Cooper John A, Nelson Scott A
Department of Cell Biology, Washington University, St. Louis, MO 63110, USA.
J Cell Biol. 2006 Jan 30;172(3):331-3. doi: 10.1083/jcb.200512153. Epub 2006 Jan 23.
Cell cycle checkpoints can delay mitotic exit in budding yeast. The master controller is the small GTPase Tem1, with inputs from a proposed guanine nucleotide exchange factor (GEF), Lte1, and a GTPase-activating protein (GAP), Bub2/Bfa1. In this issue, Fraschini et al. (p. 335) show that GAP activity of Bub2/Bfa1 appears to be dispensable for inactivation of Tem1 in cells. Their results call into question the GTP/GDP switch model for Tem1 activity, as have other results in the past. The paper also focuses attention on the two spindle pole bodies as potential sites for regulation of Tem1.
细胞周期检查点可延迟芽殖酵母中的有丝分裂退出。主要调控因子是小GTP酶Tem1,其输入来自一种假定的鸟嘌呤核苷酸交换因子(GEF)Lte1和一种GTP酶激活蛋白(GAP)Bub2/Bfa1。在本期中,弗拉斯基尼等人(第335页)表明,Bub2/Bfa1的GAP活性似乎对于细胞中Tem1的失活并非必需。他们的结果对Tem1活性的GTP/GDP开关模型提出了质疑,过去的其他结果也是如此。该论文还将注意力集中在两个纺锤极体上,认为它们是调控Tem1的潜在位点。