A Godard

Cancer Research Center of Lyon, Lyons, Rhône-Alpes, France

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Publications (72)270.93 Total impact

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    ABSTRACT: In addition to soluble acid hydrolases, many nonlysosomal proteins have been shown to bear mannose 6-phosphate (Man-6-P) residues. Quantification of the extent of mannose phosphorylation and the relevance to physiological function, however, remain poorly defined. In this study, we investigated the mannose phosphorylation status of leukemia inhibitory factor (LIF), a previously identified high affinity ligand for the cation-independent mannose 6-phosphate receptor (CI-MPR), and we analyzed the effects of this modification on its secretion and uptake in cultured cells. When media from LIF-overexpressing cells were fractionated using a CI-MPR affinity column, 35-45% of the total LIF molecules were bound and specifically eluted with free Man-6-P thus confirming LIF as a bona fide Man-6-P-modified protein. Surprisingly, mass spectrometric analysis of LIF glycopeptides enriched on the CI-MPR column revealed that all six N-glycan sites could be Man-6-P-modified. The relative utilization of these sites, however, was not uniform. Analysis of glycan-deleted LIF mutants demonstrated that loss of glycans bearing the majority of Man-6-P residues leads to higher steady-state levels of secreted LIF. Using mouse embryonic stem cells, we showed that the mannose phosphorylation of LIF mediates its internalization thereby reducing extracellular levels and stimulating embryonic stem cell differentiation. Finally, immunofluorescence experiments indicate that LIF is targeted directly to lysosomes following its biosynthesis, providing another mechanism whereby mannose phosphorylation serves to control extracellular levels of LIF. Failure to modify LIF in the context of mucolipidosis II and its subsequent accumulation in the extracellular space may have important implications for disease pathogenesis.
    Journal of Biological Chemistry 05/2011; 286(28):24855-64. · 4.65 Impact Factor
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    ABSTRACT: Stage III melanoma is refractory to common therapies and shows resistance to the anti-proliferative activity of cytokines in vitro. We previously demonstrated that, for 30% of the metastatic melanoma cell lines, oncostatin M (OSM) resistance is due to the epigenetic silencing of its receptor OSMRβ. Here we analyse, on a larger panel of short-term cultures derived from melanoma-invaded lymph nodes, other mechanisms potentially implicated in OSM resistance. For 18% of the cell lines, OSM resistance is associated with a phosphorylation defect of signal transducer and activator of transcription (STAT)3 on serine (Ser)727, in concordance with defects in the activation of various protein kinase C (PKC) isoforms, especially PKCδ. For 21% of the cell lines, OSM resistance is associated with a defect in the activation of Akt on Ser473. By the use of inhibitors, dominant negatives and small interfering (si)RNA, we show that the PKC–STAT3 Ser727, but not the Akt, pathway appears necessary for OSM anti-proliferative activity. Moreover, we bring evidence that OSM or interleukin (IL)-6, produced in lymph nodes and/or melanoma cells, could be involved in the establishment of OSM resistance during melanoma progression. These findings could be relevant for the prognosis and the treatment of stage III melanoma patients. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
    The Journal of Pathology 11/2008; 217(5):665 - 676. · 7.59 Impact Factor
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    ABSTRACT: Immunotherapy by adoptive transfer of autologous tumour-infiltrating lymphocytes (TIL) shows promising clinical results for stage III (lymph nodes metastasis) melanoma patients, but some of them remain unresponsive. Here we analysed retrospectively the impact of resistance of melanoma cells to anti-proliferative cytokines on the clinical outcome of 24 TIL-treated metastatic melanoma patients. Patient relapse-free survival correlated significantly with Oncostatin M (OSM) and/or IL-6 sensitivity of melanoma cells, but not with interferon (IFN) gamma or tumour necrosis factor (TNF) alpha sensitivity. However, OSM/IL-6 sensitivity did not correlate with other known prognostic factors. Moreover, OSM and IL-6 were produced by TIL just before their injection to patients. In immunodeficient mice, OSM reduced human melanoma xenograft tumour growth, this effect being directly through inhibition of tumour cell proliferation rather than induction of apoptosis or necrosis. Thus, OSM/IL-6 resistance of melanoma cells appears to be a new escape mechanism to TIL treatment that could be added to the existing prognostic factors for early stage melanoma patients. This mechanism of action could be also relevant in other immunotherapy protocols, and could lead to better prognosis and anti-cancer treatments.
