Water channel-carrying vesicles in the rat imcd contain cellubrevin. Franki, N., F. Macaluso, W. Schubert, L. Gunther, and R. M. Hays. Department of Medicine and Analytic Ultrastructure Center, Albert Einstein College of Medicine, Bronx, New York 10461
APStracts 2:0243C, 1995.
Antidiuretic hormone induces a cyclic process of docking, fusion and endocytosis of water channel-containing vesicles in the collecting duct. There is now evidence that docking and endocytosis is mediated by an array of proteins associated with vesicles and target membranes. In recent studies, we have shown that cellubrevin, a member of the VAMP (vesicle-associated membrane protein) family, as well as other docking proteins, are expressed in the rat inner medullary collecting duct (IMCD). We now show by immunogold electron microscopy that cellubrevin is present on vesicles containing water channels, that it is associated with both coated and uncoated vesicles, and that it is present on the apical membrane. Cellubrevin, therefore, is in a position to mediate one or more steps in ADH -induced water channel cycling. 

Received June 1995; accepted in final form 20 June 1995.
APS Manuscript Number C309-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 11 July 1995.