This research represents an interdisciplinary approach designed to elucidat chemical and molecular details of the ion channel proteins in the surface membranes of neuronal cells. In order to reach these goals several types of electrophysiological measurements will be combined with biochemical and optical techniques. Two types of neuronal preparations will be used for different projects in order exploit the advantages of The squid giant axon is especially well-suited to measurements of fast electrical signals like ion channel gating currents and for examining various optical signals. The cill bodies ef this axon are useful in measuring single channel currents and, because the Na channels are absent for several days after cell dissociation, can be used for studying Na and K channel gating currents in isolation. Since, unlike the axon, these neurons are not enveloped by Schwann cells, ion channel currents can more accurately be measured.
The specific aims i nclude: (1) determining the functional importance of amino groups on the external surface of the K channel protein, (2) determining th role of divalent cations in conformational changes of K channel proteins, (3) identifying the chemical group(s) forming the internal and external divalent cation binding sites of K channels, and (4) using quantitative analysis of electrophysiological and optical data to identify some molecula details of the conformational change process of Na and K channels. The results of this research will improve our basic understanding of the structure-function relation of ion channel proteins in neuronal cells. Thes ion channels are the targets of a variety of pharmacological and therapeuti agents and are involved in many neurological diseases. Therefore, an improved understanding of these proteins will aid in the improvement of dru design and in the treatment of neurological dysfunction.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS014138-13
Application #
3395419
Study Section
Physiology Study Section (PHY)
Project Start
1977-12-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
13
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Rochester
Department
Type
Schools of Dentistry
DUNS #
208469486
City
Rochester
State
NY
Country
United States
Zip Code
14627
Quinn, C C; Begenisich, T (2001) The influence of surface charges on quaternary ammonium block of shaker K+ channels. J Membr Biol 182:233-43
Thompson, J; Begenisich, T (2001) Affinity and location of an internal K+ ion binding site in shaker K channels. J Gen Physiol 117:373-84
Thompson, J; Begenisich, T (2000) Electrostatic interaction between charybdotoxin and a tetrameric mutant of Shaker K(+) channels. Biophys J 78:2382-91
Thompson, J; Begenisich, T (2000) Interaction between quaternary ammonium ions in the pore of potassium channels. Evidence against an electrostatic repulsion mechanism. J Gen Physiol 115:769-82
Perez-Cornejo, P (1999) H+ ion modulation of C-type inactivation of Shaker K+ channels. Pflugers Arch 437:865-70
Perez-Cornejo, P; Stampe, P; Begenisich, T (1998) Proton probing of the charybdotoxin binding site of Shaker K+ channels. J Gen Physiol 111:441-50
Spires, S; Begenisich, T (1995) Voltage-independent gating transitions in squid axon potassium channels. Biophys J 68:491-500
Perez-Cornejo, P; Begenisich, T (1994) The multi-ion nature of the pore in Shaker K+ channels. Biophys J 66:1929-38
Spires, S; Begenisich, T (1994) Modulation of potassium channel gating by external divalent cations. J Gen Physiol 104:675-92
Nealey, T; Spires, S; Eatock, R A et al. (1993) Potassium channels in squid neuron cell bodies: comparison to axonal channels. J Membr Biol 132:13-25

Showing the most recent 10 out of 21 publications