Induction of the high-affinity Na(+)-dependent glutamate transport system XAG- by hypertonic stress in the renal epithelial cell line NBL-1.
The high-affinity Na(+)-dependent glutamate transport system XAG- is induced (threefold increase in Vmax. with no change in Km) by hypertonicity in the renal epithelial cell line NBL-1. This effect is dependent on protein synthesis and glycosylation and is accompanied by an increase in EAAC1 mRNA levels. Other Na(+)-dependent transport systems in this cell line do not respond to hypertonic stress. In contrast to recent findings [Ruiz-Montasell, Gomez-Angelats, Casado, Felipe, McGivan and Pastor-Anglada (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 9569-9573] showing that increased system A activity after hyperosmotic shock results from induction of a regulatory protein, this is the first demonstration that hypertonicity may increase the expression of the gene for an amino acid transport protein itself.
Ferrer-Martinez
A
A
Departament de Bioquimica i Fisiologia, Universitat de Barcelona, Spain.
Felipe
A
A
Nicholson
B
B
Casado
J
J
Pastor-Anglada
M
M
McGivan
J
J
D027322:Amino Acid Transport System X-AG; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001692:Biological Transport; D002352:Carrier Proteins / Q000096:biosynthesis*; D002417:Cattle; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D003703:Demecolcine / Q000494:pharmacology; D004848:Epithelium; D015870:Gene Expression; D050491:Glutamate Plasma Membrane Transport Proteins; D018698:Glutamic Acid / Q000378:metabolism*; D006982:Hypertonic Solutions; D007668:Kidney; D007700:Kinetics; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D013312:Stress, Physiological; D027981:Symporters; D013997:Time Factors; D014415:Tunicamycin / Q000494:pharmacology
D027322:Amino Acid Transport System X-AG; D002352:Carrier Proteins; D050491:Glutamate Plasma Membrane Transport Proteins; D006982:Hypertonic Solutions; D012333:RNA, Messenger; D027981:Symporters; D014415:Tunicamycin; D001224:Aspartic Acid; D018698:Glutamic Acid; D003513:Cycloheximide; D003703:Demecolcine