A novel protein, Xenopus p20, influences the stability of MeCP2 through direct interaction
A novel protein, Xenopus p20, influences the stability of MeCP2 through direct interaction
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DOI：
10.1074/jbc.m402571200
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发表时间：
2004-06-11
影响因子：
4.8
通讯作者：
Landsberger, N
中科院分区：
文献类型：
--
作者：
Carro, S;Bergo, A;Landsberger, N
MeCP2是甲基CpG结合蛋白家族的创始成员，能够抑制甲基化DNA的转录。到目前为止，MeCP2的作用似乎涉及到组蛋白脱乙酰酶活性的修饰DNA的传递，随后是组蛋白甲基化活性。最近已经证明，MECP2突变会导致Rett综合征，这是一种儿童神经障碍，是女性智力低下的最常见原因之一。在这里，我们展示了一种新的20 kDa的非洲爪哇蛋白p20，能够在体内和体外与MeCP2相互作用。P20序列表明，它属于WAP(乳清酸性蛋白)蛋白家族，通常作为一种蛋白酶抑制剂发挥作用。因此，我们询问p20是否会影响MeCP2的半衰期。我们证明，确实，xp20不仅可以显著提高外源表达的MeCP2在非洲爪哇卵母细胞中的稳定性，而且还可以稳定人类内源性MeCP2。免疫共沉淀实验证实了哺乳动物的甲基CpG结合蛋白与p20相互作用的能力，该蛋白过表达WAP蛋白。谷胱甘肽S转移酶下拉分析表明，位于甲基结合区和转录抑制区之间的MeCP2残基是主要的相互作用面。我们的数据表明，MeCP2代谢的调节可能具有相关的重要性；与此相一致，先前的研究结果表明，一些Rett综合征突变的特征是MeCP2稳定性降低。
MeCP2 is the founder member of a family of methyl-CpG-binding proteins able to repress transcription from methylated DNA. To date, MeCP2 action seems to involve the delivery on modified DNA of histone deacetylase activity, followed by histone methylating activity. It has been recently demonstrated that MECP2 mutations cause Rett syndrome, a childhood neurological disorder that represents one of the most common causes of mental retardation in females. Here we show that a novel Xenopus laevis protein of 20 kDa, p20, is able to interact in vivo and in vitro with MeCP2. The p20 sequence revealed that it belongs to the family of the WAP (whey acidic protein) proteins, often functioning as a protease inhibitor. Therefore, we asked whether the p20 can influence the MeCP2 half-life. We demonstrate that, indeed, the xp20 not only can significantly increase the stability of an exogenously expressed MeCP2 in Xenopus oocytes but also can stabilize the human endogenous MeCP2. The capability of the mammalian methyl-CpG-binding protein to interact with p20 is confirmed by co-immunoprecipitation experiments performed over-expressing the WAP protein. Glutathione S-transferase pull-down assays reveal that the MeCP2 residues localized between the methyl-binding domain and the transcriptional repression domain is the primary interaction surface. Our data suggest that regulation of MeCP2 metabolism might be of relevant importance; in accordance with this, previous results have shown that some Rett syndrome mutations are characterized by a decrease in MeCP2 stability.