# Regulation of the intrinsic melanopsin-based light response in ipRGCs

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2021 · $402,891

## Abstract

Proposal Summary/Abstract:
 In the mammalian retina, there is a small subset of retinal ganglion cells (RGCs) that function as autonomous
photoreceptors and exhibit light responses independent of rod/cone-driven synaptic input. These intrinsically
photosensitive RGCs (known as, ipRGCs) relay light information to the brain to regulate several light-dependent
processes, such as circadian photoentrainment, the pupillary light reflex (PLR), sleep, and mood. ipRGCs use
the photopigment melanopsin and a G-protein coupled phototransduction cascade to respond to light, and are
now known to comprise 5 different subtypes (M1-5) that can be differentiated based on morphological and
electrophysiological criteria, projection targets, and transcription factor expression. Currently, there exists a
major gap in our understanding of how the regulation of melanopsin and its downstream phototransduction
pathways in different ipRGC subtypes govern distinct light-mediated behaviors. Based on our preliminary data,
the goal of the proposed research is to determine, in Aim I, the role of melanopsin posttranslational modifications
in ipRGC-mediated behaviors in vivo, and in Aim II, the phototransduction components that allow distinct ipRGC
subtypes to intrinsically detect light and influence ipRGC-subtype specific behaviors. These studies will provide
a critical understanding of the biochemical and molecular mechanisms by which light influences a wide range
effects on human health and performance through the regulation of circadian rhythms, sleep, mood, and learning
& memory.

## Key facts

- **NIH application ID:** 10153790
- **Project number:** 5R01EY027202-05
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** RONALD Lane BROWN
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $402,891
- **Award type:** 5
- **Project period:** 2017-05-01 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10153790

## Citation

> US National Institutes of Health, RePORTER application 10153790, Regulation of the intrinsic melanopsin-based light response in ipRGCs (5R01EY027202-05). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10153790. Licensed CC0.

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