scholarly journals Identification of residues in the first and fourth helices of human granulocyte-macrophage colony-stimulating factor involved in biologic activity and in binding to the alpha- and beta-chains of its receptor

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3500-3508 ◽  
Author(s):  
TR Hercus ◽  
B Cambareri ◽  
M Dottore ◽  
J Woodcock ◽  
CJ Bagley ◽  
...  

Residues within the first and fourth helices of human granulocyte- macrophage colony-stimulating factor (hGM-CSF) were analyzed for their role in biologic activity and interaction with the alpha- and beta- chains of the hGM-CSF receptor. Within the first helix substitution of the surface residues Glu14, Asn17, Gln20, Arg23, Arg24, and Asn27 or the buried residues Ala18, Leu25, and Leu28 did not significantly impair bioactivity or receptor binding. Substitutions at the buried residues Ala22 and Leu26 had intermediate bioactivity. However, substitutions of the surface residue Glu21 or the buried residue Ile19 reduced the relative bioactivity of the analogues to as little as 0.45% and 0.3%, respectively. Substitution of the charged surface residues of the fourth helix showed that substitution at Glu104, Lys107, and Lys111 had no significant effect on bioactivity, but substitution at Glu108 and Asp112 reduced the potency of the analogues to 34% and 7%, respectively. Receptor binding studies showed that, whereas Glu21 is the critical residue for binding to the hGM-CSF-receptor beta-chain, Asp112 is likely to be involved in binding to the GM-CSF-receptor alpha- chain. These results establish the relative contribution of residues in the first and fourth helices for GM-CSF bioactivity and receptor binding, and support a model where the fourth helix of GM-CSF interacts with the alpha-chain, and the first helix with the beta-chain of the GM- CSF receptor.

Blood ◽  
1994 ◽  
Vol 83 (12) ◽  
pp. 3500-3508 ◽  
Author(s):  
TR Hercus ◽  
B Cambareri ◽  
M Dottore ◽  
J Woodcock ◽  
CJ Bagley ◽  
...  

Abstract Residues within the first and fourth helices of human granulocyte- macrophage colony-stimulating factor (hGM-CSF) were analyzed for their role in biologic activity and interaction with the alpha- and beta- chains of the hGM-CSF receptor. Within the first helix substitution of the surface residues Glu14, Asn17, Gln20, Arg23, Arg24, and Asn27 or the buried residues Ala18, Leu25, and Leu28 did not significantly impair bioactivity or receptor binding. Substitutions at the buried residues Ala22 and Leu26 had intermediate bioactivity. However, substitutions of the surface residue Glu21 or the buried residue Ile19 reduced the relative bioactivity of the analogues to as little as 0.45% and 0.3%, respectively. Substitution of the charged surface residues of the fourth helix showed that substitution at Glu104, Lys107, and Lys111 had no significant effect on bioactivity, but substitution at Glu108 and Asp112 reduced the potency of the analogues to 34% and 7%, respectively. Receptor binding studies showed that, whereas Glu21 is the critical residue for binding to the hGM-CSF-receptor beta-chain, Asp112 is likely to be involved in binding to the GM-CSF-receptor alpha- chain. These results establish the relative contribution of residues in the first and fourth helices for GM-CSF bioactivity and receptor binding, and support a model where the fourth helix of GM-CSF interacts with the alpha-chain, and the first helix with the beta-chain of the GM- CSF receptor.


1994 ◽  
Vol 14 (7) ◽  
pp. 4335-4341 ◽  
Author(s):  
F W Quelle ◽  
N Sato ◽  
B A Witthuhn ◽  
R C Inhorn ◽  
M Eder ◽  
...  

