YAP is essential for 3D organogenesis withstanding gravity.

Cells of our body are constantly exposed to physical forces such as tissue tension. In recent years, it has been shown that such mechanical signals greatly influence a number of cellular processes, including proliferation, differentiation, and migration. Conversely, cells maintain the mechanical properties of tissues by remodeling their own extracellular environment. To date, however, it is unclear about the molecular mechanisms to maintain the mechanical environment ("mechano-homeostasis") in which extracellular mechanical cues are integrated with cell proliferation and differentiation to ensure tissue, organ and body form. In this review, we outline the molecular basis of mechanotransduction, and overview some useful techniques for measuring cellular tension. In the latter part, we describe our recent finding that a transcriptional cofactor YAP plays a crucial role in three-dimensional organ formation and its maintenance by controlling tissue tension, and functions as a key molecule governing mechano-homeostasis.