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Impaired nuclear translocation, cytoplasmic accumulation of nuclear protein and alteration of cellular physiology

核易位受损、核蛋白在细胞质中积聚以及细胞生理学改变

基本信息

批准号：
13670009
负责人：
NISHIO Koji
金额：
$ 2.18万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670009/
关键词：
nuclear translocation S1-1 nuclear body PML vimentin p53 cytoskeleton anchoring function 老化細胞核内輸送機能 S1-1 テロメラーゼヒストン c-Fos karyopherin p53 ヘリケース

项目摘要

Nuclear transport of transcription factor p53 and cFos, a several nuclear body-forming proteins, and their regulation of biological functions were investigated. Young human fibroblasts transport p53 to the nuclei. However, in senescent adult skin fibroblasts, p53 protein accumulated in the cytoplasm dominantly and localized on vimentin cytoskeleton. Ectopically expressed p53-GFP of senescent cells, retained in the cytoplasm. Nuclear transport system of senescent cells is still functional, because the nuclear import of histon H2B and hnRNP ALF-C1 is not impaired. Therefore, the impaired nuclear transport of p53 seems to be due to the anchoring to vimentin cytoskeleton. This anchoring needs the conformational change of p53,which may be induced by phosphorylation of p53. Thus the senescent cells seem to produce a putative p53-kinase which modifies the conformation of p53.S1-1 protein was discovered by Akira Inoue in 1996. So far the biological function and molecular property have been remained unknown. Through this study, I found that S1-1 protein family, p110 (full length 852AA) and p130 (full length 929AA) formed the distinct nuclear body. Primary alignment analysis of S1-1 and PML (promyelocytic leukemia) isoforms revealed the two highly conserved domains, which were termed EGKE and Z domains. Z domain was identified as a responsible molecular region for S1-1 nuclear body formation. Removal of the Z-domain significantly impaired the nuclear body formation of S1-1 and PML4. Ectopically expressed PML4 accumulated in the cytoplasm of cos7 cells. This cytoplasmic retention needs the distinct domain which exists in the carboxyterminal 74 amino acids.Cytoplasmic retention or accumulation of the distinct nuclear proteins depends on the existence of their distinct domains post-tranlational modification, and altered conformation. It is interesting if vimentin cytoskeleton involves with the cytoplasmic retention of PML4.

研究了几种核小体形成蛋白p53和cFos的核转运及其生物学功能的调控。年轻人成纤维细胞将p53转运到细胞核。而在衰老的成纤维细胞中，p53蛋白主要聚集在细胞质中，并定位于波形蛋白骨架上。衰老细胞异位表达p53-GFP，滞留在细胞质中。衰老细胞的核转运系统仍有功能，因为希斯顿H2 B和hnRNP ALF-C1的核输入未受损。因此，p53的核转运受损似乎是由于锚定到波形蛋白细胞骨架。这种锚定需要p53的构象变化，这可能由p53的磷酸化诱导。1996年Akira Inoue发现了S1 -1蛋白，它是一种能够改变p53构象的p53激酶。迄今为止，其生物学功能和分子特性仍不清楚。通过本研究，我发现S1-1蛋白家族、p110（全长852 AA）和p130（全长929 AA）形成了不同的核体。S1-1和PML（promyelocytic leukemia）亚型的初步比对分析揭示了两个高度保守的结构域，它们被称为EGKE和Z结构域。Z结构域被认为是S1-1核体形成的重要分子区域。去除Z-结构域显著损害了S1-1和PML 4的核体形成。异位表达的PML 4聚集在cos 7细胞的胞浆中。这种胞质滞留需要存在于羧基末端74个氨基酸的不同结构域，不同核蛋白质的胞质滞留或积累取决于其不同结构域的存在，翻译后修饰和构象改变。波形蛋白骨架是否参与了PML 4的胞浆滞留是一个值得关注的问题。