Regulation of I(Cl,swell) in neuroblastoma cells by G protein signaling pathways

Am J Physiol Cell Physiol. 2001 Jul;281(1):C89-98. doi: 10.1152/ajpcell.2001.281.1.C89.


Guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) activated the I(Cl,swell) anion channel in N1E115 neuroblastoma cells in a swelling-independent manner. GTPgammaS-induced current was unaffected by ATP removal and broadly selective tyrosine kinase inhibitors, demonstrating that phosphorylation events do not regulate G protein-dependent channel activation. Pertussis toxin had no effect on GTPgammaS-induced current. However, cholera toxin inhibited the current approximately 70%. Exposure of cells to 8-bromoadenosine 3',5'-cyclic monophosphate did not mimic the effect of cholera toxin, and its inhibitory action was not prevented by treatment of cells with an inhibitor of adenylyl cyclase. These results demonstrate that GTPgammaS does not act through Galpha(i/o) GTPases and that Galpha(s)/Gbetagamma G proteins inhibit the channel and/or channel regulatory mechanisms through cAMP-independent mechanisms. Swelling-induced activation of I(Cl,swell) was stimulated two- to threefold by GTPgammaS and inhibited by 10 mM guanosine 5'-O-(2-thiodiphosphate). The Rho GTPase inhibitor Clostridium difficile toxin B inhibited both GTPgammaS- and swelling-induced activation of I(Cl,swell). Taken together, these findings indicate that Rho GTPase signaling pathways regulate the I(Cl,swell) channel via phosphorylation-independent mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Animals
  • Anions / metabolism
  • Bacterial Proteins*
  • Bacterial Toxins / pharmacology
  • Cell Size / drug effects
  • Cell Size / physiology
  • Chloride Channels / metabolism*
  • Cholera Toxin / pharmacology
  • Enzyme Inhibitors / pharmacology
  • GTP-Binding Proteins / physiology*
  • Genistein / pharmacology
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Guanosine Diphosphate / analogs & derivatives*
  • Guanosine Diphosphate / pharmacology
  • Mice
  • Neuroblastoma
  • Neurons / drug effects
  • Neurons / metabolism*
  • Patch-Clamp Techniques
  • Phosphorylation
  • Second Messenger Systems / drug effects
  • Second Messenger Systems / physiology
  • Thionucleotides / pharmacology
  • Tumor Cells, Cultured
  • Tyrphostins / pharmacology
  • rho GTP-Binding Proteins / metabolism


  • Anions
  • Bacterial Proteins
  • Bacterial Toxins
  • Chloride Channels
  • Enzyme Inhibitors
  • Thionucleotides
  • Tyrphostins
  • toxB protein, Clostridium difficile
  • tyrphostin A51
  • Guanosine Diphosphate
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • guanosine 5'-O-(2-thiodiphosphate)
  • Adenosine Triphosphate
  • Cholera Toxin
  • Genistein
  • GTP-Binding Proteins
  • rho GTP-Binding Proteins