Role of Smads and TAK1 in BMP-induced growth arrest and apoptosis

Smads 和 TAK1 在 BMP 诱导的生长停滞和细胞凋亡中的作用

基本信息

批准号：
11671797
负责人：
YAMATO Kenji
金额：
$ 2.24万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11671797/
关键词：
BMP-2 G1 arrest apoptosis Bb p21^<CIP1 WAF1>Smad BMP TAK1 apoptosis cell cycle G1 arrest

项目摘要

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-β superfamily and participate in functional and morphogenetic regulation of various organs by, in part, controlling cell proliferation and apoptotic cell death . However, the mechanisms by which BMPs trigger growth inhibition and apoptosis remain to be elucidated.We have previously found that BMP-2 induces cell-cycle arrest in the G1 phase and apoptotic cell death of HS-72 mouse hybridoma cells. In this study, we showed that BMP-2 did not alter expression of cyclin D, cyclin E, cyclin-dependent kinase 2 (CDK2), CDK4, p27^<KIP1>, p16^<INK4a>, p15^<INK4b>, but enhanced expression of p21^<CIP1/WAF1>. Accumulation of p21^<CIP1/WAF1> resulted in increased binding of p21^<CIP1/WAF1> to CDK4 and concomitantly caused a profound decrease in the in vitro retinoblastoma protein (Rb) kinase activity of CDK4. Furthermore, the ectopic expression of human papilloma virus type-16 E7, an inhibitor of p21^<CIP1/WAF1> and Rb, rev … More erted G1-arrest induced by BMP-2. Expression of E6/E7, without increasing the p53 level, blocked inhibition of Rb phosphorylation and G1 arrest, but did not attenuate cell death in BMP-treated HS-72 cells. Taken together, these results suggest that inhibition of Rb phosphorylation by p21^<CIP1/WAF1> is responsible for BMP-2-mediated G1 arrest and that BMP-2-induction of apoptosis might be independent of Rb hypophosphorylation.We also demonstrated that BMP-2 activated the mouse p21^<CIP1/WAF1> promoter in HS-72 cells, and that a 29-base pair (b) region of the promoter, conserved between mice and humans, was responsive to BMP-2 as well as expression of Smad1, Smad4, and constitutively active mutants of BMP type I receptors. Furthermore, an oligoncleotide containing the 29-b region was found to be associated with Smad1 and Smad4 in the HS-72 nuclear extract. These results suggested that BMP-2 might activate p21^<CIP1/WAF1> transcription by inducing an indirect binding of Smad4 and Smad1 to the 29-b region in HS-72 cells. Less

骨形态发生蛋白 (BMP) 属于转化生长因子-β 超家族，通过部分控制细胞增殖和细胞凋亡来参与各种器官的功能和形态发生调节。然而，BMP 触发生长抑制和细胞凋亡的机制尚不清楚。仍有待阐明。我们之前发现 BMP-2 会诱导 HS-72 小鼠杂交瘤细胞的细胞周期停滞在 G1 期并导致细胞凋亡。显示 BMP-2 不会改变细胞周期蛋白 D、细胞周期蛋白 E、细胞周期蛋白依赖性激酶 2 (CDK2)、CDK4、p27^<KIP1>、p16^<INK4a>、p15^<INK4b> 的表达，但增强 p21 的表达^<CIP1/WAF1> p21^<CIP1/WAF1> 的积累导致结合增加。 p21^<CIP1/WAF1> 转化为 CDK4，并同时导致 CDK4 的体外视网膜母细胞瘤蛋白 (Rb) 激酶活性显着降低。此外，p21^<CIP1 抑制剂人乳头瘤病毒 16 型 E7 的异位表达。 /WAF1> 和 Rb，rev … 更多 E6/E7 表达诱导的 G1 停滞。增加 p53 水平，阻断对 Rb 磷酸化的抑制和 G1 期停滞，但不会减弱 BMP 处理的 HS-72 细胞中的细胞死亡。综上所述，这些结果表明 p21^<CIP1/WAF1> 对 Rb 磷酸化的抑制是起作用的。对于 BMP-2 介导的 G1 期阻滞，并且 BMP-2 诱导的细胞凋亡可能与 Rb 低磷酸化无关。我们还证明 BMP-2 激活了小鼠HS-72 细胞中的 p21^<CIP1/WAF1> 启动子，以及该启动子的 29 碱基对 (b) 区域（在小鼠和人类之间保守）对 BMP-2 以及 Smad1、Smad4 的表达有反应，此外，还发现含有 29-b 区域的寡核苷酸与 Smad1 和 Smad4 相关。 HS-72 核提取物。这些结果表明，BMP-2 可能通过诱导 Smad4 和 Smad1 与 HS-72 细胞中的 29-b 区域间接结合来激活 p21^<CIP1/WAF1> 转录。