In:
American Journal of Physiology-Cell Physiology, American Physiological Society, Vol. 289, No. 4 ( 2005-10), p. C891-C897
Abstract:
The unique characteristics of the platelet Na/Ca exchanger, i.e., its dependence on both transmembrane Na and K gradients, render it highly sensitive to Na pump inhibition. In this project, we observed that the human megakaryocytic cell line CHRF-288 expresses both the α 1 - and α 3 -isoforms of the Na-K-ATPase. Inhibition of the Na pump increased the RNA and protein expressions of sarco(endo)plasmic reticulum Ca-ATPase 2b, cytosolic Na and Ca, and the freely exchangeable Ca in the endoplasmic reticulum. These changes occurred in concert with diminished store-operated Ca entry and an increase in the maximal activity of the Na/Ca exchanger. Inhibition of the Na pump by ouabain was more effective in inducing these changes than diminishing medium K. Collectively, these observations point to an integrative effort to counteract the impact of Na pump inhibition by Ca sequestration into the endoplasmic reticulum, diminished Ca entry, and increased activity of the Na/Ca exchanger. The implications of these findings in platelet biology are discussed.
Type of Medium:
Online Resource
ISSN:
0363-6143
,
1522-1563
DOI:
10.1152/ajpcell.00080.2005
Language:
English
Publisher:
American Physiological Society
Publication Date:
2005
detail.hit.zdb_id:
1477334-X
SSG:
12
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