Expression of PGT in MDCK cell monolayers: polarized apical localization and induction of active PG transport.
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 [(3)H]PGE(2) 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 PGE(2) transport. We propose that endogenous PGT is exocytically inserted into the collecting duct apical membrane, where it could control the concentration of luminal PGs.
Endo
Shinichi
S
Department of Medicine, Division of Nephrology, Albert Einstein College of Medicine, New York, New York 10461, USA.
Nomura
Teruhisa
T
Chan
Brenda S
BS
Lu
Run
R
Pucci
Michael L
ML
Bao
Yi
Y
Schuster
Victor L
VL
D000818:Animals; D017920:Antiporters / Q000096:biosynthesis* / Q000235:genetics; D001693:Biological Transport, Active; D001961:Bromcresol Green / Q000494:pharmacology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D015232:Dinoprostone / Q000378:metabolism; D004285:Dogs; D004594:Electrophysiology; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology; D049452:Green Fluorescent Proteins; D007668:Kidney / Q000378:metabolism*; D008164:Luminescent Proteins / Q000096:biosynthesis / Q000235:genetics; D018613:Microscopy, Confocal; D027361:Organic Anion Transporters; D011448:Prostaglandin Antagonists / Q000494:pharmacology; D011453:Prostaglandins / Q000378:metabolism*; D051381:Rats
D017920:Antiporters; D004268:DNA-Binding Proteins; D008164:Luminescent Proteins; D027361:Organic Anion Transporters; D011448:Prostaglandin Antagonists; D011453:Prostaglandins; C503528:Slco2a1 protein, rat; D049452:Green Fluorescent Proteins; D001961:Bromcresol Green; D015232:Dinoprostone