Transcriptional coactivators YAP(yes associated protein)and TAZ(transcriptional coactivator with PDZ-binding motif)regulate gene expression through binding to transcription factors. Recently, some studies showed that YAP/TAZ activity responded to mechanical inputs such as stiffness of the extracellular matrix and the mechanical regulation of YAP/TAZ controlled cell proliferation or differentiation. Additionally, we revealed important roles of YAP in tissue formation and homeostasis through cellular tension and pressure. These reports indicate that YAP/TAZ are major factors in mechanotransduction connecting between the mechanical environment and cell responses.