    The Journal of Pathology 10/2008; 216(4):451-9. · 7.59 Impact Factor
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    ABSTRACT: Oncostatin M (OSM) is an interleukin-6 (IL-6) type cytokine originally described by its capacity to inhibit melanoma proliferation in vitro. Here, the mechanisms involved in resistance to growth inhibition by OSM were analysed for the first time on a large panel of metastatic melanoma cell lines. OSM resistance did not strictly correlate with IL-6, interferon-gamma or tumor necrosis factor-alpha resistance. Rather, it correlated with a specific loss of the OSM receptor-beta (OSMRbeta) subunit, in conjunction with a lower level of histone acetylation in the OSMRbeta promoter region. Treatment of various OSM-resistant melanoma cells with the histone deacetylase inhibitor Trichostatin A increased activity and histone acetylation of the OSMRbeta promoter as well as expression of OSMRbeta mRNA and protein, allowing OSM to activate the signal transducer and activator of transcription 3 (STAT3) and to inhibit proliferation. Other defects associated with OSM resistance were identified at the level of OSMRbeta transcription or protein expression, as well as downstream of or parallel to STAT3 activation. Altogether, our results suggest a role for OSM in the prevention of melanoma progression and that metastatic melanoma cells could escape this growth control by the epigenetic silencing of OSMRbeta.
    Oncogene 03/2007; 26(6):881-92. · 8.56 Impact Factor
  • Ejc Supplements - EJC SUPPL. 01/2006; 4(12):87-87.
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    ABSTRACT: Stuve-Wiedemann syndrome (SWS) is a severe autosomal recessive condition characterized by bowing of the long bones, with cortical thickening, flared metaphyses with coarsened trabecular pattern, camptodactyly, respiratory distress, feeding difficulties, and hyperthermic episodes responsible for early lethality. Clinical overlap with Schwartz-Jampel type 2 syndrome (SJS2) has suggested that SWS and SJS2 could be allelic disorders. Through studying a series of 19 families with SWS/SJS2, we have mapped the disease gene to chromosome 5p13.1 at locus D5S418 (Zmax=10.66 at theta =0) and have identified null mutations in the leukemia inhibitory factor receptor (LIFR or gp190 chain) gene. A total of 14 distinct mutations were identified in the 19 families. An identical frameshift insertion (653_654insT) was identified in families from the United Arab Emirates, suggesting a founder effect in that region. It is interesting that 12/14 mutations predicted premature termination of translation. Functional studies indicated that these mutations alter the stability of LIFR messenger RNA transcripts, resulting in the absence of the LIFR protein and in the impairment of the JAK/STAT3 signaling pathway in patient cells. We conclude, therefore, that SWS and SJS2 represent a single clinically and genetically homogeneous condition due to null mutations in the LIFR gene on chromosome 5p13.
