title: Involvement of tyrosine kinase and PI3K in the regulation of OAT3-mediated estrone sulfate transport in isolated rabbit renal proximal tubules.
abstract: It was shown previously that OAT3 activity was differentially regulated by protein kinases including MAPK, PKA, and PKC. The present study investigated the short-term effect of tyrosine kinase and phosphatidylinositol 3-kinase (PI3K) on OAT3-mediated organic anion transport in S2 segments of renal proximal tubules. Genistein, a tyrosine kinase inhibitor, and wortmannin, a PI3K inhibitor, inhibited transport of estrone sulfate, a prototypic substrate for OAT3, in a dose-dependent manner. Previously, we showed that epidermal growth factor (EGF) stimulated OAT3 activity via the MAPK pathway. In the present study, we investigated whether EGF-stimulated OAT3 activity was dependent on tyrosine kinase and PI3K. We showed that EGF stimulation of OAT3 was reduced by inhibition of tyrosine kinase or PI3K, suggesting that they play a role in the stimulatory process. Inhibitory effects also indicated that tyrosine kinase and PI3K are involved in the MAPK pathway for EGF stimulation of OAT3 in intact renal proximal tubules, with PI3K acting upstream and tyrosine kinase acting downstream of mitogen-activated/extracellular signal-regulated kinase kinase activation.
authors.affiliation: Dept. of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand 10400.
authors.forename: S
authors.initials: S
authors.lastname: Soodvilai
authors.forename: S H
authors.initials: SH
authors.lastname: Wright
authors.forename: W H
authors.initials: WH
authors.lastname: Dantzler
authors.forename: V
authors.initials: V
authors.lastname: Chatsudthipong
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000502:physiology; D004970:Estrone / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D019833:Genistein / Q000494:pharmacology; D017136:Ion Transport / Q000502:physiology; D007687:Kidney Tubules, Proximal / Q000502:physiology*; D029362:Organic Anion Transporters, Sodium-Independent / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011817:Rabbits; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D004791:Enzyme Inhibitors; D029362:Organic Anion Transporters, Sodium-Independent; D047428:Protein Kinase Inhibitors; C114338:organic anion transport protein 3; D004970:Estrone; D004815:Epidermal Growth Factor; D019833:Genistein; D019869:Phosphatidylinositol 3-Kinases; D011505:Protein-Tyrosine Kinases; C017296:estrone sulfate; D000077191:Wortmannin