Hoffmann I, Karsenti E
European Molecular Biology Laboratory, Heidelberg, Germany.
J Cell Sci Suppl. 1994;18:75-9. doi: 10.1242/jcs.1994.supplement_18.11.
Major checkpoints that gate progression through the cell cycle function at the G1/S transition, entry into mitosis and exit from mitosis. Cells use feedback mechanisms to inhibit passage through these checkpoints in response to growth control signals, incomplete DNA replication or spindle assembly. In many organisms, transition points seem to involve regulation of the activity of cyclin-dependent kinases (cdks) not only through their interactions with various cyclins, but also by phosphorylation-dephosphorylation cycles acting on the kinase activity of the cdks. These phosphorylation cycles are modulated by the regulation of the opposing kinases and phosphatases that act on cdks and form feedback loops. In this article, we discuss the role of positive and negative feedback loops in cell cycle timing and checkpoints, focusing more specifically on the regulation of the dual specificity cdc25 phosphatase.
控制细胞周期进程的主要关卡作用于G1/S转换期、进入有丝分裂期和退出有丝分裂期。细胞利用反馈机制，响应生长控制信号、DNA复制不完全或纺锤体组装情况，抑制通过这些关卡。在许多生物体中，转换点似乎不仅涉及通过细胞周期蛋白依赖性激酶（cdks）与各种细胞周期蛋白的相互作用来调节其活性，还涉及作用于cdks激酶活性的磷酸化-去磷酸化循环。这些磷酸化循环通过作用于cdks的相对激酶和磷酸酶的调节来调控，并形成反馈环。在本文中，我们讨论正负反馈环在细胞周期定时和关卡中的作用，更具体地聚焦于双重特异性cdc25磷酸酶的调节。
