Mueller P R, Coleman T R, Kumagai A, Dunphy W G
Division of Biology 216-76, Howard Hughes Medical Institute, California Institute of Technology, Pasadena 91125, USA.
Science. 1995 Oct 6;270(5233):86-90. doi: 10.1126/science.270.5233.86.
Cdc2 is the cyclin-dependent kinase that controls entry of cells into mitosis. Phosphorylation of Cdc2 on threonine-14 and tyrosine-15 inhibits the activity of the enzyme and prevents premature initiation of mitosis. Although Wee1 has been identified as the kinase that phosphorylates tyrosine-15 in various organisms, the threonine-14-specific kinase has not been isolated. A complementary DNA was cloned from Xenopus that encodes Myt1, a member of the Wee1 family that was discovered to phosphorylate Cdc2 efficiently on both threonine-14 and tyrosine-15. Myt1 is a membrane-associated protein that contains a putative transmembrane segment. Immunodepletion studies suggested that Myt1 is the predominant threonine-14-specific kinase in Xenopus egg extracts. Myt1 activity is highly regulated during the cell cycle, suggesting that this relative of Wee1 plays a role in mitotic control.
细胞周期蛋白依赖性激酶Cdc2控制细胞进入有丝分裂。Cdc2的苏氨酸-14和酪氨酸-15位点磷酸化会抑制该酶的活性，并防止有丝分裂过早启动。尽管在多种生物体中已确定Wee1是使酪氨酸-15磷酸化的激酶，但尚未分离出苏氨酸-14特异性激酶。从非洲爪蟾中克隆出一个互补DNA，它编码Myt1，Myt1是Wee1家族的成员，被发现可有效使Cdc2的苏氨酸-14和酪氨酸-15位点磷酸化。Myt1是一种膜相关蛋白，含有一个假定的跨膜片段。免疫去除研究表明，Myt1是非洲爪蟾卵提取物中主要的苏氨酸-14特异性激酶。Myt1的活性在细胞周期中受到高度调节，这表明Wee1的这个相对物在有丝分裂控制中发挥作用。
