Sato K, Betz H, Schloss P
Abteilung Neurochemie, Max-Planck-Institut für Hirnforschung, Frankfurt, Germany.
FEBS Lett. 1995 Nov 13;375(1-2):99-102. doi: 10.1016/0014-5793(95)01191-g.
Treatment of human embryonic kidney 293 cells expressing the rat gamma-aminobutyric acid (GABA) transporter 1 (GAT1) with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA) was found to decrease the velocity of specific [3H]GABA uptake. This downregulation varied with extracellular GABA concentration and was blocked by the PKC inhibitors 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine (H7) and staurosporine. An about 50% reduction of uptake velocity by PMA treatment was observed at GABA concentrations > 1 microM, whereas only a minor effect was seen at low substrate concentrations. These data indicate that GAT1 activity is downregulated by PKC activation.
