BIOPHYSICS OF GAP JUNCTION CHANNELS

Project: Research project

Project Details

Description

During the past several years we have developed a novel expression system
for gap junction channels, using communication deficient mammalian cells
to generate cell lines in which cDNAs encoding gap junction proteins
(connexins) are stably expressed. This approach differs from the more
commonly used system, injection of connexin mRNA into Xenopus oocytes, in
several ways that facilitate the study of the expressed gap junction
channels, one of the most notable being that dual whole cell recording from
pairs of mammalian cells permits examination of single channel properties.
Stable transfectants currently available include a number of mammalian gap
junction proteins, as well as that of an amphibian that show marked voltage
sensitivity. Moreover, we have expressed several mutant constructs
designed to test various hypotheses concerning gating domains of the
channel protein. This grant application seeks to use these various cell
lines to answer several questions that have been important to the gap
junction field but have been difficult to address using primary cell
cultures. We intend to 1) Determine the effect of phosphorylation state
of the gap junction proteins on physiological properties of the channels
that they form, 2) determine the effects of charge substitutions within the
third membrane spanning domain on gap junction charge and size selectivity,
3) identify the portions of the gap junction protein that form the regions
sensitive to pH and to transjunctional voltage, and 4) examine the
properties of paired connexin molecules of different types. These studies
should enormously "tend our understanding of the properties of gap junction
channels and may result in novel molecular approaches to increase or
decrease gap junction function in normal and pathological tissues.
StatusFinished
Effective start/end date1/1/9011/30/95

Funding

  • National Institute of Neurological Disorders and Stroke
  • National Institute of Neurological Disorders and Stroke
  • National Institute of Neurological Disorders and Stroke

ASJC

  • Cardiology and Cardiovascular Medicine
  • Cell Biology

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