泛素连接酶Smurf1不同亚型的功能研究

Smad泛素调节因子1(Smad ubiquitination regulatory factor 1,Smurf1)是一种HECT类的泛素连接酶,它参与许多生命活动的调节,如神经发育、细胞极性、骨的重塑和肿瘤形成等.虽然目前对Smurf1的了解较为深入,但在研究过程中并未对它的两种亚型Smurf1 L和Smurf1 S(两者在一级结构上仅相差26个氨基酸残基)进行详细区分,且偏重于对Smurf1 S的研究.因此本文对Smurf1上述两种亚型的功能(特别是Smurf1 L)进行了更加深入的探索.利用RT-PCR、免疫荧光和蛋白质印迹(Western blot)等实验技术,我们从组织表达、亚细胞定位和对底物的降解能力这三个方面深入研究了Smurf1 S和Smurf1 L的不同之处.实验结果表明:一方面,Smurf1 S的组织分布比Smurf1 L更加广泛,表达量更高;另一方面,两者的亚细胞定位也有所不同,Smurf1 L在有丝分裂期定位于纺锤体,而Smurf1 S则可能主要分布于胞质中.此外,Smurf1 S对底物的降解比Smurf1 L更彻底,且前者的降解效应有剂量依赖性.上述成果对今后更为精确地研究Smurf1的功能具有重要意义.

The Function Research on Different Isoforms of Smurf1

Smad ubiquitination regulatory factor 1 (Smurf1) is an HECT type E3 ligase and regulating a lot of life activity, such as nervous development, cell polarization, bone remodeling and tumor formation, etc. At present, it is in-deep that our knowledge about Smurf1, but people did not particularly distinguish its isoform Smurf1 L and Smurf1 S (the former have 26 amino acid more than the latter) in previous study, and most of related work tend to Smurf1 S. So this article provided some information about the function of Smurf1 L and Smurf1 S. By means of RT-PCR, immunofluorescence assay and Western blot, we studied the difference of Smurf1 L and Smurf1 S in some aspects, including tissue expression, subcellular localization and substrate degradation. The result suggested that: on the one hand, not only the tissue distribution of Smurf1 S is more widespread than Smurf1 L, but also its expression level is higher than Smurf1 L; on the other hand, their subcellular localization have also obvious distinction. Smurf1 L exist at spindles in mitotic phase, but Smurf1 S perhaps exist in cytoplasm. In addition, the degradation ability to substrate of Smurf1 S is stronger than Smurf1 L, and have dose-dependent. In short, these achievement have important significance for more precise research to Smurf1.