Protein kinase C activation regulates human serotonin transporters in HEK-293 cells via altered cell surface expression

Academic Article

Abstract

  • Antidepressant- and cocaine-sensitive serotonin (5-hydroxytryptamine, 5- HT) transporters (SERTs) dictate clearance of extracellular 5-HT after release. To explore protein kinase C-mediated SERT regulation, we generated a stable human SERT (hSERT)-expressing cell line (293-hSERT) and evaluated modulation of 5-HT activity via studies of 5-HT flux, hSERT-mediated currents under voltage clamp, and surface distribution of SERT protein. 293-hSERT cells exhibit saturable, high-affinity, and antidepressant-sensitive 5-HT uptake as well as hSERT-dependent whole-cell currents. In these cells, the protein kinase C activator β-PMA caused a time-dependent reduction in 5-HT uptake capacity (V(max)) after acute application and a reduction in SERT- mediated currents. Effects of β-PMA were mimicked by the phorbol ester β- PDBu, were not observed with the inactive β-isomers, and could be blocked by treatment of cells with the protein kinase C inhibitor staurosporine. Biotinylation/immunoblot analyses showed that activity reductions are paralleled by a staurosporine-sensitive loss of surface SERT protein. These data indicate that altered surface abundance, rather than reduced catalytic transport efficiency, mediates acute PKC-dependent modulation of 5-HT uptake.
  • Authors

    Digital Object Identifier (doi)

    Pubmed Id

  • 15598960
  • Author List

  • Qian Y; Galli A; Ramamoorthy S; Risso S; DeFelice LJ; Blakely RD
  • Start Page

  • 45
  • End Page

  • 57
  • Volume

  • 17
  • Issue

  • 1