Physiological and molecular characterization of the Na + /Ca 2+ exchanger in human platelets

In this report, we have demonstrated that Na /Ca exchanger activity in a human megakaryocytic cell line (CHRF-288 cells) is K dependent, similar to the properties previously described for Na /Ca exchange activity in human platelets. With the use of RT-PCR techniques and mRNA, the exchanger expressed...

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Published inAmerican journal of physiology. Heart and circulatory physiology Vol. 277; no. 3; pp. H911 - H917
Main Authors Kimura, Masayuki, Jeanclos, Elisabeth M, Donnelly, Robert J, Lytton, Jonathan, Reeves, John P, Aviv, Abraham
Format Journal Article
LanguageEnglish
Published United States 01.09.1999
Subjects
megakaryocytes
potassium
retinal rod
stroke
dense tubules
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Summary:In this report, we have demonstrated that Na /Ca exchanger activity in a human megakaryocytic cell line (CHRF-288 cells) is K dependent, similar to the properties previously described for Na /Ca exchange activity in human platelets. With the use of RT-PCR techniques and mRNA, the exchanger expressed in CHRF-288 cells was found to be identical to that expressed in human retinal rods. Northern blot analysis of the mRNA for the human retinal rod exchanger in CHRF-288 cells revealed a major transcript at 5.8 kb with two minor bands at 4.9 and 6.8 kb. mRNA for the retinal rod exchanger was also identified in human platelets. Using Ba influx as a measure of Na /Ca exchange activity in human platelets, we have demonstrated that exchange activity is driven by the transmembrane gradient for K as well as that for Na . We propose that the K dependence of the platelet Na /Ca exchanger could make platelets especially sensitive to daily fluctuations in salt intake.
ISSN:0363-6135
1522-1539
DOI:10.1152/ajpheart.1999.277.3.H911