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Human prostaglandin EP3 receptor isoforms show different agonist-induced internalization patterns
Heather A Bilson1, Deanah L Mitchell, Barrie Ashby
1Department of Pharmacology, Temple University, School of Medicine, 3400 North Broad Street, Philadelphia, PA 19140, USA.
FEBS Letters
|August 12, 2004
Summary
Human prostaglandin EP3 receptor isoforms exhibit distinct cellular trafficking patterns. Differential internalization upon prostaglandin E2 stimulation is linked to beta-arrestin involvement and clathrin-dependent mechanisms for specific isoforms.
Area of Science:
- Cell Biology
- Molecular Pharmacology
- G Protein-Coupled Receptors
Background:
- The human prostaglandin EP3 receptor (EP3) is a G protein-coupled receptor involved in various physiological processes.
- EP3 exists as eight isoforms, primarily differing in their C-terminal tails, suggesting potential functional variations.
Purpose of the Study:
- To investigate the differential cellular trafficking and internalization mechanisms of human prostaglandin EP3 receptor isoforms.
- To determine the role of beta-arrestin and clathrin-dependent pathways in EP3 isoform trafficking.
Main Methods:
- HEK293 cells were used to express different human prostaglandin EP3 receptor isoforms.
- Prostaglandin E2 stimulation was applied to assess receptor internalization.
- Immunofluorescence microscopy and dominant-negative Eps15 were employed to study beta-arrestin translocation and clathrin-mediated endocytosis.
Main Results:
- All EP3 isoforms were detected at the cell surface, with some showing intracellular retention.
- Prostaglandin E2 stimulation induced differential internalization: EP3.I internalized significantly, while EP3.III and EP3.IV showed no internalization.
- EP3.I and EP3.f internalization involved beta-arrestin and was clathrin-dependent, whereas EP3.II internalization was beta-arrestin-independent and not blocked by mutant Eps15. EP3.V and EP3.VI showed beta-arrestin-dependent internalization to specific cellular regions.
Conclusions:
- The carboxyl-tail of human prostaglandin EP3 receptor isoforms dictates distinct intracellular trafficking and internalization pathways.
- Specific EP3 isoforms utilize beta-arrestin and clathrin-mediated endocytosis, highlighting isoform-specific signaling and regulatory mechanisms.