Research
Transactivation of PDGFRβ by dopamine D4 receptor does not require PDGFRβ dimerization
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* Corresponding author: Fang Liu fang_liu@camh.net
- † Equal contributors
1 Department of Neuroscience, Centre for Addiction and Mental Health, University of Toronto, Toronto, M5T 1R8, Canada
2 Department of Pharmacology, University of Toronto, Toronto, M5T 1R8, Canada
3 Department of Psychiatry, University of Toronto, Toronto, M5T 1R8, Canada
Molecular Brain 2010, 3:22 doi:10.1186/1756-6606-3-22
Published: 26 July 2010Abstract
Growth factor-induced receptor dimerization and cross-phosphorylation are hallmarks of signal transduction via receptor tyrosine kinases (RTKs). G protein-coupled receptors (GPCRs) can activate RTKs through a process known as transactivation. The prototypical model of RTK transactivation involves ligand-mediated RTK dimerization and cross-phosphorylation. Here, we show that the platelet-derived growth factor receptor β (PDGFRβ) transactivation by the dopamine receptor D4 (DRD4) is not dependent on ligands for PDGFRβ. Furthermore, when PDGFRβ dimerization is inhibited and receptor phosphorylation is suppressed to near basal levels, the receptor maintains its ability to be transactivated and is still effective in signaling to ERK1/2. Hence, the DRD4-PDGFRβ-ERK1/2 pathway can occur independently of a PDGF-like ligand, PDGFRβ cross-phosphorylation and dimerization, which is distinct from other known forms of transactivation of RTKs by GPCRs.