Elucidation of the mechanisms of okadaic acid-induced apoptosis and cleavage of nucleolar proteins in osteoblasts

阐明冈田酸诱导成骨细胞凋亡和核仁蛋白裂解的机制

基本信息

批准号：
17591915
负责人：
HANEJI Tatsuji
金额：
$ 2.18万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

Protein phosphorylation and dephosphorylation has been recognized as a key mechanism in cell function. Okadaic acid (OA) is a potent inhibitor of protein phosphatases and induces apoptosis in human osteoblasts. Nuclear factor-kappa B (NF-κB) is an essential transcription factor in the control of expression of genes involved in cell growth and differentiation. Treatment of human osteoblastic MG63 cells with OA enhanced the phosphorylation level of NF-κB on serine 536, as judged from the results of Western analysis and a k protein phosphatase dephosphorylation assay. OA stimulated the transcriptional activity of NF-κB in MG63 cells by a luciferase assay. These findings indicate that OA elicit phosphorylation of NF-κB on serine 536 in MG63 cells, resulting in the translocation of phospho-NF-κB to the nucleus, thereby promoting transcriptional activity of genes.Nucleolin is an abundantly expressed nucleolar phosphoprotein and is located mainly in the nucleolus. The staining pattern of nucleolin in cultured cells is similar to that of protein phosphatase1δ. (PP1δ). Nucleolin was demonstrated to bind to PP1δ in nucleolus in human osteoblasts by using immunocytochemical and immunoprecipitation methods. AgNORs and nucleolin disappeared from the nuclei of the osteoblasts treated with OA. A major band, 110 kDa, was detected in the proteins obtained from osteoblastic cells. The level of the 110 kDa protein decreased in the apoptotic osteoblasts, whereas an additional band, 80 kDa, appeared and the level of this protein increased in the proteins prepared from OA-induced apoptotic osteoblasts. The present results indicate that PP18 directly binds to nucleolin in the nucleolus of osteoblasts and that nucleolin is cleaved during apoptosis in osteoblasts.

蛋白质磷酸化和去磷酸化已被认为是细胞功能的关键机制。冈田酸 (OA) 是蛋白质磷酸酶的有效抑制剂，可诱导人成骨细胞凋亡。 OA 处理人成骨细胞 MG63 细胞中参与细胞生长和分化的基因表达的控制增强了 NF-κB 丝氨酸的磷酸化水平。根据Western分析和k蛋白磷酸酶去磷酸化测定的结果判断，通过荧光素酶测定，OA刺激了MG63细胞中NF-κB的转录活性。这些结果表明，OA引发了MG63中丝氨酸536上的NF-κB的磷酸化。细胞，导致磷酸-NF-κB易位至细胞核，从而促进基因的转录活性。核仁蛋白是一种大量表达的核仁磷蛋白，主要位于细胞核中。通过免疫细胞化学和免疫细胞化学方法，核仁蛋白与蛋白磷酸酶 1δ (PP1δ) 的染色模式相似。 AgNOR 和核仁素从处理的成骨细胞的细胞核中消失。在从成骨细胞获得的蛋白质中检测到一条主要条带，110 kDa 蛋白质的水平在凋亡的成骨细胞中下降，而在凋亡的成骨细胞中出现了一条额外的条带，并且该蛋白质的水平增加。从 OA 诱导的凋亡成骨细胞制备的蛋白质，目前的结果表明 PP18 直接与成骨细胞核仁中的核仁素结合。核仁素在成骨细胞凋亡过程中被裂解。

项目成果

期刊论文数量（20）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The transcriptional factor Osterix directly interacts with RNA helicase A

DOI：
10.1016/j.bbrc.2007.01.150
发表时间：
2007-04-06
期刊：
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
影响因子：
3.1
作者：
Amorim, Bruna Rabelo;Okamura, Hirohiko;Haneji, Tatsuji
通讯作者：
Haneji, Tatsuji

Association of protein phosphatase 1 delta with nucleolin in osteoblastic cells and cleavage of nucleolin in apoptosis-induced cells

成骨细胞中蛋白磷酸酶 1 δ 与核仁素的关联以及凋亡诱导细胞中核仁素的裂解

DOI：
发表时间：
期刊：
Acta Histochemica et Cytochemica (in press)
影响因子：
0
作者：
小川;郁子他;Ogawa I. et al.;小川郁子;Hirohiko Okamura;Hirohiko Okamura;Michi Fujita;Hiroyuki Morimoto;Hiroyuki Morimoto;Kikuji Yamashita;Kikuji Yamashita;羽地達次;Tatsuji Haneji T.
通讯作者：
Tatsuji Haneji T.

Okadaic acid induces phosphorylation of p65NF-κB on serine 536 and activates NF-κB transcriptional activity in human osteoblastic MG63 cells

冈田酸诱导人成骨细胞 MG63 细胞中 p65NF-κB 丝氨酸 536 磷酸化并激活 NF-κB 转录活性