The activity of transport system A for neutral amino acids is adaptively stimulated upon amino acid starvation. In cultured human fibroblasts this treatment causes an increase in the expression of the ATA2 system A transporter gene. ATA2 mRNA increase and transport stimulation are suppressed by system A substrates, but they are unaffected by other amino acids. Supplementation of amino acid-starved cells with substrates of system A causes a decrease in both ATA2 mRNA and system A transport activity. These results suggest a direct relationship between ATA2 expression and system A transport activity.
The adaptive regulation of amino acid transport system A is associated to changes in ATA2 expression / Gazzola RF;Sala R;Bussolati O;Visigalli R;Dall'Asta V;Ganapathy V;Gazzola GC. - In: FEBS LETTERS. - ISSN 0014-5793. - 490(2001), pp. 11-14. [10.1016/S0014-5793(01)02126-3]