Potassium channels are specialized integral membrane proteins endowed with a remarkable capacity to accommodate the highly selective passage of potassium ions across cells. Some have the added ability to open and close in response to small changes in transmembrane voltage, and it is these voltage-gated (Kv) potassium channels that are the focus of this proposal. These proteins play crucial roles in a number of physiologic processes ranging from the propagation of information in the nervous system to the maintenance of a normal heart rhythm, and inherited mutations in many of them lead to forms of epilepsy, paralysis, and cardiac arrhythmias. The structures of some parts of Kv channels and their auxiliary subunits are now well understood, yet despite detailed study for over a decade, little is known about the construction of the voltage sensing region of these channels, or about the overall architecture of hetermultimeric channels. In light of this gap, a new method is introduced to complement established techniques of molecular biology and electrophysiology--the use of tethered quaternary ammonium blockers as molecular tape-measures. These compounds will be targeted to intracellular and extracellular regions of two classes of K+ channels: the prototypic voltage-dependent Shaker channel, and heteromultimeric channels formed from the co-assembly of Shaker-like subunits with minK-related peptides (MiRPs). The two specific aims, (1) mapping the extracellular portion of Shaker's gating module, and (2) probing the structure of MiRP-associated channels, will be instrumental in fulfilling the project's long-term objectives of creating a detailed physical map of the gating module of a Kv channel, and determining how the different parts of a Kv channel are molded together.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL068985-02
Application #
6736285
Study Section
Molecular, Cellular and Developmental Neurosciences 2 (MDCN)
Program Officer
Wang, Lan-Hsiang
Project Start
2003-04-15
Project End
2007-03-31
Budget Start
2004-04-01
Budget End
2005-03-31
Support Year
2
Fiscal Year
2004
Total Cost
$324,000
Indirect Cost
Name
Tufts University
Department
Type
DUNS #
079532263
City
Boston
State
MA
Country
United States
Zip Code
02111
Anderson, Damon S; Blaustein, Robert O (2008) Preventing voltage-dependent gating of anthrax toxin channels using engineered disulfides. J Gen Physiol 132:351-60
Darman, Rachel B; Ivy, Allison A; Ketty, Vina et al. (2006) Constraints on voltage sensor movement in the shaker K+ channel. J Gen Physiol 128:687-99