title: Regulation of glutathione synthesis via interaction between glutamate transport-associated protein 3-18 (GTRAP3-18) and excitatory amino acid carrier-1 (EAAC1) at plasma membrane.
abstract: Regulation of the cysteine transporter known as excitatory amino acid carrier-1 (EAAC1) for intracellular glutathione (GSH) content was investigated using human embryonic kidney (HEK) 293 cells as a model system. GSH content was significantly reduced by l-aspartate-beta-hydroxamate (50-250 microM), an inhibitor of both EAAC1 and GLT1, both of which are transporters to take up cysteine, whereas dihydrokainate (1-100 microM), a specific inhibitor of GLT1, failed to do so. This indicates that EAAC1 is involved in GSH content in HEK293 cells. We examined the effect of glutamate transport-associated protein 3-18 (GTRAP3-18), which is capable of interacting with EAAC1. The GSH content decreased when the GTRAP3-18 protein level at the plasma membrane was increased by methyl-beta-cyclodextrin (250 microM), rendering the cells more vulnerable to oxidative stress. Intracellular GSH increased when the GTRAP3-18 protein level at the plasma membrane was decreased by antisense oligonucleotides, rendering the cells more resistant to oxidative stress. Furthermore, we found that the increase in GSH content produced by stimulating protein kinase C, a translocator and activator of EAAC1, was inhibited by an increase in cell surface GTRAP3-18 protein. These results show GTRAP3-18 to negatively and dominantly regulate cellular GSH content via interaction with EAAC1 at the plasma membrane.
authors.affiliation: Department of Pharmacology, Teikyo University School of Medicine, 2-11-1, Kaga, Itabashi-ku, Tokyo 173-8605, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watabe
authors.forename: Koji
authors.initials: K
authors.lastname: Aoyama
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakaki
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D050580:Excitatory Amino Acid Transporter 3 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000096:biosynthesis*; D006360:Heat-Shock Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins
chemical_list: C484566:ARL6IP5 protein, human; D050580:Excitatory Amino Acid Transporter 3; D006360:Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; D026901:Membrane Transport Proteins; C493400:SLC1A1 protein, human; D005978:Glutathione