机械力传导的分子机制—细胞感知力与诱导基因表达的方式如何？

机械力传导，即机械力信号转化为生化信号的过程，在细胞生长，分化以及凋亡中起到了重要作用，是近来细胞生物学的一个研究热点。申请人在之前研究中发现细丝蛋白(FLNA)具有响应机械力变化的能力，并进一步通过定量蛋白质组学发现了数个与其机械力响应能力相关的候选分子，其中的两个(smoothelin和fimbacin)已被证实并发表。在本申请中，我们将进一步研究FLNA-Fimbacin相互作用机制并利用基因嵌入小鼠，以确定FLNA-Fimbacin相互作用在活体组织中的影响。除外，为了揭秘机械力调控基因表达的机制，申请人使用定量蛋白质组学对对机械力敏感的反式作用因子进行了高通量筛选并初步发现六个机械力敏感候选分子，本项目也将对这些分子进行验证，确定其在机械力传导中的功能。总之，拟议的项目将确定机械力传导中调控细胞力学、收缩、迁移和扩散的新组成部分，从而为治疗与机械传递有关的疾病提供新的方法。

Mechanotransduction, a conversion of mechanical forces into biochemical signal, is essential in many aspects of human life and defects of mechanotransduction lead to various diseases such as muscular dystrophies, cardiomyopathies, and even cancer progression and metastasis. Despite importance of mechanotransduction, little is known about the underlying molecular mechanisms because mechanical force is a difficult parameter to reproduce and disappear once biological samples are lysed. In consequence, what is missing in mechanotransduction research is an understanding of how forces are sensed, transmitted, and transduced into gene expression. The applicant has previously demonstrated that filamin A (FLNA), an actin cross-linking protein, act as a mechano-sensor and -transducer by changing conformation upon mechanical force. Our laboratory has recently developed a new method to detect a molecule that specifically interacts with mechanically activated FLNA and found several potential new mechano-binding partners. Two of them, smoothelin and fimbacin were confirmed to bind FLNA mechanosensing site and recently published. In this project we elucidate the role of FLNA-fimbacin interaction during development using tissue culture and mouse models.. We will also investigate how mechanical force is transduced into gene expression. More specifically, we will identify force-dependent trans-acting factors (TAFs), which bind to the cis-acting sequences to control gene expression. We have recently developed a high throughput method to detect TAFs using quantitative proteomics. Although YAP is known as a key mechanosensitive transcriptional cofactor, we detected not only YAP but also 45 protein molecules that potentially interact with open chromatin in force-dependent manner. We have already confirmed that 6 out of 45 candidates translocate from cytosol to nucleus in the presence of internal mechanical force in tissue culture cell. This project will further analyze the role of these candidate proteins in mechanotransduction.. In summary, the proposed project will identify new components that are involved in the mechanotransduction that control cell mechanics, contraction, migration, and proliferation and may thereby provide new approaches to treat diseases associated with mechanotransduction.