抄録
The rat pheochromocytoma (PC12) cells express the NMDAR1 subunit (NR1) mRNA endogenously, but only a small amount of NR1 protein. Furthermore, expression of functional NMDA receptors (NMDARs) is negligible. We reported previously that the adenoviral-mediated delivery of NMDAR2 (NR2) cDNAs not only induced the expression of functional NMDARs, but also increased the amount of NR1 protein in PC12 cells. Interestingly, the delivery of NR2C was much less prominent than that of NR2B for these effects. The C-terminal cytoplasmic domain of NR2 is known to interact with the scaffolding proteins in the plasma membrane and to play a critical role in the trafficking of NMDARs. To study the role of the C-terminal domain of NR2 for expression of NMDARs, we constructed a chimeric NR2, in which 135 amino acid residues of the C-terminus of NR2C was replaced with 273 residues of the C-terminus of NR2B. The delivery of this chimera cDNA (NR2C1115B) increased NMDAR-mediated currents to 5.8-fold of that of the wild NR2C. It also increased the amount of NR1 protein to 2.8-fold. However, these effects of delivery of the chimera cDNA were still much smaller than those of the wild NR2B cDNA in terms of expression of both functional NMDARs and NR1 protein, indicating that other unknown factors are also involved in the regulation of NMDAR expression. [Jpn J Physiol 54 Suppl:S140 (2004)]
