# Understanding mitochondrial movement and turnover in stressed and unstressed photoreceptors

> **NIH NIH F31** · UNIVERSITY OF WASHINGTON · 2022 · $41,153

## Abstract

ABSTRACT
Required to visualize the world around us, photoreceptors are post-mitotic retinal neurons that
must remain healthy and functional to respond to incoming light. Throughout a lifetime,
photoreceptors require high amounts of energy and are robust amongst various stressors
including high reactive oxygen species and light radiation. Dysfunctional photoreceptor
mitochondria can lead to disrupted or complete vision loss. Uncovering mechanisms supporting
mitochondrial dynamics during stress will yield insight into photoreceptor longevity. Developing
therapies for visual disorders involving mitochondrial dysfunction first requires an understanding
of mitochondrial dynamics in stressed and unstressed conditions. Zebrafish are ideal model
organisms as their cone photoreceptors contain a large cluster of mitochondria localized to the
cell body. In response to energy demands throughout the 24-hour day, the mitochondrial cluster
grows or shrinks accordingly. Rarely mitochondria move away from this cluster towards the
synapse or outside the photoreceptor cell. The presence of mitochondria localized away from the
cluster is increased in stressed conditions. Moving unhealthy mitochondria away from the healthy
cluster may be a specialized stress response to protect photoreceptors. It is currently unknown
how photoreceptor mitochondria are anchored or move. In aim 1 of this proposal, I will uncover
how the mitochondrial cluster is anchored in photoreceptors and how mitochondria can break free
from that cluster and move towards the synapse. Photoreceptor mitochondria have been
observed outside the photoreceptor layer and a portion of photoreceptor mitochondria colocalized
with Müller glia. Some ‘mislocalized’ photoreceptor mitochondria colocalized with Lysotracker
Green puncta within and outside the photoreceptor layer indicating mitochondrial turnover. In aim
2 of this proposal, I will determine the cell type(s) responsible for photoreceptor mitochondrial
turnover. I predict that unhealthy mitochondria are separated from the cluster and ejected from
the cell to be turned over by Müller glia machinery. Understanding the mechanisms of this stress
response will give insight into how photoreceptors remain robust throughout time. These findings
can yield insights into how retinal therapies can target mitochondrial dysfunction in
photoreceptors.

## Key facts

- **NIH application ID:** 10461549
- **Project number:** 1F31EY033983-01
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Kaitlyn Michelle Rutter
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $41,153
- **Award type:** 1
- **Project period:** 2022-06-01 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10461549

## Citation

> US National Institutes of Health, RePORTER application 10461549, Understanding mitochondrial movement and turnover in stressed and unstressed photoreceptors (1F31EY033983-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10461549. Licensed CC0.

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