Grant: $213,417 - National Institutes of Health - May. 15, 2009
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Award Description: Channelopathies, genetic disorders in brain and muscle ion channels, are useful to investigate the structural determinants of channel neuronal and skeletal muscle sodium channels to determine the mechanisms for channel functions not well understodd, including deactivation and closed-state fast inactivation. We will focus on identifying allosteric, domain-specific regulation of S4 voltage sensors in Specific Aims I to III. We will determine the domain-specific involvement of the voltage sensors in a novel form of channel closure, and then of cytoplasmic regions in the poorly understood process of closed-state inactivation. We will take advantage of the fact that these channelopathies provide point mutations in multiple channel domains. These data will support the long-term objectives of the lab of the PI to study novel channel functions, and novel mechanisms of channel dysfunction in ion channel diseases such as myotoniz and epilepsy. Undergraduates will be trained in molecular biology and patch clamp electrophysiology, and asked to design progressive, testable hypotheses on deactivation and closed-state fast inactivation. A graduate student will construct and test the effects of C terminal mutations on the kinetics and completion of closed-state fast inactivation. Together with the PI, that student will then use gating current measurements to determine the mechanisms by which the C terminus and S4-S5 linkers regulate DIII and DIV voltage sensor movements in closed-state fast inactivation.
Project Description: We have begun our work by creating mutations in voltage sensing regions of the channel in skeletal and cardiac muscle isoforms of the voltage gated sodium channel. Students have focused their research on the characterization of wild type gating parameters using patch clamp recordings. The PI has used the cut open oocyte technique to characterize both ionic and gating charge currents and charge immobilization in these wild type channels and select mutations in DII S4 voltage sensor (skeletal muscle) and the DIII-DIV inactivation linker (cardiac muscle). Our focus is on deactivation (mostly student work using patch clamp recordings) and closed-state fast inactivation (this focus of the proposal in consultation with the program officer of this proposal in response to reviwer's comments on the proposal).
Jobs Summary: Two undergraduate students were hired for summer 2009. One worked as molecular biologist for subcloning of mutations into appropriate expression vectors. The other learned the patch clamp techniqe to perform electorphysiological recordings. Two graduated students (one Biology MS 2009, one Chemistry BA 2009,) were hired to perform laboratory work. This work included animal care, surgeries, injections, and patch clamp electrophysiological recordings. (Total jobs reported: 4)
Project Status: Less Than 50% Completed
This award's data was last updated on May. 15, 2009. Help expand these official descriptions using the wiki below.