The PG transporter (PGT) is expressed in subapical vesicles in the kidney collecting duct. To gain insight into the possible function of the PGT in this tubule segment, we tagged rat PGT with green fluorescent protein at the COOH terminus and generated stable PGT-expressing Madin-Darby canine kidney cell lines. When grown on permeable filters, green fluorescent protein-PGT was expressed predominantly at the apical membrane. Although the basal-to-apical transepithelial flux of [3H]PGE2 was little changed by PGT expression, the apical-to-basolateral flux was increased 100-fold compared with wild-type cells. Analysis of driving forces revealed that this flux represents PGT-mediated active transepithelial PGE2 transport. We propose that endogenous PGT is exocytically inserted into the collecting duct apical membrane, where it could control the concentration of luminal PGs.
- Active transport
- Madin-Darby canine kidney cells
- Membrane transport
- Prostaglandin transporter
ASJC Scopus subject areas