Differential expression of na/k-atpase, ankyrin, fodrin, and e
-cadherin along the kidney nephron.
Piepenhagen, Peter A., Luanne L. Peters, Samuel E. Lux, & W. James
Nelson.
Department of Molecular & Cellular Physiology, Stanford
University School of Medicine, Stanford, CA 94305-5426
APStracts 2:0284C, 1995.
Ionic homeostasis in vertebrates is maintained by epithelial cells
that line kidney nephrons. Transport of ions and solutes is coupled
to Na+ reabsorption from the ultrafiltrate and requires specific
subcellular distribution and activity of Na/K-ATPase along the
nephron. Studies using cell culture models of renal epithelia
indicate that the subcellular distribution of Na/K-ATPase is
regulated by interactions with the submembrane cytoskeleton and E
-cadherin-mediated adherens junctions. We have now examined the
relevance of these in vitro observations to the subcellular
organization of these proteins in different nephron segments of the
adult mouse kidney using immunofluorescence microscopy. Our results
demonstrate that segmental and subcellular distributions of Na/K
-ATPase and the membrane-cytoskeletal proteins, ankyrin and fodrin,
vary in parallel along the nephron and do not parallel variations in
expression of the tight junction protein ZO-1 or E-cadherin. These
data indicate that a mechanism for restricting Na/K-ATPase subcelluar
distributions through interactions with the membrane cytoskeleton is
likely to be relevant in vivo.
Received 27 December 1994; accepted in final form 25 May 1995.
APS Manuscript Number C742-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 July 1995.