PEAK1是一个非受体酪氨酸蛋白激酶，在细胞Actin微丝、粘着斑和伪足等部位定位，可促进多种肿瘤细胞的迁移，其调控机制不明。我们发现：沉默PEAK1可阻碍粘着斑、Actin微丝和伪足的动态变化，抑制肿瘤细胞迁移；PEAK1与伪足蛋白CTTN相互作用；沉默PEAK1导致粘着斑蛋白聚集，下调CTTN、Paxillin、Vinculin和Src等蛋白的酪氨酸磷酸化，上调FAK Y397。据此，我们推测：PEAK1可能通过CTTN介导伪足Actin的聚合及FAK调节粘着斑的动态组装，调控肿瘤细胞的迁移。本项目将进一步分析PEAK1与CTTN的互作结构域，筛选PEAK1调控CTTN的酪氨酸磷酸化位点；探讨PEAK1对CTTN-Arp2/3介导Actin体外聚合的影响；研究Src在PEAK1调控粘着斑蛋白定位、相互作用和磷酸化中的作用。为PEAK1作为高转移肿瘤诊疗标志物及治疗靶点的研究提供理依据。

PEAK1 is a non-receptor protein tyrosine kinase which localized at actin cytoskeleton and focal adhesion sites, playing a crucial role in the occurrence and metastasis of high metastatic tumors, but the molecular mechanism of PEAK1-promoted tumor metastasis remained unknown. Our previous study found that knockdown of PEAK1 leads to enlarged focal adhesion and dynamic defects of pseudopodia. We identified some interaction proteins of PEAK1 by using co-immunoprecipitation coupled with LC-MS/MS. In these candidate interaction proteins, CTTN that mediated actin polymerization was proved to interact with PEAK1. Non-labeling quantitative proteomics analysis showed that tyrosine phosphorylation of CTTN is down-regulated, but FAK Y397 is up-regulated in PEAK1 knockdown cells. Therefore, we speculate that CTTN-activated actin polymerization and FAK-mediated focal adhesion turnover in pseudopodia play an important role in the process of PEAK1-promoted cell migration. We will dissect the mechanism of PEKA1-motivated cell migration from the following aspects: 1) Reveal the interaction mechanism between PEAK1 and CTTN；2）The effect of PEAK1 on CTTN tyrosine phosphorylation and the function of PEAK1 regulated CTTN phosphomodification in CTTN-Arp2/3 complex mediated actin polymerization in pseudopodia; 3) The influence of PEKA1 on the cellular localization, interaction and tyrosine phosphorylation of focal adhesion related proteins, such as FAK, Paxillin, Talin. 4) The role of Src in PEAK1-regulated tyrosine phosphorylation of FAK containing focal adhesion. These results will provide a theoretical basis for the study of PEAK1 as a marker for the diagnosis and treatment of high metastatic tumor.