Vesicle-vesicle fusion initiated in cell cytoplasm by high Ca2+ can rapidly erect large membrane boundaries. These might be used as a 'patch' for resealing plasma membrane disruptions. Three central predictions of this 'patch' hypothesis are here established in sea urchin eggs. First, we show that surface markers for plasma membrane protein and lipid are initially absent over disruption sites after resealing is complete. Second, we demonstrate that resealing capacity is strongly dependent upon local availability of fusion competent cytoplasmic organelles, specifically the reserve or yolk granule. Lastly, we demonstrate that the reserve granule is capable of rapid (t 1/2 < 1 second), Ca2+-regulated thigh threshold) fusion capable of erecting large (> 1000 μm2), continuous membrane boundaries. Production of patch vesicles for resealing may proceed by an 'emergency' fusion mechanism distinct from that utilized for the much slower, highly regulated, cytosol-requiring organelle-organelle fusion events typical of constitutive membrane trafficking pathways.
|Original language||English (US)|
|Number of pages||12|
|Journal||Journal of Cell Science|
|State||Published - Jun 28 2000|
- Plasma membrane
ASJC Scopus subject areas
- Cell Biology