Localization of amiloride-sensitive sodium channels in a6 cells by
atomic force microscopy.
Smith, Peter R., Anne Lynn Bradford, Stefan Schneider, Dale J. Benos,
and John P. Geibel.
Department of Physiology - Medical College of Pennsylvania and
Hahnemann University, Philadelphia, PA 19129, Department of
Physiology and Biophysics, The University of Alabama at Birmingham,
Birmingham, Alabama 35294, Department of Surgery and Cell & Molecular
Physiology, Yale University, New Haven, CT 06510
APStracts 3:0365C, 1996.
Atomic force microscopy (AFM) was used for high resolution imaging of
the apical distribution of epithelial Na& channels in A6 renal
epithelial cells. A6 cells grown on coverslips were labeled with
antibodies generated an against amiloride-sensitive epithelial
Na& channel complex purified from bovine renal medulla that had
been conjugated to 8 nm colloidal gold particles prior to preparation
for AFM. AFM revealed that there was a marked increase in the height
of the microvilli in cells labeled with the anti-epithelial Na&
channel antibodies, when compared to unlabeled cells or cells labeled
with rabbit non-immune IgG conjugated to colloidal gold particles. We
interpret this apparent increase in microvillar height to be due to
the anti-epithelial Na& channel antibody binding to the apical
microvilli. These data demonstrate that epithelial Na& channels
are restricted to the apical microvilli in Na& transporting renal
epithelial cells. Furthermore, they demonstrate the applicability of
using AFM for high resolution imaging of the cell surface
distribution of epithelial ion channels.
Received 13 June 1996; accepted in final form 7 November 1996.
APS Manuscript Number C339-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996