The Hippo pathway is an important evolutionarily conserved signaling pathway that controls organ size and tumor suppression by inhibiting cell proliferation and promoting apoptosis. An integral function of the Hippo pathway is to repress the activity of Yes-associated protein (YAP), a proposed oncogene whose activity is regulated by phosphorylation and subcellular localization. When the Hippo pathway is turned on, YAP is phosphorylated by LATS1/2 kinase and sequestered in the cytoplasm by 14-3-3 protein binding, rendering YAP inactive. When the Hippo pathway is off, non-phosphorylated YAP translocates to the nucleus where it associates with various transcription factors including members of the transcriptional enhancer factor (TEF) family, also known as the TEA domain (TEAD) family (TEAD1-4). Although widely expressed in tissues, the TEAD family proteins have specific tissue and developmental distributions. YAP/TEAD complexes regulate the expression of genes involved in cell proliferation and apoptosis.