Abstract
We expressed the human cystic fibrosis transmembrane conductance regulator (CFTR) in oocytes of the South African clawed frog Xenopus laevis. We performed simultaneous and continuous recording of membrane current (Im), conductance (Gm) and capacitance (Cm), the latter being a direct measure of membrane surface area. A cAMP-cocktail containing cAMP and isobutylmethylxanthine (IBMX) increased all parameters, demonstrating that CFTR activation was partly achieved by exocytotic delivery and insertion of preformed CFTR molecules into the plasma membrane. CFTR currents after cAMP-cocktail were correlated with the capacitance of the oocytes: oocytes with larger Cm exhibited larger currents. Expression of CFTR itself did not change the Cm of the oocytes. However, activation of CFTR with cAMP-cocktail increased Im and Gm 15- and 20-fold, respectively while membrane surface area increased by about 7%, indicating the functional insertion of preformed CFTR into the plasma membrane. While cAMP-cocktail yielded maximal CFTR stimulation, IBMX alone, but not caffeine or theophylline, was sufficient to stimulate more than half of the increases in Im and Gm as observed with cAMP-cocktail. Since Cm was not significantly stimulated by IBMX, we con...Continue Reading
Citations
Dec 7, 2007·Pflügers Archiv : European journal of physiology·Hermann Schillers
Oct 7, 2004·Journal of Cystic Fibrosis : Official Journal of the European Cystic Fibrosis Society·Anne VankeerberghenJean-Jacques Cassiman
Sep 21, 2011·Molecular and Cellular Biology·Simão LuzCarlos M Farinha
Apr 20, 2012·PloS One·Naziha BakouhGabrielle Planelles
Apr 12, 2002·FEBS Letters·Andrei SegalWolf Michael Weber
Feb 19, 2016·Pflügers Archiv : European journal of physiology·Alejandra G PalmaGabriela I Marino
Sep 19, 2008·American Journal of Physiology. Cell Physiology·Manuela MertlGabor Kottra
Jun 19, 2009·American Journal of Physiology. Cell Physiology·Biguang TuoHui Dong
Apr 12, 2003·Pflügers Archiv : European journal of physiology·Bogdan AmuzescuWilly Van Driessche
Nov 12, 2010·Molecular Membrane Biology·Diana FariaMargarida D Amaral
Jan 17, 2003·American Journal of Physiology. Cell Physiology·Nadia A AmeenPedro J I Salas
Oct 1, 2013·Birth Defects Research. Part A, Clinical and Molecular Teratology·Kerina J DennyTrent M Woodruff
Jan 6, 2007·PloS One·Chi ZhangMichael W Klymkowsky
Apr 6, 2007·American Journal of Physiology. Cell Physiology·Michael Auerbach, Carole M Liedtke