Study of Opioid Receptor Phosphorylation Using Cell-Labeling Method with 32P-Orthrophosphate

Phosphorylation is a posttranslational modification used to regulate the functions of a variety of proteins, including neurotransmitter receptors. Protein phosphorylation is catalyzed by protein kinases transferring a phosphate molecule from ATP to a protein substrate. The addition of the negatively charged phosphate group alters the structure of the protein and regulates its functional properties. Protein phosphorylation is a highly regulated reversible process and thus the level of receptor phosphorylation in neurons is constantly modified by neurotransmitters and other cellular signals released by surrounding neurons.