Lung morphogenesis is a complex process involving rearrangements of various cell types to achieve the branched patterning necessary to maximize gaseous exchange. Lin et al. found that YAP, a component of the Hippo pathway known to be important for organ size regulation, is required for branching. YAP is expressed throughout the murine lung epithelium. Local inhibition of YAP decreases local cell proliferation, which means inadequate force is produced to move cells and form airway branches. Genomic analysis showed that YAP regulates levels of pMLC (phosphorylated myosin light chain), which is required for cells to produce mechanical force. The YAP mechanism may also be involved in branching in other tissues.
eLife 10.7554/eLife.21130 (2017).