Relocation of the t-SNARE SNAP-23 from lamellipodia-like cell surface projections regulates compound exocytosis in mast cells

Cell. 1998 Aug 21;94(4):537-48. doi: 10.1016/s0092-8674(00)81594-9.

Abstract

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 granule-plasma membrane and granule-granule fusions.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium / pharmacology
  • Carrier Proteins / metabolism*
  • Cell Membrane / metabolism
  • Cytoskeleton / chemistry
  • Exocytosis / physiology*
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Mast Cells / drug effects
  • Mast Cells / physiology*
  • Membrane Fusion / physiology
  • Membrane Proteins / metabolism
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • R-SNARE Proteins
  • Rats

Substances

  • Carrier Proteins
  • Membrane Proteins
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • R-SNARE Proteins
  • SNAP23 protein, human
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Calcium