%0 Journal Article %1 Cond_1995_9137 %A Condrescu, M. %A Gardner, J. P. %A Chernaya, G. %A Aceto, J. F. %A Kroupis, C. %A Reeves, J. P. %D 1995 %J J. Biol. Chem. %K Actins, Adenosine Animals; CHO Calcium, Carrier Cattle; Cells; Concentration; Cricetinae; Cytochalasin D, Exchanger; Hydrogen-Ion Myocardium, Proteins, Sodium, Sodium-Calcium Transfection Triphosphate, metabolism; pharmacology; physiology; %N 16 %P 9137--9146 %T ATP-dependent regulation of sodium-calcium exchange in Chinese hamster ovary cells transfected with the bovine cardiac sodium-calcium exchanger. %U http://www.jbc.org/cgi/content/full/270/16/9137 %V 270 %X Chinese hamster ovary cells expressing the bovine cardiac Na/Ca exchanger were treated with ouabain to increase Na$^+$i and stimulate Ca$^2+$ influx by Na/Ca exchange. Depletion of cellular ATP inhibited 45Ca uptake by 40\% or more and reduced the half-maximal Na$^+$ concentration for inhibition of 45Ca uptake from 90 to 55 mM. ATP depletion also reduced the rate of rise in Ca$^2+$i when Na$^+$o was reduced and inhibited the decline in Ca$^2+$i when high Na$^+$o was restored. The effects of ATP depletion were either absent or reduced in cells expressing a mutant exchanger missing most of the cytosolic hydrophilic domain. We were unable to detect a phosphorylated form of the exchanger in immunoprecipitates from 32P-labeled cells. ATP depletion caused a breakdown in the actin cytoskeleton of the cells. Treatment of the cells with cytochalasin D mimicked the effects of ATP depletion on the Na$^+$ inhibition profile for 45Ca uptake. Thus, ATP depletion inhibits both the Ca$^2+$ influx and Ca$^2+$ efflux modes of Na/Ca exchange, and may alter the competitive interactions of extracellular Na$^+$ and Ca$^2+$ with the transporter. The latter effect appears to be related to changes in the actin cytoskeleton.

@article{Cond_1995_9137, abstract = {Chinese hamster ovary cells expressing the bovine cardiac Na/Ca exchanger were treated with ouabain to increase [{N}a$^{+}$]i and stimulate {C}a$^{2+}$ influx by Na/Ca exchange. Depletion of cellular ATP inhibited 45Ca uptake by 40\% or more and reduced the half-maximal {N}a$^{+}$ concentration for inhibition of 45Ca uptake from 90 to 55 mM. ATP depletion also reduced the rate of rise in [{C}a$^{2+}$]i when [{N}a$^{+}$]o was reduced and inhibited the decline in [{C}a$^{2+}$]i when high [{N}a$^{+}$]o was restored. The effects of ATP depletion were either absent or reduced in cells expressing a mutant exchanger missing most of the cytosolic hydrophilic domain. We were unable to detect a phosphorylated form of the exchanger in immunoprecipitates from 32P-labeled cells. ATP depletion caused a breakdown in the actin cytoskeleton of the cells. Treatment of the cells with cytochalasin D mimicked the effects of ATP depletion on the [{N}a$^{+}$] inhibition profile for 45Ca uptake. Thus, ATP depletion inhibits both the {C}a$^{2+}$ influx and {C}a$^{2+}$ efflux modes of Na/Ca exchange, and may alter the competitive interactions of extracellular {N}a$^{+}$ and {C}a$^{2+}$ with the transporter. The latter effect appears to be related to changes in the actin cytoskeleton.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Condrescu, M. and Gardner, J. P. and Chernaya, G. and Aceto, J. F. and Kroupis, C. and Reeves, J. P.}, biburl = {https://www.bibsonomy.org/bibtex/2a2c373d43b94bb820af50c04cca2534b/hake}, description = {The whole bibliography file I use.}, file = {Cond_1995_9137.pdf:Cond_1995_9137.pdf:PDF}, institution = {Department of Physiology, University of Medicine and Dentistry-New Jersey Medical School, Newark 07103, USA.}, interhash = {7f9ecdc94c80b6ffa6d4b7ec6e916630}, intrahash = {a2c373d43b94bb820af50c04cca2534b}, journal = {J. Biol. Chem.}, keywords = {Actins, Adenosine Animals; CHO Calcium, Carrier Cattle; Cells; Concentration; Cricetinae; Cytochalasin D, Exchanger; Hydrogen-Ion Myocardium, Proteins, Sodium, Sodium-Calcium Transfection Triphosphate, metabolism; pharmacology; physiology;}, month = Apr, number = 16, pages = {9137--9146}, pdf = {Cond_1995_9137.pdf}, pmid = {7721828}, timestamp = {2009-06-03T11:21:08.000+0200}, title = {ATP-dependent regulation of sodium-calcium exchange in Chinese hamster ovary cells transfected with the bovine cardiac sodium-calcium exchanger.}, url = {http://www.jbc.org/cgi/content/full/270/16/9137}, volume = 270, year = 1995 }