    The American Journal of Human Genetics 03/2004; 74(2):298-305. · 11.20 Impact Factor
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    ABSTRACT: The calcium-independent mannose 6-phosphate receptor (CIMPR) is a receptor for multiple ligands, including leukemia inhibitory factor (LIF), an IL-6 type cytokine, and IGF-II. CIMPR targets newly synthesized ligands to lysosomes and induces internalization/degradation of secreted ligands. A natural soluble form of CIMPR (sCIMPR) neutralizes IGF-II mitogenic potency on hepatocytes and fibroblasts. Herein we show that sCIMPR also inhibits LIF-driven proliferation of myeloid and lymphoid cell lines. Similar inhibition was observed with IL-6 and IL-11, two other IL-6-type cytokines that do not interact with CIMPR. Neutralizing anti-IGF-II antibodies inhibited IL-6-, IL-11-, and LIF-driven cell proliferation to the same extent as sCIMPR, suggesting that neutralization of serum IGF-II by sCIMPR plays a major role in IL-6-type cytokine-dependent cell proliferation. Confirming this idea, ERK1/2 and AKT/protein kinase B, the kinases necessary for cell proliferation and survival, were activated by IGF-II alone or by the association of IL-6-type cytokines and IGF-II. IL-6-type cytokines alone (up to 10 ng/ml) did not activate ERK1/2 or AKT, but did activate STAT3 (signal transducer and activator of transcription 3), a transcription factor necessary for the G1 to S phase cell cycle transition. Activation of ERK1/2 and AKT by IGF-II thus appears essential to sustain cellular expansion driven by IL-6-type cytokines.
    Endocrinology 01/2004; 144(12):5381-9. · 4.72 Impact Factor
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    ABSTRACT: The leukemia inhibitory factor (LIF) receptor comprises the low affinity binding chain gp190 and the high affinity converter gp130. The ectodomain of gp190 is among the most complex in the hematopoietin receptor family, because it contains two typical cytokine receptor homology domains separated by an immunoglobulin-like (Ig-like) domain. Human and murine gp190 proteins share 76% homology, but murine gp190 binds human LIF with a much higher affinity, a property attributed to the Ig-like domain. Using alanine-scanning mutagenesis of the Ig-like domain, we mapped a LIF binding site at its carboxyl terminus, mainly involving residue Phe-328. Mutation of selected residues into their orthologs in the murine receptor (Q251E and N321D) significantly increased the affinity for human LIF. Interestingly, these residues, although localized at both the amino and carboxyl terminus, make a spatially unique LIF binding site in a structural model of the Ig-like module. These results demonstrate definitively the role of the Ig-like domain in LIF binding and the potential to modulate receptor affinity in this family with very limited amino acid changes.
    Journal of Biological Chemistry 06/2003; 278(18):16253-61. · 4.65 Impact Factor
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    ABSTRACT: We studied the production of interleukin (IL)-11 and IL-8, two cytokines known to affect erythropoiesis, in polycythemia vera (PV). In vivo, IL-11 was detected more frequently in serum and bone marrow (BM) plasma of PV patients than in controls (healthy donors and patients with idiopathic erythrocytosis (IE)). In addition, serum IL-11 levels of PV patients were higher than those of controls. IL-8 was elevated in serum of both PV and IE patients (respective median levels: 38.6 and 242pg/ml, vs 4.4pg/ml for healthy donors). BM plasma IL-8 levels of PV patients (508pg/ml) were significantly higher than those of IE patients (120pg/ml). In vitro, bone marrow (BM) stromal cells (BMSC) of PV patients produced significantly more IL-11 (x6.4) and IL-8 (x8.3) than BMSC of healthy donors or IE patients. In conclusion, both IL-11 and IL-8 are overproduced in PV, apparently by BMSC; IL-8 is also overproduced in IE, by cells other than BMSC.
