Translational responses of NR2B overexpression in the cerebral cortex of transgenic mice: a liquid chromatography-based proteomic approach.

The N-methyl-D-aspartate (NMDA) receptor 2B subunit (NR2B) is important for long-term potentiation (LTP) and synaptic plasticity. The NR2B transgenic mice exhibited larger LTP in the hippocampal CA1 region and enhanced behavioral performance in several learning and memory tasks. In this study, we applied two-dimensional liquid chromatography-based proteomic approach to examine the expression levels of cerebral cortical proteins from 6-month NR2B transgenic (Tg) and their wild-type (WT) mice that were maintained on the same genetic background. Proteins were separated according to the pI in the first dimension using a chromatofocusing column and the hydrophobicity in the second dimension using a nonporous reversed-phase silica column. The DeltaVue software was applied to examine the differential expression of protein samples. Twenty six differentially expressed proteins were identified by matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF/TOF) mass spectrometry, including glutamine synthetase (GS), guanine nucleotide-releasing factor 1, carbonic anhydrase, clathrin light chain B (Lcb), enolase 1, ATP synthase, cytochrome c, THO complex 4, and M-phase phosphoprotein 1. The findings were further corroborated in an independent group of NR2B Tg and WT mice by Western blot analysis of two selected proteins. The results revealed a unique profile of cortical proteins in the NR2B transgenic mice. A close association of functional activation of NR2B with the excitatory neurotransmission and neuroplasticity has been discussed.