Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
Sci Signal. 2013 Dec 10;6(305):pe37. doi: 10.1126/scisignal.2004891.
Mammalian cells make the proliferation or quiescence decision at a specific point in the cell cycle called the restriction point, after which they become committed to proliferation and independent of growth factors for completion of mitosis. In the textbook view, this crucial transition occurs several hours after mitotic division (in the middle of G1 phase). In a Cell paper, Spencer et al. show that the restriction point should be defined not as a particular time point in G1 phase but in terms of the ON-OFF status of a bistable switch that emerges from the positive feedback in the CDK2-RB-E2F (cyclin-dependent kinase 2-retinoblastoma-E2F) interaction network.
哺乳动物细胞在细胞周期的一个特定点做出增殖或静止的决定，这个点被称为限制点，之后它们就会开始增殖，并独立于生长因子完成有丝分裂。在教科书的观点中，这个关键的转变发生在有丝分裂分裂后的几个小时（在 G1 期的中期）。在《细胞》杂志的一篇论文中，Spencer 等人表明，限制点不应被定义为 G1 期的特定时间点，而应根据从 CDK2-RB-E2F（细胞周期蛋白依赖性激酶 2-视网膜母细胞瘤-E2F）相互作用网络中的正反馈中出现的双稳态开关的开/关状态来定义。