    Cytokine 12/2002; 20(4):178-83. · 2.52 Impact Factor
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    ABSTRACT: The related members of the interleukin-6 (IL-6) family of cytokines, leukemia inhibitory factor (LIF), oncostatin M (OSM) and IL-6 are inflammatory mediators that control differentiated cell functions as well as proliferation. The cellular responsiveness to these cytokines is largely determined by the expression of the appropriate receptor proteins. The receptor expression profile for each cell type is established during differentiation and is often altered during oncogenic transformation. Since inhibition of histone deacetylases (HDAC) has the potential to re-activate epigenetically silenced genes, we asked whether inhibition of HDAC enhances the expression of IL-6 cytokine receptors and, thus, increase desirable cytokine responses. We demonstrate that treatment with FR901228 (FR), an HDAC inhibitor, increases the responsiveness to LIF in different cell types, including normal fibroblasts, epithelial cells, macrophages and splenocytes, as well as various tumor cell lines. Depending on the cell type, FR treatment also enhances the responsiveness to OSM and IL-6. These effects involve a transcriptional induction of the cytokine receptor subunits LIFRalpha, OSMRbeta, gp130, or the transcription factor STAT3. FR-specific induction of LIFRalpha occurs independently of de novo protein synthesis and cell proliferation and is mediated in part by the CBP/p300 coactivator. Chromatin immunoprecipitation experiments indicate that the expression of LIFRalpha and gp130 genes correlates with the level of acetylated histone 3 associated with the receptor promoter regions. The FR-stimulated expression of IL-6-type cytokine receptors in certain tumor cells also provided improved conditions for suppression of cell growth by taking advantage of the growth inhibitory effect of these cytokines.
    Oncogene 10/2002; 21(41):6264-77. · 8.56 Impact Factor
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    ABSTRACT: The cytokine receptor subunits gp130, leukemia inhibitory factor receptor alpha (LIFRalpha), and oncostatin M receptor beta (OSMRbeta) transduce OSM signals that regulate gene expression and cell proliferation. After ligand binding and activation of the Janus protein-tyrosine kinase/STAT and mitogen-activated protein kinase signal transduction pathways, negative feedback processes are recruited. These processes attenuate receptor action by suppression of cytokine signaling and by down-regulation of receptor protein expression. This study demonstrates that in human fibroblasts or epithelial cells, OSM first decreases the level of gp130, LIFRalpha, and OSMRbeta by ligand-induced receptor degradation and then increases the level of the receptors by enhanced synthesis. The transcriptional induction of gp130 gene by OSM involves STAT3. Various cell lines expressing receptor subunits to the different interleukin-6 class cytokines revealed that only LIFRalpha degradation is promoted by activated ERK and that degradation of gp130, OSMRbeta, and a fraction of LIFRalpha involves mechanisms that are separate from signal transduction. These mechanisms include ligand-mediated dimerization, internalization, and endosomal/lysosomal degradation. Proteosomal degradation appears to involve a fraction of receptor subunit proteins that are ubiquitinated independently of ligand binding.
    Journal of Biological Chemistry 01/2002; 276(50):47038-45. · 4.65 Impact Factor
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    ABSTRACT: The receptor for the cytokine leukemia inhibitory factor (LIF) associates the low affinity binding component gp190 and the high affinity converter gp130, both of which are members of the family of hematopoietic receptors characterized by the cytokine receptor homology (CRH) domain. The gp190 is among the very few members of this large family to contain two CRH domains. The membrane-distal one (herein called D1) is followed by an Ig-like domain, a membrane-proximal CRH domain called D2, and three type III fibronectin repeats. We raised a series of monoclonal antibodies specific for the human gp190. Among them was the blocking antibody 1C7, which was directed against the D1Ig region and which impaired the binding of LIF to gp190. Another blocking antibody, called 12D3, was directed against domain D2 and interfered with the reconstitution of the high affinity receptor complex, independently of the interaction between LIF and gp190. The blocking effect of these two antibodies concerned four cytokines known to use gp190, i.e. LIF, oncostatin M, ciliary neurotrophic factor, and cardiotrophin-1. Among 23 antibodies tested alone or in combination (two anti-D2 and 21 anti-D1Ig), only the mixture of the two anti-D2 antibodies displayed agonistic activity in the absence of the cytokine. Taken together, these results demonstrate that the two CRH domains of gp190 play different functions in ligand binding and receptor activation.
