Related Experiment Videos
Association of phorbol ester receptor down modulation with a cryptic receptor state.
Cancer Research
|December 1, 1983
Summary
Down-modulation of phorbol ester receptors in pituitary cells reveals a cryptic state upon lysis. This suggests receptor affinity and ligand specificity depend on the cellular environment, impacting cellular signaling.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Phorbol esters and thyrotropin-releasing hormone induce down-modulation of phorbol ester receptors in GH4C1 rat pituitary cells.
- Down-modulation decreases receptor number without altering binding affinity in intact cells.
Purpose of the Study:
- To investigate the mechanism of phorbol ester receptor down-modulation.
- To characterize the properties of phorbol ester receptors in intact cells versus cell lysates.
Main Methods:
- Radioligand binding assays using phorbol dibutyrate and mezerein.
- Comparison of receptor concentrations and affinities in intact cells and cell lysates.
Main Results:
- Cell lysis revealed a cryptic state of down-modulated receptors, increasing their apparent concentration in lysates compared to intact cells.
- Receptor affinity for phorbol dibutyrate decreased in cell lysates compared to intact cells.
- Receptor binding heterogeneity for mezerein was observed in cell lysates but not in intact cells.
Conclusions:
- Homologous and heterologous phorbol ester receptor down-modulation involves a cryptic state unmasked by cell lysis.
- The cellular environment influences the affinity and ligand specificity of the phorbol ester receptor.