The high-affinity receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) consists of a unique alpha chain and a beta c subunit that is shared with the receptors for interleukin-3 (IL-3) and IL-5. Two regions of the beta c chain have been defined; these include a membrane-proximal region of the cytoplasmic domain that is required for mitogenesis and a membrane-distal region that is required for activation of Ras, Raf-1, mitogen-activated protein kinase, and S6 kinase. Recent studies have implicated the cytoplasmic protein tyrosine kinase JAK2 in signalling through a number of the cytokine receptors, including the IL-3 and erythropoietin receptors. In the studies described here, we demonstrate that GM-CSF stimulation of cells induces the tyrosine phosphorylation of JAK2 and activates its in vitro kinase activity. Mutational analysis of the beta c chain demonstrates that only the membrane-proximal 62 amino acids of the cytosolic domain are required for JAK2 activation. Thus, JAK2 activation is correlated with induction of mitogenesis but does not, alone, activate the Ras pathway. Carboxyl truncations of the alpha chain, which inactivate the receptor for mitogenesis, are unable to mediate GM-CSF-induced JAK2 activation. Using baculovirus-expressed proteins, we further demonstrate that JAK2 physically associates with the beta c chain but not with the alpha chain. Together, the results further support the hypothesis that the JAK family of kinase are critical to coupling cytokine binding to tyrosine phosphorylation and ultimately mitogenesis.


Blood ◽  
1993 ◽  
Vol 81 (5) ◽  
pp. 1193-1199 ◽  
Author(s):  
CC Paul ◽  
M Tolbert ◽  
S Mahrer ◽  
A Singh ◽  
MJ Grace ◽  
...  

Abstract The cytokines interleukin-3 (IL-3); IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are known to contribute to the proliferation and differentiation of eosinophil progenitors. Recently, it was determined that the cellular receptors for these three cytokines share a common beta-chain while having unique alpha-chains. Thus, there is considerable interest in how these cytokines and their receptors interact in promoting production of eosinophils. We have established a cell line (AML14) from a patient with acute myelogenous leukemia that will consistently exhibit eosinophilic differentiation in suspension in response to IL-3, IL-5, and GM-CSF. Proliferation with only modest differentiative effects was observed in response to a single cytokine. Combinations of two cytokines gave variable results, with GM-CSF + IL-3 and IL-3 + IL-5 causing more proliferation than a single cytokine but little more differentiation. The combination of GM-CSF + IL-5 caused marked enhancement of eosinophilic differentiation with only modest augmentation of proliferation. The combination of all three cytokines was most effective in stimulating both proliferation and eosinophilic differentiation (up to 70% of cells) of AML14 cells. Specific binding of GM-CSF and IL-5 to AML14 cells can be conveniently studied by flow cytometric methods, and cross-competition of these two cytokines for their respective receptors was demonstrated. IL-3 was shown to partially compete for IL-5 binding on AML14 cells. Although specific IL- 3 binding could not be demonstrated by flow cytometry, mRNA for the alpha-chains of the IL-3, IL-5, and GM-CSF receptors and the beta-chain common to all three receptors was detected in AML14 cells. The AML14 cell line may be a useful model for the study of cooperative interactions of IL-3, IL-5, GM-CSF, and their respective receptors in the promotion of eosinophil progenitor growth and differentiation.


1994 ◽  
Vol 14 (7) ◽  
pp. 4335-4341
Author(s):  
F W Quelle ◽  
N Sato ◽  
B A Witthuhn ◽  
R C Inhorn ◽  
M Eder ◽  
...  

The high-affinity receptor for granulocyte-macrophage colony-stimulating factor (GM-CSF) consists of a unique alpha chain and a beta c subunit that is shared with the receptors for interleukin-3 (IL-3) and IL-5. Two regions of the beta c chain have been defined; these include a membrane-proximal region of the cytoplasmic domain that is required for mitogenesis and a membrane-distal region that is required for activation of Ras, Raf-1, mitogen-activated protein kinase, and S6 kinase. Recent studies have implicated the cytoplasmic protein tyrosine kinase JAK2 in signalling through a number of the cytokine receptors, including the IL-3 and erythropoietin receptors. In the studies described here, we demonstrate that GM-CSF stimulation of cells induces the tyrosine phosphorylation of JAK2 and activates its in vitro kinase activity. Mutational analysis of the beta c chain demonstrates that only the membrane-proximal 62 amino acids of the cytosolic domain are required for JAK2 activation. Thus, JAK2 activation is correlated with induction of mitogenesis but does not, alone, activate the Ras pathway. Carboxyl truncations of the alpha chain, which inactivate the receptor for mitogenesis, are unable to mediate GM-CSF-induced JAK2 activation. Using baculovirus-expressed proteins, we further demonstrate that JAK2 physically associates with the beta c chain but not with the alpha chain. Together, the results further support the hypothesis that the JAK family of kinase are critical to coupling cytokine binding to tyrosine phosphorylation and ultimately mitogenesis.


