mice and conventional B cells are greatly diminished, yet substantial numbers of peritoneal B-1 cells are present. Since humans with XSCID have essentially no mature T cells, it is especially striking that T cells are readily apparent in gamma c-/Y mice. This observation indicates that in these mice, the gamma c-dependent block in T cell development is less severe than it is in humans. It is possible but unproven that thymic stromal derived lymphopoietin, TSLP, contributes to thymocyte development in these mice. Since B-cell numbers are normal in humans with XSCID, it is also striking that gamma c-/Y mice paradoxically exhibit greatly diminished numbers of B cells. This likely indicates that IL-7 signaling plays a critical role in pre-B cell maturation in mice but is less important in humans. Thus, the abnormalities observed in gamma c-/Y mice have provided clues to assist in dissecting the role of cytokines and their receptors in lymphoid development and have also identified interesting differences in the regulation of this process in mice and humans.
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Affiliation(s)
- W J Leonard
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, NIH, Bethesda, MD 20892, USA
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219
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Gilmour KC, Pine R, Reich NC. Interleukin 2 activates STAT5 transcription factor (mammary gland factor) and specific gene expression in T lymphocytes. Proc Natl Acad Sci U S A 1995; 92:10772-6. [PMID: 7479881 PMCID: PMC40694 DOI: 10.1073/pnas.92.23.10772] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Although prolactin and interleukin 2 (IL-2) can elicit distinct physiological responses, we have found that their signal pathways share a common signal transducer and activator of transcription, STAT5. STAT5 was originally identified as a mammary gland factor induced by prolactin in lactating breast cells. Here we demonstrate that STAT5 is activated after IL-2 stimulation of two responsive lymphocyte cell lines, Nb2 and YT. Activation of STAT5 is measured both by IL-2-induced tyrosine phosphorylation and by IL-2-induced DNA binding. The STAT5 DNA recognition site is the same as the interferon gamma-activated site (GAS) in the interferon regulatory factor 1 gene. We demonstrate that the GAS element is necessary and sufficient for transcriptional induction by both IL-2 and prolactin in T lymphocytes. These results indicate that the role of STAT5 in the regulation of gene expression is not restricted to mammary cells or to prolactin, but is an integral part of the signal pathway of a critical immunomodulatory cytokine, IL-2.
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Affiliation(s)
- K C Gilmour
- Department of Pathology, State University of New York, Stony Brook 11794, USA
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220
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Kozak CA, Leonard WJ. Genetic mapping of the interleukin 1 receptor alpha and beta chain genes in the mouse. Mamm Genome 1995; 6:823-4. [PMID: 8597644 DOI: 10.1007/bf00539014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- C A Kozak
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0460, USA
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221
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Willerford DM, Chen J, Ferry JA, Davidson L, Ma A, Alt FW. Interleukin-2 receptor alpha chain regulates the size and content of the peripheral lymphoid compartment. Immunity 1995; 3:521-30. [PMID: 7584142 DOI: 10.1016/1074-7613(95)90180-9] [Citation(s) in RCA: 871] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Interleukin-2 receptor alpha chain (IL-2R alpha) expression occurs at specific stages of early T and B lymphocyte development and is induced upon activation of mature lymphocytes. Young mice that lack IL-2R alpha have phenotypically normal development of T and B cells. However, as adults, these mice develop massive enlargement of peripheral lymphoid organs associated with polyclonal T and B cell expansion, which, for T cells, is correlated with impaired activation-induced cell death in vivo. Older IL-2R alpha-deficient mice also develop autoimmune disorders, including hemolytic anemia and inflammatory bowel disease. Thus, IL-2R alpha is essential for regulation of both the size and content of the peripheral lymphoid compartment, probably by influencing the balance between clonal expansion and cell death following lymphocyte activation.
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Affiliation(s)
- D M Willerford
- Howard Hughes Medical Institute, Department of Pediatrics, Children's Hospital, Boston, Massachusetts 02115, USA
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222
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Moreau JL, Bossus M, de Groote D, François C, Jacques Y, Tartar A, Thèze J. Characterization of a monoclonal antibody directed against the NH2 terminal area of interleukin-2 (IL-2) and inhibiting specifically the binding of IL-2 to IL-2 receptor beta chain (IL-2R beta). Mol Immunol 1995; 32:1047-56. [PMID: 8544854 DOI: 10.1016/0161-5890(95)00084-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
An anti-human IL-2 mAb (19B11/beta) was found to selectively block the binding of IL-2 to TS1 beta cells expressing the interleukin-2 receptor beta (IL-2R beta) without affecting binding to TS1 alpha cells expressing the IL-2R alpha receptor. It also specifically inhibits the IL-2 driven cell proliferation in TS1 beta cells. These observations have lead to the hypothesis that its epitope is related to an IL-2 area involved in binding with IL-2R beta chain. This epitope was identified using various peptides covering the N-terminal half (including alpha helix A) of the 133 amino acids of IL-2. MAb 19B11/beta does not recognize peptides 30-54 and 44-54 but recognizes peptides 1-22 and 1-30 with a good affinity. Furthermore, threonine in position no. 3 was found to be critical for the binding of mAb 19B11/beta. A relationship between the epitope of mAb 19B11/beta and the glycosylation of the IL-2 molecule was observed. This further demonstrates that the NH2 terminal area of IL-2 is critical for IL-2/IL-2R beta interactions. Two other mAbs were studied during the course of this work. They served as control for the study of mAb 19B11/beta and provide some additional insight concerning the question of IL-2/IL-2R structure-function. MAb 16F11/alpha selectively blocks the IL-2 binding to TS1 alpha cells. The epitope of mAb 16F11 is conformational and it was not possible to study the corresponding IL-2/IL-2R alpha region of interaction. Epitope of mAb 3H9 is localized between residues 30 and 54 and does not affect the binding of IL-2 to IL-2R alpha.
