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Access Type
WSU Access
Date of Award
January 2023
Degree Type
Thesis
Degree Name
M.S.
Department
Biochemistry and Molecular Biology
First Advisor
Maik Hüttemann
Abstract
In a previous report, we showed that phosphomimetic substitution of cytochrome c Tyrosine 48 (Y48) decreases respiration and binding to cardiolipin and abolishes ability to trigger downstream caspase activation. In this study, we investigated the effect of Y48 modification in fibroblast cell lines that expressed either the Y48E phosphomimetic Cytc, unphosphorylated wild-type (WT) Cytc, or Y48F Cytc. Our findings revealed that Y48E Cytc caused partial inhibition of mitochondrial respiration, which corresponded with lower mitochondrial membrane potentials (ΔΨm) and reduced reactive oxygen species (ROS) production. When subjected to an oxygen-glucose deprivation/reoxygenation (OGD/R) model, which simulates ischemia/reperfusion injury, the Y48E phosphomimetic cell line showed lower ROS production compared to the unphosphorylated WT Cytc cell line, which generated higher levels of ROS upon reoxygenation. As a result, the Y48E Cytc cell line had significantly lower cell death rates when exposed to OGD/R, confirming the cytoprotective role of Y48 phosphorylation of Cytc. In summary, our research indicates that the loss of Y48 phosphorylation in Cytc during ischemia leads to reperfusion injury by driving maximum electron transport chain flow, hyperpolarization of ΔΨm, bursts of ROS, and death of cells through apoptosis.
Recommended Citation
Vuljaj, Susanna, "Characterization Of Cytochrome C Tyrosine 48 Phosphorylation" (2023). Wayne State University Theses. 924.
https://digitalcommons.wayne.edu/oa_theses/924