Receptor Binding Assay Protocol
Receptors located on the membranes of cells have an enormous impact on human health. Receptors have specialized functions and bind to specific ligands such as insulin and dopamine. Insulin attachment to an insulin receptor initiates a cascade of events that regulate the cell's intake of sugar; reduced receptor function can result in type 2 diabetes. Similarly, dysfunctional dopamine receptors can result in depression.
Other People Are Reading
-
Format
-
Receptor binding assays -- or ligand binding assays -- monitor the ligand-receptor interaction. The assay can be in a wide variety of formats. The receptors can be on whole cells, pieces of membrane or purified. The ligands are typically bound to a marker that can be visualized or quantified such as dyes, and fluorescent or radioactive labels.
Example
-
Clinical laboratories routinely analyze breast tumors for estrogen receptors because estrogen stimulates tumor growth; the presence of receptors impacts treatment. They grind up the tumor sample, purify the receptors and mix them with different concentrations of estrogen attached to a radioactive marker such as tritium. After 16 hours, they remove the unattached estrogen with charcoal and the remaining sample is analyzed for radioactivity in a scintillation counter; the higher the readout, the greater the number of receptors.
-
Uses
-
In addition to diagnostic use, binding assays are important tools in drug development. These assays can be modified to look at which cells have particular receptors, the affinity of new drugs for receptors or ways to block receptors. For example, scientists looked for drugs to block the estrogen receptor to prevent estrogen-fueled tumor growth; the result was tamoxifen.
-
References
Resources
- Photo Credit Duncan Smith/Photodisc/Getty Images
