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Receptor tyrosine kinase transactivation: fine-tuning synaptic transmission
1Cell Biology Research Group, Robarts Research Institute, Department of Physiology and Pharmacology, University of Western Ontario, 100 Perth Drive, PO Box 5015, London, Ontario, Canada N6A 5K8. ferguson@robarts.ca
Abstract:
G-protein-coupled receptors generate signals that promote gene transcription through the 'transactivation' of receptor tyrosine kinases (RTKs) and activation of the mitogen-activated protein kinase (MAPK) cascade -- a process that involves RTK autophosphorylation and endocytosis. Pioneering work now suggests that D4-dopamine-receptor-mediated transactivation of the platelet-derived growth factor beta receptor has immediate effects on synaptic neurotransmission via Ca(2+)-dependent inactivation of NMDA receptors. The demonstration of a physiological role for RTK transactivation in the CNS provides novel opportunities for understanding how aberrant dopamine signalling might contribute to cognitive and attention deficits associated with schizophrenia and attention-deficit hyperactivity disorder.
Insights
Dopamine D4 receptors transactivate growth factor receptors, impacting brain signaling. This finding offers new insights into dopamine
Area of Science:
- Neuroscience
- Molecular Biology
- Pharmacology
Background:
- G-protein-coupled receptors (GPCRs) signal via receptor tyrosine kinases (RTKs) and MAPK pathways.
- RTK activation involves autophosphorylation and endocytosis.
Purpose of the Study:
- To investigate dopamine D4 receptor-mediated transactivation of platelet-derived growth factor beta receptor (PDGFβR).
- To determine the impact of this transactivation on synaptic neurotransmission and NMDA receptor function.
- To explore the implications for cognitive disorders.
Main Methods:
- Investigated GPCR-RTK transactivation mechanisms.
- Utilized neurophysiological assays to measure synaptic activity.
- Examined calcium-dependent NMDA receptor inactivation.
Main Results:
- Dopamine D4 receptor stimulation transactivates PDGFβR.
- This transactivation leads to rapid modulation of synaptic neurotransmission.
- Ca(2+)-dependent inactivation of NMDA receptors was observed.
Conclusions:
- RTK transactivation plays a physiological role in the central nervous system (CNS).
- Aberrant dopamine signaling may underlie cognitive deficits in schizophrenia and ADHD.
- Provides a novel mechanism for understanding dopamine's role in brain function.