Hsp70 and Hsp40 chaperone activities in the cytoplasm and the nucleus of mammalian cells
Hsp70 and Hsp40 chaperone activities in the cytoplasm and the nucleus of mammalian cells
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DOI：
10.1074/jbc.272.52.33283
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发表时间：
1997-12-26
影响因子：
4.8
通讯作者：
Kampinga, HH
中科院分区：
文献类型：
--
作者：
Michels, AA;Kanon, B;Kampinga, HH
研究了体内哺乳动物细胞中 Hsp40-Hsp70 伴侣机器的存在和功能，在与编码人 Hsp40 的基因共转染的细胞中分析了在仓鼠 O23 成纤维细胞中瞬时表达的萤火虫荧光素酶的热失活速率（Ohtsuka，K. (1993) Biochem. Biophys. Res. Commun.。 197, 235-240)、人诱导型 Hsp70 (Hunt, C. 和 Morimoto, R. I. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 6455-6459)，或两者的组合，而人 Hsp70 在仓鼠细胞中的单独表达足以在高温期间保护萤火虫荧光素酶震惊，人类 Hsp40 的单独表达并不是，而是， 导致荧光素酶的热敏感性小幅但显着的增加。仅当人 Hsp70 也表达时，人 Hsp40 的表达才导致热保护。在这种条件下，荧光素酶从热失活状态重新激活的速率增加，但热休克期间的失活速率不受影响。使用将萤火虫荧光素酶引导至细胞质或细胞核的构建体（Michels, A. A.、Nguyen, V. -T.、Konings, A. W. T.、Kampinga, H. H.和 Bensaude, O. (1995) Eur. J. Biochem. 234, 382-389)，已证明在两个区室中都发现了这些伴侣功能。我们的数据提供了关于 Hsp40/Hsp70 伴侣复合物如何在哺乳动物细胞体内充当热保护器的第一个证据。
The existence and function of a Hsp40-Hsp70 chaperone machinery in mammalian cells in vivo was investigated, The rate of heat inactivation of firefly luciferase transiently expressed in hamster O23 fibroblasts was analyzed in cells co-transfected with the gene encoding the human Hsp40 (Ohtsuka, K. (1993) Biochem. Biophys. Res. Commun. 197, 235-240), the human inducible Hsp70 (Hunt, C., and Morimoto, R. I. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 6455-6459), or a combination of both, Whereas the expression of human Hsp70 alone in hamster cells was sufficient for the protection of firefly luciferase during heat shock, expression of the human Hsp40 alone was not, Rather, this led to a small but significant increase in the heat sensitivity of luciferase. The expression of the human Hsp40 only led to heat protection when the human Hsp70 was expressed as well. Under such conditions the rate of luciferase reactivation from the heat-inactivated state was increased, but the rate of inactivation during heat shock was not affected. Using constructs that direct firefly luciferase either to the cytoplasm or to the nucleus (Michels, A. A., Nguyen, V. -T., Konings, A. W. T., Kampinga, H. H., and Bensaude, O. (1995) Eur. J. Biochem. 234, 382-389), it was demonstrated that these chaperone functions are found in both compartments. Our data provide the first evidence on how the Hsp40/Hsp70 chaperone complex acts as heat protector in mammalian cells in vivo.