Hyperthermia alters the interaction of proteins of the Mre11 complex in irradiated cells.
Hyperthermia alters the interaction of proteins of the Mre11 complex in irradiated cells.
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高温会改变受辐射细胞中 Mre11 复合体蛋白质的相互作用。
DOI：
10.1002/cyto.a.20955
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Dynlacht,JosephR
中科院分区：
文献类型：
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作者：
Gerashchenko,BogdanI;Gooding,Gerirose;Dynlacht,JosephR
哺乳动物细胞对热的辐射增敏被认为涉及对DNA双链断裂(DSB)修复的抑制。Mre11复合体(由Mre11、Rad50和Nbs1组成)参与DSB的修复，并在辐射诱导的DSB部位形成焦点。热诱导大量的Mre11、Rad50和Nbs1从细胞核到细胞质的移位，但关于热如何影响仍留在细胞核中的蛋白质的完整性，或改变加热照射细胞中DNA修复中心的形成/消失的动力学，人们知之甚少。在这里，我们表明，高温改变了受辐射的人黑色素瘤细胞中Mre11复合体蛋白之间的相互作用，并抑制了修复灶的形成。在X射线照射和/或加热后的不同时间(41.5℃或42.5℃，2小时)，固定细胞并对mre11、Rad50和NBs1进行染色。比较受热和/或照射细胞中蛋白质的共定位和核病灶的形成和消失，用共聚焦显微镜测定。在受热照射的细胞中，病灶的形成被抑制2-8小时，而Mre11复合体的蛋白共定位在处理后12-24小时减少。受照细胞在41.5℃受热后24 h内可恢复共定位，但在42.5℃受热后较长时间被抑制。受热受照细胞的共定位减少表明蛋白质相互作用减弱，核内Mre11复合体受热后解体。这种变化可能至少部分参与了热辐射增敏和抑制DSB修复。此外，Mre11复合体的拆解和重新组装的动力学似乎取决于处理温度。©2010国际细胞学促进会。
Radiosensitization of mammalian cells by heat is believed to involve the inhibition of repair of DNA double‐strand breaks (DSBs). The Mre11 complex (composed of Mre11, Rad50, and Nbs1) is involved in DSB repair and forms foci at sites of radiation‐induced DSBs. Heat induces the translocation of a significant amount of Mre11, Rad50, and Nbs1 from the nucleus to the cytoplasm, but little is known about how heat affects the integrity of the proteins still remaining in nuclei, or alters kinetics of formation/disappearance of DNA repair foci in heated, irradiated cells. Here, we show that hyperthermia alters the interaction between proteins of the Mre11 complex in irradiated human melanoma cells and inhibits the formation of repair foci. At various times after X‐irradiation and/or heating (2 h at 41.5 or 42.5°C), the cells were fixed and stained for Mre11, Rad50, and Nbs1. Colocalization of proteins and formation and disappearance of nuclear foci in heated and/or irradiated cells, determined using confocal microscopy, were compared. In heated, irradiated cells, focus formation was inhibited for 2–8 h, and colocalization of the proteins of the Mre11 complex was reduced for 12–24 h post‐treatment. Colocalization was recovered in irradiated cells within 24 h after heating at 41.5°C, but was inhibited longer after heating at 42.5°C. The decreased colocalization in heated, irradiated cells suggests that there is a decrease in protein interaction, and Mre11 complexes in nuclei disassemble after heating. Such changes could be involved, at least in part, in heat radiosensitization and inhibition of DSB repair. Also, the kinetics of disassembly and reassembly of Mre11 complexes appears to be dependent upon treatment temperature. © 2010 International Society for Advancement of Cytometry.