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Affiliation(s)
- J L Moreau
- Unité d'Immunogénétique Cellulaire, Institut Pasteur, Paris, France
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223
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Liu KD, Lai SY, Goldsmith MA, Greene WC. Identification of a variable region within the cytoplasmic tail of the IL-2 receptor beta chain that is required for growth signal transduction. J Biol Chem 1995; 270:22176-81. [PMID: 7545674 DOI: 10.1074/jbc.270.38.22176] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Interleukin-2 (IL-2) regulates numerous biological events, including T lymphocyte proliferation. Interleukin-2 receptor (IL-2R)-mediated signaling is triggered by ligand-induced heterodimerization of the IL-2R beta and gamma c subunits, which results in the activation of signaling intermediates that are associated with either IL-2R beta or gamma c. Previous mutagenesis studies of the IL-2R beta cytoplasmic tail demonstrated that the partially conserved box 1 and box 2 motifs and specific tyrosine residues are critical for growth signaling. By deletion and alanine scanning mutagenesis, another set of residues that are critical for IL-2R-mediated signaling has now been identified. These residues lie within the divergent 35-amino acid "spacer" region separating box 1 and box 2. The role of this receptor subregion in early phases of IL-2R signaling was evaluated using BA/F3 stable cell lines expressing three functionally impaired mutants from this region. All three cell lines displayed substantially diminished growth responsiveness to IL-2. Receptor-mediated STAT factor activation, IL-2R beta phosphorylation, and Janus kinase activation were also markedly impaired. These findings indicate that this variable spacer region, which we have termed the V-box, is essential for the initiation of IL-2R-mediated signal transduction.
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Affiliation(s)
- K D Liu
- Gladstone Institute of Virology and Immunology, School of Medicine, University of California, San Francisco 94141, USA
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224
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Goldsmith MA, Lai SY, Xu W, Amaral MC, Kuczek ES, Parent LJ, Mills GB, Tarr KL, Longmore GD, Greene WC. Growth signal transduction by the human interleukin-2 receptor requires cytoplasmic tyrosines of the beta chain and non-tyrosine residues of the gamma c chain. J Biol Chem 1995; 270:21729-37. [PMID: 7665592 DOI: 10.1074/jbc.270.37.21729] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
To evaluate the possible role for receptor-based tyrosine phosphorylation in growth signaling induced by interleukin-2 (IL-2), a series of substitution tyrosine mutants of the IL-2 receptor beta and gamma c chains was prepared and analyzed. Concurrent mutation of all six of the cytoplasmic tyrosines present in the beta chain markedly inhibited IL-2-induced growth signaling in both pro-B and T cell lines. Growth signaling in a pro-B cell line was substantially reconstituted when either of the two distal tyrosines (Tyr-392, Tyr-510) was selectively restored in the tyrosine-negative beta mutant, whereas reconstitution of the proximal tyrosines (Tyr-338, Tyr-355, Tyr-358, Tyr-361) did not restore this signaling function. Furthermore, at least one of the two cytoplasmic tyrosines that is required for beta chain function was found to serve as a phosphate acceptor site upon induction with IL-2. Studies employing a chimeric receptor system revealed that tyrosine residues of the beta chain likewise were important for growth signaling in T cells. In contrast, although the gamma c subunits is a target for tyrosine phosphorylation in vivo, concurrent substitution of all four cytoplasmic tyrosines of this chain produced no significant effect on growth signaling by chimeric IL-2 receptors. However, deletion of either the Box 1, Box 2, or intervening (V-Box) regions of gamma c abrogated receptor function. Therefore, tyrosine residues of beta but not of gamma c appear to play a pivotal role in regulating growth signal transduction through the IL-2 receptor, either by influencing cytoplasmic domain folding or by serving as sites for phosphorylation and subsequent association with signaling intermediates. These findings thus highlight a fundamental difference in the structural requirements for IL-2R beta and gamma c in receptor-mediated signal transduction.
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Affiliation(s)
- M A Goldsmith
- Gladstone Institute of Virology and Immunology, Department of Medicine, School of Medicine, University of California, San Francisco 94141-9100, USA
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225
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Kawahara A, Minami Y, Miyazaki T, Ihle JN, Taniguchi T. Critical role of the interleukin 2 (IL-2) receptor gamma-chain-associated Jak3 in the IL-2-induced c-fos and c-myc, but not bcl-2, gene induction. Proc Natl Acad Sci U S A 1995; 92:8724-8. [PMID: 7568005 PMCID: PMC41039 DOI: 10.1073/pnas.92.19.8724] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The interleukin 2 receptor (IL-2R) consists of three subunits, the IL-2R alpha, IL-2R beta c, and IL-2R gamma c chains. Two Janus family protein tyrosine kinases (PTKs), Jak1 and Jak3, were shown to associate with IL-2R beta c and IL-2R gamma c, respectively, and their PTK activities are increased after IL-2 stimulation. A Jak3 mutant with truncation of the C-terminal PTK domain lacks its intrinsic kinase activity but can still associate with IL-2R gamma c. In a hematopoietic cell line, F7, that responds to either IL-2 or IL-3, overexpression of this Jak3 mutant results in selective inhibition of the IL-2-induced activation of Jak1/Jak3 PTKs and of cell proliferation. Of the three target nuclear protooncogenes of the IL-2 signaling, c-fos and c-myc genes, but not the bcl-2 gene, were found to be impaired. On the other hand, overexpression of the dominant negative form of the IL-2R gamma c chain, which lacks most of its cytoplasmic domain, in F7 cells resulted in the inhibition of all three protooncogenes. These results provide a further molecular basis for the critical role of Jak3 in IL-2 signaling and also suggest a Jak PTK-independent signaling pathway(s) for the bcl-2 gene induction by IL-2R.
