Berridge M J
Laboratory of Molecular Signalling, The Babraham Institute, Cambridge, UK.
Novartis Found Symp. 2001;239:52-64; discussion 64-7, 150-9.
Ca2+ is a universal second messenger used to regulate a wide range of cellular processes such as fertilization, proliferation, contraction, secretion, learning and memory. Cells derive signal Ca2+ from both internal and external sources. The Ca2+ flowing through these channels constitute the elementary events of Ca2+ signalling. Ca2+ can act within milliseconds in highly localized regions or it can act much more slowly as a global wave that spreads the signal throughout the cell. Various pumps and exchangers are responsible for returning the elevated levels of Ca2+ back to the resting state. The mitochondrion also plays a critical role in that it helps the recovery process by taking Ca2+ up from the cytoplasm. Alterations in the ebb and flow of Ca2+ through the mitochondria can lead to cell death. A good example of the complexity of Ca2+ signalling is its role in regulating cell proliferation, such as the activation of lymphocytes. The Ca2+ signal needs to be present for over two hours and this prolonged period of signalling depends upon the entry of external Ca2+ through a process of capacitative Ca2+ entry. The Ca2+ signal stimulates gene transcription and thus initiates the cell cycle processes that culminate in cell division.
钙离子是一种通用的第二信使，用于调节多种细胞过程，如受精、增殖、收缩、分泌、学习和记忆。细胞从内部和外部来源获取信号钙离子。流经这些通道的钙离子构成了钙离子信号传导的基本事件。钙离子可以在高度局部化的区域内毫秒级起作用，也可以作为一种在整个细胞中传播信号的全局波而作用得慢得多。各种泵和交换器负责将升高的钙离子水平恢复到静息状态。线粒体也起着关键作用，它通过从细胞质中摄取钙离子来帮助恢复过程。钙离子通过线粒体的涨落变化可导致细胞死亡。钙离子信号传导复杂性的一个很好例子是其在调节细胞增殖中的作用，如淋巴细胞的激活。钙离子信号需要存在两个多小时，而这种延长的信号传导期取决于通过钙池调控性钙离子内流过程使外部钙离子进入。钙离子信号刺激基因转录，从而启动最终导致细胞分裂的细胞周期过程。
