Molecular basis of the interactions between the p73 N terminus and p300: Effects on transactivation and modulation by phosphorylation
Molecular basis of the interactions between the p73 N terminus and p300: Effects on transactivation and modulation by phosphorylation
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DOI：
10.1073/pnas.0900383106
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发表时间：
2009-03-03
影响因子：
11.1
通讯作者：
Fersht, Alan R.
中科院分区：
文献类型：
--
作者：
Burge, Sarah;Teufel, Daniel P.;Fersht, Alan R.
转录因子p73属于p53蛋白家族，并且可以与p53共同反式激活许多靶基因。在这里，我们通过使用生物物理和细胞测量来表征p73 N末端与转录辅激活因子p300的四个结构域以及与负调节因子Mdm 2的相互作用。我们发现，与p53一样，p73的N末端含有两个不同的反式激活亚结构域，包括残基10-30和残基46-67。p73的N端结合弱的Taz 1，Kix，和IBiD域的p300，但与亚微摩尔的亲和力Taz 2，在以前的报告相反。我们发现较弱的p73 N末端的p300结构域在体外与QS和T14 A突变体的细胞系中的反式激活活性的显着降低，并在体外与磷酸化模拟T14 D的紧密结合在体内增加相关。此外，我们发现T14的磷酸化使p73 N末端对Taz 2的亲和力增加了10倍。磷酸化模拟p73 α T14 D引起反式激活水平增加。
The transcription factor p73 belongs to the p53 family of proteins and can transactivate a number of target genes in common with p53. Here, we characterized the interaction of the p73 N terminus with four domains of the transcriptional coactivator p300 and with the negative regulator Mdm2 by using biophysical and cellular measurements. We found that, like p53, the N terminus of p73 contained two distinct transactivation subdomains, comprising residues 10-30 and residues 46-67. The p73 N terminus bound weakly to the Taz1, Kix, and IBiD domains of p300 but with submicromolar affinity for Taz2, in contrast to previous reports. We found weaker binding of the p73 N terminus to the p300 domains in vitro correlated with a significant decrease in transactivation activity in a cell line for the QS and T14A mutants, and tighter binding of the phosphomimetic T14D in vitro correlated with an increase in vivo. Further, we found that phosphorylation of T14 increased the affinity of the p73 N terminus for Taz2 10-fold. The phosphomimetic p73 alpha T14D caused increased levels of transactivation.