Caveolin-1 modulates mechanotransduction responses to substrate stiffness through actin-dependent control of YAP

The transcriptional regulator YAP orchestrates important cell functions, determining tissue homeostasis, organ growth control, and tumorigenesis. Mechanical stimuli are a key input to YAP activity, but the mechanisms controlling this regulation remain largely uncharacterized. We show that CAV1 positively modulates the YAP mechanoresponse to substrate stiffness through actin cytoskeleton-dependent and Hippo kinase-independent mechanisms. RHO activity is necessary but not sufficient for CAV1-dependent mechanoregulation of YAP activity. Systematic quantitative interactomic studies and image-based siRNA screenings provide evidence that this actin-dependent regulation is determined by YAP interaction with the 14-3-3 protein YWHAH. Constitutive YAP activation rescued phenotypes associated with CAV1 loss, including defective ECM remodeling. CAV1-mediated control of YAP activity was validated in vivo in a model of pancreatitis-driven acinar-to-ductal metaplasia. We propose that this CAV1-YAP mechanotransduction system controls a significant share of cell programs linked to these two pivotal regulators, with potentially broad physiological and pathological implications. Overall design: RNA-Seq in WT and Cav1KO mouse embryonic fibroblasts (MEFs) cultured on stiff or soft polyacrylamide hydrogels转录调控因子YAP（YAP）可协调诸多关键细胞功能，参与组织稳态维持、器官生长调控及肿瘤发生进程。机械刺激是调控YAP活性的关键上游信号，但目前该调控的分子机制仍未得到系统阐明。本研究证实，小窝蛋白1（CAV1）可通过肌动蛋白细胞骨架依赖、Hippo激酶（Hippo kinase）非依赖的途径，正向调控YAP对基质刚度的机械应答。Rho GTP酶（RHO）的活性对于CAV1依赖的YAP活性机械调控是必需的，但并非充分条件。系统性定量相互作用组学研究与基于成像的小干扰RNA（siRNA）筛选实验表明，这种肌动蛋白依赖的调控机制源于YAP与14-3-3蛋白YWHAH的相互作用。组成型激活的YAP可挽救CAV1缺失引发的多种表型，包括细胞外基质（ECM）重塑缺陷。CAV1介导的YAP活性调控在胰腺炎驱动的腺泡-导管化生模型中得到了体内验证。本研究提出，这套CAV1-YAP机械转导系统可调控这两个关键调控因子相关的大量细胞程序，具有广泛的生理与病理潜在意义。实验整体设计：对培养于刚性或柔性聚丙烯酰胺水凝胶上的野生型（WT）与Cav1基因敲除型（Cav1KO）小鼠胚胎成纤维细胞（MEFs）开展RNA测序（RNA-Seq）。