Modulation by protein kinase A of a cloned rat brain potassium channel expressed in Xenopus oocytes

Pflugers Arch. 1994 Sep;428(2):186-93. doi: 10.1007/BF00374857.


A potassium channel from rat brain was expressed in Xenopus oocytes in order to study modulation of channel function by phosphorylation via protein kinase A. Application of 8-Br-cAMP to oocytes expressing the drk1 channel (with the first 139 amino acids of the N terminus deleted, delta Ndrk1) caused a voltage-independent elevation of current amplitude, which was not seen for endogenous currents or for wild-type full-length drk1 channel. This effect on delta Ndrk1 was blocked by pre-injection of oocytes with Walsh-peptide protein kinase A inhibitor, suggesting mediation via protein kinase A. The protein kinase inhibitor also reduced both delta Ndrk1 and full-length drk1 currents. Substitution of the serine residues by alanine at one or both of the two consensus protein kinase A phosphorylation sites on the C terminus (residues 440 and 492) of delta Ndrk1 resulted in a loss of function of the expressed channels. These results indicate that phosphorylation via protein kinase A modulates drk1 channel function and that both consensus phosphorylation sites seems to be essential for channels to function.

MeSH terms

  • 8-Bromo Cyclic Adenosine Monophosphate / pharmacology
  • Animals
  • Base Sequence
  • Brain Chemistry
  • Cloning, Molecular
  • Cyclic AMP-Dependent Protein Kinases / antagonists & inhibitors
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Delayed Rectifier Potassium Channels
  • Female
  • Molecular Sequence Data
  • Oocytes / metabolism
  • Patch-Clamp Techniques
  • Phosphorylation
  • Point Mutation
  • Potassium Channel Blockers
  • Potassium Channels / drug effects
  • Potassium Channels / genetics
  • Potassium Channels / metabolism*
  • Potassium Channels, Voltage-Gated*
  • RNA, Complementary / pharmacology*
  • Rats
  • Xenopus laevis


  • Delayed Rectifier Potassium Channels
  • Potassium Channel Blockers
  • Potassium Channels
  • Potassium Channels, Voltage-Gated
  • RNA, Complementary
  • 8-Bromo Cyclic Adenosine Monophosphate
  • Cyclic AMP-Dependent Protein Kinases