Arabidopsis ATPase family gene 1-like protein 1 is a calmodulin-binding AAA+-ATPase with a dual localization in chloroplasts and mitochondria
Arabidopsis ATPase family gene 1-like protein 1 is a calmodulin-binding AAA+-ATPase with a dual localization in chloroplasts and mitochondria
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DOI：
10.1111/j.1742-4658.2009.07102.x
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发表时间：
2009-07-01
期刊：
影响因子：
5.4
通讯作者：
Vothknecht, Ute C.
中科院分区：
文献类型：
--
作者：
Bussemer, Johanna;Chigri, Fatima;Vothknecht, Ute C.
AAA(+)- atp酶超家族成员（与各种细胞活动相关的atp酶）存在于所有生命王国中，它们参与非常多样化的细胞过程，包括蛋白质降解，膜融合或细胞分裂。拟南芥基因组编码大约140种不同的蛋白质，这些蛋白质被认为是这个超家族的成员，尽管大多数这些蛋白质的确切功能尚不清楚。利用叶绿体蛋白对钙调素琼脂糖进行同源层析，我们从酵母中纯化了一个由AT4G30490编码的50 kDa的蛋白，该蛋白与ATPase家族基因1蛋白相似。结构分析表明，该蛋白具有AAA(+)- atp酶超家族成员的单一AAA-结构域特征，并且包含atp酶家族基因1-样亚家族蛋白特有的所有特征。体外拉下和交联实验证实了钙依赖性蛋白与钙调蛋白的结合。钙调蛋白结合域位于AAA-结构域内靠近Walker a基序的20个氨基酸区域。我们的分析进一步表明，该蛋白定位于线粒体和叶绿体中，进一步支持了这两种内共生细胞器与细胞钙信号网络的结合。相同的钙调素结合蛋白在线粒体和叶绿体中的定位可能是一种通过钙信号协调调节这两个细胞器过程的手段。
Members of the AAA(+)- ATPase superfamily ( ATPases associated with various cellular activities) are found in all kingdoms of life and they are involved in very diverse cellular processes, including protein degradation, membrane fusion or cell division. The Arabidopsis genome encodes approximately 140 different proteins that are putative members of this superfamily, although the exact function of most of these proteins remains unknown. Using af. nity chromatography on calmodulin- agarose with chloroplast proteins, we purified a 50 kDa protein encoded by AT4G30490 ith similarity to the ATPase family gene 1 protein from yeast. Structural analysis showed that the protein possesses a single AAA- domain characteristic for members of the AAA(+)- ATPase superfamily and that this contains all features specific to proteins of the ATPase family gene 1- like subfamily. In vitro pull- down as well as cross- linking assays corroborate calcium- dependent binding of the protein to calmodulin. The calmodulin binding domain could be located to a region of 20 amino acids within the AAA- domain in close proximity to the Walker A motif. Our analysis further showed that the protein is localized in both mitochondria and chloroplasts, further supporting the incorporation of both endosymbiotic organelles into the calcium- signaling network of the cell. Localization of the same calmodulin- binding protein into mitochondria and chloroplasts could be a means to provide a coordinated regulation of processes in both organelles by calcium signals.