Physiological and molecular characterization of the Na+/Ca2+ exchanger in human platelets.
Physiological and molecular characterization of the Na+/Ca2+ exchanger in human platelets.
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人血小板中 Na /Ca2 交换器的生理和分子特征。
DOI：
10.1152/ajpheart.1999.277.3.h911
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Aviv,A
中科院分区：
文献类型：
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作者：
Kimura,M;Jeanclos,EM;Donnelly,RJ;Lytton,J;Reeves,JP;Aviv,A
在本报告中，我们证明了人巨核细胞系（CHRF-288 细胞）中的 Na+/Ca2+ 交换活性是 K+ 依赖性的，类似于之前描述的人血小板中 Na+/Ca2+ 交换活性的特性。通过使用RT-PCR技术和mRNA，发现CHRF-288细胞中表达的交换剂与人视网膜杆中表达的交换剂相同。对 CHRF-288 细胞中人视网膜视杆交换器 mRNA 的 Northern 印迹分析显示，主要转录物位于 5.8 kb，两条次要条带位于 4.9 和 6.8 kb。视网膜杆状交换器的 mRNA 也在人类血小板中被鉴定出来。使用 Ba2+ 流入量作为人血小板中 Na+/Ca2+ 交换活性的量度，我们证明交换活性是由 K+ 和 Na+ 的跨膜梯度驱动的。我们认为，血小板 Na+/Ca2+ 交换器的 K+ 依赖性可能使血小板对盐摄入量的日常波动特别敏感。
In this report, we have demonstrated that Na+/Ca2+exchanger activity in a human megakaryocytic cell line (CHRF-288 cells) is K+dependent, similar to the properties previously described for Na+/Ca2+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 Ba2+influx as a measure of Na+/Ca2+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+/Ca2+exchanger could make platelets especially sensitive to daily fluctuations in salt intake.