Platelet-derived-growth-factor stimulation of the p42/p44 mitogen-activated protein kinase pathway in airway smooth muscle: role of pertussis-toxin-sensitive G-proteins, c-Src tyrosine kinases and phosphoinositide 3-kinase

A M Conway, S Rakhit, S Pyne, N J Pyne

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Abstract

The mechanism used by the platelet-derived growth factor receptor (PDGFR) to activate the mitogen-activated- protein-kinase (p42/p44 MAPK) pathway was investigated in cultured airway smooth muscle (ASM) cells. We have found that pertussis toxin (PTX, which was used to inactivate the heterotrimeric G-protein Gi) induced an approx. 40-50% decrease in the activation of c-Src and p42/p44 MAPK by PDGF. An essential role for c-Src was confirmed using the c-Src inhibitor, PP1, which abolished p42/p44 MAPK activation (PP1 and PTX were without effect on PDGFR tyrosine phosphorylation). Furthermore, the PTX-dependent decrease in c-Src and p42/p44 MAPK activation appeared correlated. These findings suggest that the PDGFR can utilize the PTX-sensitive G-protein, Gi, to regulate c-Src and subsequent p42/p44 MAPK activation. Phosphoinositide 3-kinase (PI3K) has been shown by others to be involved in p42/p44 MAPK activation. This is confirmed here by experiments which showed that PI3K inhibitors (wortmannin and LY294002) reduced the activation of p42/p44 MAPK by PDGF. PI3K activity was increased in Grb-2 immunoprecipitates from PDGF-stimulated cells and was decreased by pretreating these cells with PTX. These findings show that Gi might also promote Grb-2-PI3K complex formation and that Grb-2 may be a site at which PI3K is integrated into the p42/p44 MAPK cascade. In conclusion, our results demonstrate that Gi enables the PDGFR to signal more efficiently to p42/p44 MAPK, and this appears to be achieved through the regulation of c-Src and Grb-2/PI3K, which are intermediates in the p42/p44 MAPK cascade.
LanguageEnglish
Pages171-177
Number of pages7
JournalBiochemical journal
Volume337
Issue number2
DOIs
Publication statusPublished - 15 Jan 1999

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1-Phosphatidylinositol 4-Kinase
Mitogen-Activated Protein Kinase 3
Mitogen-Activated Protein Kinase 1
Platelet-Derived Growth Factor
Pertussis Toxin
Phosphatidylinositols
Mitogen-Activated Protein Kinases
GTP-Binding Proteins
Smooth Muscle
Muscle
Phosphotransferases
Platelet-Derived Growth Factor Receptors
Chemical activation
CSK tyrosine-protein kinase
Heterotrimeric GTP-Binding Proteins
Phosphorylation
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Smooth Muscle Myocytes
Tyrosine
Cells

Keywords

  • adenosine diphosphate ribose
  • animals
  • calcium-calmodulin-dependent protein kinases
  • cells, cultured
  • enzyme activation
  • GTP-binding protein alpha subunits, Gi-Go
  • guinea pigs
  • mitogen-activated protein kinase 1
  • mitogen-activated protein kinase 3
  • mitogen-activated protein kinases
  • models, biological
  • muscle, smooth
  • pertussis toxin
  • phosphatidylinositol 3-kinases
  • phosphorylation
  • platelet-derived growth factor
  • receptors, platelet-derived growth factor
  • respiratory system
  • signal transduction
  • virulence factors, bordetella
  • src-family kinases

Cite this

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title = "Platelet-derived-growth-factor stimulation of the p42/p44 mitogen-activated protein kinase pathway in airway smooth muscle: role of pertussis-toxin-sensitive G-proteins, c-Src tyrosine kinases and phosphoinositide 3-kinase",
abstract = "The mechanism used by the platelet-derived growth factor receptor (PDGFR) to activate the mitogen-activated- protein-kinase (p42/p44 MAPK) pathway was investigated in cultured airway smooth muscle (ASM) cells. We have found that pertussis toxin (PTX, which was used to inactivate the heterotrimeric G-protein Gi) induced an approx. 40-50{\%} decrease in the activation of c-Src and p42/p44 MAPK by PDGF. An essential role for c-Src was confirmed using the c-Src inhibitor, PP1, which abolished p42/p44 MAPK activation (PP1 and PTX were without effect on PDGFR tyrosine phosphorylation). Furthermore, the PTX-dependent decrease in c-Src and p42/p44 MAPK activation appeared correlated. These findings suggest that the PDGFR can utilize the PTX-sensitive G-protein, Gi, to regulate c-Src and subsequent p42/p44 MAPK activation. Phosphoinositide 3-kinase (PI3K) has been shown by others to be involved in p42/p44 MAPK activation. This is confirmed here by experiments which showed that PI3K inhibitors (wortmannin and LY294002) reduced the activation of p42/p44 MAPK by PDGF. PI3K activity was increased in Grb-2 immunoprecipitates from PDGF-stimulated cells and was decreased by pretreating these cells with PTX. These findings show that Gi might also promote Grb-2-PI3K complex formation and that Grb-2 may be a site at which PI3K is integrated into the p42/p44 MAPK cascade. In conclusion, our results demonstrate that Gi enables the PDGFR to signal more efficiently to p42/p44 MAPK, and this appears to be achieved through the regulation of c-Src and Grb-2/PI3K, which are intermediates in the p42/p44 MAPK cascade.",
keywords = "adenosine diphosphate ribose, animals, calcium-calmodulin-dependent protein kinases, cells, cultured, enzyme activation, GTP-binding protein alpha subunits, Gi-Go, guinea pigs, mitogen-activated protein kinase 1, mitogen-activated protein kinase 3, mitogen-activated protein kinases, models, biological, muscle, smooth, pertussis toxin, phosphatidylinositol 3-kinases, phosphorylation, platelet-derived growth factor, receptors, platelet-derived growth factor, respiratory system, signal transduction, virulence factors, bordetella, src-family kinases",
author = "Conway, {A M} and S Rakhit and S Pyne and Pyne, {N J}",
year = "1999",
month = "1",
day = "15",
doi = "10.1042/0264-6021:3370171",
language = "English",
volume = "337",
pages = "171--177",
journal = "Biochemical Journal",
issn = "0264-6021",
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TY - JOUR

