ISSN:
1573-675X
Keywords:
Apoptosis
;
CD95
;
cell volume
;
Na/K-ATPase
;
potassium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract To investigate the involvement of K+ efflux in apoptotic cell shrinkage, we monitored efflux of the K+ congener,86 Rb+, and cell volume during CD95-mediated apoptosis in Jurkat cells. An anti-CD95 antibody caused apoptosis associated with intracellular GSH depletion, a significant increase in 86Rb+ efflux, and a decrease in cell volume compared with control cells. Preincubating Jurkat cells with Val-Ala-Asp-chloromethylketone (VAD-cmk), an inhibitor of caspase proteases, prevented the observed 86Rb+ efflux and cell shrinkage induced by the anti- CD95 antibody. A wide range of inhibitors against most types of K+ channels could not inhibit CD95-mediated efflux of86 Rb+, however, the uptake of86 Rb+ by Jurkat cells was severely compromised when treated with anti-CD95 antibody. Uptake of86 Rb+ in Jurkat cells was sensitive to ouabain (a specific Na+/K+-ATPase inhibitor), demonstrating Na+/K+-ATPase dependent K+ uptake. Ouabain induced significant86 Rb+ efflux in untreated cells, as well as it seemed to compete with86 Rb+ efflux induced by the anti-CD95 antibody, supporting a role for Na+/K+-ATPase in the CD95-mediated86 Rb+ efflux. Ouabain treatment of Jurkat cells did not cause a reduction in cell volume, although together with the anti-CD95 antibody, ouabain potentiated CD95-mediated cell shrinkage. This suggests that the observed inhibition of Na++/K+-ATPase during apoptosis may also facilitate apoptotic cell shrinkage.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009684713784
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