The broad,long-term objective of this proposal is to develop a detailed understanding of structure-function relationships within the voltage- dependent sodium channel molecule.
The Specific Aims are: 1) To clarify the functional significance of each of the four S4 segments within the tetrameric sodium channel molecule; 2) To clarify the interactions between activation and fast inactivation at the structural level; 3) To clarify the effects of """"""""distant"""""""" sites on activity of the S4 segments within each domain. The experimental design involves detailed functional analysis of mutant channels expressed in Xenopus oocytes following site directed mutagenesis to alter specific regions of the channel molecule. The details of this design reflect our sophisticated approach to electrophysiological analysis of sodium channel mechanisms and our recent advances in this area. The methods used involve voltage-clamp analyses of channel properties (in which we have much expertise) and molecular biological methods which are relatively new to our laboratory. We have recruited a coinvestigator from this campus with extensive experience in site-directed mutagenesis and have developed collaborative agreements with other investigators to ensure appropriate support for this initiative. Our proposed work is strongly health-related since the sodium channel molecule is affected by many drugs and is the basis for the electrical excitability of cardiac muscle, skeletal muscle and nerve cells.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS021151-07A2
Application #
3402023
Study Section
Physiology Study Section (PHY)
Project Start
1984-07-01
Project End
1996-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
7
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Hawaii
Department
Type
Organized Research Units
DUNS #
121911077
City
Honolulu
State
HI
Country
United States
Zip Code
96822
Gessner, Guido; Macianskiene, Regina; Starkus, John G et al. (2010) The amiodarone derivative KB130015 activates hERG1 potassium channels via a novel mechanism. Eur J Pharmacol 632:52-9
Starkus, John G; Varga, Zoltan; Schonherr, Roland et al. (2003) Mechanisms of the inhibition of Shaker potassium channels by protons. Pflugers Arch 447:44-54
Varga, Zoltan; Rayner, Martin D; Starkus, John G (2002) Cations affect the rate of gating charge recovery in wild-type and W434F Shaker channels through a variety of mechanisms. J Gen Physiol 119:467-85
Starkus, J G; Heinemann, S H; Rayner, M D (2000) Voltage dependence of slow inactivation in Shaker potassium channels results from changes in relative K(+) and Na(+) permeabilities. J Gen Physiol 115:107-22
Bao, H; Hakeem, A; Henteleff, M et al. (1999) Voltage-insensitive gating after charge-neutralizing mutations in the S4 segment of Shaker channels. J Gen Physiol 113:139-51
Starkus, J G; Kuschel, L; Rayner, M D et al. (1998) Macroscopic Na+ currents in the ""Nonconducting"" Shaker potassium channel mutant W434F. J Gen Physiol 112:85-93
Ruben, P C; Fleig, A; Featherstone, D et al. (1997) Effects of clamp rise-time on rat brain IIA sodium channels in Xenopus oocytes. J Neurosci Methods 73:113-22
Starkus, J G; Kuschel, L; Rayner, M D et al. (1997) Ion conduction through C-type inactivated Shaker channels. J Gen Physiol 110:539-50
Starkus, J G; Schlief, T; Rayner, M D et al. (1995) Unilateral exposure of Shaker B potassium channels to hyperosmolar solutions. Biophys J 69:860-72
Fleig, A; Ruben, P C; Rayner, M D (1994) Kinetic mode switch of rat brain IIA Na channels in Xenopus oocytes excised macropatches. Pflugers Arch 427:399-405

Showing the most recent 10 out of 19 publications