# Molecular Basis of Photoreceptor Wiring

> **NIH NIH R01** · UNIVERSITY OF FLORIDA · 2024 · $607,327

## Abstract

PROJECT SUMMARY
 Mammalian rod and cone photoreceptors are indispensible for vision. They convert light into an electrical
responses, which are then propagated across the retinal circuitry and into the brain. Fundamental to this
information transmission is the specificity of synaptic connections between rod and cone photoreceptors and
their downstream partners, the bipolar cells. Deficits in synaptic transmission between photoreceptors and
bipolar cells are known to cause congenital stationary blindness in humans, a condition characterized by poor
light sensitivity and is a frequent co-morbidity with many other ocular conditions. Our long term goal is to
elucidate the molecular and cellular mechanisms by which photoreceptors establish synapses with bipolar cells.
We believe that a better understand of the mechanisms underlying blinding conditions will ultimately help in
devising strategies for their treatment.
 In this renewal application, we will continue our highly productive Multi-PI team effort that thus far has led
to major advances in understanding photoreceptor synaptic biology, We now turn our attention to a radically
new set of trans-synaptic adhesion molecules at cone synapses. Specifically, we will focus on the molecules
LRIT1 and adhesion GPCR – LPHN3, which our preliminary data show operate at cone synapses. Through cell
biological, biochemical, electrophysiological (single cell and whole retina), and behavioral experiments we will
elucidate the mechanism of action LRIT1 and LPHN3, which will reveal key properties of these synapses that
support vision over a wide range of light intensities. We hypothesize that LRIT1 and LPHN3 are critically
involved in shaping the function of CaV1.4 calcium channels that mediate neurotransmitter from photoreceptor
terminals through mechanisms that in part that involve inhibitory feedback between cones through horizontal
cells. We will test this hypothesis by pursuing two complementary Specific Aims that will (i) investigate
mechanistic role of LRIT1 in controlling the cone photoreceptor output, and (ii) elucidate the molecular basis of
LPHN3 effects from horizontal cells in regulating calcium channel activity at cone photoreceptor terminals.

## Key facts

- **NIH application ID:** 10878355
- **Project number:** 2R01EY028033-07A1
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Kirill A. Martemyanov
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $607,327
- **Award type:** 2
- **Project period:** 2017-05-01 → 2028-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10878355

## Citation

> US National Institutes of Health, RePORTER application 10878355, Molecular Basis of Photoreceptor Wiring (2R01EY028033-07A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10878355. Licensed CC0.

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