Osmotic regulation of ATA2 mRNA expression and amino acid transport System A activity.
When porcine endothelial cells were exposed to hypertonicity, both the level of ATA2 (amino acid transporter 2) mRNA and activity of amino acid transport System A increased transiently, peaking after about 6 and 9 h, respectively. Cycloheximide, like actinomycin D, prevented both responses, showing that an earlier step also involves protein synthesis. Withdrawal of hypertonicity after 6 h increased the rate of down regulation. These findings confirm that ATA2 is a major isoform of System A and show that changes in the expression of ATA2 mRNA precede both the induction and subsequent down regulation of transport activity.
Alfieri
R R
RR
Dipartimento di Medicina Sperimentale, Sezione di Patologia Molecolare e Immunologia, Università degli Studi di Parma, Parma, 43100, Italy.
Petronini
P G
PG
Bonelli
M A
MA
Caccamo
A E
AE
Cavazzoni
A
A
Borghetti
A F
AF
Wheeler
K P
KP
D026924:Amino Acid Transport System A; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006982:Hypertonic Solutions / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D013552:Swine; D014162:Transfection; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology*; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
D026924:Amino Acid Transport System A; D000596:Amino Acids; D002352:Carrier Proteins; D006982:Hypertonic Solutions; D008565:Membrane Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D015091:beta-Alanine; C012924:2,2-dimethyl-beta-alanine; D003609:Dactinomycin; D003513:Cycloheximide