Translocation of annexin I to plasma membranes and phagosomes in human neutrophils upon stimulation with opsonized zymosan: possible role in phagosome function.
Annexin I in the cytosol of resting neutrophils was translocated to the plasma membranes upon addition of opsonized zymosan (OZ). Maximum translocation could be detected 1 min after stimulation with OZ, and decreased thereafter. Subcellular fractionation studies demonstrated that annexin I could not be detected in the granule fractions in either resting or activated cells, but was found in association with the phagosome fraction. The marked translocation of annexin I was unique to OZ, since formyl-Met-Leu-Phe induced only slight translocation of annexin I to the plasma membranes, and phorbol 12-myristate 13-acetate had no effect at all. The mechanism regulating the translocation of annexin I is not clear. Annexin I is not phosphorylated in resting or stimulated cells. The correlation between the elevation in the intracellular calcium ion concentration ([Ca2+]i) and the degree of translocation of annexin I to the plasma membranes induced by the different stimuli, together with the inhibition of these processes by the addition of EGTA, indicate that the translocation of annexin I can probably be attributed to the rise in [Ca2+]i. However, this cannot be the sole mechanism since ionomycin, which caused an increase in [CA2+]i similar to that induced by OZ, was less efficient than OZ in inducing translocation of annexin I. The induction of annexin I translocation to the plasma membrane by OZ, which was the only agent that induced phagosome formation, and the detection of annexin I in the phagosome fraction, suggest that annexin I participates in phagosome function.
Kaufman
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M
Laboratory of Infectious Diseases, Faculty of Health Sciences, Soroka Medical Center of Kupat Holim, Ben-Gurion University of the Negev, Beer Sheva, Israel.
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Levy
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D017305:Annexin A1 / Q000097:blood*; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism; D003573:Cytochrome b Group / Q000097:blood; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D019255:NADPH Oxidases; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D009195:Peroxidase / Q000097:blood; D010588:Phagosomes / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood; D013481:Superoxides / Q000097:blood; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D015054:Zymosan / Q000494:pharmacology*
D017305:Annexin A1; D003573:Cytochrome b Group; D013481:Superoxides; D015054:Zymosan; C036888:cytochrome b558; D009195:Peroxidase; D019255:NADPH Oxidases; D000254:Sodium-Potassium-Exchanging ATPase; D013755:Tetradecanoylphorbol Acetate