Presynaptic localization of GluK5 in rod photoreceptors suggests a novel function of high affinity glutamate receptors in the mammalian retina

PLoS One. 2017 Feb 24;12(2):e0172967. doi: 10.1371/journal.pone.0172967. eCollection 2017.


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.

MeSH terms

  • Alcohol Oxidoreductases
  • Animals
  • Co-Repressor Proteins
  • DNA-Binding Proteins / metabolism
  • Mice, 129 Strain
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Organ Specificity
  • Phosphoproteins / metabolism
  • Presynaptic Terminals / metabolism*
  • Protein Transport
  • Receptors, Kainic Acid / metabolism*
  • Retina / metabolism
  • Retina / ultrastructure
  • Retinal Rod Photoreceptor Cells / metabolism*
  • Retinal Rod Photoreceptor Cells / ultrastructure


  • Co-Repressor Proteins
  • DNA-Binding Proteins
  • Gluk1 kainate receptor
  • Phosphoproteins
  • Receptors, Kainic Acid
  • Alcohol Oxidoreductases
  • Ctbp2 protein, mouse

Grants and funding

This work was supported by the German Research Foundation (FR 620/14-1 to MF); Landesforschungsförderung by the State of Hamburg (LFF-FV27, project P3) to MF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.