Characterization of the 105-kDa molecular chaperone - Identification, biochemical properties, and localization
Characterization of the 105-kDa molecular chaperone - Identification, biochemical properties, and localization
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DOI：
10.1046/j.1432-1033.2002.03272.x
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发表时间：
2002-11-01
期刊：
影响因子：
--
通讯作者：
Takada, G
中科院分区：
文献类型：
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作者：
Matsumori, M;Itoh, H;Takada, G
我们已经表征了睾丸和大脑特异的105-kDa蛋白的生化特性，该蛋白与抗牛HSP90抗体发生交叉反应。该蛋白通过热应激在生殖细胞中诱导，产生一种属于热休克蛋白之一的蛋白[Kumagai，J.，Fukuda，J.，KoDama，H.，Murata，M.，Kawamura，K.，Itoh，H.&Tanaka，T.(2000)EUR。J.生物化学。267、3073-3078]。在本研究中，我们对蛋白质的生化性质进行了表征。该105 kDa蛋白在体外作为分子伴侣抑制柠檬酸合成酶的聚集。ATP/MgCl2对105-kDa蛋白抑制柠檬酸合成酶聚集有轻微影响。该蛋白具有伴侣活性。与其他分子伴侣热休克蛋白70一样，该蛋白能够与三磷酸腺苷琼脂糖凝胶结合。测定了该蛋白的部分氨基酸序列(24个氨基酸残基)，与小鼠睾丸和脑特异性APG-1和渗透压应激蛋白94(OSP94)的氨基酸序列一致。免疫印迹显示105 kDa蛋白仅在类似OSP94的大鼠肾脏切片的髓质中检测到。纯化的105 kDa蛋白与抗APG-1抗体发生交叉反应。这些结果表明，APG-1和OSP94都与105 kDa的蛋白相同。105 kDa蛋白/APG-1/OSP94与HSP90有高度同源性。HSP90区域也是免疫反应的部位。在大鼠睾丸和脑中，抗牛HSP90抗体可能与类似于HSP90的105 kDa蛋白发生交叉反应。我们已经研究了该蛋白在大鼠脑中的定位和发育诱导。在免疫组织化学分析中，该蛋白主要分布在大鼠脑内神经和神经胶质细胞的胞浆中。虽然105 kDa蛋白在所有大鼠脑节段都有表达，但在大脑皮层和海马区表达较快，在小脑中表达较慢。
We have characterized the biochemical properties of the testis and brain-specific 105-kDa protein which is cross-reacted with an anti-bovine HSP90 antibody. The protein was induced in germ cells by heat stress, resulting in a protein which is one of the heat shock proteins [Kumagai, J., Fukuda, J., Kodama, H., Murata, M., Kawamura, K., Itoh, H. & Tanaka, T. (2000) Eur. J. Biochem. 267, 3073-3078]. In the present study, we characterized the biochemical properties of the protein. The 105-kDa protein inhibited the aggregation of citrate synthase as a molecular chaperone in vitro. ATP/MgCl2 has a slight influence of the suppression of the citrate synthase aggregation by the 105-kDa protein. The protein possessed chaperone activity. The protein was able to bind to ATP Sepharose like the other molecular chaperone HSP70. A partial amino-acid sequence (24 amino-acid residues) of the protein was determined and coincided with those of the mouse testis- and brain-specific APG-1 and osmotic stress protein 94 (OSP94). The 105-kDa protein was detected only in the medulla of the rat kidney sections similar to OSP94 upon immunoblotting. The purified 105-kDa protein was cross-reacted with an antibody against APG-1. These results suggested that APG-1 and OSP94 are both identical to the 105-kDa protein. There were highly homologous regions between the 105-kDa protein/APG-1/OSP94 and HSP90. The region of HSP90 was also an immunoreactive site. An anti-bovine HSP90 antibody may cross-react with the 105-kDa protein similar to HSP90 in the rat testis and brain. We have investigated the localization and developmental induction of the protein in the rat brain. In the immunohistochemical analysis, the protein was mainly detected in the cytoplasm of the nerve and glial cells of the rat brain. Although the 105-kDa protein was localized in all rat brain segments, the expression pattern was fast in the cerebral cortex and hippocampus and slow in the cerebellum.