TY - JOUR
T1 - Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates KCNQ3 K channels by interacting with four cytoplasmic channel domains
AU - Choveau, Frank S.
AU - De la Rosa, Victor
AU - Bierbower, Sonya M.
AU - Hernandez, Ciria C.
AU - Shapiro, Mark S.
N1 - Funding Information:
This work was supported by National Institutes of Health Grants R01 NS150305, R01 NS094461, and R56 NS153503 (to M. S. S.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2018 Choveau et al.
PY - 2018/12/14
Y1 - 2018/12/14
N2 - Phosphatidylinositol 4,5-bisphosphate (PIP2) in the plasma membrane regulates the function of many ion channels, including M-type (potassium voltage-gated channel subfamily Q member (KCNQ), Kv7) K channels; however, the molecular mechanisms involved remain unclear. To this end, we here focused on the KCNQ3 subtype that has the highest apparent affinity for PIP2 and performed extensive mutagenesis in regions suggested to be involved in PIP2 interactions among the KCNQ family. Using perforated patch-clamp recordings of het-erologously transfected tissue culture cells, total internal reflection fluorescence microscopy, and the zebrafish (Danio rerio) voltage-sensitive phosphatase to deplete PIP2 as a probe, we found that PIP2 regulates KCNQ3 channels through four different domains: 1) the A–B helix linker that we previously identified as important for both KCNQ2 and KCNQ3, 2) the junction between S6 and the A helix, 3) the S2–S3 linker, and 4) the S4 –S5 linker. We also found that the apparent strength of PIP2 interactions within any of these domains was not coupled to the voltage dependence of channel activation. Extensive homology modeling and docking simulations with the WT or mutant KCNQ3 channels and PIP2 were consistent with the experimental data. Our results indicate that PIP2 modulates KCNQ3 channel function by interacting synergistically with a minimum of four cytoplasmic domains.
AB - Phosphatidylinositol 4,5-bisphosphate (PIP2) in the plasma membrane regulates the function of many ion channels, including M-type (potassium voltage-gated channel subfamily Q member (KCNQ), Kv7) K channels; however, the molecular mechanisms involved remain unclear. To this end, we here focused on the KCNQ3 subtype that has the highest apparent affinity for PIP2 and performed extensive mutagenesis in regions suggested to be involved in PIP2 interactions among the KCNQ family. Using perforated patch-clamp recordings of het-erologously transfected tissue culture cells, total internal reflection fluorescence microscopy, and the zebrafish (Danio rerio) voltage-sensitive phosphatase to deplete PIP2 as a probe, we found that PIP2 regulates KCNQ3 channels through four different domains: 1) the A–B helix linker that we previously identified as important for both KCNQ2 and KCNQ3, 2) the junction between S6 and the A helix, 3) the S2–S3 linker, and 4) the S4 –S5 linker. We also found that the apparent strength of PIP2 interactions within any of these domains was not coupled to the voltage dependence of channel activation. Extensive homology modeling and docking simulations with the WT or mutant KCNQ3 channels and PIP2 were consistent with the experimental data. Our results indicate that PIP2 modulates KCNQ3 channel function by interacting synergistically with a minimum of four cytoplasmic domains.
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U2 - 10.1074/jbc.RA118.005401
DO - 10.1074/jbc.RA118.005401
M3 - Article
C2 - 30348901
AN - SCOPUS:85058519882
VL - 293
SP - 19411
EP - 19428
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 50
ER -