Please use this identifier to cite or link to this item:
|Scopus||Web of Science®||Altmetric|
|Title:||Labile zinc and zinc transporter ZnT4 in mast cell granules: Role in regulation of caspase activation and NF-KB translocation|
|Citation:||Journal of Immunology, 2004; 172(12):7750-7760|
|Publisher:||Amer Assoc Immunologists|
|Lien H. Ho, Richard E. Ruffin, Chiara Murgia, Lixin Li, Steven A. Krilis, and Peter D. Zalewski|
|Abstract:||The granules of mast cells and other inflammatory cells are known to be rich in zinc (Zn), a potent caspase inhibitor. The functions of granular Zn, its mechanism of uptake, and its relationship to caspase activation in apoptosis are unclear. The granules of a variety of mast cell types fluoresced intensely with the Zn-specific fluorophore Zinquin, and fluorescence was quenched by functional depletion of Zn using a membrane-permeable Zn chelator N, N, N', N'-tetrakis (2-pyridyl-methyl)ethylenediamine (TPEN). Zn levels were also depleted by various mast cell activators, including IgE/anti-IgE, and Zn was rapidly replenished during subsequent culture, suggesting an active uptake mechanism. In support of the latter, mast cells contained high levels of the vesicular Zn transporter ZnT4, especially in the more apical granules. Immunofluorescence and immunogold labeling studies revealed significant pools of procaspase-3 and -4 in mast cell granules and their release during degranulation. Functional depletion of Zn by chelation with TPEN, but not by degranulation, resulted in greatly increased susceptibility of mast cells to toxin-induced caspase activation, as detected using a fluorogenic substrate assay. Release of caspases during degranulation was accompanied by a decreased susceptibility to toxins. Zn depletion by chelation, but not by degranulation, also resulted in nuclear translocation of the antiapoptotic, proinflammatory transcription factor NF-B. These findings implicate a role for ZnT4 in mast cell Zn homeostasis and suggest that granule pools of Zn may be distinct from those regulating activation of procaspase-3 and NF-B.|
|Keywords:||Cell Line; Cytoplasmic Granules; Mast Cells; Humans; Zinc; Caspases; Carrier Proteins; Cation Transport Proteins; NF-kappa B; Microscopy, Fluorescence; Cell Degranulation; Enzyme Activation; Active Transport, Cell Nucleus; Homeostasis; Toxins, Biological; Caspase 3; Caspases, Initiator|
|Description:||Copyright © 2004 by The American Association of Immunologists|
|Appears in Collections:||Medicine publications|
Files in This Item:
There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.