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.
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.
|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|
|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|
|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|
|D'Avanzo, Nazzareno; McCusker, Emily C; Powl, Andrew M et al. (2013) Differential lipid dependence of the function of bacterial sodium channels. PLoS One 8:e61216|
|D'Avanzo, Nazzareno; Lee, Sun-Joo; Cheng, Wayland W L et al. (2013) Energetics and location of phosphoinositide binding in human Kir2.1 channels. J Biol Chem 288:16726-37|
|Wang, Shizhen; Lee, Sun-Joo; Heyman, Sarah et al. (2012) Structural rearrangements underlying ligand-gating in Kir channels. Nat Commun 3:617|
|Cheng, Wayland W L; McCoy, Jason G; Thompson, Ameer N et al. (2011) Mechanism for selectivity-inactivation coupling in KcsA potassium channels. Proc Natl Acad Sci U S A 108:5272-7|
|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|
|Cheng, Wayland W L; D'Avanzo, Nazzareno; Doyle, Declan A et al. (2011) Dual-mode phospholipid regulation of human inward rectifying potassium channels. Biophys J 100:620-8|
|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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