Glutamate Receptor-Like Ion Channels in Arabidopsis thaliana

Abstract

Ionotropic glutamate receptors (iGluRs) are glutamate-gated nonselective cation channels (NSCC) that mediate rapid conduction of impulses through the synapses in central nervous system of animals. At one time, signaling through the iGluRs was thought to be limited to the animal system but with the discovery of 20 glutamate receptor-like genes (GLRs) in Arabidopsis thaliana has paved the way for the study of glutamate receptors in an organism lacking nervous system. These 20 genes expressed in diverse tissue throughout the plant and designated as putative glutamate receptor. They were named as putative glutamate receptor on the basis of high similarity of their deduced amino acid sequences with members of the iGluR superfamily. Furthermore, these nonselective ion channels share the properties similar to those of animal iGluRs. The information based on sequence similarity predicts that A. thaliana glutamate receptors (AtGLRs) also exist as the integral membrane proteins like iGluRs. Through the application of specific antagonists or agonists, designated as inhibitors or stimulators respectively, the putative function of AtGLRs has been associated to an array of processes. Comprehensive information about glutamate receptors of A. thaliana is given in this chapter.