Inward rectifying potassium (Kir) channels regulate excitability in many tissues, and multiple diseases result from mutations of Kir channel genes. The long-term goal of this project is to understand the molecular details of Kir channel function. Previously, we discovered that soluble cytoplasmic polyamines cause inward rectification and demonstrated their mechanism and sites of action in the channel. We have developed novel systems for large-scale purification of bacterial and human Kir channels, and have succeeded in functional analysis of these recombinant channel proteins in reconstituted membrane systems. Together with ideas generated by recent crystal structures of both pro- and eukaryotic Kir channels, our novel approaches to biochemical and functional analysis of these channels allow us to develop and address exciting new questions and hypotheses regarding the fundamental basis of Kir channel activity. We will determine the molecular mechanisms by which lipids regulate gating in model Kir channels, and the dynamic structural changes that accompany gating, by combinations of biochemical and electrophysiological recordings.

Public Health Relevance

Inward rectifier potassium channels control excitability in many tissues and defects in these channels in humans lead to multiple diseases, including cardiac arrhythmias, diabetes, vascular dysfunction, epilepsy and other disorders of cell excitability. The novel approaches that we have uniquely developed put us in position to bring previously unobtainable insights to the molecular mechanisms of the functioning of these channels. As such, the work will provide fundamental information for developing rational therapies to treat human diseases resulting from channel dysfunction.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL054171-17A1
Application #
8579279
Study Section
Biophysics of Neural Systems Study Section (BPNS)
Program Officer
Krull, Holly
Project Start
1995-05-01
Project End
2018-07-31
Budget Start
2013-08-15
Budget End
2014-07-31
Support Year
17
Fiscal Year
2013
Total Cost
$361,760
Indirect Cost
$123,760
Name
Washington University
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Wang, Shizhen; Vafabakhsh, Reza; Borschel, William F et al. (2016) Structural dynamics of potassium-channel gating revealed by single-molecule FRET. Nat Struct Mol Biol 23:31-6
Lee, Sun-Joo; Ren, Feifei; Zangerl-Plessl, Eva-Maria et al. (2016) Structural basis of control of inward rectifier Kir2 channel gating by bulk anionic phospholipids. J Gen Physiol 148:227-37
Méndez-González, Miguel P; Kucheryavykh, Yuriy V; Zayas-Santiago, Astrid et al. (2016) Novel KCNJ10 Gene Variations Compromise Function of Inwardly Rectifying Potassium Channel 4.1. J Biol Chem 291:7716-26
Zubcevic, Lejla; Wang, Shizhen; Bavro, Vassiliy N et al. (2015) Modular Design of the Selectivity Filter Pore Loop in a Novel Family of Prokaryotic 'Inward Rectifier' (NirBac) channels. Sci Rep 5:15305
Li, Dan C; Nichols, Colin G; Sala-Rabanal, Monica (2015) Role of a Hydrophobic Pocket in Polyamine Interactions with the Polyspecific Organic Cation Transporter OCT3. J Biol Chem 290:27633-43
Zubcevic, Lejla; Bavro, Vassiliy N; Muniz, Joao R C et al. (2014) Control of KirBac3.1 potassium channel gating at the interface between cytoplasmic domains. J Biol Chem 289:143-51
Fürst, Oliver; Nichols, Colin G; Lamoureux, Guillaume et al. (2014) Identification of a cholesterol-binding pocket in inward rectifier K(+) (Kir) channels. Biophys J 107:2786-96
Sala-Rabanal, Monica; Li, Dan C; Dake, Gregory R et al. (2013) Polyamine transport by the polyspecific organic cation transporters OCT1, OCT2, and OCT3. Mol Pharm 10:1450-8
Lee, Sun-Joo; Wang, Shizhen; Borschel, William et al. (2013) Secondary anionic phospholipid binding site and gating mechanism in Kir2.1 inward rectifier channels. Nat Commun 4:2786
Kurata, Harley T; Akrouh, Alejandro; Li, Jenny B W et al. (2013) Scanning the topography of polyamine blocker binding in an inwardly rectifying potassium channel. J Biol Chem 288:6591-601

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