ABSTRACT
Phosphorylation is a fundamental and pervasive mechanism widely known to regulate the functions of proteins,94,133 and lipids.8 Phosphorylation of specific amino acid residues is a reversible process controlled enzymatically by the competing activities of protein kinases that catalyze phosphorylation and phosphoprotein phosphatases that catalyze dephosphorylation. Several years before the cloning of glutamate receptors, phosphorylation was found to increase NMDA currents, and dephosphorylation to decrease these currents in neurons from the hippocampus.76 Since then, two principal protein kinase/phosphatase families have been studied extensively related to regulation of NMDA receptors (NMDARs) in the central nervous system: those that act at serine/threonine residues and those that act at tyrosine residues.
