Quantification of annexin I in subcellular fractions of human neutrophils reveals an exclusive cytosolic localisation.
Annexin I is an abundant cytosolic protein in human neutrophils. Besides its intracellular location, annexin I is found as an extracellular protein and the pathway for secretion has been of interest since the protein lacks a signal sequence for secretion. It was recently shown that annexin I is stored in the secretory gelatinase granules of human neutrophils, suggesting that the protein might be released through a granule mobilisation and fusion process resembling classical secretion. In this study we have determined the intracellular localisation of annexin I in human neutrophils using subcellular fractionation, protein separation by SDS-PAGE and immunoblotting, and show that virtually all annexin I is localised in the cell cytosol.
Movitz
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The Phagocyte Research Laboratory, Department of Medical Microbiology and Immunology, Göteborg University, Göteborg, S-413 46, Sweden. charlotta.movitz@microbio.gu.se
Dahlgren
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D017305:Annexin A1 / Q000032:analysis*; D002478:Cells, Cultured; D003600:Cytosol / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D009504:Neutrophils / Q000737:chemistry*; D013347:Subcellular Fractions / Q000737:chemistry
D017305:Annexin A1