Blood ◽  
1995 ◽  
Vol 86 (7) ◽  
pp. 2679-2688 ◽  
Author(s):  
A Mire-Sluis ◽  
LA Page ◽  
M Wadhwa ◽  
R Thorpe

In the present study, we have used a human erythroleukemia cell line, TF-1, that proliferates in response to granulocyte macrophage colony stimulating factor (GM-CSF), interleukin-3 (IL-3), and interleukin-5 (IL-5) to investigate the role of receptors for these cytokines in signal transduction mechanisms involved in proliferative responses. The receptors for GM-CSF, IL-3, and IL-5 each possess a cytokine specific alpha subunit, but all three share a common beta chain. Using an immunoblotting system designed to detect phosphotyrosine containing proteins and a permeabilized cell system to detect rapid changes in phosphate turnover on proteins, we show that while GM-CSF and IL-3 use tyrosine phosphorylation to mediate mitogenic signal transduction, IL-5 uses tyrosine dephosphorylation in its signaling pathway. The use of different signaling pathways by these cytokines can be confirmed in a biologic system whereby the proliferation induced in culture by GM-CSF and IL-3 is inhibited by tyrosine kinase inhibitors, but that induced by IL-5 is enhanced. Conversely, GM-CSF- and IL-3-induced proliferation is stimulated by a tyrosine phosphatase inhibitor, yet IL-5-induced proliferation is inhibited. Inhibitors of protein kinase C inhibit IL-3- and GM-CSF-, but not IL-5-induced proliferation. We suggest that, because all these cytokines share the identical beta chain of their receptors, the cytokine specific alpha chain mediates the linkage of each receptor to the individual biochemical signal transduction pathways responsible for the different biologic activities of these cytokines.


Blood ◽  
1995 ◽  
Vol 86 (7) ◽  
pp. 2679-2688 ◽  
Author(s):  
A Mire-Sluis ◽  
LA Page ◽  
M Wadhwa ◽  
R Thorpe

Abstract In the present study, we have used a human erythroleukemia cell line, TF-1, that proliferates in response to granulocyte macrophage colony stimulating factor (GM-CSF), interleukin-3 (IL-3), and interleukin-5 (IL-5) to investigate the role of receptors for these cytokines in signal transduction mechanisms involved in proliferative responses. The receptors for GM-CSF, IL-3, and IL-5 each possess a cytokine specific alpha subunit, but all three share a common beta chain. Using an immunoblotting system designed to detect phosphotyrosine containing proteins and a permeabilized cell system to detect rapid changes in phosphate turnover on proteins, we show that while GM-CSF and IL-3 use tyrosine phosphorylation to mediate mitogenic signal transduction, IL-5 uses tyrosine dephosphorylation in its signaling pathway. The use of different signaling pathways by these cytokines can be confirmed in a biologic system whereby the proliferation induced in culture by GM-CSF and IL-3 is inhibited by tyrosine kinase inhibitors, but that induced by IL-5 is enhanced. Conversely, GM-CSF- and IL-3-induced proliferation is stimulated by a tyrosine phosphatase inhibitor, yet IL-5-induced proliferation is inhibited. Inhibitors of protein kinase C inhibit IL-3- and GM-CSF-, but not IL-5-induced proliferation. We suggest that, because all these cytokines share the identical beta chain of their receptors, the cytokine specific alpha chain mediates the linkage of each receptor to the individual biochemical signal transduction pathways responsible for the different biologic activities of these cytokines.


Blood ◽  
1993 ◽  
Vol 81 (5) ◽  
pp. 1193-1199
Author(s):  
CC Paul ◽  
M Tolbert ◽  
S Mahrer ◽  
A Singh ◽  
MJ Grace ◽  
...  