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Affiliation(s)
- A Kawahara
- Institute of Molecular and Cellular Biology, Osaka University, Japan
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226
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Affiliation(s)
- J M Blechman
- Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel
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227
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Taniguchi T, Miyazaki T, Minami Y, Kawahara A, Fujii H, Nakagawa Y, Hatakeyama M, Liu ZJ. IL-2 signaling involves recruitment and activation of multiple protein tyrosine kinases by the IL-2 receptor. Ann N Y Acad Sci 1995; 766:235-44. [PMID: 7486666 DOI: 10.1111/j.1749-6632.1995.tb26671.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The IL-2 receptor (IL-2R) consists of three subunits, the IL-2R alpha, IL-2R beta, and IL-2R gamma chains, the last of which is also used in the receptors for IL-4, IL-7, IL-9, IL-13, and IL-15. The IL-2-induced proliferative signals emanate from the cytoplasmic domains of IL-2R beta and IL-2R gamma, but the nature and function of the signaling molecules that transmit these signals are not fully understood. Here we summarize our current understanding of the mechanisms by which IL-2R transmit signals by using multiple protein kinases. In fact, at least four protein tyrosine kinases (PTKs) are physically associated with IL-2R: p56lck (and its members), Syk PTK, and the Janus kinases, Jak1 and Jak3. cDNA expression studies revealed that the activation of these PTKs is critical for IL-2-induced proliferative signal transmission. Our findings indicate that a unique property of the IL-2R cytoplasmic domains is to recruit a variety of signaling molecules, which may suggest a mechanism by which these PTKs and other signaling molecules function in concert.
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Affiliation(s)
- T Taniguchi
- Institute for Molecular and Cellular Biology, Osaka University, Japan
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228
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Hanke JH, Pollok BA, Changelian PS. Role of tyrosine kinases in lymphocyte activation: targets for drug intervention. Inflamm Res 1995; 44:357-71. [PMID: 8846193 DOI: 10.1007/bf01797862] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Recent developments in our understanding of lymphocyte receptor-associated signalling events have offered many new potential targets for modifying antigen and cytokine receptor signalling events in immune-related diseases such as allergy, autoimmunity and transplant rejection. As discussed below, these targets are largely tissue-restricted and are functionally confined to a limited set of receptors. Therefore, it is anticipated that selective inhibitors of these signalling events would offer safe and effective therapies for immunologically-based diseases. First, we review T and B cell antigen receptor signalling as targets for inhibiting lymphocyte responses. Second, targets in lymphocyte cytokine receptor signalling pathways are discussed. Finally, we review strategies for inhibition of receptor signalling.
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Affiliation(s)
- J H Hanke
- Pfizer Central Research, Groton, CT 06340, USA
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229
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de Saint Basile G, di Santo JP, Fischer A. Genetic studies in severe combined immunodeficiency. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1995; 76:S165-7. [PMID: 7554461 DOI: 10.1016/s0090-1229(95)90090-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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230
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Reinecker HC, Podolsky DK. Human intestinal epithelial cells express functional cytokine receptors sharing the common gamma c chain of the interleukin 2 receptor. Proc Natl Acad Sci U S A 1995; 92:8353-7. [PMID: 7667294 PMCID: PMC41155 DOI: 10.1073/pnas.92.18.8353] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Interleukin (IL) 2 signaling requires the dimerization of the IL-2 receptor beta (IL-2R beta) and common gamma (gamma c) chains. The gamma is also a component of the receptors for IL-4, IL-7, and IL-9. To assess the extent and role of the receptor signal transducing system utilizing the gamma c chain on human intestinal epithelial cells, the expression of gamma c, IL-2R beta, and receptor chains specific for IL-4, IL-7, and IL-9 was assessed by reverse transcription-coupled PCR on human intestinal epithelial cell lines and on isolated primary human intestinal epithelial cells. Caco-2, HT-29, and T-84 cells were found to express transcripts for the gamma c and IL-4R chains constitutively. IL-2R beta chain expression was demonstrated in Caco-2 and HT-29 but not in T-84 cells. None of the cell lines expressed mRNA for the IL-2R alpha chain. After stimulation with epidermal growth factor for 24 h Caco-2, HT-29, and T-84 cells expressed transcripts for IL-7R. In addition, Caco-2 and HT-29 cells expressed mRNA for the IL-9R. Receptors for IL-2, IL-4, IL-7, and IL-9 on intestinal epithelial cells lines appeared to be functional; stimulation with these cytokines caused rapid tyrosine phosphorylation of proteins. The relevance of the observations in intestinal epithelial cell lines for intestinal epithelial function in vivo was supported by the demonstration of transcripts for gamma c, IL-2R beta, IL-4R, IL-7R, and IL-9R in primary human intestinal epithelial cells.
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Affiliation(s)
- H C Reinecker
- Department of Medicine, Massachusetts General Hospital, Boston 02114, USA
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231
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Frank DA, Robertson MJ, Bonni A, Ritz J, Greenberg ME. Interleukin 2 signaling involves the phosphorylation of Stat proteins. Proc Natl Acad Sci U S A 1995; 92:7779-83. [PMID: 7544001 PMCID: PMC41229 DOI: 10.1073/pnas.92.17.7779] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
One of the most important cytokines involved in immune response regulation is interleukin 2 (IL-2), a potent activator of the proliferation and function of T lymphocytes and natural killer cells. The mechanisms by which the effects of IL-2 are propagated within cells are not understood. While the binding of IL-2 to its receptor was recently shown to lead to the activation of two kinases, Jak-1 and Jak-3, subsequent steps in the signaling pathway to the nucleus that lead to the activation of specific genes had not been characterized. Since many cytokines that activate Jak kinases also lead to the tyrosine phosphorylation and activation of members of the Stat family of transcription factors, the ability of IL-2 to trigger Stat phosphorylation was examined. Exposure of activated human T lymphocytes or of a natural killer cell line (NKL) to IL-2 leads to the phosphorylation of Stat1 alpha, Stat1 beta, and Stat3, as well as of two Stat-related proteins, p94 and p95. p94 and p95 share homology with Stat1 at the phosphorylation site and in the Src homology 2 (SH2) domain, but otherwise are immunologically distinct from Stat1. These Stat proteins were found to translocate to the nucleus and to bind to a specific DNA sequence. These findings suggest a mechanism by which IL-2 binding to its receptor may activate specific genes involved in immune cell function.
