Cloning, expression and modulation of a mouse NMDA receptor subunit

The primary structure and presence of two forms of the mouse N-methyl-d-aspartate (NMDA) receptor channel subunit ζl have been disclosed by cloning and sequencing the cDNAs. The ζl subunit shows -20% amino acid sequence identities with the rodent α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)- or kainate-selective GluR subunits and has structural features common to neurotransmitter-gated ion channels. Functional homomeric ζl channels expressed in Xenopus oocytes by injection of the subunit specific mRNA exhibit current responses characteristics for the NMDA receptor channel such as activation by glycine, Ca²⁺ permeability, blocking by Mg²⁺ and activation by polyamine. It has been found that the ζl channel activity is positively modulated by treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA).