Selective induction of glial glutamate transporter GLT-1 by hypertonic stress in C6 glioma cells.
Glial glutamate transporter GLT-1 mRNA was selectively induced in C6 glioma cells exposed to hypertonic stress (HS), while the expression of two other subtypes, GLAST and EAAC1, was suppressed. HS increased phosphorylation of the MAPK family, ERK, p38 MAPK, and JNK. Treatment with a PKC inhibitor showed that phosphorylation of both p38 MAPK and JNK is PKC-dependent but ERK phosphorylation is independent. Inhibition of either ERK or p38 MAPK did not abolish GLT-1 mRNA induction. Inhibition of PKC also had no effect. These findings indicate that the induction of GLT-1 mRNA by HS is independent of the MAPK pathways. This is the first report that the expression of glial glutamate transporters is osmotically regulated.
Imura
T
T
Department of Neurology, Graduate School of Medicine, Kyoto, Japan.
Shimohama
S
S
Kageyama
T
T
Kimura
J
J
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis / Q000235:genetics*; D000470:Alkaloids; D027322:Amino Acid Transport System X-AG; D000818:Animals; D053119:Benzophenanthridines; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics; D027341:Excitatory Amino Acid Transporter 1; D050580:Excitatory Amino Acid Transporter 3; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma; D050491:Glutamate Plasma Membrane Transport Proteins; D006982:Hypertonic Solutions; D007093:Imidazoles / Q000494:pharmacology; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010617:Phenanthridines / Q000494:pharmacology; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D027981:Symporters; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D018528:ATP-Binding Cassette Transporters; D000470:Alkaloids; D027322:Amino Acid Transport System X-AG; D053119:Benzophenanthridines; D002352:Carrier Proteins; D027341:Excitatory Amino Acid Transporter 1; D050580:Excitatory Amino Acid Transporter 3; D005419:Flavonoids; D050491:Glutamate Plasma Membrane Transport Proteins; D006982:Hypertonic Solutions; D007093:Imidazoles; D010617:Phenanthridines; D011725:Pyridines; C493398:Slc1a1 protein, rat; C493392:Slc1a3 protein, rat; D027981:Symporters; C016299:chelerythrine; D020928:Mitogen-Activated Protein Kinases; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one