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Affiliation(s)
- D A Frank
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA
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232
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Keegan AD, Johnston JA, Tortolani PJ, McReynolds LJ, Kinzer C, O'Shea JJ, Paul WE. Similarities and differences in signal transduction by interleukin 4 and interleukin 13: analysis of Janus kinase activation. Proc Natl Acad Sci U S A 1995; 92:7681-5. [PMID: 7544000 PMCID: PMC41209 DOI: 10.1073/pnas.92.17.7681] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The cytokines interleukin (IL) 4 and IL-13 induce many of the same biological responses, including class switching to IgE and induction of major histocompatibility complex class II antigens and CD23 on human B cells. It has recently been shown that IL-4 induces the tyrosine phosphorylation of a 170-kDa protein, a substrate called 4PS, and of the Janus kinase (JAK) family members JAK1 and JAK3. Because IL-13 has many functional effects similar to those of IL-4, we compared the ability of IL-4 and IL-13 to activate these signaling molecules in the human multifactor-dependent cell line TF-1. In this report we demonstrate that both IL-4 and IL-13 induced the tyrosine phosphorylation of 4PS and JAK1. Interestingly, although IL-4 induced the tyrosine phosphorylation of JAK3, we did not detect JAK3 phosphorylation in response to IL-13. These data suggest that IL-4 and IL-13 signal in similar ways via the activation of JAK1 and 4PS. However, our data further indicate that there are significant differences because IL-13 does not activate JAK3.
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Affiliation(s)
- A D Keegan
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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233
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Gaffen SL, Lai SY, Xu W, Gouilleux F, Groner B, Goldsmith MA, Greene WC. Signaling through the interleukin 2 receptor beta chain activates a STAT-5-like DNA-binding activity. Proc Natl Acad Sci U S A 1995; 92:7192-6. [PMID: 7543676 PMCID: PMC41305 DOI: 10.1073/pnas.92.16.7192] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
To explore the possible involvement of STAT factors ("signal transducers and activators of transcription") in the interleukin 2 receptor (IL-2R) signaling cascade, murine HT-2 cells expressing chimeric receptors composed of the extracellular domain of the erythropoietin receptor fused to the cytoplasmic domains of the IL-2R beta or -gamma c chains were prepared. Erythropoietin or IL-2 activation of these cells resulted in rapid nuclear expression of a DNA-binding activity that reacted with select STAT response elements. Based on reactivity with specific anti-STAT antibodies, this DNA-binding activity was identified as a murine homologue of STAT-5. Induction of nuclear expression of this STAT-5-like factor was blocked by the addition of herbimycin A, a tyrosine kinase inhibitor, but not by rapamycin, an immunophilin-binding antagonist of IL-2-induced proliferation. The IL-2R beta chain appeared critical for IL-2-induced activation of STAT-5, since a mutant beta chain lacking all cytoplasmic tyrosine residues was incapable of inducing this DNA binding. In contrast, a gamma c mutant lacking all of its cytoplasmic tyrosine residues proved fully competent for the induction of STAT-5. Physical binding of STAT-5 to functionally important tyrosine residues within IL-2R beta was supported by the finding that phosphorylated, but not nonphosphorylated, peptides corresponding to sequences spanning Y392 and Y510 of the IL-2R beta tail specifically inhibited STAT-5 DNA binding.
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Affiliation(s)
- S L Gaffen
- Gladstone Institute of Virology and Immunology, School of Medicine, University of California, San Francisco 94143, USA
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234
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Somberg RL, Pullen RP, Casal ML, Patterson DF, Felsburg PJ, Henthorn PS. A single nucleotide insertion in the canine interleukin-2 receptor gamma chain results in X-linked severe combined immunodeficiency disease. Vet Immunol Immunopathol 1995; 47:203-13. [PMID: 8571541 DOI: 10.1016/0165-2427(94)05400-m] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The immunologic and genetic analysis of a 14-week-old-male cardigan Welsh corgi puppy that presented with failure to thrive, diarrhea, and intermittent vomiting are described. The lack of palpable lymph nodes, the premature death of a male sibling, and similar clinical signs in a male cousin suggested that a primary immunodeficiency disease might be responsible for his poor clinical condition. Quantitation of serum immunoglobulins revealed low concentrations of IgG and undetectable IgA, yet normal concentrations of IgM. A complete blood cell count showed a slight anemia and lymphopenia. Although the peripheral blood contained a normal percentage of T cells, with an increased CD4:CD8 ratio, they were unable to proliferate in response to phytohemagglutinin (PHA) and/or interleukin 2 (IL-2). Furthermore, following PHA activation, the peripheral blood lymphocytes (PBL) demonstrated a nearly complete lack of IL-2 binding. All of these laboratory findings were identical with our previous findings from dogs with X-linked severe combined immunodeficiency (XSCID) that is due to a mutation in their IL-2 receptor gamma (IL-2R gamma) chain. Examination of the corgi's IL-2R gamma cDNA revealed an insertion of a cytosine following nucleotide 582, resulting in a premature stop codon prior to the transmembrane domain. The insertion also created an EcoO109 restriction enzyme site that enabled us to detect the mutation in the patient's genomic DNA. This new mutation in the IL-2R gamma chain discovered in a cardigan Welsh corgi puppy results in XSCID with similar immunologic abnormalities as observed in dogs with the same disease resulting from a different IL-2R gamma chain mutation.
