Tyrosine kinase potentiates NMDA receptor currents by reducing tonic zinc inhibition.
Activation of the tyrosine kinase Src potentiates NMDA-receptor currents, which is thought to be necessary for induction of hippocampal long-term potentiation. Although the carboxy(C)-terminal domain of the NR2A subunit contains potential tyrosine phosphorylation sites, the mechanisms by which Src modulates synaptic plasticity and NMDA receptor currents is not fully understood. Here we present evidence from NR1 mutants and splice variants that Src potentiates NMDA-receptor currents by reducing the tonic inhibition of receptors composed of NR1 and NR2A subunits by extracellular zinc. Using site-directed mutagenesis, we have identified three C-terminal tyrosine residues of NR2A that are required for Src's modulation of the zinc sensitivity of NMDA receptors. Our data link two modulatory sites of NMDA receptors that were previously thought to be independent.
Zheng
F
F
Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. fzheng@emory.edu
Gingrich
M B
MB
Traynelis
S F
SF
Conn
P J
PJ
D002460:Cell Line; D002614:Chelating Agents / Q000494:pharmacology; D004351:Drug Resistance; D004492:Edetic Acid / Q000494:pharmacology; D004553:Electric Conductivity; D006801:Humans; D010446:Peptide Fragments / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D014443:Tyrosine / Q000737:chemistry / Q000502:physiology; D015032:Zinc / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000494:pharmacology; D019061:src-Family Kinases / Q000494:pharmacology
D002614:Chelating Agents; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; D014443:Tyrosine; D004492:Edetic Acid; D011505:Protein-Tyrosine Kinases; D019061:src-Family Kinases; D015032:Zinc