University of Wisconsin-Madison, Department of Botany, Madison, WI 53706, USA.
Curr Opin Plant Biol. 2011 Dec;14(6):715-20. doi: 10.1016/j.pbi.2011.08.001. Epub 2011 Aug 22.
The cytoplasmic Ca(2+) signals that participate in nearly all aspects of plant growth and development encode information as binary switches or information-rich signatures. They are the result of influx (thermodynamically passive) and efflux (thermodynamically active) activities mediated by membrane transport proteins. On the influx side, confirming the molecular identities of Ca(2+)-permeable channels is still a major research topic. Cyclic nucleotide-gated channels and glutamate receptor-like channels are candidates well supported by evidence. On the efflux side, CAX antiporters and P-type ATPase pumps are the principal molecular entities. Both of these active transporters load Ca(2+) into specific compartments and have the potential to reduce the magnitude and duration of a Ca(2+) transient. Recent studies indicate calmodulin-activated Ca(2+) pumps in endomembrane systems can dampen the magnitude and duration of a Ca(2+) transient that could otherwise grow into a Ca(2+) cell death signature. An important challenge following molecular characterization of the influx and efflux pathways is to understand how they are coordinately regulated to produce a Ca(2+) switch or encode specific information into a Ca(2+) signature.
参与几乎所有植物生长和发育方面的细胞质 Ca(2+)信号作为二进制开关或信息丰富的特征进行编码。它们是由膜转运蛋白介导的流入（热力学被动）和流出（热力学主动）活动的结果。在流入方面，确定 Ca(2+)通透通道的分子身份仍然是一个主要的研究课题。环核苷酸门控通道和谷氨酸受体样通道是有充分证据支持的候选通道。在流出方面，CAX 反向转运体和 P 型 ATP 酶泵是主要的分子实体。这两种主动转运蛋白将 Ca(2+)装载到特定的隔室中，并有可能降低 Ca(2+)瞬变的幅度和持续时间。最近的研究表明，内膜系统中的钙调蛋白激活 Ca(2+)泵可以减弱 Ca(2+)瞬变的幅度和持续时间，否则 Ca(2+)瞬变可能会发展成 Ca(2+)细胞死亡特征。在对流入和流出途径进行分子特征描述之后，一个重要的挑战是了解它们如何协调调节以产生 Ca(2+)开关或将特定信息编码到 Ca(2+)特征中。
