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.

National Institute of Health (NIH)
Research Project (R01)
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Biophysics of Neural Systems Study Section (BPNS)
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Krull, Holly
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Washington University
Anatomy/Cell Biology
Schools of Medicine
Saint Louis
United States
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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
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D'Avanzo, Nazzareno; Hyrc, Krzysztof; Enkvetchakul, Decha et al. (2011) Enantioselective protein-sterol interactions mediate regulation of both prokaryotic and eukaryotic inward rectifier K+ channels by cholesterol. PLoS One 6:e19393
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McCusker, Emily C; D'Avanzo, Nazzareno; Nichols, Colin G et al. (2011) Simplified bacterial "pore" channel provides insight into the assembly, stability, and structure of sodium channels. J Biol Chem 286:16386-91

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