Tethering of the platelet-derived growth factor beta receptor to g-protein-coupled receptors: a novel platform for integrative signaling by these receptor classes in mammalian cells

Forbes Alderton, Soma Rakhit, Kok Choi Kong, Timothy Palmer, Balwinder Sambi, Nigel Pyne, Susan Pyne

Research output: Contribution to journalArticle

137 Citations (Scopus)

Abstract

Here we provide evidence to show that the platelet-derived growth factor β receptor is tethered to endogenous G-protein-coupled receptor(s) in human embryonic kidney 293 cells. The tethered receptor complex provides a platform on which receptor tyrosine kinase and G-protein-coupled receptor signals can be integrated to produce more efficient stimulation of the p42/p44 mitogen-activated protein kinase pathway. This was based on several lines of evidence. First, we have shown that pertussis toxin (which uncouples G-protein-coupled receptors from inhibitory G-proteins) reduced the platelet-derived growth factor stimulation of p42/p44 mitogen-activated protein kinase. Second, transfection of cells with inhibitory G-protein α subunit increased the activation of p42/p44 mitogen-activated protein kinase by platelet-derived growth factor. Third, platelet-derived growth factor stimulated the tyrosine phosphorylation of the inhibitory G-protein α subunit, which was blocked by the platelet-derived growth factor kinase inhibitor, tyrphostin AG 1296. We have also shown that the platelet-derived growth factor β receptor forms a tethered complex with Myc-tagged endothelial differentiation gene 1 (a G-protein-coupled receptor whose agonist is sphingosine 1-phosphate) in cells co-transfected with these receptors. This facilitates platelet-derived growth factor-stimulated tyrosine phosphorylation of the inhibitory G-protein α subunit and increases p42/p44 mitogen-activated protein kinase activation. In addition, we found that G-protein-coupled receptor kinase 2 and β-arrestin I can associate with the platelet-derived growth factor β receptor. These proteins play an important role in regulating endocytosis of G-protein-coupled receptor signal complexes, which is required for activation of p42/p44 mitogen-activated protein kinase. Thus, platelet-derived growth factor β receptor signaling may be initiated by G-protein-coupled receptor kinase 2/β-arrestin I that has been recruited to the platelet-derived growth factor β receptor by its tethering to a G-protein-coupled receptor(s). These results provide a model that may account for the co-mitogenic effect of certain G-protein-coupled receptor agonists with platelet-derived growth factor on DNA synthesis.
Original languageEnglish
Pages (from-to)28578-28585
Number of pages8
JournalJournal of Biological Chemistry
Volume276
DOIs
Publication statusPublished - 2001

Keywords

  • beta receptor
  • kidney cells
  • endocytosis
  • platelet-derived growth factor

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