title: Characterization of a plant glutamate receptor activity.
abstract: Bioinformatic approaches have allowed the identification of twenty genes, grouped into three subfamilies, encoding for homologues of animal ionotropic glutamate receptors (iGLRs) in the Arabidopsis thaliana model plant. Indirect evidence suggests that plant iGLRs function as non-selective cation channels. In the present work we provide biochemical and electrophysiological evidences for the chloroplast localization of glutamate receptor(s) of family 3 (iGLR3) in spinach. A specific antibody, recognizing putative receptors of family 3 locates iGLR3 to the inner envelope membrane of chloroplasts. In planar lipid bilayer experiments, purified inner envelope vesicles from spinach display a cation-selective electrophysiological activity which is inhibited by DNQX (6,7-dinitroquinoxaline-2,3-dione), considered to act as an inhibitor on both animal and plant iGLRs. These results identify for the first time the intracellular localization of plant glutamate receptor(s) and a DNQX-sensitive, glutamate-gated activity at single channel level in native membrane with properties compatible with those predicted for plant glutamate receptors.
authors.affiliation: Department of Biology, University of Padova, Padova, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Teardo
authors.forename: Anna
authors.initials: A
authors.lastname: Segalla
authors.forename: Elide
authors.initials: E
authors.lastname: Formentin
authors.forename: Manuela
authors.initials: M
authors.lastname: Zanetti
authors.forename: Oriano
authors.initials: O
authors.lastname: Marin
authors.forename: Giorgio Mario
authors.initials: GM
authors.lastname: Giacometti
authors.forename: Fiorella
authors.initials: F
authors.lastname: Lo Schiavo
authors.forename: Mario
authors.initials: M
authors.lastname: Zoratti
authors.forename: Ildikò
authors.initials: I
authors.lastname: Szabò
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D010940:Plant Proteins / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D058468:Receptors, Ionotropic Glutamate / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism; D018724:Spinacia oleracea / Q000378:metabolism
chemical_list: D008051:Lipid Bilayers; D010940:Plant Proteins; D011810:Quinoxalines; D058468:Receptors, Ionotropic Glutamate; C056723:FG 9041