Role for non-proteolytic control of M-phase-promoting factor activity at M-phase exit.
Role for non-proteolytic control of M-phase-promoting factor activity at M-phase exit.
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DOI：
10.1371/journal.pone.0000247
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发表时间：
2007-02-28
期刊：
影响因子：
3.7
通讯作者：
Grieco D
中科院分区：
文献类型：
--
作者：
D'Angiolella V;Palazzo L;Santarpia C;Costanzo V;Grieco D
M期促进因子(MPF；Cyclin B-cdk1复合体)在M期开始时通过去除THR-14和Tyr-15处CDK1的抑制磷酸化而被激活。在M期退出时，MPF被泛素依赖的细胞周期蛋白分解所破坏。因此，通过抑制磷酸化来控制MPF的活性在调节进入而不是脱离M期的过程中被认为是特别关键的。然而，利用非洲爪哇卵的体外细胞周期系统，我们表明，在M期退出过程中，CDK1的抑制磷酸化有助于控制MPF的活性。通过在减数分裂和有丝分裂退出过程中以非常短的间隔采样提取液，我们发现与Cyclin B1相关的CDK1在Tyr-15发生了短暂的抑制磷酸化，并且Cyclin B1-CDK1活性下降的速度比Cyclin B1的含量下降得更快。在M期退出过程中，MPF的抑制磷酸化与cdc25C、MPF磷酸酶的磷酸化变化以及CDK1与MPF激酶Wee1的物理相互作用有关。在减数分裂和有丝分裂阶段，MPF的下调分别需要Ca++/钙调蛋白依赖的蛋白激酶II(CaMKII)和cAMP依赖的蛋白激酶(PKA)的活性。用突变的Cyclin B1-cdk1AF复合体处理M期提取物，该复合体不能被磷酸化抑制，破坏了后期促进复合体/环体(APC/C)与其共激活剂CDC20的结合，并改变了M期退出。因此，及时退出M期需要蛋白分解依赖和蛋白分解非依赖的MPF失活机制的紧密耦合。
M-phase Promoting Factor (MPF; the cyclin B-cdk 1 complex) is activated at M-phase onset by removal of inhibitory phosphorylation of cdk1 at thr-14 and tyr-15. At M-phase exit, MPF is destroyed by ubiquitin-dependent cyclin proteolysis. Thus, control of MPF activity via inhibitory phosphorylation is believed to be particularly crucial in regulating transition into, rather than out of, M-phase. Using the in vitro cell cycle system derived form Xenopus eggs, here we show, however, that inhibitory phosphorylation of cdk1 contributes to control MPF activity during M-phase exit. By sampling extracts at very short intervals during both meiotic and mitotic exit, we found that cyclin B1-associated cdk1 underwent transient inhibitory phosphorylation at tyr-15 and that cyclin B1-cdk1 activity fell more rapidly than the cyclin B1 content. Inhibitory phosphorylation of MPF correlated with phosphorylation changes of cdc25C, the MPF phosphatase, and physical interaction of cdk1 with wee1, the MPF kinase, during M-phase exit. MPF down-regulation required Ca++/calmodulin-dependent kinase II (CaMKII) and cAMP-dependent protein kinase (PKA) activities at meiosis and mitosis exit, respectively. Treatment of M-phase extracts with a mutant cyclin B1-cdk1AF complex, refractory to inhibition by phosphorylation, impaired binding of the Anaphase Promoting Complex/Cyclosome (APC/C) to its co-activator Cdc20 and altered M-phase exit. Thus, timely M-phase exit requires a tight coupling of proteolysis-dependent and proteolysis-independent mechanisms of MPF inactivation.
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影响因子：
11.8
作者：
Arnaoutov, A;Dasso, M
通讯作者：
Dasso, M
影响因子：
64.8
作者：
LORCA, T;CRUZALEGUI, FH;DOREE, M
通讯作者：
DOREE, M
影响因子：
9.2
作者：
D'Angiolella, V;Costanzo, V;Grieco, D
通讯作者：
Grieco, D
影响因子：
16
作者：
Costanzo, V;Robertson, K;Gautier, J
通讯作者：
Gautier, J
影响因子：
64.8
作者：
MURRAY, AW;KIRSCHNER, MW
通讯作者：
KIRSCHNER, MW