title: Regulation of the mouse retinal taurine transporter (TAUT) by protein kinases in Xenopus oocytes.
abstract: The goal was to investigate the role of protein kinases in modulating taurine transporter activity in Xenopus laevis oocytes expressing the mouse retinal Na+/C-/taurine transporter. The currents generated by the taurine transporter were studied with a two-electrode voltage clamp and we recorded the maximal current (Imax), presteady-state charge transfer Q, and membrane capacitance Cm. 8-Br-cAMP, a membrane-permeable activator of the cAMP-dependent protein kinase (PKA), decreased Imax (41%), Q (41%) and Cm (10%). Similarly, 1 microM sn-1,2-dioctanoylglycerol (DOG), an activator of the Ca2+/diacylglycerol-dependent protein kinase (PKC), decreased Imax (56%), Q (37%), and Cm (9%). Calyculin A, a specific inhibitor of protein phosphatases 1 and 2A, also produced effects similar to those of 8-Br-cAMP and DOG, and decreased Imax (64 %), Q (38%), and Cm (10%). We conclude that the taurine transporter is regulated by activators of PKA and PKC, and regulation occurs largely by changes in the number of transporters in the plasma membrane.
authors.affiliation: Department of Physiology, UCLA School of Medicine, Center for the Health Sciences, Los Angeles, CA 90095-1751, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Loo
authors.forename: J R
authors.initials: JR
authors.lastname: Hirsch
authors.forename: H K
authors.initials: HK
authors.lastname: Sarkar
authors.forename: E M
authors.initials: EM
authors.lastname: Wright
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000187:drug effects / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004075:Diglycerides / Q000494:pharmacology; D004594:Electrophysiology / Q000379:methods; D004705:Endocytosis / Q000502:physiology; D004789:Enzyme Activation; D005089:Exocytosis / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation; D008387:Marine Toxins; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000502:physiology*; D026901:Membrane Transport Proteins; D051379:Mice; D009865:Oocytes / Q000378:metabolism* / Q000502:physiology; D010080:Oxazoles / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D011493:Protein Kinase C / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012160:Retina / Q000737:chemistry*; D012964:Sodium / Q000378:metabolism; D014982:Xenopus laevis; D000099247:Taurine Transporters
chemical_list: D015124:8-Bromo Cyclic Adenosine Monophosphate; D002352:Carrier Proteins; D002712:Chlorides; D017868:Cyclic AMP-Dependent Protein Kinases; D004075:Diglycerides; D008387:Marine Toxins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D010080:Oxazoles; D010749:Phosphoprotein Phosphatases; D011493:Protein Kinase C; D011994:Recombinant Proteins; D012964:Sodium; D000099247:Taurine Transporters; C044295:1,2-dioctanoylglycerol; C059041:calyculin A