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Affiliation(s)
- R L Somberg
- Department of Clinical Studies, University of Pennsylvania, School of Veterinary Medicine, Philadelphia 19104-6010, USA
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235
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De Jong MO, Rozemuller H, Bauman JG, Visser JW. Biotinylation of interleukin-2 (IL-2) for flow cytometric analysis of IL-2 receptor expression. Comparison of different methods. J Immunol Methods 1995; 184:101-12. [PMID: 7622862 DOI: 10.1016/0022-1759(95)00080-t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The main prerequisites for the use of biotinylated ligands to study the expression of growth factor receptors on heterogeneous cell populations, such as peripheral blood or bone marrow, by flow cytometric methods, are that the biotinylated ligand retains its binding ability and that binding of the biotinylated ligand to the receptor does not inhibit the subsequent interaction of biotin with fluorescently tagged avidin or streptavidin. Using interleukin-2 (IL-2), we compared the usefulness of various biotinylation reagents, NHS-biotin, S-NHS-biotin, S-NHS-LC-biotin, DBB and photobiotin, and developed optimal biotinylation conditions for the preparation of biologically active biotin-labeled IL-2 and the detection of IL-2 receptor expressing cells by flow cytometry. As determined by spot blot analysis, biotinylation of IL-2 was most efficient at the highest biotin-to-protein (B:P) ratio used. At a B:P ratio of 100, most of the biological activity of IL-2 was retained when S-NHS-LC-biotin was used. In contrast, most of the biological activity of IL-2 samples that were labeled with NHS-biotin or photobiotin was lost under these conditions. Biotin-labeled IL-2 preparations were tested in order to detect IL-2 receptors on IL-2 dependent CTLL-2 cells by flow cytometry after sequential staining with the biotinylated IL-2 and fluorescence tagged streptavidin. A high B:P ratio generally resulted in a high specific fluorescence intensity of the cells, particularly when S-NHS-LC-biotin was used as the biotinylation reagent. Biotin-IL-2 could also be used to detect IL-2 receptors expressed by lymphocytes in peripheral blood and bone marrow. Comparison of staining of lymphocytes with biotinylated IL-2 and an antibody against the IL-2 receptor alpha chain demonstrated that only a subset of the cells that showed a strong fluorescence signal after staining with biotinylated IL-2 expressed high numbers of the IL-2 receptor alpha chain. This is in agreement with the expression of functional IL-2 receptors on resting T cells and NK cells which do not express the alpha chain. After stimulation with PHA, virtually all lymphocytes expressed the alpha chain, whereas only part of these cells showed a strong fluorescence signal after staining with biotin-IL-2, while the rest of the cells had very low numbers of IL-2 binding sites. Our results demonstrate that, in addition to staining individual receptor subunits with antibodies, staining with biotinylated IL-2 is a useful indicator of functional IL-2 receptor expression.
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Affiliation(s)
- M O De Jong
- Department of Hematology, Erasmus University Rotterdam, Netherlands
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236
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Migone TS, Lin JX, Cereseto A, Mulloy JC, O'Shea JJ, Franchini G, Leonard WJ. Constitutively activated Jak-STAT pathway in T cells transformed with HTLV-I. Science 1995; 269:79-81. [PMID: 7604283 DOI: 10.1126/science.7604283] [Citation(s) in RCA: 447] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human T cell lymphotropic virus I (HTLV-I) is the etiological agent for adult T cell leukemia and tropical spastic paraparesis (also termed HTLV-I-associated myelopathy). HTLV-I-infected peripheral blood T cells exhibit an initial phase of interleukin-2 (IL-2)-dependent growth; over time, by an unknown mechanism, the cells become IL-2-independent. Whereas the Jak kinases Jak1 and Jak3 and the signal transducer and activator of transcription proteins Stat3 and Stat5 are activated in normal T cells in response to IL-2, this signaling pathway was constitutively activated in HTLV-I-transformed cells. In HTLV-I-infected cord blood lymphocytes, the transition from IL-2-dependent to IL-2-independent growth correlated with the acquisition of a constitutively activated Jak-STAT pathway, which suggests that this pathway participates in HTLV-I-mediated T cell transformation.
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Affiliation(s)
- T S Migone
- Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
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237
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Wu Z, Johnson KW, Goldstein B, Choi Y, Eaton SF, Laue TM, Ciardelli TL. Solution assembly of a soluble, heteromeric, high affinity interleukin-2 receptor complex. J Biol Chem 1995; 270:16039-44. [PMID: 7608165 DOI: 10.1074/jbc.270.27.16039] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In this study, we report the use of coiled-coil (leucine zipper) molecular recognition for the solution assembly of stable, high affinity, heteromeric interleukin-2 receptor complexes. Co-expression of interleukin-2 receptor alpha and beta extracellular domains (ectodomains), each fused to seven coiled-coil heptad repeats, resulted in the formation of heteromeric complexes that bound interleukin-2 in a cooperative fashion and with much higher affinity than similar homomeric complexes. The dissociation constants for these solution complexes are within the range of values reported for the comparable cell surface "pseudo high affinity" interleukin-2 receptor. Ligand-induced cross-linking of homomeric or heteromeric receptor subunits is the common signal transmission mechanism employed by hematopoietin receptors. Individual receptor ectodomains, however, often do not bind ligand with measurable affinity. This is the first study to demonstrate the feasibility of coiled-coil mediated preassembly of cytokine receptor complexes.
