Heparin affects signaling pathways stimulated by fibroblast growth factor-1 and -2 in type II cells

2004 ◽  
Vol 287 (1) ◽  
pp. L191-L200 ◽  
Author(s):  
Donna R. Newman ◽  
Cheng-Ming Li ◽  
Rebecca Simmons ◽  
Jody Khosla ◽  
Philip L. Sannes
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Basement Membrane ◽  
Dna Synthesis ◽  
Signaling Pathways ◽  
Fibroblast Growth Factor ◽  
Type Ii ◽  
Fibroblast Growth ◽  
End Points ◽  
Mitogen Activated Protein

Undersulfation of the basement membrane matrix of alveolar type II (AT2) cells compared with that of neighboring type I cells is believed to account for some of the known morphological and functional differences between these pneumocytes. Heparin, a model for sulfated components of basement membrane matrices, is known to inhibit fibroblast growth factor (FGF)-2-stimulated DNA synthesis as well as gene expression of FGF-2 and its receptor in AT2 cells. To determine whether these end points result from specific effects of heparin on FGF-related signaling pathways, isolated rat AT2 cells were treated with 100 ng/ml FGF-1 or FGF-2 in the presence of up to 500 μg/ml heparin. In addition, experiments were done on cells grown in the presence of 20 mM sodium chlorate (sulfation inhibitor). High-dose heparin reduced FGF-1- or FGF-2-stimulated phosphorylation of mitogen-activated protein kinase kinases (MEK1/2), p44/42 mitogen-activated protein kinases (MAPK/ERK1/2), stress-activated protein kinase/c-Jun NH2-terminal kinase, Akt/protein kinase B, and p90RSK. FGF-2-stimulated signaling was more sensitive to heparin's effects than was signaling stimulated by FGF-1. Heparin had an additive effect on the reduced [3H]thymidine incorporation in FGF-2-treated AT2 cells caused by inhibition of the MEK/ERK pathway by the MEK inhibitor PD-98059. The data suggest that heparin's known capacity to alter DNA synthesis and, possibly, other biological end points is realized via cross talk between multiple signaling pathways.

scholarly journals p42/mitogen-activated protein kinase as a converging target for different growth factor signaling pathways: use of pertussis toxin as a discrimination factor.

1991 ◽  
Vol 2 (8) ◽  
pp. 675-684 ◽  
Author(s):  
G L'Allemain ◽  
J Pouyssegur ◽  
M J Weber
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Protein Kinase ◽  
Map Kinase ◽  
Signaling Pathways ◽  
Fibroblast Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Pertussis Toxin ◽  
Fibroblast Growth ◽  
Mitogen Activated Protein

Mitogen-activated protein (MAP) kinase is a 42-kDa serine/threonine-specific protein kinase that requires phosphorylation on both tyrosine and threonine residues for activity. This enzyme is rapidly and transiently activated in quiescent cells after addition of various agonists, including insulin, epidermal growth factor, platelet-derived growth factor, and phorbol esters. We show here that addition of the growth factors thrombin or basic fibroblast growth factor to CCL39 fibroblasts rapidly induces tyrosine phosphorylation of the p42 MAP kinase protein and concomitantly stimulates MAP kinase enzymatic activity. To elucidate the signaling pathways utilized in this activation, we took advantage of the sensitivity of CCL39 cells to the toxin of bordetella pertussis, which ADP-ribosylates two Gi proteins in this cell system. We show that pretreatment of cells with the toxin inhibited thrombin stimulation of MAP kinase by greater than 75% but had no detectable effect on the stimulation induced by basic fibroblast growth factor. We also demonstrate that these two growth factors that synergize for mitogenicity are able to cooperate in activation of MAP kinase and that this synergism is partially sensitive to pertussis toxin. Finally, we describe a 44-kDa protein, the tyrosine phosphorylation of which appears to be coregulated with p42 MAP kinase. We conclude that p42 MAP kinase (and the pp44 protein) are at or are downstream from a point of convergence of two different receptor-induced signaling pathways and might well play a key role in integrating those signals.

scholarly journals Fibroblast growth factor-2 binds to small heparin-derived oligosaccharides and stimulates a sustained phosphorylation of p42/44 mitogen-activated protein kinase and proliferation of rat mammary fibroblasts

2002 ◽  
Vol 366 (1) ◽  
pp. 235-244 ◽  
Author(s):  
Maryse DELEHEDDE ◽  
Malcolm LYON ◽  
John T. GALLAGHER ◽  
Philip S. RUDLAND ◽  
David G. FERNIG
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Dna Synthesis ◽  
Fibroblast Growth Factor ◽  
Chain Length ◽  
Heparan Sulphate ◽  
Optical Biosensor ◽  
Mitogen Activated Protein Kinase ◽  
Fibroblast Growth ◽  
Mitogen Activated Protein

