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J. Hoffmann, C. Villmann, M. Werner, and M. Hollmann (2006).
Investigation via ion pore transplantation of the putative relationship between glutamate receptors and K⁺ channels.
Molecular and Cellular Neuroscience 33(4): 358-370.
doi: 10.1016/j.mcn.2006.08.004

The pore domains of ionotropic glutamate receptors (iGluRs) and potassium channels (K⁺) channels) show several structural similarities. To test for functional compatibility, we transferred pore regions from prokaryotic, invertebrate, and vertebrate K⁺ channels into pharmacologically representative iGluRs and vice versa. Although the chimeric proteins were expressed on the cell surface, only one of 45 pore chimeras showed ion channel function: The kainate receptor subunit GluR6, carrying the pore loop plus adjacent transmembrane domains of the prokaryotic, glutamate-gated, K⁺-selective GluR0, adopted several electrophysiological properties of the donor pore upon pore transplantation. This suggests that, despite structural similarities between iGluR and K⁺ channel pores, there is a lack of functional compatibility so that K⁺ channel pores cannot be gated by the iGluR gating machinery, and vice versa. However, K⁺-selective pores can be gated in an iGluR sequence environment, given a similar signal transduction mechanism as appears to be present in GluR0.