Am J Physiol Cell Physiol Watch the video to learn how APS reaches out to developing nations.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 294: C797-C809, 2008. First published January 2, 2008; doi:10.1152/ajpcell.00493.2007
0363-6143/08 $8.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental Figure
Right arrow All Versions of this Article:
294/3/C797    most recent
00493.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Liao, H.
Right arrow Articles by Castle, D.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Liao, H.
Right arrow Articles by Castle, D.

PROTEIN AND VESICLE TRAFFICKING, CYTOSKELETON

Nonredundant function of secretory carrier membrane protein isoforms in dense core vesicle exocytosis

Haini Liao,1 Jie Zhang,1 Svetlana Shestopal,1 Gabor Szabo,2 Anna Castle,1 and David Castle1

1Department of Cell Biology and Cell and Developmental Biology Program and 2Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia

Submitted 18 October 2007 ; accepted in final form 1 January 2008

Five secretory carrier membrane proteins (SCAMP-1, -2, -3, -4, and -5) have been characterized in mammalian cells. Previously, SCAMP-1 and -2 have been implicated to function in exocytosis. RNA inhibitor-mediated deficiency of one or both of these SCAMPs interferes with dense core vesicle (DCV) exocytosis in neuroendocrine PC12 cells as detected by amperometry. Knockdowns of these SCAMPs each decreased the number and frequency of depolarization-induced exocytotic events. SCAMP-2 but not SCAMP-1 depletion also delayed the onset of exocytosis. Both knockdowns, however, altered fusion pore dynamics, increasing rapid pore closure and decreasing pore dilation. In contrast, knockdowns of SCAMP-3 and -5 only interfered with the frequency of fusion pore opening and did not affect the dynamics of newly opened pores. None of the knockdowns noticeably affected upstream events, including the distribution of DCVs near the plasma membrane and calcium signaling kinetics, although norepinephrine uptake/storage was moderately decreased by deficiency of SCAMP-1 and -5. Thus, SCAMP-1 and -2 are most closely linked to the final events of exocytosis. Other SCAMPs collaborate in regulating fusion sites, but the roles of individual isoforms appear at least partially distinct.

neuroendocrine secretion; membrane fusion; amperometry


Address for reprint requests and other correspondence: D. Castle, Dept. of Cell Biology, Univ. of Virginia, Charlottesville, VA 22908 (e-mail: jdc4r{at}virginia.edu)






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2008 by the American Physiological Society.