The Effects of S-glutathionylation on the Structure and Function of the Mitochondrial Calcium Uniporter (MCU)

Most calcium (Ca2+) entry into the mitochondrial matrix is regulated by the mitochondrial calcium uniporter (MCU). The amino (N)-terminal domain (NTD) of MCU is a regulatory component of the channel. S-Glutathionylation of Cys97 on the MCU-NTD leads to robust MCU activation and increased matrix Ca2+. Here, I characterized the biophysical and structural changes induced by Cys97 S-glutathionylation by applying optical spectroscopy, light scattering, solution nuclear magnetic resonance (NMR) and live cell functional experiments. S-Glutathionylation increased solvent exposed hydrophobicity, destabilized and caused large structural perturbations in the MCU-NTD. An S-glutathiomimetic mutation was able to closely recapitulate these biophysical and structural effects, but in the absence of oxidative stress. Indeed, HeLa cells expressing MCU with the S-glutathiomimetic mutation, showed increased mitochondrial Ca2+ uptake compared to wild-type MCU expressing cells. Thus, my research revealed new insights into the impact of S-glutathionylation on MCU-NTD and identified the S-glutathiomimetic mutation as a valuable research tool.

Name thesis:degree_name

M Sc

Discipline thesis:degree_discipline

Physiology and Pharmacology

Grantor dc:publisher

The University of Western Ontario

Year dc:date.issued

2024

Author dc:creator

• Pawakian, Arine

Advisor dc:contributor.advisor

• Stathopulos, Peter B.

• calcium signaling
• mitochondrial bioenergetics
• mitochondrial calcium uptake
• oxidative stress
• post-translational modifications
• protein structure
• reactive oxygen species
• S-glutathiomimetic
• S-gluthathionylation

Language dc:language.iso

en_ca

Handle dc:identifier.uri

https://hdl.handle.net/20.500.14721/37577

OAI identifier oai:identifier

oai:uwo.scholaris.ca:20.500.14721/37577