Negative Regulation of YAP by LATS1 Underscores Evolutionary Conservation of the Drosophila Hippo Pathway

Abstract

The Hippo pathway defines a novel signaling cascade regulating cell proliferation and survival in Drosophila, which involves the negative regulation of the transcriptional coactivator Yorkie by the kinases Hippo and Warts. We have recently shown that the human ortholog of Yorkie, YAP, maps to a minimal amplification locus in mouse and human cancers, and that it mediates dramatic transforming activity in MCF10A primary mammary epithelial cells. Here, we show that LATS proteins (mammalian orthologs of Warts) interact directly with YAP in mammalian cells and that ectopic expression of LATS1, but not LATS2, effectively suppresses the YAP phenotypes. Furthermore, shRNA-mediated knockdown of LATS1 phenocopies YAP overexpression. Because this effect can be suppressed by simultaneous YAP knockdown, it suggests that YAP is the primary target of LATS1 in mammalian cells. Expression profiling of genes induced by ectopic expression of YAP or by knockdown of LATS1 reveals a subset of potential Hippo pathway targets implicated in epithelial-to-mesenchymal transition, suggesting that this is a key feature of YAP signaling in mammalian cells. [Cancer Res 2008;68(8):2789-94]

Phosphorylation of Tyr188 in the WW domain of YAP1 plays an essential role in YAP1-induced cellular transformation

“…9,21,26 Our present results suggested that the modification of YAP1 at tyrosine 188 regulates its oncogenic functions (Fig. 3).…”

“…19,20 Plasmid constructs YAP1-2 gamma expression construct was described previously. 21 YAP1 tyrosine mutants and shYAP1 resistant constructs were established by PCR-based mutagenesis and mutant constructs were confirmed by DNA sequencing. For RNA preparation and qRT-PCR detection, RNA was extracted using the Trizol reagent (Invitrogen).…”

“…21,35,36 Real-time qRT-PCR was performed using the RNA harvested from the vector control, YAP1-WT and YAP1-Y188F transduced MCF10A cells. The levels of CTGF, Cyr61 and FN1 were significantly reduced upon YAP1-Y188F expression as compared to the WT (Fig.…”

The Hippo in the room: A new look at a key pathway in cell growth and transformation

“…49 In vitro, overexpression of Lats1 or Lats2 is sufficient to suppress ephithelial-messenchymal transition and tumor growth of cancer cells while their downregulation result in cell overgrowth and transformation. 32,35,36,44,45,50 …”

“…Interaction of YAP with 14-3-3 proteins leads to its cytoplasmic retention and inactivation. 31,32,50,57 Under conditions of elevated Hippo pathway activity, such as in the setting of cell contact inhibition, YAP can be phosphorylated by Lats1/2 on Ser381, which provides a priming signal for CK1 to phosphorylate a phosphodegron in YAP. This recruits β-TRCP, leading to YAP ubiquitination and degradation.…”