Discovery and mechanism of BK channel gating modulators

项目总结

PROJECT SUMMARY Large conductance calcium-activated K channels (SLO-1 or BK channels) play a key physiological role in limiting smooth muscle contractility and neuronal excitability. Deletion of BK channel pore-forming (alpha) or modulatory (beta) subunits in gene-targeted animal models can lead to diseases that include arterial hypertension, bladder and erectile dysfunction, and neurological disorders including epilepsy; mutations in human BK channel subunits are linked to generalized epilepsy with paroxysmal dyskinesia (GEPD), asthma, and autism spectrum disorders. BK channel activators could thus become components of treatment regimens for cardiovascular and/or neurological disease. To exploit BK channels as a potential medical target, it will be important to expand our molecular arsenal of BK channel activators and learn their mechanisms of action. Doing so will lead to advances in an overall effort to understand BK channel gating mechanisms and ultimately find new treatments for cardiovascular and neurological disease. Under this proposal, we will achieve these goals through a combination of 1) cell-based fluorescent screening, which is aimed at discovery of novel gating modulators for BK channels comprised of tissue-specific subunit combinations, and 2) systematic electrophysiological experiments to determine whether these drugs modulate BK channel function through interactions with the Ca2+-sensor, voltage-sensor, or pore domains of the channel. This equipment supplement will be used for purchase of an isothermal titration calorimeter (ITC) that is capable of directly determining thermodynamic binding constants in drug-receptor interactions. This tool will greatly enhance our research to yield fundamental insights toward BK channel gating mechanisms that may further lead to new treatments for disease.