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Regulation of translation by protein phosphorylation.

通过蛋白质磷酸化调节翻译。

基本信息

批准号：
14580638
负责人：
SHIMA Hiroshi
金额：
$ 2.3万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14580638/
关键词：
phosphorylation dephosphorylation kinase phosphatase PP1 tautomycetin MARK GSK3β S6キナーゼ raf Aurora kinase gsk3b 細胞増殖

项目摘要

In order to clarify regulation of translation by protein phosphorylation, we examined function of two protein phosphatases, PP1 and MKP-7 in cells.1.Recently we found that tautomycetin/TC is an inhibitor of PP1. To examine whether TC inhibits PP1 in cultured cells, cells are treated with TC and then PP1 and PP2A activities in the cell extract were analyzed. TC was shown to inhibit PP1 completely without affecting PP2A in the cells.2.When cells are treated with TC, MEK/ERK activation was inhibited. By co-expression of raf together with either wild type or inactive mutant type of PP1 catalytic subunit, we concluded that PP1 activity is necessary for activation of Raf/MEK/ERK pathway.3. PP1 was shown to bind and negatively regulate Aurora kinases.4.GSK3β was shown to associate with PP1/1-2 heterodimer and phosphorylate Thr72 of 1-2 in the cultured cells. It was suggested that GSK3β functions as molecular switch for PPIC by inactivating the inhibitory activity of 1-2 by phosphorylation5.By two hybrid screening, PP1 catalytic subunit was identified as scapinin binding protein. It was suggested that PP1 is targeted to non-chromatin structure by scapinin, where it may function as a regulator of gene expression.6.We newly identified a novel MAPK binding motif commonly conserved in MAPK phosphatases. MKP-7, a JNK specific phosphatase, was shown to be phosphorylated by ERK upon several stimuli.

为了阐明蛋白质磷酸化对翻译的调控，我们检测了细胞中两种蛋白质磷酸酶PP1和MKP-7的功能。1.最近我们发现tautomycetin/TC是PP1的抑制剂。为了检查 TC 是否抑制培养细胞中的 PP1，用 TC 处理细胞，然后分析细胞提取物中的 PP1 和 PP2A 活性。 TC能完全抑制PP1而不影响细胞内的PP2A。2.用TC处理细胞时，MEK/ERK活化被抑制。通过raf与野生型或失活突变型PP1催化亚基的共表达，我们得出结论：PP1活性是Raf/MEK/ERK通路激活所必需的。 3． PP1显示出与Aurora激酶结合并负向调节。4.GSK3β显示出与PP1/1-2异二聚体结合并磷酸化培养细胞中1-2的Thr72。推测GSK3β通过磷酸化使1-2的抑制活性失活，从而作为PPIC的分子开关发挥作用5。通过两次杂交筛选，PP1催化亚基被鉴定为scapinin结合蛋白。有人提出，PP1通过scapinin靶向非染色质结构，从而可能起到基因表达调节因子的作用。6.我们新鉴定了一种新的MAPK结合基序，该基序通常在MAPK磷酸酶中保守。 MKP-7 是一种 JNK 特异性磷酸酶，在多种刺激下会被 ERK 磷酸化。