The pH cycling of individual granules in secreting (serotonin-loaded) mast cells is quantitatively examined using multicolor multiphoton fluorescence microscopy. A typical exocytosis event consists of maximal calcium rise at time zero, granule alkalization a few seconds later and, finally, complete contents release at a fraction of a second after alkalization. Membrane fusion is either transient, as indicated by subsequent granule reacidification, or ‘full’, as indicated by a granule disappearance with a collapse of its membrane into the plasma membrane. The relative frequency of these two coexisting behaviors (the ‘kiss-to-collapse’ ratio) is approximately 2:1. A typical transiently fusing granule experiences multiple alkalization/acidification cycles after addition of exogenous antigen. Between recycling granules, coalescence events are frequent, with 80% resulting in a collapse of the formed granule complex to the plasma membrane. The full dynamics of secretion encompass a complex combination of these granule activities.
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JOURNAL ARTICLE| 01 November 2000
Single granule pH cycling in antigen-induced mast cell secretion
Online Issn: 1477-9137
Print Issn: 0021-9533
© 2000 by Company of Biologists
J Cell Sci (2000) 113 (21): 3839–3850.
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R.M. Williams, W.W. Webb; Single granule pH cycling in antigen-induced mast cell secretion. J Cell Sci 1 November 2000; 113 (21): 3839–3850. doi: https://doi.org/10.1242/jcs.113.21.3839
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