Csermely P, Kajtár J, Hollósi M, Oikarinen J, Somogyi J
Institute of Biochemistry I., Semmelweis University, School of Medicine, Budapest, Hungary.
Biochem Biophys Res Commun. 1994 Aug 15;202(3):1657-63. doi: 10.1006/bbrc.1994.2124.
The 90 kDa heat shock protein (hsp90) is a member of the "chaperone-complex" of steroid receptors believed to be partially or transiently localized in the cell nucleus. Demonstrating that hsp90 has an ATP binding site and autophosphorylating activity we have observed that histones, especially histone H1, are able to modulate the autophosphorylation of hsp90 [Csermely, P. and Kahn, C.R. (1991) J. Biol. Chem. 266, 4943-4950]. Our present data suggest a direct interaction of hsp90 with histones, showing that hsp90 is able to bind histone-agarose and enhances the binding of histones to DNA. Circular dichroism spectra of rat liver chromatin indicate that hsp90 induces a tighter, condensed state of the chromatin structure which is resistant against disruption by high salt treatment. Interactions of hsp90 with the chromatin may be important in regulating the transcriptional activity of steroid receptors and other transcription factors.
90 kDa热休克蛋白（hsp90）是类固醇受体“伴侣复合物”的成员之一，据信该复合物部分或短暂定位于细胞核中。通过证明hsp90具有ATP结合位点和自磷酸化活性，我们观察到组蛋白，尤其是组蛋白H1，能够调节hsp90的自磷酸化[Csermely, P.和Kahn, C.R.（1991年）《生物化学杂志》266卷，4943 - 4950页]。我们目前的数据表明hsp90与组蛋白直接相互作用，显示hsp90能够结合组蛋白琼脂糖，并增强组蛋白与DNA的结合。大鼠肝脏染色质的圆二色光谱表明，hsp90诱导染色质结构形成更紧密、凝聚的状态，这种状态对高盐处理的破坏具有抗性。hsp90与染色质的相互作用可能在调节类固醇受体和其他转录因子的转录活性方面具有重要意义。
