Annexin I is stored within gelatinase granules of human neutrophil and mobilized on the cell surface upon adhesion but not phagocytosis

Cell Biol Int. 2000;24(3):163-74. doi: 10.1006/cbir.1999.0468.


Annexin I, a member of the calcium- and phospholipid-binding annexin superfamily of proteins, is largely present in human neutrophils. To determine its exact intracellular distribution a combination of flow cytometry, confocal microscopy and electron microscopy analyses were performed on resting human neutrophils as well as on cells which had been activated. In resting neutrophils, annexin I was found to be present in small amounts in the nucleus, in the cytoplasm and partially also associated with the plasma membrane. The cytoplasmic pool of annexin I was predominant, and the protein was co-localized with gelatinase (marker of gelatinase granules), but not with human serum albumin or CD35 (markers of secretory vesicles), or with lysosomes. Electron microscopy showed the presence of annexin I inside the gelatinase granules. Neutrophil adhesion to monolayers of endothelial cells, but not phagocytosis of particles of opsonized zymosan, provoked an intense mobilization of annexin I, with a marked externalization on the outer leaflet of the plasma membrane. Remaining intracellular annexin I was also found in proximity of the plasma membrane. These results provide a novel mechanism for annexin I secretion from human neutrophils, which is via a degranulation event involving gelatinase granules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Annexin A1 / metabolism*
  • Cell Adhesion
  • Cell Membrane / metabolism
  • Cytoplasmic Granules / metabolism
  • Endothelium, Vascular / cytology
  • Gelatinases / metabolism*
  • Humans
  • Intercellular Adhesion Molecule-1 / metabolism
  • Neutrophils / immunology
  • Neutrophils / metabolism*
  • Neutrophils / physiology
  • Phagocytosis / immunology
  • Platelet Endothelial Cell Adhesion Molecule-1 / metabolism


  • Annexin A1
  • Platelet Endothelial Cell Adhesion Molecule-1
  • Intercellular Adhesion Molecule-1
  • Gelatinases