Intracellular localization and de novo synthesis of FcRIII in human
neutrophil granulocytes
CR Jost, TW Huizinga, R de Goede, JA Fransen, PA Tetteroo, MR Daha and LA Ginsel
Laboratory for Electron Microscopy, University of Leiden, The Netherlands.
Immunoelectron microscopic studies in human neutrophils showed that FcRIII
was present on the plasma membrane, in the Golgi complex, and in many small
vesicles (120 to 180 nm). FcRIII was not found in specific or azurophilic
granules as shown by immunogold double-labeling experiments, visualizing
both FcRIII and either lactoferrin (a marker of specific granules) or
myeloperoxidase (a marker for azurophilic granules). Because the occurrence
of FcRIII in the Golgi complex suggested that biosynthesis of this receptor
occurs in these cells, metabolic labeling experiments were performed.
Immunoprecipitation of FcRIII from NP-40 lysates of cells labeled with
35S-methionine showed a diffuse 50- to 70-Kd band corresponding with the
band noted after immunoprecipitation of FcRIII from surface iodinated
cells. These findings show that de novo synthesis of FcRIII occurs in
neutrophils and suggest that at least some of the small vesicles containing
FcRIII derive from the Golgi complex and thus are involved in transport of
newly synthesized FcRIII to the plasma membrane.
Volume 75,
Issue 1,
pp. 144-151,
01/01/1990
Copyright © 1990 by The American Society of Hematology
