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Updated: Jun 1, 2026
10:24
Detection of Ligand-activated G Protein-coupled Receptor Internalization by Confocal Microscopy
Published on: April 9, 2017
Glycine receptor internalization by protein kinases activation
Miguel Ángel Velázquez-Flores1, Rocío Salceda
1División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510 México, D.F., México. mvflores@email.ifc.unam.mx
Synapse (New York, N.Y.)
|June 10, 2011
Summary
Protein kinases A (PKA) and C (PKC) activation significantly reduces glycine receptor (GlyR) binding in rat retina. Kinase activation also decreases plasma membrane GlyR expression and increases receptor phosphorylation.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Glycine receptor (GlyR) function in the central nervous system is modulated by protein kinases A (PKA) and C (PKC).
- The precise molecular mechanisms underlying this modulation remain incompletely understood.
Purpose of the Study:
- To investigate the effects of PKA and PKC activation on glycine and strychnine binding to GlyRs in the rat retina.
- To elucidate the role of these kinases in regulating GlyR expression and phosphorylation.
Main Methods:
- Radioligand binding assays using [(3)H]glycine and [(3)H]strychnine on intact rat retina.
- Kinetic analysis to determine binding sites and affinities.
- Assessment of GlyR expression in plasma membrane and microsomal fractions.
- Immunoprecipitation studies to detect receptor phosphorylation.
Main Results:
- Specific binding of [(3)H]glycine and [(3)H]strychnine to GlyRs was observed with distinct affinities and binding sites.
- Activation of PKA and PKC significantly decreased specific radioligand binding (60-85%).
- Kinase activation led to a ~50% decrease in plasma membrane GlyR expression, with a corresponding increase in the microsomal fraction upon PKA activation.
- Immunoprecipitation confirmed time-dependent phosphorylation of GlyR by activated PKA and PKC.
Conclusions:
- PKA and PKC activation negatively regulate GlyR function in the rat retina by reducing ligand binding and altering receptor localization.
- Kinase-mediated phosphorylation plays a key role in these regulatory processes.
- GlyR function in the retina is subject to cross-regulation by G protein-coupled receptors that activate PKA and PKC.
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