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System xc‐ is Localized to Early Endosomes which Facilitates Regulated Membrane Trafficking
Author(s) -
Goltz Abby,
Wixson Matthew,
Chase Leah A.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.813.8
Subject(s) - endosome , endocytosis , microbiology and biotechnology , chemistry , intracellular , glutathione , glutamate receptor , biochemistry , hydrogen peroxide , cell membrane , extracellular , membrane , cell , biology , enzyme , receptor
The membrane transporter, System x c − , catalyzes the exchange of cystine and glutamate across the membrane of many cell types. As such, this transporter plays significant roles in controlling intracellular cysteine levels and ultimately, the synthesis of glutathione, and regulating extracellular levels of glutamate, the primary excitatory neurotransmitter in the brain. Previous studies in our lab have demonstrated that hydrogen peroxide (whether added exogenously or produced endogenously) regulates the trafficking of System x c − to the plasma and that this process is responsible for maintenance of glutathione levels under conditions of oxidative stress. The objective of this study was to determine the mechanism by which peroxide regulates trafficking of System x c − . Using immunocytochemistry, we have demonstrated that System x c − is localized to early endosomes in naïve cells. Upon exposure to peroxide, however the endosomes appear to disperse, resulting an increase in System x c − expression on the membrane. We are currently using cell surface biotinylation assays to determine whether peroxide exposure increases the rate of delivery of System x c − to the membrane or whether it decreases the rate of removal (endocytosis) of System x c − from the membrane. This research was supported by the Campbell Foundation, the NSF REU and MRI Programs, and the Biology and Chemistry Departments at Hope College.