Vesicle fusion proteins in rat inner medullary collecting duct ( imcd) and
amphibian bladder.
Franki, Nicholas, Frank Macaluso, Yang Gao, and Richard M. Hays.
Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY
10461, Tel. (718) 430-3158, FAX (718) 824-2765
APStracts 2:0032C, 1995.
The delivery of water channels to the apical membrane in response to
antidiuretic hormone (ADH) requires the targeting of channel -containing
vesicles to specific sites in the membrane, followed by fusion and
exocytosis. A complex array of proteins are now believed to mediate targeting
and fusion in eukaryotic cells. They include N-ethylmaleimide - sensitive
fusion protein (NSF), soluble NSF attachment proteins (SNAPs), and
cellubrevin, a vesicle - associated protein present in the nerve terminal. We
have asked whether these proteins are in epithelial cells of the rat IMCD and
the amphibian bladder. Immunoblots on both tissues showed the presence of NSF
and [alpha]-SNAP. Cellubrevin was present in immunoblots of the IMCD, but not
the bladder. Immunogold electron microscopy showed NSF, [alpha]-SNAP and
cellubrevin in rat IMCD cells, with vesicular labeling. In the bladder, NSF
was seen on vesicles and aggrephores. We would conclude that components of the
vesicle targeting and fusion system are present in kidney and amphibian
bladder, and may mediate a wide variety of fusion events, including those
initiated by ADH.
Received 13 October 1994; accepted in final form 6 December 1994
APS Manuscript Number C612-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1994 The American Physiological Society.
Published in APStracts on 27 February 1995.