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Affiliation(s)
- Z Wu
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, New Hampshire 03755, USA
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238
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Morrone G, Bond HM, Cuomo C, Agosti V, Petrella A, Pagnano AM, Della Corte A, Marasco O, Venuta S. Differential regulation of the expression of interleukin-2 receptor gamma-chain during the in vitro differentiation of human myeloid cells. Biochem J 1995; 308 ( Pt 3):909-14. [PMID: 8948450 PMCID: PMC1136810 DOI: 10.1042/bj3080909] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The common gamma-chain (gamma c) is a shared component of cell-surface receptors for the interleukins- 2, -4 and -7, and possibly others. We studied its expression in cells and cell lines of myeloid origin and found ubiquitous presence of gamma c mRNA in all cells examined. Differential regulation of gamma c expression was observed in myeloid cell lines induced to differentiate in vitro. In K-562 erythromyeloid cells, a sharp rise in the levels of gamma c mRNA and protein accompanied megakaryocytic, but not erythroid, differentiation. Surface binding of interleukin-2, as well as the transcripts for cognate receptor chains, were scarcely detectable in K-562 cells, whereas a significant increase in the binding of granulocyte-macrophage colony-stimulating factor specifically occurred during their megakaryocytic maturation. Our data indicate that expression of gamma c is a common feature of human myeloid cells, and suggest that its expression may be a requirement for human myelopoiesis.
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Affiliation(s)
- G Morrone
- Department of Experimental and Clinical Medicine, Faculty of Medicine, Catanzaro, Italy
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239
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Wu Z, Johnson KW, Ciardelli TL. Ligand binding analysis of interleukin-2 receptor complexes using surface plasmon resonance. J Immunol Methods 1995; 183:127-30. [PMID: 7602130 DOI: 10.1016/0022-1759(95)00040-h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this study we have employed surface plasmon resonance to examine the kinetic binding constants of a new class of soluble cytokine receptor complexes. The solution assembly of both homomeric and heteromeric interleukin-2 receptor ectodomain complexes has been achieved using coiled-coil molecular recognition. These complexes were immobilized on a biosensor surface and the kinetic binding constants were determined. The values obtained for these parameters compared favorably with those reported in studies of comparable cell surface complexes. The combination of these methods provides a powerful approach to the ligand interactions of cytokine receptors.
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Affiliation(s)
- Z Wu
- Department of Pharmacology and Toxicology, Dartmouth Medical School, Hanover, NH 03755, USA
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240
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Fujii H, Nakagawa Y, Schindler U, Kawahara A, Mori H, Gouilleux F, Groner B, Ihle JN, Minami Y, Miyazaki T. Activation of Stat5 by interleukin 2 requires a carboxyl-terminal region of the interleukin 2 receptor beta chain but is not essential for the proliferative signal transmission. Proc Natl Acad Sci U S A 1995; 92:5482-6. [PMID: 7777534 PMCID: PMC41719 DOI: 10.1073/pnas.92.12.5482] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The high-affinity interleukin 2 (IL-2) receptor (IL-2R) consists of three subunits: the IL-2R alpha, IL-2R beta c, and IL-2R gamma c chains. Two members of the Janus kinase family, Jak1 and Jak3, are associated with IL-2R beta c and IL-2R gamma c, respectively, and they are activated upon IL-2 stimulation. The cytokine-mediated Jak kinase activation usually results in the activation of a family of latent transcription factors termed Stat (signal transducer and activator of transcription) proteins. Recently, the IL-2-induced Stat protein was purified from human lymphocytes and found to be the homologue of sheep Stat5/mammary gland factor. We demonstrate that the human Stat5 is activated by IL-2 and that Jak3 is required for the efficient activation. The cytoplasmic region of the IL-2R beta c chain required for activation of Stat5 is mapped within the carboxyl-terminal 147 amino acids. On the other hand, this region is not essential for IL-2-induced cell proliferation.
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Affiliation(s)
- H Fujii
- Institute for Molecular and Cellular Biology, Osaka University, Japan
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241
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Boise LH, Minn AJ, June CH, Lindsten T, Thompson CB. Growth factors can enhance lymphocyte survival without committing the cell to undergo cell division. Proc Natl Acad Sci U S A 1995; 92:5491-5. [PMID: 7777536 PMCID: PMC41721 DOI: 10.1073/pnas.92.12.5491] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Growth factors have been defined by their ability to promote the proliferative expansion of receptor-bearing cells. For example, antigen-activated T cells expressing the alpha beta gamma form of the interleukin 2 (IL-2) receptor will proliferate in response to IL-2. In contrast, resting T cells, which express the IL-2 receptor beta and gamma chains, do not proliferate in response to IL-2. We demonstrate that the survival of resting T cells following gamma irradiation is greatly enhanced by pretreatment with IL-2. The radioprotective effect of IL-2 is dose dependent, does not result from the induction of cell proliferation, and does not require expression of the IL-2 receptor alpha chain. Thus, the beta gamma IL-2 receptor expressed on resting T cells can transduce signals that promote cell survival without committing the T cell to undergo cell division. IL-4 and IL-7, but not IL-1, IL-3, or IL-6, were also found to enhance the survival of quiescent T cells following gamma irradiation. Thus, certain growth factor-receptor interactions can serve to maintain cell viability in a manner that is independent of their ability to initiate or maintain cell proliferation. These data may have important implications for the use of growth factors in patients being treated with radiation and/or chemotherapy.
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Affiliation(s)
- L H Boise
- Gwen Knapp Center, Howard Hughes Medical Institute, University of Chicago, IL 60637, USA
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242
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Karnitz LM, Burns LA, Sutor SL, Blenis J, Abraham RT. Interleukin-2 triggers a novel phosphatidylinositol 3-kinase-dependent MEK activation pathway. Mol Cell Biol 1995; 15:3049-57. [PMID: 7760801 PMCID: PMC230536 DOI: 10.1128/mcb.15.6.3049] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Phosphatidylinositol 3-kinase (PI3-K) has been implicated as a signal-transducing component in interleukin-2 (IL-2)-induced mitogenesis. However, the function of this lipid kinase in regulating IL-2-triggered downstream events has remained obscure. Using the potent and specific PI3-K inhibitor, wortmannin, we assessed the role of PI3-K in IL-2-mediated signaling and proliferation in the murine T-cell line CTLL-2. Addition of the drug to exponentially growing cells resulted in an accumulation of cells in the G0/G1 phase of the cell cycle. Furthermore, wortmannin also partially suppressed IL-2-induced S-phase entry in G1-synchronized cells. Analysis of IL-2-triggered signaling pathways revealed that wortmannin pretreatment resulted in complete inhibition of IL-2-provoked p70 S6 kinase activation and also attenuated IL-2-induced MAP kinase activation at drug concentrations identical to those required for inhibition of PI3-K catalytic activity. Wortmannin also diminished the IL-2-triggered activation of the MAP kinase activator, MEK, but did not inhibit activation of Raf, the canonical upstream activator of MEK. These results suggest that a novel wortmannin-sensitive activation pathway regulates MEK and MAP kinase in IL-2-stimulated T lymphocytes.