We examine the relationship between the chain length of heparin-derived oligosaccharides, fibroblast growth factor (FGF)-2 binding kinetics and the ability of the oligosaccharides to allow FGF-2-induced proliferation of chlorate-treated rat mammary fibroblasts. First, using an optical biosensor, we show that FGF-2 did not bind disaccharides, but definitively bound to tetrasaccharides. As the chain length increased from tetrasaccharide to octasaccharide, there was a substantial increase in kass (564000M−1·s−1 to 2000000M−1·s−1, respectively) and affinity (Kd 77nM to 11nM, respectively) for FGF-2. From decasaccharides and longer, the kass and affinity for FGF-2 was reduced substantially (tetradecasaccharide kass 470000M−1·s−1, Kd 30nM). In chlorate-treated, and hence sulphated, glycosaminoglycan-deficient cells, FGF-2 alone or in the presence of disaccharides did not stimulate DNA synthesis and it only elicited an early transient dual phosphorylation of p42/44 mitogen-activated protein kinase (MAPK). In the same cells FGF-2 in the presence of tetrasaccharides and longer oligosaccharides was able to restore DNA synthesis and enable the sustained dual phosphorylation of p42/44MAPK. However, the oligosaccharides from tetrasaccharides to octasaccharides were less potent in proliferation assays than deca- and longer oligosaccharides. Therefore, there was no correlation between the binding parameters and the potency of the oligosaccharides in DNA synthesis assays. These results demonstrate that tetrasaccharides are able to bind FGF-2 and enable FGF-2 to stimulate cell proliferation, which sets important boundary conditions for models of the FGF-2—heparan sulphate—FGF receptor complex.

Functional components of basic fibroblast growth factor signaling that inhibit lung elastin gene expression

2001 ◽  
Vol 281 (4) ◽  
pp. L766-L775 ◽  
Author(s):  
Isabel Carreras ◽  
Celeste B. Rich ◽  
Julie A. Jaworski ◽  
Sandra J. Dicamillo ◽  
Mikhail P. Panchenko ◽  
...  
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Fibroblast Growth Factor ◽  
Mitogen Activated Protein Kinase ◽  
Activator Protein 1 ◽  
Fibroblast Growth ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Elastin Gene

Previously, we have demonstrated that basic fibroblast growth factor (bFGF) decreases elastin gene transcription in confluent rat lung fibroblasts via the binding of a Fra-1-c-Jun heterodimer to an activator protein-1-cAMP response element in the distal region of the elastin promoter. In the present study, we show that bFGF activates the mitogen-activated protein kinase extracellular signal-regulated kinase 1/2, resulting in the translocation of phosphorylated extracellular signal-regulated kinase 1/2 into the nucleus followed by increased binding of Elk-1 to the serum response element of the c-Fos promoter, transient induction of c-Fos mRNA, and sustained induction of Fra-1 mRNA. The addition of PD-98059, an inhibitor of mitogen-activated protein kinase kinase, abrogates the bFGF-dependent repression of elastin mRNA expression. Comparative analyses of confluent and subconfluent fibroblast cultures reveal significant differences in elastin mRNA levels and activator protein-1 protein factors involved in the regulation of elastin transcription. These findings suggest that bFGF modulates specific cellular events that are dependent on the state of the cell and provide a rationale for the differential responses that can be expected in development and injury or repair situations.

scholarly journals Fibroblast Growth Factor Homologous Factors and the Islet Brain-2 Scaffold Protein Regulate Activation of a Stress-activated Protein Kinase

2002 ◽  
Vol 277 (51) ◽  
pp. 49111-49119 ◽  
Author(s):  
Jon Schoorlemmer ◽  
Mitchell Goldfarb
Keyword(s):  
Growth Factor ◽  
Protein Kinase ◽  
Fibroblast Growth Factor ◽  
Scaffold Protein ◽  
Adult Brain ◽  
Mitogen Activated Protein Kinase ◽  
Fibroblast Growth ◽  
Mitogen Activated Protein ◽  
Mixed Lineage Kinase 3

Fibroblast growth factor homologous factors (FHFs) form native intracellular complexes with the mitogen-activated protein kinase (MAPK) scaffold protein islet-brain 2 (IB2) in adult brain. FHF binding to IB2 facilitates recruitment of the MAPK p38δ (SAPK4), while failing to stimulate binding of JNK, the preferred kinase of the related scaffold IB1 (JIP-1). We now report further biochemical evidence supporting FHFs as regulators of IB2 scaffold activity. Mixed lineage kinase 3 (MLK3) and IB2 synergistically activate p38δ but not the MAPKs JNK-1 and p38α. Binding of p38δ to IB2 is mediated by the carboxyl-terminal half of the scaffold (IB2Δ1–436). FHF2 also binds weakly to IB2Δ1–436and can thereby increase p38δ interaction with IB2Δ1–436. FHF-induced recruitment of p38δ to IB2 is accompanied by increased levels of activated p38δ, and synergistic activation of p38δ by MLK3 and IB2 is further enhanced by FHF2. Consistent with a role for FHFs as signaling molecules, FHF2 isolated from rat brain is serine/threonine-phosphorylated, and FHF can serve as a substrate for p38δin vitro. These results support the existence of a signaling module in which IB2 scaffolds a MLK3/MKK/p38δ kinase cascade. FHFs aid in recruitment of p38 to IB2 and may serve as kinase substrates.

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