    Journal of Biological Chemistry 12/2001; 276(51):47975-47981. · 4.65 Impact Factor
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    ABSTRACT: Cytokines are of potential importance in the pathogenesis of cutaneous T-cell mediated disorders, including cutaneous T-cell lymphoma (CTCL). To compare interleukin (IL)-15 expression in certain inflammatory cutaneous diseases, with that in CTCL (mycosis fungoides and Sézary syndrome). IL-15 mRNA and protein expression were examined by in situ hybridization and immunohistochemistry, respectively, on formalin-fixed, paraffin-embedded biopsies of normal human skin, atopic dermatitis, psoriasis, parapsoriasis and CTCL. Despite similar expression of IL-15 mRNA, we found differences in IL-15 protein expression between normal human skin, atopic dermatitis and psoriasis on the one hand, and parapsoriasis and CTCL on the other. IL-15 protein expression was not detected in normal human skin, atopic dermatitis or psoriasis, but was detected, mainly at low levels but in a few patients at higher levels, in epidermal keratinocytes in parapsoriasis, mycosis fungoides and Sézary syndrome. Induction of keratinocyte IL-15 expression appears to be a feature of CTCL. The factors stimulating such an expression remain unknown.
    British Journal of Dermatology 06/2001; 144(5):1016-23. · 3.76 Impact Factor
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    ABSTRACT: Leukemia inhibitory factor (LIF) signals via the heterodimeric receptor complex comprising the LIF receptor alpha subunit (LIFRalpha) and the common signal transducing subunit for interleukin-6 cytokine receptors, gp130. This study demonstrates that in different cell types, the level of LIFRalpha decreases during treatment with LIF or the closely related cytokine oncostatin M (OSM). Moreover, insulin and epidermal growth factor induce a similar LIFRalpha down-regulation. The regulated loss of LIFRalpha is specific since neither gp130 nor OSM receptor beta shows a comparable change in turnover. LIFRalpha down-regulation correlates with reduced cell responsiveness to LIF. Using protein kinase inhibitors and point mutations in LIFRalpha, we demonstrate that LIFRalpha down-regulation depends on activation of extracellular signal-regulated kinase 1/2 and phosphorylation of the cytoplasmic domain of LIFRalpha at serine 185. This modification appears to promote the endosomal/lysosomal pathway of the LIFRalpha. These results suggest that extracellular signal-regulated kinase-activating factors like OSM and growth factors have the potential to lower specifically LIF responsiveness in vivo by regulating LIFRalpha half-life.
    Journal of Biological Chemistry 10/2000; 275(37):28793-801. · 4.65 Impact Factor
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    ABSTRACT: Radio-iodinated cytokines and monoclonal antibodies directed at the IL-2R beta- and gamma-chains were used to analyze the structure of the cell-surface IL-15 and IL-2 receptors expressed by the human lymphoma cell clone YT-2C2. YT-2C2 cells are IL-2R alpha negative and express IL-2R gamma (15,000 molecules/cell) in excess of IL-2R beta (11,000 molecules/cell). Accordingly, they display a number of beta/gamma complexes of intermediate affinity for IL-2 and IL-15 which is equivalent to the number of beta-chains. Both cytokines compete for binding to this beta/gamma complex. There are about 800 high affinity IL-15 receptors, suggesting the presence of a similar number of IL-15R alpha-chains. Within the common intermediate affinity beta/gamma-complex, the anti-beta-chain A41 mAb defines an epitope which is similarly engaged in IL-2 and IL-15 binding, whereas the anti-beta-chain 284 mAb defines an epitope which does not display similar interaction with either cytokines. Thus, although IL-2 and IL-15 compete for binding to this beta/gamma-complex, they do not use similar binding areas. Cross-linking and immunoprecipitation experiments have shown that the high affinity IL-15 receptors comprises IL-2R beta/gamma, in association with IL-15R alpha and that the three chains can be efficiently cross-linked to IL-15 and co-immunoprecipitated. Contrary to the intermediate affinity situation, high affinity IL-15 binding and subunit cross-linking were not affected by excess amounts of IL-2, A41 or 284 mAb, suggesting that when engaged in the IL-15 high affinity complex, the beta- and gamma-chains adopt different conformations, at least with respect to IL-15 binding. Finally, we provide evidence for the participation of a novel 35 kDa component within the high affinity structure. This component is immunoprecipitated with anti-IL-2R gamma mAb but not with anti-IL-2R beta mAb and might correspond to a truncated form of IL-2R gamma-chain.
