Institut für Botanik, Universität Münster, Schlossplatz 4, 48149 Münster, Germany.
Plant J. 2010 Jan;61(2):211-22. doi: 10.1111/j.1365-313X.2009.04045.x. Epub 2009 Oct 12.
During adaptation and developmental processes cells respond through nonlinear calcium-decoding signaling cascades, the principal components of which have been identified. However, the molecular mechanisms generating specificity of cellular responses remain poorly understood. Calcineurin B-like (CBL) proteins contribute to decoding calcium signals by specifically interacting with a group of CBL-interacting protein kinases (CIPKs). Here, we report the subcellular localization of all 10 CBL proteins from Arabidopsis and provide a cellular localization matrix of a plant calcium signaling network. Our findings suggest that individual CBL proteins decode calcium signals not only at the plasma membrane and the tonoplast, but also in the cytoplasm and nucleus. We found that distinct targeting signals located in the N-terminal domain of CBL proteins determine the spatially discrete localization of CBL/CIPK complexes by COPII-independent targeting pathways. Our findings establish the CBL/CIPK signaling network as a calcium decoding system that enables the simultaneous specific information processing of calcium signals emanating from different intra- and extracellular stores, and thereby provides a mechanism underlying the specificity of cellular responses.
在适应和发育过程中，细胞通过非线性钙解码信号级联反应作出响应，其中主要成分已经确定。然而，产生细胞反应特异性的分子机制仍知之甚少。钙调神经磷酸酶 B 样蛋白（CBL）通过与一组 CBL 相互作用蛋白激酶（CIPK）特异性相互作用，有助于解码钙信号。在这里，我们报告了拟南芥中所有 10 种 CBL 蛋白的亚细胞定位，并提供了植物钙信号网络的细胞定位矩阵。我们的研究结果表明，单个 CBL 蛋白不仅在质膜和液泡膜上，而且在细胞质和核内解码钙信号。我们发现，CBL 蛋白 N 端结构域中的不同靶向信号决定了 CBL/CIPK 复合物通过非 COPII 靶向途径进行空间离散定位。我们的研究结果将 CBL/CIPK 信号网络确立为一种钙解码系统，使来自不同胞内和胞外库的钙信号能够同时进行特异性信息处理，从而为细胞反应特异性提供了一种机制。
