Article

A coordinated phosphorylation by Lats and CK1 regulates YAP stability through SCF(beta-TRCP)

Department of Pharmacology and Moores Cancer Center, University of California at San Diego, La Jolla, California 92093-0815, USA.
Genes & development (Impact Factor: 10.8). 01/2010; 24(1):72-85. DOI: 10.1101/gad.1843810
Source: PubMed

ABSTRACT

The Yes-associated protein (YAP) transcription coactivator is a key regulator of organ size and a candidate human oncogene. YAP is inhibited by the Hippo pathway kinase cascade, at least in part via phosphorylation of Ser 127, which results in YAP 14-3-3 binding and cytoplasmic retention. Here we report that YAP is phosphorylated by Lats on all of the five consensus HXRXXS motifs. Phosphorylation of Ser 381 in one of them primes YAP for subsequent phosphorylation by CK1delta/epsilon in a phosphodegron. The phosphorylated phosphodegron then recruits the SCF(beta-TRCP) E3 ubiquitin ligase, which catalyzes YAP ubiquitination, ultimately leading to YAP degradation. The phosphodegron-mediated degradation and the Ser 127 phosphorylation-dependent translocation coordinately suppress YAP oncogenic activity. Our study identified CK1delta/epsilon as new regulators of YAP and uncovered an intricate mechanism of YAP regulation by the Hippo pathway via both S127 phosphorylation-mediated spatial regulation (nuclear-cytoplasmic shuttling) and the phosphodegron-mediated temporal regulation (degradation).

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    • "Phosphorylation of YAP and TAZ leads to their binding with 14-3-3, and the 14-3-3 binding causes cytoplasmic sequestration of YAP/TAZ (Zhao et al. 2007). Moreover, LATS-induced phosphorylation triggers subsequent phosphorylation of YAP/TAZ by Casein kinase 1δ/ε and recruitment of the SCF E3 ubiquitin ligase, leading to eventual YAP/TAZ ubiquitination and degradation (Liu et al. 2010; Zhao et al. 2010). In "
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    ABSTRACT: The Hippo pathway was initially identified in Drosophila melanogaster screens for tissue growth two decades ago and has been a subject extensively studied in both Drosophila and mammals in the last several years. The core of the Hippo pathway consists of a kinase cascade, transcription coactivators, and DNA-binding partners. Recent studies have expanded the Hippo pathway as a complex signaling network with >30 components. This pathway is regulated by intrinsic cell machineries, such as cell– cell contact, cell polarity, and actin cytoskeleton, as well as a wide range of signals, including cellular energy status, mechanical cues, and hormonal signals that act through G-protein-coupled receptors. The major functions of the Hippo pathway have been defined to restrict tissue growth in adults and modulate cell proliferation, differentiation, and migration in developing organs. Furthermore, dysregulation of the Hippo pathway leads to aberrant cell growth and neoplasia. In this review, we focus on recent developments in our understanding of the molecular actions of the core Hippo kinase cascade and discuss key open questions in the regulation and function of the Hippo pathway.
    Preview · Article · Jan 2016 · Genes & Development
    • "Two upstream pathways are known to regulate YAP/TAZ stability and nuclear export. First, YAP/TAZ proteins are phosphorylated by the LATS kinases, which promote their nuclear export and degradation by the b-TrCP ubiquitin ligase (Zhao et al., 2010). The effect of MYC appeared to be independent of LATS kinases because MYC induction did not induce phosphorylation of YAP at the canonical LATS site S127 (Figure 2F). "
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    ABSTRACT: In several developmental lineages, an increase in MYC expression drives the transition from quiescent stem cells to transit-amplifying cells. We show that MYC activates a stereotypic transcriptional program of genes involved in cell growth in mammary epithelial cells. This change in gene expression indirectly inhibits the YAP/ TAZ co-activators, which maintain the clonogenic potential of these cells. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. MYC-dependent growth strains cellular energy resources and stimulates AMP-activated kinase (AMPK). PLD6 alters mitochondrial fusion and fission dynamics downstream of MYC. This change activates AMPK, which in turn inhibits YAP/TAZ. Mouse models and human pathological data show that MYC enhances AMPK and suppresses YAP/TAZ activity in mammary tumors.
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    • "Progress in this direction has been limited by a general lack of probes that allow protein activity to be monitored in living tissues. As many biochemical activities are known to result in the stabilization, destruction or relocalization of target proteins (Stamos and Weis, 2013; Zhao et al., 2010), fluorescent timer approaches that allow measurement of protein population age in vivo provide a potentially generic solution to this problem. "
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    ABSTRACT: Studies on signalling dynamics in living embryos have been limited by a scarcity of in vivo reporters. Tandem fluorescent protein timers provide a generic method for detecting changes in protein population age and thus provide readouts for signalling events that lead to changes in protein stability or location. When imaged with quantitative dual-colour fluorescence microscopy, tandem timers offer detailed 'snapshot' readouts of signalling activity from subcellular to organismal scales, and therefore have the potential to revolutionize studies in developing embryos. Here we use computer modelling and embryo experiments to explore the behaviour of tandem timers in developing systems. We present a mathematical model of timer kinetics and provide software tools that will allow experimentalists to select the most appropriate timer designs for their biological question, and guide interpretation of the obtained readouts. Through the generation of a series of novel zebrafish reporter lines, we confirm experimentally that our quantitative model can accurately predict different timer responses in developing embryos and explain some less expected findings. For example, increasing the FRET efficiency of a tandem timer actually increases the ability of the timer to detect differences in protein half-life. Finally, while previous studies have used timers to monitor changes in protein turnover, our model shows that timers can also be used to facilitate the monitoring of gene expression kinetics in vivo.
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