The cytokines interleukin-3 (IL-3); IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are known to contribute to the proliferation and differentiation of eosinophil progenitors. Recently, it was determined that the cellular receptors for these three cytokines share a common beta-chain while having unique alpha-chains. Thus, there is considerable interest in how these cytokines and their receptors interact in promoting production of eosinophils. We have established a cell line (AML14) from a patient with acute myelogenous leukemia that will consistently exhibit eosinophilic differentiation in suspension in response to IL-3, IL-5, and GM-CSF. Proliferation with only modest differentiative effects was observed in response to a single cytokine. Combinations of two cytokines gave variable results, with GM-CSF + IL-3 and IL-3 + IL-5 causing more proliferation than a single cytokine but little more differentiation. The combination of GM-CSF + IL-5 caused marked enhancement of eosinophilic differentiation with only modest augmentation of proliferation. The combination of all three cytokines was most effective in stimulating both proliferation and eosinophilic differentiation (up to 70% of cells) of AML14 cells. Specific binding of GM-CSF and IL-5 to AML14 cells can be conveniently studied by flow cytometric methods, and cross-competition of these two cytokines for their respective receptors was demonstrated. IL-3 was shown to partially compete for IL-5 binding on AML14 cells. Although specific IL- 3 binding could not be demonstrated by flow cytometry, mRNA for the alpha-chains of the IL-3, IL-5, and GM-CSF receptors and the beta-chain common to all three receptors was detected in AML14 cells. The AML14 cell line may be a useful model for the study of cooperative interactions of IL-3, IL-5, GM-CSF, and their respective receptors in the promotion of eosinophil progenitor growth and differentiation.


1990 ◽  
Vol 1 (4) ◽  
pp. 327-335 ◽  
Author(s):  
S Chiba ◽  
K Shibuya ◽  
Y F Piao ◽  
A Tojo ◽  
N Sasaki ◽  
...  

Two proteins forming the receptor for human granulocyte-macrophage colony-stimulating factor (GM-CSF)1 were identified and characterized. One with apparent Mr of about 80,000 was defined as alpha-chain and has Kd of 0.7-2.8 nM. The other binding molecule with apparent Mr of about 135,000 was defined as beta-chain and is related to the high-affinity binding with Kd of 10-40 pM. The binding kinetic studies confirmed that the 125I-GM-CSF associated slower to and dissociated more rapidly from the alpha-chain than the beta-chain. The alpha-chain is expressed not only on hemopoietic cells but also on full-term placental tissues, choriocarcinoma cells, and other solid tumor cells. In contrast, the distribution of the beta-chain is restricted on hemopoietic cells. The alpha-chain probably corresponds to the low-affinity GM-CSF receptor whose cDNA has been cloned and sequenced.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jani Lappalainen ◽  
Nicolas Yeung ◽  
Su D. Nguyen ◽  
Matti Jauhiainen ◽  
Petri T. Kovanen ◽  
...  

AbstractIn atherosclerotic lesions, blood-derived monocytes differentiate into distinct macrophage subpopulations, and further into cholesterol-filled foam cells under a complex milieu of cytokines, which also contains macrophage-colony stimulating factor (M-CSF) and granulocyte–macrophage-colony stimulating factor (GM-CSF). Here we generated human macrophages in the presence of either M-CSF or GM-CSF to obtain M-MØ and GM-MØ, respectively. The macrophages were converted into cholesterol-loaded foam cells by incubating them with acetyl-LDL, and their atheroinflammatory gene expression profiles were then assessed. Compared with GM-MØ, the M-MØ expressed higher levels of CD36, SRA1, and ACAT1, and also exhibited a greater ability to take up acetyl-LDL, esterify cholesterol, and become converted to foam cells. M-MØ foam cells expressed higher levels of ABCA1 and ABCG1, and, correspondingly, exhibited higher rates of cholesterol efflux to apoA-I and HDL2. Cholesterol loading of M-MØ strongly suppressed the high baseline expression of CCL2, whereas in GM-MØ the low baseline expression CCL2 remained unchanged during cholesterol loading. The expression of TNFA, IL1B, and CXCL8 were reduced in LPS-activated macrophage foam cells of either subtype. In summary, cholesterol loading converged the CSF-dependent expression of key genes related to intracellular cholesterol balance and inflammation. These findings suggest that transformation of CSF-polarized macrophages into foam cells may reduce their atheroinflammatory potential in atherogenesis.


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