The second PI(3,5)P2 binding site in the S0 helix of KCNQ1 stabilizes PIP2-at the primary PI1 site with potential consequences on intermediate-to-open state transition

Maurice Dellin; Ina Rohrbeck; Purva Asrani; Julian A Schreiber; Nadine Ritter; Frank Glorius; Bernhard Wünsch; Thomas Budde; Louisa Temme; Timo Strünker; Birgit Stallmeyer; Frank Tüttelmann; Sven G Meuth; Marc Spehr; Johann Matschke; Andrea Steinbicker; Christos Gatsogiannis; Raphael Stoll; Nathalie Strutz-Seebohm; Guiscard Seebohm

doi:10.1515/hsz-2022-0247

The second PI(3,5)P₂ binding site in the S0 helix of KCNQ1 stabilizes PIP₂-at the primary PI1 site with potential consequences on intermediate-to-open state transition

Biol Chem. 2023 Feb 23;404(4):241-254. doi: 10.1515/hsz-2022-0247. Print 2023 Mar 28.

Authors

Maurice Dellin¹, Ina Rohrbeck¹, Purva Asrani², Julian A Schreiber^{1

3}, Nadine Ritter^{1

4}, Frank Glorius^{4

5}, Bernhard Wünsch^{3

4}, Thomas Budde^{4

6}, Louisa Temme^{3

4}, Timo Strünker^{4

7

8}, Birgit Stallmeyer⁹, Frank Tüttelmann⁹, Sven G Meuth¹⁰, Marc Spehr¹¹, Johann Matschke¹², Andrea Steinbicker¹³, Christos Gatsogiannis¹⁴, Raphael Stoll², Nathalie Strutz-Seebohm¹, Guiscard Seebohm^{1

4}

Affiliations

¹ IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Robert-Koch Str. 45, D-48149, Münster, Germany.
² Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy and RUBiospek|NMR, Ruhr University of Bochum, Universitätsstraße 150, D-44780, Bochum, Germany.
³ Institut für Pharmazeutische und Medizinische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149, Münster, Germany.
⁴ GRK 2515, Chemical biology of ion channels (Chembion), Westfälische Wilhelms-Universität Münster, Münster, Germany.
⁵ Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstrasse 40, D-48149, Münster, Germany.
⁶ Institute of Physiology I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, D-48149, Münster, Germany.
⁷ Centre of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Domagkstraße 11, D-48149, Münster, Germany.
⁸ Cells in Motion Interfaculty Centre, University of Münster, Münster, Germany.
⁹ Institute of Reproductive Genetics, University of Münster, Vesaliusweg 12-14, D-48149, Münster, Germany.
¹⁰ Department of Neurology, Heinrich Heine University Düsseldorf, Moorenstraße 5, D-40225, Düsseldorf, Germany.
¹¹ Department of Chemosensation, Institute for Biology II, RWTH Aachen University, Worringerweg 3, D-52074, Aachen, Germany.
¹² Institute of Cell Biology (Cancer Research), University Hospital Essen, University of Duisburg-Essen, D-45147, Essen, Germany.
¹³ Goethe University Frankfurt and University Hospital Frankfurt, Theodor-Stern-Kai 7, D-60590, Frankfurt, Germany.
¹⁴ Institute for Medical Physics and Biophysics and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster, Münster, Busso-Peus Strasse 10, D-48149, Germany.

PMID: 36809224
DOI: 10.1515/hsz-2022-0247

Abstract

The Phosphatidylinositol 3-phosphate 5-kinase Type III PIKfyve is the main source for selectively generated phosphatidylinositol 3,5-bisphosphate (PI(3,5)P₂), a known regulator of membrane protein trafficking. PI(3,5)P₂ facilitates the cardiac KCNQ1/KCNE1 channel plasma membrane abundance and therewith increases the macroscopic current amplitude. Functional-physical interaction of PI(3,5)P₂ with membrane proteins and its structural impact is not sufficiently understood. This study aimed to identify molecular interaction sites and stimulatory mechanisms of the KCNQ1/KCNE1 channel via the PIKfyve-PI(3,5)P₂ axis. Mutational scanning at the intracellular membrane leaflet and nuclear magnetic resonance (NMR) spectroscopy identified two PI(3,5)P₂ binding sites, the known PIP₂ site PS1 and the newly identified N-terminal α-helix S0 as relevant for functional PIKfyve effects. Cd²⁺ coordination to engineered cysteines and molecular modeling suggest that repositioning of S0 stabilizes the channel s open state, an effect strictly dependent on parallel binding of PI(3,5)P₂ to both sites.

Keywords: electrophysiology; molecular modeling; phosphatidylinositol; phosphoinositides; phospholipid; potassium channels.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Binding Sites
Cell Membrane / metabolism
KCNQ1 Potassium Channel* / chemistry
KCNQ1 Potassium Channel* / genetics
KCNQ1 Potassium Channel* / metabolism
Mutation
Phosphatidylinositol 4,5-Diphosphate* / chemistry
Phosphatidylinositol 4,5-Diphosphate* / metabolism

Substances

Phosphatidylinositol 4,5-Diphosphate
KCNQ1 Potassium Channel