For regulated secretion, mast cells and several other cell types utilize compound exocytosis, a combination of granule-plasma membrane and granule- granule fusions. The molecular machinery that controls this massive export process has not been identified. We report that SNAP-23, a t-SNARE related to SNAP-25, relocates in response to stimulation from plasma membrane lamellipodia-like projections to granule membranes in permeabilized mast cells. While relocation is a prerequisite for secretion, it can occur without membrane fusion and will expedite a subsequent secretory response. After relocation, SNAP-23 is required for exocytosis, implying a crucial role in promoting membrane fusion. Thus, relocation of this SNARE regulates compound exocytosis and links granuleplasma membrane and granule-granule fusions.
|Number of pages||12|
|State||Published - Aug 21 1998|
Bibliographical noteFunding Information:
We thank Drs. Pietro DeCamilli, Judith White, and Samuel Green for reading this manuscript; Drs. Carl Creutz, Samuel Green, Anna Castle, and members of the Castle lab for valuable discussion. We are grateful to Drs. Pam Tuma, Ann Hubbard, Pietro DeCamilli, Reinhard Jahn, and Michael Caplan for providing antibodies; to Jan Redick and Bonnie Sheppard (Electron Microscope Facility) for providing cell sections for immunogold labeling; and to the UVA Biomolecular Research Facility for peptide synthesis. Special thanks to Dr. Theo Wu for initial Western blotting to identify SNAREs in mast cells. These studies were supported by a grant from the National Institutes of Health (DE09655).
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology (all)