1. Characterization of a metabotropic glutamate receptor type 5-green fluorescent protein chimera (mGluR5-GFP): pharmacology, surface expression, and differential effects of Homer-1a and Homer-1c.
- Author
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Coutinho V, Kavanagh I, Sugiyama H, Tones MA, and Henley JM
- Subjects
- Animals, CHO Cells drug effects, CHO Cells metabolism, Carrier Proteins biosynthesis, Cricetinae, Dimerization, Dose-Response Relationship, Drug, Excitatory Amino Acid Antagonists pharmacology, Green Fluorescent Proteins, Homer Scaffolding Proteins, Humans, Immunoblotting, Neuropeptides biosynthesis, Precipitin Tests, Pyridines pharmacology, Receptor, Metabotropic Glutamate 5, Receptors, Metabotropic Glutamate antagonists & inhibitors, Receptors, Metabotropic Glutamate biosynthesis, Recombinant Fusion Proteins antagonists & inhibitors, Recombinant Fusion Proteins biosynthesis, Signal Transduction drug effects, Signal Transduction physiology, Transfection methods, Carrier Proteins physiology, Luminescent Proteins genetics, Neuropeptides physiology, Receptors, Metabotropic Glutamate genetics, Receptors, Metabotropic Glutamate metabolism, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism
- Abstract
Metabotropic glutamate receptor 5 (mGluR5) can modulate synaptic transmission by increasing intracellular Ca2+ and it plays a role in several forms of synaptic plasticity. We have constructed a fusion of human mGluR5 and green fluorescent protein (mGluR5-GFP). Expression of mGluR5-GFP in clonal cell lines yielded a functional fluorescent receptor with pharmacological profiles similar to wild-type mGluR5. mGluR5-GFP coimmunoprecipitated with Homer-1c, indicating that addition of GFP to the C-terminal did not prevent Homer binding. Coexpression of wild-type mGluR5 or mGluR5-GFP with Homer 1c, but not Homer-1a, resulted in reduced receptor surface localization and the formation of intracellular clusters. Neither Homer-1a nor Homer-1c had any effect on mGluR1 or mGluR1-GFP distribution. mGluR5-GFP expressed alone or in combination with Homer-1a formed dimers in HEK cells. Coexpression with Homer-1c, however, prevented mGluR5-GFP dimerization. Neither Homer altered the agonist profiles of mGluR5 or mGluR5-GFP. These data indicate that the functional expression of mGluR5 is regulated by Homer-1c and demonstrate that mGluR5-GFP provides a useful tool to study the molecular pharmacology and cell biology of mGluRs in real-time., (Copyright 2001 Academic Press.)
- Published
- 2001
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