Delayed activation of the plasma membrane calcium pump by a sudden increase in Ca2+:: fast pumps reside in fast cells
Delayed activation of the plasma membrane calcium pump by a sudden increase in Ca2+:: fast pumps reside in fast cells
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DOI：
10.1054/ceca.2001.0212
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发表时间：
2001-07-01
期刊：
影响因子：
4
通讯作者：
Penniston, JT
中科院分区：
文献类型：
--
作者：
Caride, AJ;Filoteo, AG;Penniston, JT
有四个基因编码质膜钙泵（PMCA）的亚型。两个剪接位点的存在增加了PMCA的变异性。已经描述了PMCA变体之间的功能差异，但对这种巨大多样性的泵的自适应优势知之甚少。在本文中，我们研究了不同的异构体如何响应于Ca 2+浓度的突然增加。我们发现不同的PMCA被Ca ~（2+）以不同的速率激活，PMCA 3f和2a是最快的，4 b是最慢的。Ca 2+激活的速率取决于钙调素结合的速率和钙调素激活的幅度。结果发现，2a位于心脏和内耳毛细胞的静纤毛，3f位于骨骼肌，4 b位于Jurkat细胞。心肌和骨骼肌以及静纤毛在细胞质Ca 2+峰值后非常迅速地恢复，而在Jurkat细胞中，恢复需要长达一分钟。在静纤毛中，2a是Ca 2+输出的唯一方法，使得它们的分析异常简单。这表明，这些速率的PMCA激活的Ca 2+与Ca 2+浓度衰减后的细胞中，这些变体的PMCA表达的Ca 2+尖峰的速度。结果表明，表达的PMCA类型将与细胞内Ca ~（2+）信号的速度相对应。(C)2001年哈考特出版社有限公司
There are four genes encoding isoforms of the plasma membrane Ca2+ pump (PMCA). PMCA variability is increased by the presence of two splicing sites. Functional differences between the variants of PMCA have been described, but little is known about the adaptive advantages of this great diversity of pumps. In this paper we studied how the different isoforms respond to a sudden increase in Ca2+ concentration. We found that different PMCAs are activated by Ca2+ at different rates, PMCA 3f and 2a being the fastest, and 4b the slowest. The rate of activation by Ca2+ depends both on the rate of calmodulin binding and the magnitude of the activation by calmodulin. We found that 2a is located in heart and the stereocilia of inner ear hair cells, 3f in skeletal muscle and 4b was identified in Jurkat cells. Both cardiac and skeletal muscle, and stereocilia recover very rapidly after a cytoplasmic Ca2+ peak, while in Jurkat cells the recovery takes up to a minute. In stereocilia, 2a is the only method for export of Ca2+, making the analysis of them unusually straightforward. This indicates that these rates of PMCA activation by Ca2+ are correlated with the speed of Ca2+ concentration decay after a Ca2+ spike in the cells in which these variants of PMCA are expressed. The results suggest that the type of PMCA expressed will correspond with the speed of Ca2+ signals in the cell. (C) 2001 Harcourt Publishers Ltd.