Presence of dynamin--syntaxin complexes associated with secretory granules in adrenal chromaffin cells

J Neurochem. 2000 Oct;75(4):1511-9. doi: 10.1046/j.1471-4159.2000.0751511.x.

Abstract

Dynamin proteins have been implicated in many aspects of endocytosis, including clathrin-mediated endocytosis, internalization of caveolae, synaptic vesicle recycling, and, more recently, vesicular trafficking to and from the Golgi complex. To provide further insight into the function(s) of dynamin in neuroendocrine cells, we have examined its intracellular distribution in cultured chromaffin cells by subcellular fractionation, immunoreplica analysis, and confocal immunofluorescence. We found that dynamin, presumably the dynamin-2 isoform, is associated specifically with the membrane of purified secretory chromaffin granules. Oligomerization state analysis by sucrose density velocity gradients indicated that the granule-associated dynamin is in a monomeric form. Immunoprecipitation experiments coupled to double-labeling immunofluorescence cytochemistry revealed that the granular dynamin is associated with a syntaxin component that is not involved in the granule-bound SNARE complex. The possibility that dynamin participates in the coupling of the exocytotic and endocytotic reaction through the building of a granular membrane subset of proteins is discussed.

MeSH terms

  • Adrenal Glands / cytology
  • Adrenal Glands / metabolism*
  • Animals
  • Cattle
  • Cells, Cultured
  • Chelating Agents / pharmacology
  • Chromaffin Cells / cytology
  • Chromaffin Cells / metabolism*
  • Chromaffin Granules / chemistry
  • Chromaffin Granules / metabolism*
  • Detergents / chemistry
  • Dimerization
  • Dynamin I
  • Dynamins
  • Fluorescent Antibody Technique
  • GTP Phosphohydrolases / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
  • Guanosine Triphosphate / metabolism
  • Guanosine Triphosphate / pharmacology
  • Intracellular Membranes / chemistry
  • Intracellular Membranes / metabolism
  • Membrane Proteins / metabolism*
  • Precipitin Tests
  • Protein Binding / drug effects
  • Qa-SNARE Proteins

Substances

  • Chelating Agents
  • Detergents
  • Membrane Proteins
  • Qa-SNARE Proteins
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate
  • Dynamin I
  • GTP Phosphohydrolases
  • Dynamins