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Affiliation(s)
- L M Karnitz
- Department of Immunology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA
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243
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He TC, Jiang N, Zhuang H, Wojchowski DM. Erythropoietin-induced recruitment of Shc via a receptor phosphotyrosine-independent, Jak2-associated pathway. J Biol Chem 1995; 270:11055-61. [PMID: 7538110 DOI: 10.1074/jbc.270.19.11055] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Based on the recently implicated role of Shc as a signaling effector for type I cytokine receptors, factors which mediate the recruitment and phosphorylation of Shc in the erythropoietin receptor (EPOR) system have been studied. FDC-P1 cells stably expressing the wild type murine EPOR supported the EPO-induced association of Shc with Jak2 and its rapid tyrosine phosphorylation. However, this did not depend upon the presence of phosphotyrosine sites within the EPOR and was mediated by a mitogenically deficient receptor form (EPOR329) lacking cytoplasmic tyrosine residues. This was shown both by Western blotting of Shc and Jak2 co-immunoprecipitates and through the development of an in vitro assay for cytokine-induced Shc phosphorylation. The direct association of Shc with Jak2 also was observed and was shown to depend upon EPO-exposure and the SH2 subdomain of Shc. Together, these studies indicate that Jak2, in part, may mediate the EPO-induced phosphorylation of Shc.
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Affiliation(s)
- T C He
- Department of Biochemistry & Molecular Biology, Pennsylvania State University, University Park 16802, USA
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244
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Soldaini E, Pla M, Beermann F, Espel E, Corthésy P, Barangé S, Waanders GA, MacDonald HR, Nabholz M. Mouse interleukin-2 receptor alpha gene expression. Delimitation of cis-acting regulatory elements in transgenic mice and by mapping of DNase-I hypersensitive sites. J Biol Chem 1995; 270:10733-42. [PMID: 7738012 DOI: 10.1074/jbc.270.18.10733] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The alpha chain of the interleukin-2 receptor (IL-2R alpha) is a key regulator of lymphocyte proliferation. To analyze the mechanisms controlling its expression in normal cells, we used the 5'-flanking region (base pairs -2539/+93) of the mouse gene to drive chloramphenicol acetyltransferase expression in four transgenic mouse lines. Constitutive transgene activity was restricted to lymphoid organs. In mature T lymphocytes, transgene and endogenous IL-2R alpha gene expression was stimulated by concanavalin A and up-regulated by IL-2 with very similar kinetics. In thymic T cell precursors, IL-1 and IL-2 cooperatively induced transgene and IL-2R alpha gene expression. These results show that regulation of the endogenous IL-2R alpha gene occurs mainly at the transcriptional level. They demonstrate that cis-acting elements in the 5'-flanking region present in the transgene confer correct tissue specificity and inducible expression in mature T cells and their precursors in response to antigen, IL-1, and IL-2. In a complementary approach, we screened the 5' end of the endogenous IL-2R alpha gene for DNase-I hypersensitive sites. We found three lymphocyte specific DNase-I hypersensitive sites. Two, at -0.05 and -5.3 kilobase pairs, are present in resting T cells. A third site appears at -1.35 kilobase pairs in activated T cells. It co-localizes with IL-2-responsive elements identified by transient transfection experiments.
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Affiliation(s)
- E Soldaini
- Swiss Institute for Experimental Cancer Research (ISREC), Epalinges, Switzerland
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245
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Malek TR, Furse RK, Fleming ML, Fadell AJ, He YW. Biochemical identity and characterization of the mouse interleukin-2 receptor beta and gamma c subunits. J Interferon Cytokine Res 1995; 15:447-54. [PMID: 7648447 DOI: 10.1089/jir.1995.15.447] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Although the mouse IL-2 receptor (IL-2R) beta and gamma c subunits have been identified by molecular cloning, the biochemical identity of these subunits has not yet been established. In the present study, the mouse IL-2R was biochemically characterized from cell lines expressing normal and aberrant IL-2R. Using novel monoclonal antibodies specific for the beta or gamma c subunits, we established that the M(r) of the beta chain is 90,000-100,000 and that of the gamma c subunit is 75,000-80,000. Analysis of transfected EL4 cells that expressed alpha, gamma c, and truncated beta subunits or mutant EL4 cells, which selectively lacked cell surface gamma c, revealed that no other material migrated to a position on SDS-PAGE characteristic of IL-2/IL-2R beta and IL-2/IL-2R gamma c cross-linked complexes, respectively. Thus, the beta and gamma c subunits appear to be the sole IL-2R constituents of these IL-2 cross-linked complexes. The IL-2/IL-2R gamma c, but not the IL-2/IL-2R beta, complex exhibited enhanced mobility after SDS-polyacrylamide gel electrophoresis under nonreducing conditions, suggesting a more compact structure for gamma c as a result of intrachain disulfide bonds. The primary posttranslational modification of the mouse beta and gamma c subunits is N-linked glycosylation. These biochemical studies reconcile past uncertainties concerning the subunit composition of the mouse IL-2R and are consistent with a model of the IL-2R containing only three subunits.
