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

Authors
  • Wilson, G G
  • O'Neill, C A
  • Sivaprasadarao, A
  • Findlay, J B
  • Wray, D
Type
Published Article
Journal
Pflügers Archiv : European journal of physiology
Publication Date
Sep 01, 1994
Volume
428
Issue
2
Pages
186–193
Identifiers
PMID: 7971176
Source
Medline
License
Unknown

Abstract

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.

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