Adam Z, Adamska I, Nakabayashi K, Ostersetzer O, Haussuhl K, Manuell A, Zheng B, Vallon O, Rodermel S R, Shinozaki K, Clarke A K
Department of Agricultural Botany, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Plant Physiol. 2001 Apr;125(4):1912-8. doi: 10.1104/pp.125.4.1912.
The identity and scope of chloroplast and mitochondrial proteases in higher plants has only started to become apparent in recent years. Biochemical and molecular studies suggested the existence of Clp, FtsH, and DegP proteases in chloroplasts, and a Lon protease in mitochondria, although currently the full extent of their role in organellar biogenesis and function remains poorly understood. Rapidly accumulating DNA sequence data, especially from Arabidopsis, has revealed that these proteolytic enzymes are found in plant cells in multiple isomeric forms. As a consequence, a systematic approach was taken to catalog all these isomers, to predict their intracellular location and putative processing sites, and to propose a standard nomenclature to avoid confusion and facilitate scientific communication. For the Clp protease most of the ClpP isomers are found in chloroplasts, whereas one is mitochondrial. Of the ATPase subunits, the one ClpD and two ClpC isomers are located in chloroplasts, whereas both ClpX isomers are present in mitochondria. Isomers of the Lon protease are predicted in both compartments, as are the different forms of FtsH protease. DegP, the least characterized protease in plant cells, has the most number of isomers and they are predicted to localize in several cell compartments. These predictions, along with the proposed nomenclature, will serve as a framework for future studies of all four families of proteases and their individual isomers.
高等植物中叶绿体和线粒体蛋白酶的种类及作用范围直到近年来才开始逐渐明晰。生化和分子研究表明，叶绿体中存在Clp、FtsH和DegP蛋白酶，线粒体中存在Lon蛋白酶，尽管目前它们在细胞器生物发生和功能中的全部作用仍知之甚少。迅速积累的DNA序列数据，尤其是来自拟南芥的数据，显示这些蛋白水解酶在植物细胞中以多种异构体形式存在。因此，我们采用了一种系统的方法来对所有这些异构体进行分类，预测它们在细胞内的位置和假定的加工位点，并提出一个标准的命名法，以避免混淆并促进科学交流。对于Clp蛋白酶，大多数ClpP异构体存在于叶绿体中，而有一种存在于线粒体中。在ATP酶亚基中，一种ClpD和两种ClpC异构体位于叶绿体中，而两种ClpX异构体都存在于线粒体中。Lon蛋白酶的异构体在两个区室中都有预测，FtsH蛋白酶的不同形式也是如此。DegP是植物细胞中研究最少的蛋白酶，其异构体数量最多，预计它们定位于几个细胞区室中。这些预测以及提议的命名法将为未来对所有四个蛋白酶家族及其各自异构体的研究提供一个框架。
