Regulation of System B0 amino-acid-transport activity in the renal epithelial cell line NBL-1 and concomitant changes in SAAT1 hybridizing transcripts
| Autor: | S Plakidou-Dymock, Michael J. A. Tanner, John D. McGivan |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1994 |
| Předmět: |
Phenylalanine
Cycloheximide Biology Kidney Biochemistry Epithelium Isobutyric acid Cell Line chemistry.chemical_compound Methionine Animals Amino Acids Molecular Biology Alanine chemistry.chemical_classification Alanine transport Sodium Biological Transport Cell Biology Membrane transport Blotting Northern Amino acid Culture Media Kinetics Amino Acid Transport Systems Neutral chemistry beta-Alanine Amino Acid Transport Systems Basic RNA Cattle Carrier Proteins DNA Probes Research Article |
| Popis: | alpha-(Methylamino)isobutyric acid (MeAIB) insensitive Na(+)-dependent alanine transport activity in the bovine kidney cell line NBL-1 was increased upon amino acid starvation (> or = 20% over control levels). When L-phenylalanine (3 mM) was included in the starvation medium the increase was further enhanced (> or = 85% over control levels). In cells grown in control medium the Vmax, for MeAIB-insensitive Na+/alanine co-transport was found to be 6.0 +/- 0.7 nmol/3 min per mg (Km 41 +/- 12 microM) and for L-phenylalanine-treated amino-acid-starved cells the Vmax. was 21 +/- 5 nmol/3 min per mg (Km 92 +/- 40 microM). The increase in Vmax. was prevented by cycloheximide. Substrate specificity analysis identified the L-phenylalanine-induced transport system as System B0. [35S]Methionine labelling of cells during the amino acid starvation/phenylalanine treatments resulted in the differential labelling of a protein of 78 kDa. Northern-blot analysis using a SAAT1-specific probe revealed the presence of a new transcript (3.2 kb) in RNA extracted from cells incubated in amino acid starvation medium with L-phenylalanine included. The present findings suggest a novel means of control for System B0 by the use of physiological stress. It is also proposed that SAAT1 and System-B0 transcripts have considerable sequence similarity. |
| Databáze: | OpenAIRE |
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