LRIT1 Modulates Adaptive Changes in Synaptic Communication of Cone Photoreceptors

Ignacio Sarria, Yan Cao, Yuchen Wang, Norianne T. Ingram, Cesare Orlandi, Naomi Kamasawa, Alexander V. Kolesnikov, Johan Pahlberg, Vladimir J. Kefalov, Alapakkam P. Sampath, Kirill A. Martemyanov

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Cone photoreceptors scale dynamically the sensitivity of responses to maintain responsiveness across wide range of changes in luminance. Synaptic changes contribute to this adaptation, but how this process is coordinated at the molecular level is poorly understood. Here, we report that a cell adhesion-like molecule, LRIT1, is enriched selectively at cone photoreceptor synapses where it engages in a trans-synaptic interaction with mGluR6, the principal receptor in postsynaptic ON-bipolar cells. The levels of LRIT1 are regulated by the neurotransmitter release apparatus that controls photoreceptor output. Knockout of LRIT1 in mice increases the sensitivity of cone synaptic signaling while impairing its ability to adapt to background light without overtly influencing the morphology or molecular composition of photoreceptor synapses. Accordingly, mice lacking LRIT1 show visual deficits under conditions requiring temporally challenging discrimination of visual signals in steady background light. These observations reveal molecular mechanisms involved in scaling synaptic communication in the retina. Sarria et al. show LRIT1 accumulates at photoreceptors synapses. It forms a complex with a key receptor involved in processing neurotransmitter output of photoreceptors. They show that this protein plays an essential role in synaptic communication of cone photoreceptors and impacts daylight vision.

Original languageEnglish
Pages (from-to)3562-3573
Number of pages12
JournalCell Reports
Volume22
Issue number13
DOIs
StatePublished - Mar 27 2018

Keywords

  • G protein coupled receptors
  • ON-bipolar neurons
  • cone photoreceptors
  • leucine-rich repeat proteins
  • synaptic transmission

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