Student Author(s)

Anna Koppin, Hope College

Faculty Mentor(s)

Dr. Leah Chase, Biology and Chemistry

Document Type

Poster

Event Date

4-12-2024

Abstract

System xc- is a membrane transport system that plays a critical role in mitigating oxidative stress. Past work in our lab has shown that System xc- localizes to the plasma membrane allowing for increased activity to support production of antioxidants during oxidative stress. In this study, we sought to determine if post-translational modification (PTM) of the transporter regulates its trafficking. A C-terminal 3KR mutant (K422,472,473R) exhibited decreased membrane localization and activity, suggesting that PTM at one of these sites increases activity. Further, we observed that K473R exhibits a 7 kD decrease in the molecular weight, indicating that K473 may be modified under basal conditions. We determined that this loss in molecular weight is not due to ubiquitination. In addition, we found that K473R exhibited complete loss of xCT activity and loss of membrane expression. K473Q, an acetylated lysine mimic, appears to lead to an intermediate molecular weight loss, an intermediate level of membrane expression, and complete loss of xCT activity. We are currently working to identify the PTMs that K473 acetylation might regulate. Regardless, these preliminary data suggest that acetylation at K473 could serve as a potential mechanism by which System xc- activity and trafficking is regulated.

Comments

This work was supported by the Schaap Science Undergraduate Research Fund.

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