    European cytokine network 07/2000; 11(2):207-15. · 1.90 Impact Factor
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    ABSTRACT: This study investigates the production of interleukin (IL-)1beta by cultured human bone marrow stromal cells. RT-PCR experiments indicate that two-thirds of cultures constitutively express IL-1beta mRNA transcripts. Their cell-associated IL-1beta levels are elevated after stimulation with tumour necrosis factor (TNF-)alpha but not with cytokines such as IL-1alpha, IL-3, IL-4, IL-6, IL-7, IL-10, SCF, G-CSF, M-CSF and TGF-beta or lipid mediators such as PGE2, LTB4, LXA4, LXB4, 12-HETE, 15-HETE and PAF. Addition of IL-4, but not IL-10 or TGF-beta, reduces the TNF-alpha-induced cell-associated IL-1beta. IL-1beta is never detected in bone marrow stromal cell supernatants whatever the stimulant added. In conclusion the pro-inflammatory molecule TNF-alpha stimulates bone marrow stromal cell-associated IL-1beta levels while the anti-inflammatory cytokine IL-4 reduces the TNF-alpha-induced effect. These results strengthen the key regulatory role of IL-4 on the production of haematopoietic cytokines by human bone marrow stromal cells.
    Cytokine 06/2000; 12(5):499-502. · 2.52 Impact Factor
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    ABSTRACT: We report the existence of eight different interleukin-15 receptor alpha-chain (IL-15Ralpha) transcripts resulting from exon-splicing mechanisms within the IL-15Ralpha gene. Two main classes of transcripts can be distinguished that do or do not (Delta2 isoforms) contain the exon 2-coding sequence. Both classes were expressed in numerous cell lines and tissues (including peripheral blood lymphocytes) at comparable levels and could be transcribed in COS-7 cells, and the proteins were expressed at the cell surface. Both receptor forms displayed numerous glycosylation states, reflecting differential usage of a single N-glycosylation site as well as extensive O-glycosylations. Whereas IL-15Ralpha bound IL-15 with high affinity, Delta2IL-15Ralpha was unable to bind IL-15, thus revealing the indispensable role of the exon 2-encoded domain in cytokine binding. A large proportion of IL-15Ralpha was expressed at the nuclear membrane with some intranuclear localization, supporting a potential direct action of the IL-15.IL-15Ralpha complex at the nuclear level. In sharp contrast, Delta2IL-15Ralpha was found only in the non-nuclear membrane compartments, indicating that the exon 2-encoded domain (which is shown to contain a potential nuclear localization signal) plays an important role in receptor post-translational routing. Together, our data indicate that exon 2 splicing of human IL-15Ralpha is a natural process that might play regulatory roles at different levels.
    Journal of Biological Chemistry 10/1999; 274(38):26978-84. · 4.65 Impact Factor
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    ABSTRACT: Bone marrow stromal cells regulate marrow haematopoiesis by secreting interleukins (IL) such as IL-8. Lipid mediators modulate IL-8 synthesis in numerous cell types. We have investigated the effects of 5 lipid mediators (PAF, PGE(2), LTB(4), 12-HETE and 15-HETE) on the spontaneous and cytokine-induced IL-8 synthesis by human bone marrow stromal cells. By using reverse-transcriptase polymerase chain reaction (RT-PCR) we demonstrate that these cells constitutively express IL-8 transcripts. By using a specific ELISA, we found that the production of IL-8 by marrow stromal cells is enhanced after stimulation with 12-HETE (1 microM) both in serum-free and serum-containing culture medium. LTB(4)(1 microM) enhances IL-8 production only in serum-supplemented medium. PAF, PGE(2)and 15-HETE (1 microM to 0.1 nM) have no effect on the spontaneous and serum-induced production of IL-8 by human bone marrow stromal cells. PGE(2)(1 microM or 10 nM) reduces marrow stromal cell IL-8 synthesis in response to IL-1alpha or TNF-alpha. In contrast, PAF, 12-HETE, 15-HETE and LTB(4)have no effect. In conclusion, various lipid mediators modulate the spontaneous, serum- or cytokine-induced IL-8 synthesis by bone marrow stromal cells, highlighting, for the first time, their potential role in the regulation of IL-8 production within the human bone marrow.
