Honda R, Ohba Y, Nagata A, Okayama H, Yasuda H
Division of Biology, Faculty of Pharmaceutical Sciences, Kanazawa University, Ishikawa, Japan.
FEBS Lett. 1993 Mar 8;318(3):331-4. doi: 10.1016/0014-5793(93)80540-b.
In mammalian cells, p34cdc2 kinase undergoes phosphorylation at threonine-14, tyrosine-15 and threonine-161 in the S and G2 phases of the cell cycle. At the onset of mitosis, the kinase becomes dephosphorylated at threonine-14 and tyrosine-15, resulting in activation. Cdc25 phosphatase has been shown to dephosphorylate tyrosine-15 in vitro, but whether it also does at threonine-14 remains unclear. In this study, we have found that human cdc25B phosphatase dephosphorylates both threonine-14 and tyrosine-15 but not threonine-161.
在哺乳动物细胞中，p34cdc2激酶在细胞周期的S期和G2期，其苏氨酸-14、酪氨酸-15和苏氨酸-161位点会发生磷酸化。在有丝分裂开始时，该激酶在苏氨酸-14和酪氨酸-15位点发生去磷酸化，从而被激活。已证明Cdc25磷酸酶在体外可使酪氨酸-15去磷酸化，但它是否也能使苏氨酸-14去磷酸化尚不清楚。在本研究中，我们发现人cdc25B磷酸酶可使苏氨酸-14和酪氨酸-15都去磷酸化，但不能使苏氨酸-161去磷酸化。
