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Cancer Cell death Cell cycle Cytoskeleton Exo/endocytosis Differentiation Division Organelles Signalling Stem cells Trafficking
Cell Biology International (2010) 34, 3–12 (Printed in Great Britain)
Review article
Secretory vesicles transiently dock and fuse at the porosome to discharge contents during cell secretion
Bhanu P. Jena1
Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, U.S.A.


In contrast with the observation in electron micrographs of partially empty vesicles in cells following secretion, it has been believed since the 1950s that during cell secretion, secretory vesicles completely merge at the cell plasma membrane, resulting in the diffusion of intravesicular contents to the cell exterior and the compensatory retrieval of the excess membrane by endocytosis. In the interim, a large body of work has been published arguing both for and against the complete merger of secretory vesicle membrane at the cell plasma membrane during secretion. The only definitive determination of the mechanism of cell secretion remained in its direct observation at nanometre resolution in live cells. In the past decade, this finally became a reality through the power and scope of the atomic force microscope, which has made it possible to resolve a major conundrum in cell biology. This paradigm shift in our understanding of cell secretion is briefly outlined here.


Key words: atomic force microscopy, membrane fusion, pancreatic acinar cell, porosome, secretoy vesicle, SNARE

Abbreviations: AFM, atomic force microscopy, GH, growth hormones, NSF, N-ethylmaleimide-sensitive factor, VAMP, vesicle-associated membrane protein, ZG, zymogen granules

1email bjena@med.wayne.edu.


Received 30 September 2009/10 October 2009; accepted 29 October 2009

Published online 16 December 209, doi:10.1042/CBI20090161


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ISSN Print: 1065-6995
ISSN Electronic: 1095-8355
Published by Portland Press Limited on behalf of the International Federation for Cell Biology (IFCB)