Difference in the centrosome duplication regulatory activity among p53 'hot spot' mutants: potential role of Ser 315 phosphorylation-dependent centrosome binding of p53.
Difference in the centrosome duplication regulatory activity among p53 'hot spot' mutants: potential role of Ser 315 phosphorylation-dependent centrosome binding of p53.
复制标题
p53“热点”突变体中心体复制调节活性的差异：p53 Ser 315 磷酸化依赖性中心体结合的潜在作用。
DOI：
10.1038/sj.onc.1204848
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Fukasawa,K
中科院分区：
文献类型：
--
作者：
Tarapore,P;Tokuyama,Y;Horn,HF;Fukasawa,K
P53抑癌蛋白通过多条途径调节中心体复制，而P53‘S反式激活功能的主要靶点p21Waf1/Cip1(Waf1)已被证明是其中的效应者之一。然而，目前还不清楚P53‘S Waf1独立的中心体复制调控通路是否需要其反式激活功能。在人类癌症中，特定的P53残基发生高频突变。这些“热点”突变使P53‘S的反式激活功能丧失。如果P53以不依赖于反式激活的方式调节中心体复制，不同的“热点”突变体可能会以不同的方式调节中心体复制。为了检验这一点，我们检测了两个“热点”突变体(R175H和R249S)对其中心体复制调控活动的影响。我们发现R175H失去了调节中心体复制的能力，而R249S部分保留了它。此外，R249S与野生型P53相似，与未复制的中心体和复制的中心体相关，而R175H只与复制的中心体相关，而不与未复制的中心体相关。由于细胞周期蛋白依赖性激酶2(CDK2)触发中心体复制的启动，而P53在Ser315上被CDK2磷酸化，我们检测了将Ser315替换为Ala(A)和Asp(D)的p53突变体，这两个突变都保留了反式激活功能。我们发现S315D保留了完整的中心体复制活性，而S315A只保留了部分中心体复制活性。此外，S315D既与未复制的中心体有关，也与复制的中心体有关，而S315A只与复制的中心体有关，而不与未复制的中心体有关。因此，P53以反式激活依赖和反式激活非依赖的方式控制中心体复制周期，并且受Ser315上的磷酸化控制的与未复制的中心体结合的能力对于P53介导的中心体复制的整体调控可能是重要的。
The p53 tumor suppressor protein regulates centrosome duplication through multiple pathways, and p21 Waf1/Cip1 (Waf1), a major target of p53's transactivation function, has been shown to be one of the effectors. However, it had been unclear whether the p53's Waf1-independent centrosome duplication regulatory pathways require its transactivation function. In human cancers, specific residues of p53 are mutated at a high frequency. These ‘hot spot’mutations abrogate p53's transactivation function. If p53 regulates centrosome duplication in a transactivation-independent manner, different ‘hot spot’mutants may regulate centrosome duplication differently. To test this, we examined the effect of two ‘hot spot’mutants (R175H and R249S) for their centrosome duplication regulatory activities. We found that R175H lost the ability to regulate centrosome duplication, while R249S partially retained it. Moreover, R249S associates with both unduplicated and duplicated centrosomes similar to wild-type p53, while R175H only associates with duplicated, but not unduplicated centrosomes. Since cyclin-dependent kinase 2 (CDK2) triggers initiation of centrosome duplication, and p53 is phosphorylated on Ser 315 by CDK2, we examined the p53 mutants with a replacement of Ser 315 to Ala (A) and Asp (D), both of which retain the transactivation function. We found that S315D retained a complete centrosome duplication activity, while S315A only partially retained it. Moreover, S315D associates with both unduplicated and duplicated centrosomes, while S315A associates with only duplicated, but not unduplicated centrosomes. Thus, p53 controls the centrosome duplication cycle both in transactivation-dependent and transactivation-independent manners, and the ability to bind to unduplicated centrosomes, which is controlled by phosphorylation on Ser 315, may be important for the overall p53-mediated regulation of centrosome duplication.