Mechanism of PLC-mediated Kir3 current inhibition

Inna Keselman, Miguel Fribourg, Dan P. Felsenfeld, Diomedes E. Logothetis

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

A large number of ion channels maintain their activity through direct interactions with phosphatidylinositol bisphosphate (PIP2). For such channels, hydrolysis of PIP2 causes current inhibition. It has become controversial whether the inhibitory effects on channel activity represent direct effects of PIP2 hydrolysis or of downstream PKC action. We studied Phospholipase C (PLC)-dependent inhibition of G protein-activated inwardly rectifying K + (Kir3) channels. By monitoring simultaneously channel activity and PIP2 hydrolysis, we determined that both direct PIP2 depletion and PKC actions contribute to Kir3 current inhibition. We show that the PKC-induced effects strongly depend on PIP2 levels in the membrane. At the same time, we show that PKC destabilizes Kir3/PIP2 interactions and enhances the effects of PIP2 depletion on channel activity. These results demonstrate that PIP2 depletion and PKC-mediated effects reinforce each other and suggest that both of these interdependent mechanisms contribute to Kir3 current inhibition. This mechanistic insight may explain how even minor changes in PIP2 levels can have profound effects on Kir3 activity. We also show that stabilization of Kir3/PIP2 interactions by Gbg attenuates both PKC and Gq-mediated current inhibition, suggesting that diverse pathways regulate Kir3 activity through modulation of channel interactions with PIP2.

Original languageEnglish (US)
Pages (from-to)113-123
Number of pages11
JournalChannels
Volume1
Issue number2
DOIs
StatePublished - Jan 1 2007
Externally publishedYes

Fingerprint

Type C Phospholipases
Hydrolysis
Inwardly Rectifying Potassium Channel
Phosphatidylinositols
Ion Channels
GTP-Binding Proteins
Stabilization
Modulation
Membranes
Monitoring

Keywords

  • Fluorescence Resonance Energy Transfer (FRET)
  • PIP2
  • PIP2 hydrolysis
  • Protein Kinase C

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry

Cite this

Keselman, I., Fribourg, M., Felsenfeld, D. P., & Logothetis, D. E. (2007). Mechanism of PLC-mediated Kir3 current inhibition. Channels, 1(2), 113-123. https://doi.org/10.4161/chan.4321

Mechanism of PLC-mediated Kir3 current inhibition. / Keselman, Inna; Fribourg, Miguel; Felsenfeld, Dan P.; Logothetis, Diomedes E.

In: Channels, Vol. 1, No. 2, 01.01.2007, p. 113-123.

Research output: Contribution to journalArticle

Keselman, I, Fribourg, M, Felsenfeld, DP & Logothetis, DE 2007, 'Mechanism of PLC-mediated Kir3 current inhibition', Channels, vol. 1, no. 2, pp. 113-123. https://doi.org/10.4161/chan.4321
Keselman I, Fribourg M, Felsenfeld DP, Logothetis DE. Mechanism of PLC-mediated Kir3 current inhibition. Channels. 2007 Jan 1;1(2):113-123. https://doi.org/10.4161/chan.4321
Keselman, Inna ; Fribourg, Miguel ; Felsenfeld, Dan P. ; Logothetis, Diomedes E. / Mechanism of PLC-mediated Kir3 current inhibition. In: Channels. 2007 ; Vol. 1, No. 2. pp. 113-123.
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