PDK1 regulates cell proliferation and cell cycle progression through control of cyclin D1 and p27Kip1 expression
PDK1 regulates cell proliferation and cell cycle progression through control of cyclin D1 and p27Kip1 expression
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DOI：
10.1074/jbc.m802589200
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发表时间：
2008-06-20
影响因子：
4.8
通讯作者：
Kasuga, Masato
中科院分区：
文献类型：
--
作者：
Nakamura, Kyoko;Sakaue, Hiroshi;Kasuga, Masato
PDK 1（3-磷酸肌醇依赖性蛋白激酶1）是磷酸肌醇3-激酶信号传导的关键介质。为了深入了解PDK 1在细胞增殖和细胞周期控制中的生理重要性，我们从Pdk 1的“floxed”等位基因纯合子小鼠和野生型小鼠中建立了永生化小鼠胚胎成纤维细胞（MEFs）。通过逆转录病毒介导的基因转移引入Cre重组酶导致Pdk 1（lox/lox）MEFs中PDK 1的缺失，但在Pdk 1（+/+）MEFs中没有。胰岛素样生长因子-1诱导的PDK 1的各种下游效应物（包括Akt、糖原合成酶激酶3、核糖体蛋白S6和p70 S6激酶）的磷酸化在PDK 1耗尽（Pdk 1-KO）MEFs中被显著抑制。血清诱导的细胞增殖速率降低;细胞周期从G（0）-G（1）期向S期的进展延迟，并且在Pdk 1-KO MEFs中G（2）-M期的细胞周期进展受损。这些细胞还表现出p27（Kip 1）表达水平的增加和细胞周期蛋白D1表达水平的降低在细胞周期的进展。Pdk 1-KO MEFs中从G（0）-G（1）到S期的细胞周期进展缺陷通过细胞周期蛋白D1的强制表达来挽救，而这些细胞中G（2）-M进展缺陷的挽救需要细胞周期蛋白D1的过表达和通过RNA干扰的p27（Kip 1）的缺失。这些数据表明，PDK 1通过控制细胞周期蛋白D1和p27（Kip 1）的表达在细胞增殖和细胞周期进程中起重要作用。
PDK1 (3-phosphoinositide-dependent protein kinase 1) is a key mediator of signaling by phosphoinositide 3-kinase. To gain insight into the physiological importance of PDK1 in cell proliferation and cell cycle control, we established immortalized mouse embryonic fibroblasts (MEFs) from mice homozygous for a "floxed" allele of Pdk1 and from wild-type mice. Introduction of Cre recombinase by retrovirus-mediated gene transfer resulted in the depletion of PDK1 in Pdk1(lox/lox) MEFs but not in Pdk1(+/+) MEFs. The insulin-like growth factor-1-induced phosphorylation of various downstream effectors of PDK1, including Akt, glycogen synthase kinase 3, ribosomal protein S6, and p70 S6 kinase, was markedly inhibited in the PDK1-depleted (Pdk1-KO) MEFs. The rate of serum-induced cell proliferation was reduced; progression of the cell cycle from the G(0)-G(1) phase to the S phase was delayed, and cell cycle progression at G(2)-M phase was impaired in Pdk1-KO MEFs. These cells also manifested an increased level of p27(Kip1) expression and a reduced level of cyclin D1 expression during cell cycle progression. The defect in cell cycle progression from the G(0)-G(1) to the S phase in Pdk1-KO MEFs was rescued by forced expression of cyclin D1, whereas rescue of the defect in G(2)-M progression in these cells required both overexpression of cyclin D1 and depletion of p27(Kip1) by RNA interference. These data indicate that PDK1 plays an important role in cell proliferation and cell cycle progression by controlling the expression of both cyclin D1 and p27(Kip1).