Protein Trafficking and Polarity in Kidney Epithelium: From Cell Biology to Physiology. Brown, Dennis, and Jennifer L. Stow. Renal Unit and Department of Pathology, Massachusetts General Hospital and Harvard medical School, Boston, Massachusetts.
APStracts 2:0001P, 1996.
ABSTRACT
The transepithelial movement of fluids, electrolytes, and larger molecules is achieved by the activity of a host of specialized transporting proteins, including enzymes, receptors, and channels, that are located on either the apical, basal, or lateral plasma membrane domains of epithelial cells. In the kidney as well as in all other organs, this remarkable polarity of epithelial cells depends on the selective insertion of newly synthesized and recycling proteins and lipids into distinct plasma membrane domains and on the maintenance and modulation of these specialized domains once they are established during epithelial development. This review addresses the mechanisms by which epithelial cells control the movement of membrane components within the cell to ensure that they are delivered to the correct target membrane. Among the topics discussed are targeting signals within membrane proteins, the role of the cytoskeleton and the tight junctional barrier in cell polarity, and the requirement for accessory proteins in the targeting process, including GTP-binding proteins, and proteins that are involved in vesicle docking and fusion events. The final part of the review is devoted uniquely to the polarized targeting of functionally defined proteins in various kidney cell types. In concluding, examples of how a breakdown in these trafficking pathways may be related to some disease states are presented. 

APS Manuscript Number P-10-5.
Article publication scheduled January 1996 Physiological Reviews.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 22 January 96