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Affiliation(s)
- T R Malek
- Department of Microbiology and Immunology, University of Miami School of Medicine, FL 33136, USA
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246
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Marasco WA. Intracellular antibodies (intrabodies) as research reagents and therapeutic molecules for gene therapy. IMMUNOTECHNOLOGY : AN INTERNATIONAL JOURNAL OF IMMUNOLOGICAL ENGINEERING 1995; 1:1-19. [PMID: 9373329 DOI: 10.1016/1380-2933(95)00001-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- W A Marasco
- Division of Human Retrovirology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
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247
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Miyazaki T, Liu ZJ, Kawahara A, Minami Y, Yamada K, Tsujimoto Y, Barsoumian EL, Permutter RM, Taniguchi T. Three distinct IL-2 signaling pathways mediated by bcl-2, c-myc, and lck cooperate in hematopoietic cell proliferation. Cell 1995; 81:223-31. [PMID: 7736574 DOI: 10.1016/0092-8674(95)90332-1] [Citation(s) in RCA: 294] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two interleukin-2 receptor-dependent signaling pathways have thus far been identified: the c-fos/c-jun induction pathway mediated by src family protein-tyrosine kinases and the c-myc induction pathway. Here, we provide evidence for the existence of a third, rapamycin-sensitive pathway, which results in the induction of another proto-oncogene, bcl-2. In the hematopoietic cell line BAF-B03, the expression of any two of lckF505 (an active form of p56lck), Bcl-2, or c-Myc is sufficient to promote transit of the cell cycle, regardless of the activation state of the third pathway. We also provide evidence that epidermal growth factor receptor signaling may act through the same pathway that involves p56lck. These studies demonstrate a novel approach to dissecting signaling pathways regulating cellular proliferation.
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Affiliation(s)
- T Miyazaki
- Institute for Molecular and Cellular Biology, Osaka University, Japan
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248
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Abstract
Cytokines are a family of soluble mediators of cell-to-cell communication that includes interleukins, interferons, and colony-stimulating factors. The characteristic features of cytokines lie in their functional redundancy and pleiotropy. Most of the cytokine receptors that constitute distinct superfamilies do not possess intrinsic protein tyrosine kinase (PTK) domains, yet receptor stimulation usually invokes rapid tyrosine phosphorylation of intracellular proteins, including the receptors themselves. It is now clear that these receptors are capable of recruiting or activating (or both) a variety of nonreceptor PTKs to induce downstream signaling pathways. Thus, the intracytoplasmic structure of cytokine receptors has evolved so as to allow the combined action of different PTK family members expressed in different cell types, which may ultimately determine the activity of cytokines.
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Affiliation(s)
- T Taniguchi
- Department of Immunology, Faculty of Medicine, University of Tokyo, Japan
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249
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Morella KK, Lai CF, Kumaki S, Kumaki N, Wang Y, Bluman EM, Witthuhn BA, Ihle JN, Giri J, Gearing DP. The action of interleukin-2 receptor subunits defines a new type of signaling mechanism for hematopoietin receptors in hepatic cells and fibroblasts. J Biol Chem 1995; 270:8298-310. [PMID: 7713938 DOI: 10.1074/jbc.270.14.8298] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The gene regulatory functions of the human IL-2 receptor (IL-2R) were reconstituted in transiently transfected hepatoma cells. The combination of IL-2R beta and -gamma mediated a strong stimulation via the cytokine response element of the alpha 1-acid glycoprotein gene and the hematopoietin receptor response element, but none via the IL-6 response element or the sis-inducible element. IL-2R alpha enhanced 10-fold the sensitivity of the IL-2R beta.gamma complex to respond to IL-2 or IL-15, but did not modify the specificity or the magnitude of maximal gene regulation. A homodimerizing chimeric receptor G-CSFR-IL-2R beta could mimic the IL-2R action. The IL-2R-mediated gene regulation was similar to that seen with receptors for IL-4 and IL-7, but differed from that for IL-6 type cytokines, thrombopoietin, erythropoietin, and growth hormone. The activation of STAT proteins by the IL-2R was assessed in transfected L-cells and COS-1 cells. Although IL-2R subunits were highly expressed in these cells, no STAT protein activation was detectable. Transient overexpression of JAK3 was unable to change the signaling specificity of the hematopoietin receptors in rat hepatoma, L-, and COS cells, but established a prominent activation of the IL-6 response elements by the IL-2R and IL-4R in HepG2 cells. The data support the model that the IL-2R and related hematopoietin receptors produce at least two separate signals which control gene expression.
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Affiliation(s)
- K K Morella
- Department of Molecular and Cellular Biology, Roswell Park Cancer Institute, Buffalo, New York 14263, USA
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250
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Raivio E, Oetken C, Oker-Blom C, Engberg C, Akerman K, Lindqvist C. Expression of the human interleukin-2 receptor gamma chain in insect cells using a baculovirus expression vector. Scand J Immunol 1995; 41:338-42. [PMID: 7899821 DOI: 10.1111/j.1365-3083.1995.tb03576.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The gene encoding the gamma-chain of the human Interleukin-2 receptor was expressed in lepidopteran insect cells using the baculovirus expression vector system. The corresponding gene was inserted under the polyhedrin promoter of the Autographa californica nuclear polyhedrosis virus and expressed in the Spodoptera frugiperda insect cell line Sf9 during viral infection. The recombinant receptor protein was identified by immunoblotting in cell lysates, prepared from insect cells infected with the recombinant virus. At 40 h post infection the corresponding protein was detected as two major bands with apparent molecular weights of 50-60 kDa using a rabbit anti-human IL-2R gamma-receptor specific antiserum. Metabolic labelling with [35S]-methionine and SDS-PAGE analysis of the recombinant baculovirus infected insect cells verified the immunoblotting data. The expressed IL-2R gamma- protein could also be determined on the surface of infected insect cells by flow cytometer analysis.
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Affiliation(s)
- E Raivio
- Abo Akademi University, Department of Biochemistry and Pharmacy, Finland
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