title: Presynaptic localization of GluK5 in rod photoreceptors suggests a novel function of high affinity glutamate receptors in the mammalian retina.
abstract: Kainate receptors mediate glutamatergic signaling through both pre- and presynaptic receptors. Here, we studied the expression of the high affinity kainate receptor GluK5 in the mouse retina. Double-immunofluoresence labeling and electron microscopic analysis revealed a presynaptic localization of GluK5 in the outer plexiform layer. Unexpectedly, we found GluK5 almost exclusively localized to the presynaptic ribbon of photoreceptor terminals. Moreover, in GluK5-deficient mutant mice the structural integrity of synaptic ribbons was severely altered pointing to a novel function of GluK5 in organizing synaptic ribbons in the presynaptic terminals of rod photoreceptors.
authors.affiliation: Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Haumann
authors.affiliation: Institute of Embryology and Stem Cell Biology, Department of Biomedicine, University of Basel, Basel, Switzerland.
authors.forename: Dirk
authors.initials: D
authors.lastname: Junghans
authors.affiliation: Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Anstötz
authors.affiliation: Institute for Structural Neurobiology, Center for Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Frotscher
mesh_terms: D000429:Alcohol Oxidoreductases; D000818:Animals; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins / Q000378:metabolism; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009928:Organ Specificity; D010750:Phosphoproteins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism*; D021381:Protein Transport; D018092:Kainic Acid Receptors / Q000378:metabolism*; D012160:Retina / Q000378:metabolism / Q000648:ultrastructure; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D000429:Alcohol Oxidoreductases; D056970:Co-Repressor Proteins; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D018092:Kainic Acid Receptors; C111341:Ctbp2 protein, mouse