Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9410575 | Molecular Brain Research | 2005 | 15 Pages |
Abstract
Hippocampal N-methyl-d-aspartate receptors (NMDARs) contribute to the expression of certain types of synaptic plasticity, such as long-term potentiation (LTP). It is well documented that tyrosine kinases increase NMDAR phosphorylation and potentiate NMDAR function. However, it is unclear how these phosphorylation changes result in enhanced NMDAR activity. We previously reported that NMDAR surface expression can be increased by LTP-inducing stimulation via tyrosine kinase-dependent mechanisms in the adult hippocampus [D.R. Grosshans, D.A. Clayton, S.J. Coultrap, M.D. Browning, Nat. Neurosci., 5 (2002) 27-33]. We therefore hypothesized that tyrosine phosphorylation of the NMDAR may enhance the trafficking of the receptor to the synaptic membrane. Here, we show that the stoichiometry of NR2A and NR2B tyrosine phosphorylation is significantly higher in synaptosomal membranes than intracellular microsomal/light membranes. Interestingly, NR2B tyrosine-1472, but not NR1 serine-896 or -897, phosphorylation is significantly higher in synaptosomal membranes than intracellular microsomal/light membranes. Furthermore, treatment of hippocampal slices with either a tyrosine phosphatase inhibitor or a tyrosine kinase inhibitor alters NMDAR tyrosine phosphorylation and produces a corresponding change in the concentration of NMDARs in the synaptosomal membrane fraction. Taken together, these data support the hypothesis that tyrosine phosphorylation may enhance NMDAR activity by increasing the number of NMDARs at the synaptic membrane.
Keywords
SDSLavendustin ALP1calcium/calmodulin protein kinase IINMDARAMPARCaMKIIaCSFN-methyl-d-aspartateNMDAEPSPNMDA receptorLocalizationlong-term potentiationLTPsodium dodecyl sulfateendoplasmic reticulumSerine phosphorylationTyrosine phosphorylationSacrificeartificial cerebrospinal fluidRegional localization of receptors and transmittersTyrosine kinase inhibitorexcitatory postsynaptic potentialLava
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Authors
Susan M. Goebel, Rachel M. Alvestad, Steven J. Coultrap, Michael D. Browning,