Analysis of Protein Dephosphorylation in Intact Cells and Extracts

Protein phosphorylation/dephosphorylation systems have evolved as a primary means through which cellular processes are regulated posttranslationally. Indeed, most transmembrane signals exert their biological effects, at least in part, by altering the balance of protein kinase and phosphatase activity within cells. The nervous system is particularly enriched both in protein kinases and protein phosphatases, and these mediate a spectrum of transient to long-term signaling events. Protein kinases are enzymes that transfer a phosphoryl group from ATP to serine, threonine, or tyrosine residues. Protein phosphatases reverse this action by hydrolyzing phosphoryl groups from these residues.