These authors contributed equally to this work.
PI 3-kinase regulation of dopamine uptake
Article first published online: 7 MAY 2002
Journal of Neurochemistry
Volume 81, Issue 4, pages 859–869, May 2002
How to Cite
Carvelli, L., Morón, J. A., Kahlig, K. M., Ferrer, J. V., Sen, N., Lechleiter, J. D., Leeb-Lundberg, L. M. F., Merrill, G., Lafer, E. M., Ballou, L. M., Shippenberg, T. S., Javitch, J. A., Lin, R. Z. and Galli, A. (2002), PI 3-kinase regulation of dopamine uptake. Journal of Neurochemistry, 81: 859–869. doi: 10.1046/j.1471-4159.2002.00892.x
- Issue published online: 7 MAY 2002
- Article first published online: 7 MAY 2002
- Received February 4, 2002; revised manuscript received February 19, 2002; accepted February 19, 2002.
The magnitude and duration of dopamine (DA) signaling is defined by the amount of vesicular release, DA receptor sensitivity, and the efficiency of DA clearance, which is largely determined by the DA transporter (DAT). DAT uptake capacity is determined by the number of functional transporters on the cell surface as well as by their turnover rate. Here we show that inhibition of phosphatidylinositol (PI) 3-kinase with LY294002 induces internalization of the human DAT (hDAT), thereby reducing transport capacity. Acute treatment with LY294002 reduced the maximal rate of [3H]DA uptake in rat striatal synaptosomes and in human embryonic kidney (HEK) 293 cells stably expressing the hDAT (hDAT cells). In addition, LY294002 caused a significant redistribution of the hDAT from the plasma membrane to the cytosol. Conversely, insulin, which activates PI 3-kinase, increased [3H]DA uptake and blocked the amphetamine-induced hDAT intracellular accumulation, as did transient expression of constitutively active PI 3-kinase. The LY294002-induced reduction in [3H]DA uptake and hDAT cell surface expression was inhibited by expression of a dominant negative mutant of dynamin I, indicating that dynamin-dependent trafficking can modulate transport capacity. These data implicate DAT trafficking in the hormonal regulation of dopaminergic signaling, and suggest that a state of chronic hypoinsulinemia, such as in diabetes, may alter synaptic DA signaling by reducing the available cell surface DATs.