    Cytokine 09/1999; 11(8):606-10. · 2.52 Impact Factor
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    ABSTRACT: Leukemia inhibitory factor (LIF) is a multifunctional cytokine belonging to the interleukin-6 subfamily of helical cytokines, all of which use the glycoprotein (gp) 130 subunit for signal transduction. The specific receptor for LIF, gp190, binds this cytokine with low affinity and is also required for signal transduction. We have recently reported that glycosylated LIF produced by transfected Chinese hamster ovary cells also binds to a lectin-like receptor, mannose 6-phosphate/insulin-like growth factor II receptor (Man-6-P/IGFII-R) (Blanchard, F., Raher, S., Duplomb, L., Vusio, P., Pitard, V., Taupin, J. L., Moreau, J. F., Hoflack, B., Minvielle, S., Jacques, Y., and Godard, A. (1998) J. Biol. Chem. 273, 20886-20893). The present study shows that (i) mannose 6-phosphate-containing LIF is naturally produced by a number of normal and tumor cell lines; (ii) other cytokines in the interleukin-6 family do not bind to Man-6-P/IGFII-R; and (iii) another unrelated cytokine, macrophage-colony-stimulating factor, is also able to bind to Man-6-P/IGFII-R in a mannose 6-phosphate-sensitive manner. No functional effects or signal transductions mediated by this lectin-like receptor were observed in various biological assays after LIF binding, and mannose 6-phosphate-containing LIF was as active as non-glycosylated LIF. However, mannose 6-phosphate-sensitive LIF binding resulted in rapid internalization and degradation of the cytokine on numerous cell lines, which suggests that Man-6-P/IGFII-R plays an important role in regulating the amounts of LIF available in vivo.
    Journal of Biological Chemistry 09/1999; 274(35):24685-93. · 4.65 Impact Factor
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    ABSTRACT: The gp190 transmembrane protein, the low affinity receptor for the leukemia inhibitory factor (LIF), belongs to the hematopoietin family of receptors characterized by the cytokine binding domain (CBD). gp190 is one of the very few members of this family to contain two such domains. The membrane-proximal CBD (herein called D2) is separated from the membrane-distal one (called D1) by an immunoglobulin-like (Ig) domain and is followed by three fibronectin type III repeats. We used truncated gp190 mutants and a blocking anti-gp190 monoclonal antibody to study the role of these repeats in low affinity receptor function. Our results showed that the D1Ig region was involved in LIF binding, while D2 appeared to be crucial for the proper folding of D1, suggesting functionally important interactions between the two CBDs in the wild-type protein. In addition, a point mutation in the carboxyl terminus of the Ig region strongly impaired ligand binding. These findings suggest that at least two distinct sites, both located within the D1Ig region, are involved in LIF binding to gp190, and more generally, that ligand binding sites on these receptors may well be located outside the canonical CBDs.
    Journal of Biological Chemistry 06/1999; 274(20):14482-9. · 4.65 Impact Factor

Publication Stats

1k Citations
270.93 Total Impact Points

Institutions

  • 2008
    • Cancer Research Center of Lyon
      Lyons, Rhône-Alpes, France
  • 1995–2000
    • Unité Inserm U1077
      Caen, Lower Normandy, France
  • 1999
    • Centre Hospitalier Universitaire de Nantes
      Naoned, Pays de la Loire, France
  • 1987–1993
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France