Induction of high affinity glutamate transport activity by amino acid deprivation is dependent on cellular glutamate concentrations in renal epithelial cells does not involve an increase in the amount of transporter protein

1996 ◽  
Vol 24 (3) ◽  
pp. 481S-481S ◽  
Author(s):  
Benjamin Nicholson ◽  
John D. McGivan
Keyword(s):  
Amino Acid ◽  
Epithelial Cells ◽  
Glutamate Transport ◽  
Amino Acid Deprivation ◽  
Transport Activity ◽  
Renal Epithelial Cells ◽  
Transporter Protein ◽  
High Affinity

Regulation of high-affinity glutamate transport by amino acid deprivation and hyperosmotic stress

1999 ◽  
Vol 277 (4) ◽  
pp. F498-F500 ◽  
Author(s):  
J. D. McGivan ◽  
B. Nicholson
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Glutamate Transporter ◽  
Indirect Evidence ◽  
Glutamate Transport ◽  
Mrna Levels ◽  
Amino Acid Deprivation ◽  
Free Medium ◽  
Transport Activity ◽  
High Affinity

High-affinity glutamate transport activity is induced by stress in NBL-1 cells. Exposure of cells to hyperosmotic medium led to an induction of the EAAC1 glutamate transporter, preceded by a large increase in EAAC1 mRNA levels. Culture of cells in amino acid-free medium also caused a protein synthesis-dependent increase in glutamate transport activity, but this was not accompanied by an increase of either EAAC1 mRNA or protein. Indirect evidence suggests that the increase in EAAC1 activity in the latter case may be due to the synthesis of an activator protein in response to decreased intracellular glutamate concentrations.

scholarly journals Regulation of the glutamate transporter by amino acid deprivation and associated effects on the level of EAAC1 mRNA in the renal epithelial cell line NBL-I

1993 ◽  
Vol 295 (3) ◽  
pp. 749-755 ◽  
Author(s):  
S Plakidou-Dymock ◽  
J D McGivan
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Epithelial Cell ◽  
Cell Line ◽  
Glutamate Transport ◽  
Epithelial Cell Line ◽  
Amino Acid Deprivation ◽  
Renal Epithelial Cell ◽  
High Affinity ◽  
Renal Epithelial Cell Line

The glutamate transport system of the bovine renal epithelial cell line NBL-1 was studied. The Km for Na(+)-dependent glutamate transport was found to be 13.8 +/- 2.4 microM (Vmax. 365 +/- 19.2 pmol/3 min per mg) and for Na(+)-dependent aspartate transport 4.5 +/- 1.1 microM (Vmax. 108 +/- 6.3 pmol/3 min per mg). The Km values are in close agreement with those expected for high-affinity Na(+)-dependent glutamate transport by System XAG-. Upon deprivation of amino acids, the Vmax. for Na+/aspartate co-transport rose to 203 +/- 6.0 pmol/3 min per mg (Km 3.8 +/- 0.5 microns). A probe was constructed to the high-affinity excitatory amino acid carrier (EAAC1) [Kanai and Hediger (1992) Nature (London) 360, 467-471]. The probe hybridized to a 3.5 kb transcript. On deprivation of amino acids, the level of EAAC1 mRNA decreased sharply before the measurable increase in transport levels, but was subsequently restored to control levels. A motif, which we propose is linked to amino acid deprivation, was found in the EAAC1 primary sequence.

scholarly journals Analysis of Cationic Amino Acid Transport Activity in Canine Lens Epithelial Cells

2013 ◽  
Vol 62 (4) ◽  
pp. 311-317 ◽  
Author(s):  
Hideharu Ochiai ◽  
Jun Moriyama ◽  
Nobuyuki Kanemaki ◽  
Reiichiro Sato ◽  
Ken Onda
Keyword(s):  
Amino Acid ◽  
Epithelial Cells ◽  
Amino Acid Transport ◽  
Lens Epithelial Cells ◽  
Acid Transport ◽  
Transport Activity ◽  
Cationic Amino Acid

scholarly journals AgtA, the Dicarboxylic Amino Acid Transporter of Aspergillus nidulans, Is Concertedly Down-Regulated by Exquisite Sensitivity to Nitrogen Metabolite Repression and Ammonium-Elicited Endocytosis

2009 ◽  
Vol 8 (3) ◽  
pp. 339-352 ◽  
Author(s):  
Angeliki Apostolaki ◽  
Zoi Erpapazoglou ◽  
Laura Harispe ◽  
Maria Billini ◽  
Panagiota Kafasla ◽  
...  
Keyword(s):  
Amino Acid ◽  
Aspergillus Nidulans ◽  
Amino Acid Transporter ◽  
Acid Transport ◽  
Transport Activity ◽  
High Affinity ◽  
Nitrogen Metabolite Repression ◽  
Dicarboxylic Amino Acid ◽  
Specific Induction ◽  
Acid Transporter

ABSTRACT We identified agtA, a gene that encodes the specific dicarboxylic amino acid transporter of Aspergillus nidulans. The deletion of the gene resulted in loss of utilization of aspartate as a nitrogen source and of aspartate uptake, while not completely abolishing glutamate utilization. Kinetic constants showed that AgtA is a high-affinity dicarboxylic amino acid transporter and are in agreement with those determined for a cognate transporter activity identified previously. The gene is extremely sensitive to nitrogen metabolite repression, depends on AreA for its expression, and is seemingly independent from specific induction. We showed that the localization of AgtA in the plasma membrane necessitates the ShrA protein and that an active process elicited by ammonium results in internalization and targeting of AgtA to the vacuole, followed by degradation. Thus, nitrogen metabolite repression and ammonium-promoted vacuolar degradation act in concert to downregulate dicarboxylic amino acid transport activity.

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