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The presence of stomatin in detergent‐insoluble domains of neutrophil granule membranes
Author(s) -
FeukLagerstedt Elisabeth,
Samuelsson Marie,
Mosgoeller Wilhelm,
Movitz Charlotta,
Rosqvist Åsa,
Bergström Jörgen,
Larsson Thomas,
Steiner Marianne,
Prohaska Rainer,
Karlsson Anna
Publication year - 2002
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.72.5.970
Subject(s) - azurophilic granule , granule (geology) , immunoelectron microscopy , biology , membrane , microbiology and biotechnology , percoll , exocytosis , cell fractionation , secretory vesicle , organelle , membrane protein , biochemistry , centrifugation , immunology , inflammation , myeloperoxidase , paleontology , immunohistochemistry
Neutrophil azurophil granules, traditionally regarded as the neutrophil counterpart to lysosomes, lack the lysosomal marker lysosome‐associated membrane glycoprotein and have recently been suggested to be nonlysosomal secretory organelles. The membrane of the azurophil granules is poorly characterized—CD63 and CD68 are the only membrane proteins identified so far. Here, azurophil granule membranes were isolated by Percoll gradient subcellular fractionation. Using matrix‐assisted laser desorption ionization time of flight mass spectrometry of tryptic peptides from an isolated protein, stomatin was identified in these membranes. Using immunoelectron microscopy and immunoblot analysis of isolated organelles, stomatin was found to be subcellularly localized, not only to the azurophil granules but also by a major part to the specific granules and by a minor part to the secretory vesicles/plasma membrane. We also show the presence of detergent‐insoluble, low‐density membrane domains in the plasma membrane and the granule membranes and found stomatin to be localized to these domains.