Intracellular crosstalk mediated by calcium ions (Ca2+) is fundamentally important for understanding regulation of cellular function. Cellular Ca2+ fluxes and mitochondrial Ca2+ dynamics, influence the activity of mitochondrial enzymes involved in energy metabolism and cellular redox. These changes influence post-translational modification of proteins in mitochondria, the cytoplasm and the nucleus, which control cell functions such as energy metabolism and transcription. We hypothesize that Ca2+ signaling by mitochondria in photoreceptors is critical for their function and survival. The study proposed here will define how photoreceptor activity is regulated by mitochondrial Ca2+ to meet the specialized demands of this unique sensory neuron. Using genetically encoded Ca2+ indicators and in vivo imaging, we have documented large Ca2+ fluctuations in the cell bodies and mitochondria of zebrafish cone photoreceptors. We also developed methods for manipulating Ca2+ in cell bodies and mitochondria and for detecting protein modifications and cellular redox changes. We will use these methods to determine how Ca2+ fluxes within photoreceptors are processed by mitochondria. We will study how mitochondria regulate Ca2+ in photoreceptor cell bodies and the role of the mitochondrial Ca2+ uniporter (Aim 1). We also will determine how Ca2+ controls the cytoplasmic redox potential and acylation of proteins (Aim 2).

Public Health Relevance

Photoreceptor neurons rely on calcium ions (Ca2+) for signaling, function and viability. Defects in mitochondrial Ca2+ regulation have been linked to cell death. Understanding the roles of mitochondria in cellular Ca2+ dynamics in photoreceptors is fundamentally important for understanding diseases in which photoreceptor neurons in the retina degenerate.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY026020-03
Application #
9402618
Study Section
Biology of the Visual System Study Section (BVS)
Program Officer
Neuhold, Lisa
Project Start
2016-01-01
Project End
2019-12-31
Budget Start
2018-01-01
Budget End
2018-12-31
Support Year
3
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Washington
Department
Biochemistry
Type
Schools of Medicine
DUNS #
605799469
City
Seattle
State
WA
Country
United States
Zip Code
98195
Giarmarco, Michelle M; Cleghorn, Whitney M; Hurley, James B et al. (2018) Preparing Fresh Retinal Slices from Adult Zebrafish for Ex Vivo Imaging Experiments. J Vis Exp :
Kanow, Mark A; Giarmarco, Michelle M; Jankowski, Connor Sr et al. (2017) Biochemical adaptations of the retina and retinal pigment epithelium support a metabolic ecosystem in the vertebrate eye. Elife 6:
Giarmarco, Michelle M; Cleghorn, Whitney M; Sloat, Stephanie R et al. (2017) Mitochondria Maintain Distinct Ca2+ Pools in Cone Photoreceptors. J Neurosci 37:2061-2072
Brockerhoff, Susan E (2017) Genome Editing to Study Ca2+ Homeostasis in Zebrafish Cone Photoreceptors. Adv Exp Med Biol 1016:91-100