Krishna P, Gloor G
Department of Plant Sciences, University of Western Ontario, London, Canada.
Cell Stress Chaperones. 2001 Jul;6(3):238-46. doi: 10.1379/1466-1268(2001)006<0238:thfopi>2.0.co;2.
The 90-kDa heat shock protein (Hsp90) is an essential molecular chaperone in eukaryotic cells, with key roles in the folding and activation of proteins involved in signal transduction and control of the cell cycle. A search for Hsp90 sequences in the Arabidopsis thaliana genome revealed that this family includes 7 members. The AtHsp90-1 through AtHsp90-4 proteins constitute the cytoplasmic subfamily, whereas the AtHsp90-5, AtHsp90-6, and AtHsp90-7 proteins are predicted to be within the plastidial, mitochondrial, and endoplasmic reticulum compartments, respectively. The deduced amino acid sequences of each of the cytoplasmic proteins contains the highly conserved C-terminal pentapeptide MEEVD. All of the AtHsp90 sequences include a conserved adenosine triphosphate-binding domain, whereas only the cytoplasmic and endoplasmic reticulum-resident sequences include an adjacent charged linker domain that is common in mammalian and yeast sequences. The occurrence of multiple AtHsp90 proteins in the cytoplasm and of family members in other subcellular compartments suggests a range of specific functions and target polypeptides.
90千道尔顿热休克蛋白（Hsp90）是真核细胞中一种重要的分子伴侣，在参与信号转导和细胞周期调控的蛋白质折叠与激活过程中发挥关键作用。对拟南芥基因组中Hsp90序列的搜索发现，该家族包含7个成员。AtHsp90 - 1至AtHsp90 - 4蛋白构成细胞质亚家族，而AtHsp90 - 5、AtHsp90 - 6和AtHsp90 - 7蛋白预计分别位于质体、线粒体和内质网区室中。每个细胞质蛋白的推导氨基酸序列都包含高度保守的C末端五肽MEEVD。所有AtHsp90序列都包含一个保守的三磷酸腺苷结合结构域，而只有细胞质和内质网驻留序列包含一个相邻的带电荷连接结构域，这在哺乳动物和酵母序列中很常见。细胞质中多种AtHsp90蛋白以及其他亚细胞区室中的家族成员的存在表明其具有一系列特定功能和靶多肽。