T1 - Platelet-derived-growth-factor stimulation of the p42/p44 mitogen-activated protein kinase pathway in airway smooth muscle

T2 - Biochemical Journal

AU - Conway, A M

AU - Rakhit, S

AU - Pyne, S

AU - Pyne, N J

PY - 1999/1/15

Y1 - 1999/1/15

N2 - The mechanism used by the platelet-derived growth factor receptor (PDGFR) to activate the mitogen-activated- protein-kinase (p42/p44 MAPK) pathway was investigated in cultured airway smooth muscle (ASM) cells. We have found that pertussis toxin (PTX, which was used to inactivate the heterotrimeric G-protein Gi) induced an approx. 40-50% decrease in the activation of c-Src and p42/p44 MAPK by PDGF. An essential role for c-Src was confirmed using the c-Src inhibitor, PP1, which abolished p42/p44 MAPK activation (PP1 and PTX were without effect on PDGFR tyrosine phosphorylation). Furthermore, the PTX-dependent decrease in c-Src and p42/p44 MAPK activation appeared correlated. These findings suggest that the PDGFR can utilize the PTX-sensitive G-protein, Gi, to regulate c-Src and subsequent p42/p44 MAPK activation. Phosphoinositide 3-kinase (PI3K) has been shown by others to be involved in p42/p44 MAPK activation. This is confirmed here by experiments which showed that PI3K inhibitors (wortmannin and LY294002) reduced the activation of p42/p44 MAPK by PDGF. PI3K activity was increased in Grb-2 immunoprecipitates from PDGF-stimulated cells and was decreased by pretreating these cells with PTX. These findings show that Gi might also promote Grb-2-PI3K complex formation and that Grb-2 may be a site at which PI3K is integrated into the p42/p44 MAPK cascade. In conclusion, our results demonstrate that Gi enables the PDGFR to signal more efficiently to p42/p44 MAPK, and this appears to be achieved through the regulation of c-Src and Grb-2/PI3K, which are intermediates in the p42/p44 MAPK cascade.

AB - The mechanism used by the platelet-derived growth factor receptor (PDGFR) to activate the mitogen-activated- protein-kinase (p42/p44 MAPK) pathway was investigated in cultured airway smooth muscle (ASM) cells. We have found that pertussis toxin (PTX, which was used to inactivate the heterotrimeric G-protein Gi) induced an approx. 40-50% decrease in the activation of c-Src and p42/p44 MAPK by PDGF. An essential role for c-Src was confirmed using the c-Src inhibitor, PP1, which abolished p42/p44 MAPK activation (PP1 and PTX were without effect on PDGFR tyrosine phosphorylation). Furthermore, the PTX-dependent decrease in c-Src and p42/p44 MAPK activation appeared correlated. These findings suggest that the PDGFR can utilize the PTX-sensitive G-protein, Gi, to regulate c-Src and subsequent p42/p44 MAPK activation. Phosphoinositide 3-kinase (PI3K) has been shown by others to be involved in p42/p44 MAPK activation. This is confirmed here by experiments which showed that PI3K inhibitors (wortmannin and LY294002) reduced the activation of p42/p44 MAPK by PDGF. PI3K activity was increased in Grb-2 immunoprecipitates from PDGF-stimulated cells and was decreased by pretreating these cells with PTX. These findings show that Gi might also promote Grb-2-PI3K complex formation and that Grb-2 may be a site at which PI3K is integrated into the p42/p44 MAPK cascade. In conclusion, our results demonstrate that Gi enables the PDGFR to signal more efficiently to p42/p44 MAPK, and this appears to be achieved through the regulation of c-Src and Grb-2/PI3K, which are intermediates in the p42/p44 MAPK cascade.

KW - adenosine diphosphate ribose

KW - animals

KW - calcium-calmodulin-dependent protein kinases

KW - cells, cultured

KW - enzyme activation

KW - GTP-binding protein alpha subunits, Gi-Go

KW - guinea pigs

KW - mitogen-activated protein kinase 1

KW - mitogen-activated protein kinase 3

KW - mitogen-activated protein kinases

KW - models, biological

KW - muscle, smooth

KW - pertussis toxin

KW - phosphatidylinositol 3-kinases

KW - phosphorylation

KW - platelet-derived growth factor

KW - receptors, platelet-derived growth factor

KW - respiratory system

KW - signal transduction

KW - virulence factors, bordetella

KW - src-family kinases

U2 - 10.1042/0264-6021:3370171

DO - 10.1042/0264-6021:3370171

M3 - Article

VL - 337

SP - 171

EP - 177

JO - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

IS - 2

ER -