Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
High molecular weight polymers block cortical granule exocytosis in sea urchin eggs at the level of granule matrix disassembly.
Chandler DE
,
Whitaker M
,
Zimmerberg J
.
???displayArticle.abstract???
Recently, we have shown that high molecular weight polymers inhibit cortical granule exocytosis at total osmolalities only slightly higher than that of sea water (Whitaker, M., and J. Zimmerberg. 1987. J. Physiol. 389:527-539). In this study, we visualize the step at which this inhibition occurs. Lytechinus pictus and Strongylocentrotus purpuratus eggs were exposed to 0.8 M stachyose or 40% (wt/vol) dextran (average molecular mass of 10 kD) in artificial sea water, activated with 60 microM of the calcium ionophore A23187, and then either fixed with glutaraldehyde and embedded or quick-frozen and freeze-fractured. Stachyose (2.6 osmol/kg) appears to inhibit cortical granule exocytosis by eliciting formation of a granule-free zone (GFZ) in the egg cortex which pushes granules away from the plasma membrane thus preventing their fusion. In contrast, 40% dextran (1.58 osmol/kg) does not result in a GFZ and cortical granules undergo fusion. In some specimens, the pores joining granule and plasma membranes are relatively small; in other cases, the exocytotic pocket has been stabilized in an omega configuration and the granule matrix remains intact. These observations suggest that high molecular weight polymers block exocytosis because of their inability to enter the granule matrix: they retard the water entry that is needed for matrix dispersal.
Anderson,
Oocyte differentiation in the sea urchin, Arbacia punctulata, with particular reference to the origin of cortical granules and their participation in the cortical reaction.
1968, Pubmed,
Echinobase
Anderson,
Oocyte differentiation in the sea urchin, Arbacia punctulata, with particular reference to the origin of cortical granules and their participation in the cortical reaction.
1968,
Pubmed
,
Echinobase
Bilinski,
Secretory protein decondensation as a distinct, Ca2+-mediated event during the final steps of exocytosis in Paramecium cells.
1981,
Pubmed
Chandler,
Membrane fusion during secretion: cortical granule exocytosis in sex urchin eggs as studied by quick-freezing and freeze-fracture.
1979,
Pubmed
,
Echinobase
Chandler,
The vitelline layer of the sea urchin egg and its modification during fertilization. A freeze-fracture study using quick-freezing and deep-etching.
1980,
Pubmed
,
Echinobase
Chandler,
Arrest of membrane fusion events in mast cells by quick-freezing.
1980,
Pubmed
Chandler,
Comparison of quick-frozen and chemically fixed sea-urchin eggs: structural evidence that cortical granule exocytosis is preceded by a local increase in membrane mobility.
1984,
Pubmed
,
Echinobase
Chandler,
Exocytosis involves highly localized membrane fusions.
1984,
Pubmed
Cohen,
Fusion of phospholipid vesicles with planar phospholipid bilayer membranes. II. Incorporation of a vesicular membrane marker into the planar membrane.
1980,
Pubmed
Cohen,
Parameters affecting the fusion of unilamellar phospholipid vesicles with planar bilayer membranes.
1984,
Pubmed
ENDO,
The role of the cortical granules in the formation of the fertilization membrane in the eggs of sea urchins. II.
1961,
Pubmed
,
Echinobase
Eddy,
Changes in the topography of the sea urchin egg after fertilization.
1976,
Pubmed
,
Echinobase
Edwards,
Light microscopic observations on the release of vesicles by isolated chromaffin cells.
1984,
Pubmed
Gilligan,
Stimulation and inhibition of secretion in Paramecium: role of divalent cations.
1983,
Pubmed
Hampton,
Effects of changes in osmolality on the stability and function of cultured chromaffin cells and the possible role of osmotic forces in exocytosis.
1983,
Pubmed
Heuser,
Synaptic vesicle exocytosis captured by quick freezing and correlated with quantal transmitter release.
1979,
Pubmed
Kazilek,
Hyperosmotic inhibition of calcium signals and exocytosis in rabbit neutrophils.
1988,
Pubmed
Lubbock,
Novel role of calcium in exocytosis: mechanism of nematocyst discharge as shown by x-ray microanalysis.
1981,
Pubmed
Ornberg,
Beginning of exocytosis captured by rapid-freezing of Limulus amebocytes.
1981,
Pubmed
Pollard,
Evidence for control of serotonin secretion from human platelets by hydroxyl ion transport and osmotic lysis.
1977,
Pubmed
Pollard,
An osmotic mechanism for exocytosis from dissociated chromaffin cells.
1984,
Pubmed
Steinhardt,
Intracellular calcium release at fertilization in the sea urchin egg.
1977,
Pubmed
,
Echinobase
Swann,
The part played by inositol trisphosphate and calcium in the propagation of the fertilization wave in sea urchin eggs.
1986,
Pubmed
,
Echinobase
Verdugo,
Hydration kinetics of exocytosed mucins in cultured secretory cells of the rabbit trachea: a new model.
1984,
Pubmed
Veron,
Sequential biochemical and morphological events during assembly of the fertilization membrane of the sea urchin.
1977,
Pubmed
,
Echinobase
Whitaker,
Calcium-dependent exocytosis in an in vitro secretory granule plasma membrane preparation from sea urchin eggs and the effects of some inhibitors of cytoskeletal function.
1983,
Pubmed
,
Echinobase
Whitaker,
Inhibition of secretory granule discharge during exocytosis in sea urchin eggs by polymer solutions.
1987,
Pubmed
,
Echinobase
Zimmerberg,
Irreversible swelling of secretory granules during exocytosis caused by calcium.
1985,
Pubmed
,
Echinobase
Zimmerberg,
Exocytosis of sea urchin egg cortical vesicles in vitro is retarded by hyperosmotic sucrose: kinetics of fusion monitored by quantitative light-scattering microscopy.
1985,
Pubmed
,
Echinobase
Zimmerberg,
Simultaneous electrical and optical measurements show that membrane fusion precedes secretory granule swelling during exocytosis of beige mouse mast cells.
1987,
Pubmed
Zimmerberg,
Molecular mechanisms of membrane fusion: steps during phospholipid and exocytotic membrane fusion.
1987,
Pubmed
Zimmerberg,
Polymer inaccessible volume changes during opening and closing of a voltage-dependent ionic channel.
1986,
Pubmed
