Article

Loss of the Tumor Suppressor CYLD Enhances Wnt/β-Catenin Signaling through K63-Linked Ubiquitination of Dvl

Department of Cell Biology, University Medical Center Utrecht, Heidelberglaan 100, 3584CX Utrecht, The Netherlands.
Molecular cell (Impact Factor: 14.02). 03/2010; 37(5):607-19. DOI: 10.1016/j.molcel.2010.01.035
Source: PubMed

ABSTRACT

The mechanism by which Wnt receptors transduce signals to activate downstream beta-catenin-mediated target gene transcription remains incompletely understood but involves Frizzled (Fz) receptor-mediated plasma membrane recruitment and activation of the cytoplasmic effector Dishevelled (Dvl). Here, we identify the deubiquitinating enzyme CYLD, the familial cylindromatosis tumor suppressor gene, as a negative regulator of proximal events in Wnt/beta-catenin signaling. Depletion of CYLD from cultured cells markedly enhances Wnt-induced accumulation of beta-catenin and target gene activation. Moreover, we demonstrate hyperactive Wnt signaling in human cylindroma skin tumors that arise from mutations in CYLD. At the molecular level, CYLD interacts with and regulates K63-linked ubiquitination of Dvl. Enhanced ubiquitination of the polymerization-prone DIX domain in CYLD-deficient cells positively links to the signaling activity of Dvl. Together, our results argue that loss of CYLD instigates tumor growth in human cylindromatosis through a mechanism in which hyperubiquitination of polymerized Dvl drives enhancement of Wnt responses.

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Available from: Daniele V F Tauriello
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    • "As a member of USPs subfamily, CYLD can antagonize Lysine-63 polyubiquitin chain conjugation (Kovalenko et al., 2003; Trompouki et al., 2003b). As mentioned previously, CYLD is involved in NF-κB, Wnt/β-catenin and JNK signaling pathway (Reiley et al., 2004; Tauriello et al., 2010; Trompouki et al., 2003b). By using CYLD knock-out mice, a recent study shows that in TGF-β-treated T cells, CYLD deficiency causes enhanced TAK1 and p38 mitogen-activated protein kinase activities (Zhao et al., 2011). "
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    • "We have shown here that OTULIN binding to LUBAC reverses the LUBAC-mediated suppression of canonical Wnt activation. CYLD is also a negative regulator of canonical Wnt signaling (Tauriello et al. 2010). However, in our preliminary analyses, CYLD failed to counteract LUBAC-mediated suppression of the Wnt signaling effectively, suggesting that the CYLD-HOIP interaction may not be involved in regulation of Wnt signaling. "
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    • "Fz and Dsh also act in canonical Wnt signalling and, interestingly, are known to be regulated by ubiquitylation in this context. In flies, Fz levels are modulated by the deubiquitylating enzyme dUBPY (Mukai et al., 2010), and in vertebrates Dsh homologues are regulated by ubiquitylation pathways involving KLHL12 and Cyld (Angers et al., 2006; Tauriello et al., 2010). However, no studies have described a role for ubiquitylation in regulating Fz and Dsh levels in planar polarity. "
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