粘着斑(FA)在整联蛋白结合位点提供细胞与细胞外基质(ECM)的连接,并在ECM和肌动蛋白细胞骨架之间传递机械力。细胞通过激活机械敏感性信号通路来感知和响应周围环境的物理刺激,一个叫做机械传导的过程.在这项研究中,我们使用具有不同张力耐受性(Ttol)的RGD-肽缀合的DNA张力计系绳(TGTs)来确定不同大小的FA成熟和YAP核易位所需的分子力。我们发现,在不同Ttol的TGTs上接种的细胞中FA大小的限制小于1μm,2μm,3μm,对于43pN的Ttol值,为6μm,50pN,54pN,和56pN,分别。这表明整合素之间的分子张力随着FA大小在整个FA成熟过程中的增加而逐渐增加。对于YAP核易位,仅在Ttol≥54pN的TGT上接种的细胞中观察到显着的YAP核定位,但在Ttol≤50pN的TGT上没有,表明YAP核易位的整合素之间的分子力阈值在50pN-54pN的范围内。
Focal adhesions (FAs) provide the cells linkages to extracellular matrix (ECM) at sites of integrins binding and transmit mechanical forces between the ECM and the actin cytoskeleton. Cells sense and respond to physical stimuli from their surrounding environment through the activation of mechanosensitive signaling pathways, a process called mechanotransduction. In this study, we used RGD-peptide conjugated DNA tension gauge tethers (TGTs) with different tension tolerance (Ttol) to determine the molecular forces required for FA maturation in different sizes and YAP nuclear translocation. We found that the limitation of FA sizes in cells seeded on TGTs with different Ttol were less than 1 μm, 2 μm, 3 μm, and 6 μm for Ttol values of 43 pN, 50 pN, 54 pN, and 56 pN, respectively. This suggests that the molecular tension across integrins increases gradually as FA size increases throughout FA maturation. For YAP nuclear translocation, significant YAP nuclear localization was observed only in the cells seeded on the TGTs with Ttol ≥ 54 pN, but not on TGTs with Ttol ≤ 50 pN, suggesting a threshold of molecular force across integrins for YAP nuclear translocation lies in the range of 50 pN-54 pN.