Protein kinase CK2 is coassembled with small conductance Ca 2+-activated K+ channels and regulates channel gating

Wolfgang Bildl, Tim Strassmaier, Henrike Thurm, Jens Andersen, Silke Eble, Dominik Oliver, Marlies Knipper, Matthias Mann, Uwe Schulte, John P. Adelman, Bernd Fakler

Research output: Contribution to journalArticlepeer-review

148 Scopus citations


Small conductance Ca2+-activated K+ channels (SK channels) couple the membrane potential to fluctuations in intracellular Ca 2+ concentration in many types of cells. SK channels are gated by Ca2+ ions via calmodulin that is constitutively bound to the intracellular C terminus of the channels and serves as the Ca2+ sensor. Here we show that, in addition, the cytoplasmic N and C termini of the channel protein form a polyprotein complex with the catalytic and regulatory subunits of protein kinase CK2 and protein phosphatase 2A. Within this complex, CK2 phosphorylates calmodulin at threonine 80, reducing by 5-fold the apparent Ca2+ sensitivity and accelerating channel deactivation. The results show that native SK channels are polyprotein complexes and demonstrate that the balance between kinase and phosphatase activities within the protein complex shapes the hyperpolarizing response mediated by SK channels.

Original languageEnglish (US)
Pages (from-to)847-858
Number of pages12
Issue number6
StatePublished - Sep 16 2004
Externally publishedYes

ASJC Scopus subject areas

  • Neuroscience(all)


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