Heat-induced alterations in the localization of HSP72 and HSP73 as measured by indirect immunohistochemistry and immunogold electron microscopy
Heat-induced alterations in the localization of HSP72 and HSP73 as measured by indirect immunohistochemistry and immunogold electron microscopy
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DOI：
10.1177/002215540004800302
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发表时间：
2000-03-01
影响因子：
3.2
通讯作者：
Anderson, RL
中科院分区：
文献类型：
--
作者：
Ellis, S;Killender, M;Anderson, RL
热休克蛋白是应激诱导蛋白家族，充当新生蛋白的分子伴侣，并协助保护和修复构象因应激而改变的蛋白。 HSP72 和 HSP73 是哺乳动物细胞的两种主要胞质/核应激蛋白，具有广泛的序列同源性。 HSP73 是组成型表达，而 HSP72 是高度应激诱导型的。然而，尚不清楚为什么会表达两种同工型以及这两种蛋白质在细胞中是否具有不同的功能。为了帮助描述功能，我们使用两种不同的检测方法完成了热应激前后 HSP72 和 HSP73 在细胞中定位的详细研究。通过间接免疫组织化学，这两种蛋白质的定位相似，在非应激细胞中的细胞质和细胞核中，加热后立即易位到核仁。通过更灵敏的免疫金电子显微镜技术，注意到定位的差异。在非应激细胞中，HSP72 主要位于核内，位于异染色质区域和核仁中。 HSP73 分布在整个细胞中，大多数细胞质标记与线粒体相关。有丝分裂染色体也被大量标记。应激后，HSP72 集中在细胞核和核仁中，HSP73 定位在细胞核、核仁和细胞质中，线粒体上的标记增加。这些定位差异表明 HSP72 和 HSP73 可能与不同的蛋白质或复合物结合，因此在细胞中具有不同但重叠的功能。
The heat shock proteins are a family of stress-inducible proteins that act as molecular chaperones for nascent proteins and assist in protection and repair of proteins whose conformation is altered by stress. HSP72 and HSP73 are two major cytosolic/nuclear stress proteins of mammalian cells, with extensive sequence homology. HSP73 is constitutively expressed, whereas HSP72 is highly stress-inducible. However, it is unclear why two isoforms are expressed and whether these two proteins have different functions in the cell. To assist in the delineation of function, we have completed a detailed study of the localization of HSP72 and HSP73 in the cell before and after heat stress, using two different methods of detection. By indirect immunohistochemistry, the localization of these two proteins is similar, cytoplasmic-and nuclear in nonstressed cells with a translocation to nucleoli immediately after heat,By the more sensitive immunogold electron microscopy technique, differences in localization were noted. In nonstressed cells, HSP72 was primarily nuclear, localized in heterochromatic regions and in nucleoli. HSP73 was distributed throughout the cell, with most cytoplasmic label associated with mitochondria. Mitotic chromosomes were also heavily labeled. After stress, HSP72 concentrated in nuclei and nucleoli and HSP73 localized to nuclei, nucleoli, and cytoplasm, with increased label over mitochondria. These differences in localization suggest that the HSP72 and HSP73 may associate with different proteins or complexes and hence have different but overlapping functions in the cell.