YAP1 Protein, Human (His)

YAP1, a multifaceted transcriptional regulator, serves as a critical downstream target in the Hippo signaling pathway, orchestrating organ size control and tumor suppression by modulating proliferation and apoptosis. The pathway involves a kinase cascade where STK3/MST2 and STK4/MST1, in coordination with SAV1, phosphorylate and activate LATS1/2, leading to the phosphorylation and inactivation of YAP1 and WWTR1/TAZ oncoproteins. YAP1 is pivotal in regulating tissue tension and 3D tissue shape by influencing cortical actomyosin network formation through ARHGAP18. Moreover, it plays a key role in controlling cell proliferation, with its nuclear translocation inhibited by LATS1/2 phosphorylation. YAP1's collaboration with TEAD transcription factors is essential for stimulating gene expression, cell growth, anchorage-independent growth, and epithelial mesenchymal transition (EMT) induction. Additionally, it suppresses ciliogenesis by acting as a transcriptional corepressor of TEAD4 target genes AURKA and PLK1, and in conjunction with WWTR1, it regulates TGFB1-dependent SMAD2 and SMAD3 nuclear accumulation. YAP1 further activates the C-terminal fragment (CTF) of ERBB4 isoform 3.