PDK1 is required for the hormonal signaling pathway leading to meiotic resumption in starfish oocytes
PDK1 is required for the hormonal signaling pathway leading to meiotic resumption in starfish oocytes
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DOI：
10.1016/j.ydbio.2004.08.036
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发表时间：
2004-12-15
影响因子：
2.7
通讯作者：
Kishimoto, T
中科院分区：
文献类型：
--
作者：
Hiraoka, D;Hori-Oshima, S;Kishimoto, T
减数分裂的恢复通常是在细胞外成熟诱导激素的控制下。它相当于体细胞有丝分裂中的G2-M期转变，受细胞周期蛋白B-Cdc 2激酶的调节。然而，从激素到细胞周期蛋白B-Cdc 2的完整信号通路在任何生物体中都还不清楚。分析减数分裂恢复的模型系统是海星卵母细胞，其中Akt/蛋白激酶B（PKB）在导致细胞周期蛋白B-Cdc 2活化的激素信号传导中起关键介导剂。在这里，我们表明，在海星卵母细胞中，当PDK 1活性被抑制的中和抗体，成熟诱导激素未能诱导细胞周期蛋白B-Cdc 2激活在减数分裂G2-M相变，即使PDK 2活性变得可检测。这些观察分配一个新的角色PDK 1的激素信号中间朝向减数分裂恢复。他们进一步支持PDK 2是不同于PDK 1和Akt的分子，并且在没有PDK 1活性的情况下，PDK 2活性不足以完全激活Akt。(C)2004年爱思唯尔公司All rights reserved.
Meiotic resumption is generally under the control of an extracellular maturation-inducing hormone. It is equivalent to the G2-M phase transition in somatic cell mitosis and is regulated by cyclin B-Cdc2 kinase. However, the complete signaling pathway from the hormone to cyclin B-Cdc2 is yet unclear in any organism. A model system to analyze meiotic resumption is the starfish oocyte, in which Akt/protein kinase B (PKB) plays a key mediator in hormonal signaling that leads to cyclin B-Cdc2 activation. Here we show in starfish oocytes that when PDK1 activity is inhibited by a neutralizing antibody, maturation-inducing hormone fails to induce cyclin B-Cdc2 activation at the meiotic G2-M phase transition, even though PDK2 activity becomes detectable. These observations assign a novel role to PDK1 for a hormonal signaling intermediate toward meiotic resumption. They further support that PDK2 is a molecule distinct from PDK1 and Akt, and that PDK2 activity is not sufficient for the full activation of Akt in the absence of PDK1 activity. (C) 2004 Elsevier Inc. All rights reserved.