PACT调控细胞迁移的分子机制

Interferon-inducible double-stranded RNA-dependent protein kinase activator A (PACT) is a dsRNA-associating protein, and its deficiency can lead to malfunction in neuronal development. SNPs in PACT gene is associated with worse survival in colon cancer, and colon cancer at advanced stages showed higher PACT level than earlier stages. However, the detailed molecular mechanism is still largely unknown. We have found that PACT knock-down in post-natal day (PD) 4 could significantly inhibit cerebella granule neurons (CGNs) migration, further experiments on cell lines confirm the role PACT played in regulation of migration. Importantly, by virtue of Tandem Affinity Purification and Mass Spectrometry we identified Ubc9 as an interaction partner of PACT. Overexpression of Ubc9 efficiently rescued inhibition of Cell migration caused by knock-down of of PACT, implying that Ubc9 is involved in PACT-regulated cell migration. In this project, we will firstly investigate whether the regulatory effect of PACT-Ubc9 complex on cell migration is based on its regulation of cell skeleton. If so, we will further identify other proteins residing downstream of PACT-Ubc9 complex and involved in the regulation of cell skeleton and migration. Taken together, we would eventually elucidate the molecular mechanism by which PACT regulates migration. Our results may provide clues for the therapy of migration relevant diseases.

干扰素诱导双链RNA依赖蛋白激活蛋白PACT是一个双链RNA结合蛋白。研究表明PACT缺失引起神经系统发育不良，PACT的基因单核苷酸多态性与结肠癌较差的预后相关，且结肠癌病人组织芯片中，PACT蛋白水平上调 。我们前期研究发现敲低新生小鼠颗粒细胞前体中的PACT抑制细胞迁移, 继而验证了在细胞系中，PACT对细胞迁移的调控也同样适用。运用亲和纯化加质谱技术我们发现Ubc9(为SUMO结合酶E2)能够与PACT相互作用,且过量表达Ubc9能够缓解PACT敲低引发的细胞迁移抑制。本课题将首先确定PACT-Ubc9复合体是否通过调节细胞骨架影响细胞迁移, 进而鉴定参与该复合体调控细胞骨架的其它蛋白,阐明其相互调节关系,最终揭示PACT调控细胞迁移的分子机制。本研究有望为细胞迁移相关疾病的治疗提供新的思路。