IRSp53和MIM同源结构域IMD相互作用蛋白质的鉴定

Identification of Proteins Interacting with the Homology Domain of IRSp53 and MIM

IRSp53（胰岛素受体酪氨酸激酶底物）和MIM（肿瘤转移消失蛋白）的同源结构域（IMD结构域）在IR—Sp53／MIM家族调控肌动蛋白动态变化的过程中起重要作用。IMD结构域具有使肌动蛋白纤维成束的活性，与小分子GTPase家族Racl也存在相互作用。然而，IMD结构域是否存在其它相互作用蛋白并不清楚。本研究利用GST pull down技术结合质谱分析从大鼠小脑中筛选IMD结构域的相互作用蛋白，得到了几个候选蛋白。其中，神经发育中下调蛋白NEDD9与IRSp53及MIM在小脑中存在类似的分布，体外实验进一步证明了两者之间的相互作用，暗示NEDD9是一种新的IMD结构域相互作用蛋白质。

IRSp53 （The insulin receptor tyrosine kinase substrate p53 ） and MIM （Missing in metastasis） homology domain （IMD） is an important domain for the normal function of IRSp53/MIM family in the regulation of actin dynamics. It has been reported that the IMD domain alone had the F-acting bundling activity and also associated with small GT- Pase Racl. However, whether there are other proteins interacting with IMD domain remains unknown. In this study, GST pull-down combined with MS analysis was used to screen the GST-IMD interacting proteins in the rat cerebellum and several candidates had been identified. Among them, NEDD9 protein （ neural precursor cell expressed, developmentally down-regulated 9） had a similar distribution in cerebellum to those of IRSp53 and MIM, and its interaction with GST- IMD was further verified in the in vitro experiment, implicating that NEDD9 could be a new candidate of IMD domain interaction proteins.