page_title: YAP1
section_title: Biochemical Regulation
hierarchical_section_title: YAP1 / Regulation / Biochemical Regulation
caption_attribution_description: English: On the left, YAP/TAZ is allowed into the nucleus for transcription. On the right, a series of signaling cascade kinases prevent YAP from localizing to the nucleus for transcription.
context_page_description: YAP1, also known as YAP or YAP65, is a protein that acts as a transcriptional regulator by activating the transcription of genes involved in cell proliferation and suppressing apoptotic genes. YAP1 is inhibited in the Hippo signaling pathway which allows the cellular control of organ size and tumor suppression. YAP1 was first identified by virtue of its ability to associate with the SH3 domain of Yes and Src protein tyrosine kinases. YAP1 is a potent oncogene, which is amplified in various human cancers.
context_section_description: At the biochemical level, YAP is part of and regulated by the Hippo signaling pathway where a kinase cascade results in its “inactivation”, along with that of TAZ. In this signaling cascade, TAO kinases phosphorylate Ste20-like kinases, MST1/2, at their activation loops (Thr183 for MST1 and Thr180 for MST2). Active MST1/2 then phosphorylate SAV1 and MOB1A/B which are scaffold proteins that assist in the recruitment and phosphorylation of LATS1/2. LATS1/2 can also be phosphorylated by two groups of MAP4Ks. LATS1/2 then phosphorylate YAP and TAZ which causes them to bind with 14-3-3, resulting in cytoplasmic sequestration of YAP and TAZ. The result of the activation of this pathway is the restriction of YAP/TAZ from entering the cell nucleus.
caption: On the left, the signaling cascade is inactivated so YAP readily localizes to the nucleus for transcription. On the right, the signal cascade causes YAP to localize to the cytoplasm, preventing transcription.
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