A cyclin-dependent kinase inhibitor, butyrolactone I, inhibits phosphorylation of RB protein and cell cycle progression.
A cyclin-dependent kinase inhibitor, butyrolactone I, inhibits phosphorylation of RB protein and cell cycle progression.
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发表时间：
1994-09
期刊：
影响因子：
8
通讯作者：
M. Kitagawa;H. Higashi;Takahashi Is;T. Okabe;H. Ogino;Y. Taya;S. Hishimura;A. Okuyama
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作者：
M. Kitagawa;H. Higashi;Takahashi Is;T. Okabe;H. Ogino;Y. Taya;S. Hishimura;A. Okuyama
Butyrolactone I 是细胞周期蛋白依赖性激酶 (cdk) 家族的选择性抑制剂。它抑制 cdk2 和 cdc2 激酶，但几乎不影响 C-激酶、A-激酶、酪蛋白激酶、MAP 激酶或 EGF 受体酪氨酸激酶（Kitakawa 等人，1993，Oncogene，8, 2425-2432）。我们研究了丁内酯 I 对细胞周期以及视网膜母细胞瘤蛋白 (pRB) 磷酸化的影响。丁内酯 I 在体外抑制杆状病毒产生的细胞周期蛋白 A-cdk2 催化的 pRB 磷酸化。此外，它还抑制 WI38 细胞培养物中 pRB 的磷酸化和细胞周期从 G1 期进展到 S 期。因血清饥饿而停滞在G0期的WI38细胞在血清刺激后在细胞周期中进展。 10小时血清刺激后pRB被磷酸化。血清刺激16小时后，[3H]胸苷掺入细胞开始增加。这些过程被丁内酯 I 抑制。流式细胞术分析表明，暴露于丁内酯 I 抑制细胞周期从 G1 期进展到 S 期。这些数据表明 DNA 合成的起始被丁内酯 I 抑制，并且细胞周期被停滞在 G1 期。丁内酯 I 还抑制人 WI38 细胞中的 H1 组蛋白磷酸化及其 G2/M 进程。 tsFT210 细胞是一种温度敏感的 cdc2 突变细胞系，在非允许温度下在 G2/M 同步化，丁内酯 I 在允许温度下抑制这些细胞在 G2/M 的细胞周期进程。因此，丁内酯 I（一种细胞周期蛋白依赖性激酶家族抑制剂）可阻止细胞周期调节蛋白 pRB 和 H1 组蛋白的磷酸化，分别抑制 G1/S 和 G2/M 的细胞周期。这些结果表明，pRB 和 H1 组蛋白的磷酸化可能分别在 G1/S 和 G2/M 进程中发挥关键作用，尽管 cdks 对其他蛋白质的磷酸化可能参与 G1/S 和 G2/M 进程。
Butyrolactone I is a selective inhibitor of the cyclin-dependent kinase (cdk) family. It inhibits both cdk2 and cdc2 kinase, but scarcely affects C-kinase, A-kinase, casein kinases, MAP kinase or EGF receptor-tyrosine kinase (Kitagawa et al., 1993, Oncogene, 8, 2425-2432). We studied the effects of butyrolactone I on the cell cycle as well as on phosphorylation of retinoblastoma protein (pRB). Butyrolactone I inhibited phosphorylation of pRB catalyzed by cyclin A-cdk2 produced by baculovirus in vitro. Furthermore, it inhibited phosphorylation of pRB and cell cycle progression from G1 to S phase in WI38 cell cultures. WI38 cells arrested at the G0 phase by serum starvation progressed in the cell cycle after serum stimulation. pRB was phosphorylated after 10 h serum stimulation. Incorporation of [3H]thymidine into the cells began to increase after 16 h serum stimulation. These processes were inhibited by butyrolactone I. Flow cytometric analysis showed that exposure to butyrolactone I inhibited progression of the cell cycle from G1 to S phase. These data suggested that initiation of DNA synthesis was inhibited by butyrolactone I and that the cell cycle was arrested in the G1 phase. Butyrolactone I also inhibited H1 histone phosphorylation in human WI38 cells and their G2/M progression. tsFT210 cells, a temperature-sensitive cdc2 mutant cell line, were synchronized at G2/M at a nonpermissive temperature, butyrolactone I inhibited the cell cycle progression of these cells at G2/M at the permissive temperature. Thus butyrolactone I, a cyclin-dependent kinase family inhibitor, which prevented the phosphorylations of the cell cycle-regulating proteins pRB and H1 histone, inhibited the cell cycle at G1/S and G2/M, respectively. These results suggest that the phosphorylations of pRB and H1 histone may play crucial roles in G1/S and G2/M progression, respectively, although it is possible that phosphorylations of other proteins by cdks are involved in G1/S and G2/M progression.