14-3-3 proteins act as negative regulators of the inducer Cdc25 in Xenopus egg extracts
14-3-3 proteins act as negative regulators of the inducer Cdc25 in Xenopus egg extracts
复制标题
DOI：
10.1091/mbc.9.2.345
复制
发表时间：
1998-02-01
影响因子：
3.3
通讯作者：
Dunphy, WG
中科院分区：
文献类型：
--
作者：
Kumagai, A;Yakowec, PS;Dunphy, WG
Cdc25 是一种双特异性磷酸酶，可在有丝分裂时使 Cdc2-细胞周期蛋白 B 复合物去磷酸化，在细胞周期中受到高度调控。在非洲爪蟾卵提取物中，Cdc25 与 14-3-3 蛋白的两种亚型相关。 Cdc25 主要与 14-3-3 epsilon 复合，并在较小程度上与 14-3-3 zeta 复合。这些 14-3-3 蛋白与 Cdc25 的关联在细胞周期中变化很大：在间期期间结合很高，但在有丝分裂时几乎不存在。与 14-3-3 的相互作用是通过爪蟾 Cdc25 Ser-287 磷酸化介导的，该磷酸化位于共有的 14-3-3 结合位点中。该残基上有点突变的重组 Cdc25 (Cdc25-S287A) 无法与 14-3-3 结合。在非洲爪蟾卵提取物中添加 Cdc25-S287A 突变体可加速有丝分裂，并克服由于未复制和受损 DNA 的存在而导致的检查点介导的有丝分裂进入停滞。这些发现表明 14-3-3 蛋白在控制 G(2)-M 转变中充当 Cdc25 的负调节因子。
Cdc25, the dual-specificity phosphatase that dephosphorylates the Cdc2-cyclin B complex at mitosis, is highly regulated during the cell cycle. In Xenopus egg extracts, Cdc25 is associated with two isoforms of the 14-3-3 protein. Cdc25 is complexed primarily with 14-3-3 epsilon and to a lesser extent with 14-3-3 zeta. The association of these 14-3-3 proteins with Cdc25 varies dramatically during the cell cycle: binding is high during interphase but virtually absent at mitosis. Interaction with 14-3-3 is mediated by phosphorylation of Xenopus Cdc25 at Ser-287, which resides in a consensus 14-3-3 binding site. Recombinant Cdc25 with a point mutation at this residue (Cdc25-S287A) is incapable of binding to 14-3-3. Addition of the Cdc25-S287A mutant to Xenopus egg extracts accelerates mitosis and overrides checkpoint-mediated arrests of mitotic entry due to the presence of unreplicated and damaged DNA. These findings indicate that 14-3-3 proteins act as negative regulators of Cdc25 in controlling the G(2)-M transition.