Activation of Smurf E3 Ligase Promoted by Smoothened Regulates Hedgehog Signaling through Targeting Patched Turnover

Huang, Shoujun; Zhang, Zhao; Zhang, Chunxia; Lv, Xiangdong; Zheng, Xiu-Deng; Chen, Zhenping; Sun, Liwei; Wang, Hailong; Zhu, Yuanxiang; Zhang, Jing; Yang, Songbai; Lu, Yi; Sun, Qing; Tao, Yi; Liu, Feng; Zhao, Yun; Chen, Dahua

doi:10.1371/journal.pbio.1001721

Cited by 43 publications

(59 citation statements)

References 52 publications

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“…It has also been shown previously that binding of E3 ubiquitin ligases, specifically Smurf2 and Itch1, was required for repression of Ptch1 activity (28,30,44). In contrast, in similar transient assays, we determined that Shh ligand inhibited the repression of Smo by Ptch1 regardless of whether the domains required for Ptch1 binding to Smurf2 and Itch1 were present.…”

Section: Discussionsupporting

confidence: 66%

“…⌬C ) near the end of the middle loop domain in combination with deletions in the C terminus retained binding activity to GFP ML. Furthermore, we observed that point mutations in the polyproline motifs, determined previously to mediate binding to proteins with SH2, SH3, or WW domains (26,28,30), did not affect binding of Ptch1 to itself.…”

Section: Two Intracellular Regions Of Murine Ptch1 Mediate Itsmentioning

confidence: 62%

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Activities of the Cytoplasmic Domains of Patched-1 Modulate but Are Not Essential for the Regulation of Canonical Hedgehog Signaling

Fleet

Lee

Tamachi

et al. 2016

Journal of Biological Chemistry

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The Hedgehog (Hh) pathway is a highly conserved signaling cascade crucial for cell fate determination during embryogenesis. Response to the Hh ligands is mediated by the receptor Patched-1 (Ptch1), a 12-pass transmembrane glycoprotein. Despite its essential role in Hh signaling and its activity as a tumor suppressor, Ptch1 remains largely uncharacterized. We demonstrate here that Ptch1 binds to itself to form oligomeric structures. Oligomerization is mediated by two distinct, structurally disordered, intracellular domains spanning amino acids 584 -734 ("middle loop") and 1162-1432 (C terminus). However, oligomerization is not required for Ptch1-dependent regulation of the canonical Hh pathway operating through Smo. Expression of a mutant protein that deletes both regions represses the Hh pathway and responds to the addition of Hh ligand independent of its inability to bind other factors such as Smurf2. Additionally, deletion of the cytoplasmic middle loop domain generates a Ptch1 mutant that, despite binding to Hh ligand, constitutively suppresses Hh signaling and increases the length of primary cilia. Constitutive activity because of deletion of this region is reversed by further deletion of specific sequences in the cytoplasmic C-terminal domain. These data reveal an interaction between the cytoplasmic domains of Ptch1 and that these domains modulate Ptch1 activity but are not essential for regulation of the Hh pathway.

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Section: Discussionsupporting

confidence: 66%

Section: Two Intracellular Regions Of Murine Ptch1 Mediate Itsmentioning

confidence: 62%

Activities of the Cytoplasmic Domains of Patched-1 Modulate but Are Not Essential for the Regulation of Canonical Hedgehog Signaling

Fleet

Lee

Tamachi

et al. 2016

Journal of Biological Chemistry

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“…Drosophila Patched (Ptc), which has a CTD highly homologous to that of PTCH1, was reported by different investigators to associate with Nedd4 and Smurf through a PPXY motif (29,40).…”

Section: Discussionmentioning

confidence: 99%

“…Smurf was shown to induce Ptc ubiquitylation and degradation in cultured S2 cells and in the wing disc, while Nedd4 was also shown to reduce the halflife of Ptc (29,40). Interaction with both E3 ligases depends on the CTD PPXY motif, and mutation to PPXA results in the aberrant internalization of Ptc and inhibition of Hh-stimulated transcriptional activity of cubitus interruptus (Ci) (29,40). The importance of the CTD of Ptc/PTCH1 in the regulation of its stability and turnover is thus conserved across phyla.…”

Section: Discussionmentioning

confidence: 99%

Patched-1 Proapoptotic Activity Is Downregulated by Modification of K1413 by the E3 Ubiquitin-Protein Ligase Itchy Homolog

Chen

Chinchilla

Fombonne

et al. 2014

Molecular and Cellular Biology

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The Hedgehog (Hh) receptor Patched-1 (PTCH1) opposes the activation of Gli transcription factors and induces cell death through a Gli-independent pathway. Here, we report that the C-terminal domain (CTD) of PTCH1 interacts with and is ubiquitylated on K1413 by the E3 ubiquitin-protein ligase Itchy homolog (Itch), a Nedd4 family member. Itch induces the ubiquitylation of K1413, the reduction of PTCH1 levels at the plasma membrane, and degradation, activating Gli transcriptional activity in the absence of Hh ligands. Silencing of Itch stabilizes PTCH1 and increases its level of retention at the plasma membrane. Itch is the preferential PTCH1 E3 ligase in the absence of Hh ligands, since of the other seven Nedd4 family members, only WW domain-containing protein 2 (WWP2) showed a minor redundant role. Like Itch depletion, mutation of the ubiquitylation site (K1314R) resulted in the accumulation of PTCH1 at the plasma membrane, prolongation of its half-life, and increased cell death by hyperactivation of caspase-9. Remarkably, Itch is the main determinant of PTCH1 stability under resting conditions but not in response to Sonic Hedgehog. In conclusion, our findings reveal that Itch is a key regulator of ligand-independent Gli activation and noncanonical Hh signaling by the governance of basal PTCH1 internalization and degradation.

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“…Knockdown of ptc (an inhibitor of the Hh pathway; Beachy et al, 2004;Huang et al, 2013;Jiang and Hui, 2008;Jiang et al, 2016) increased the number of Zfh1 + cells (Fig. 3F,G,I).…”

Section: The Sumo Pathway Genetically Interacts With the Hh Pathwaymentioning

confidence: 99%

SUMO regulates somatic cyst stem cells maintenance and directly targets hedgehog pathway in adult Drosophila testis

Pan

Zhang

et al. 2016

Development

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SUMO (Small ubiquitin-related modifier) modification (SUMOylation) is a highly dynamic post-translational modification (PTM) that plays important roles in tissue development and disease progression. However, its function in adult stem cell maintenance is largely unknown. Here, we report the function of SUMOylation in somatic cyst stem cell (CySC) self-renewal in adult Drosophila testis. The SUMO pathway cell-autonomously regulates CySC maintenance. Reduction of SUMOylation promotes premature differentiation of CySCs and impedes the proliferation of CySCs, which leads to a reduction in the number of CySCs. Consistent with this, CySC clones carrying a mutation of the SUMO-conjugating enzyme are rapidly lost. Furthermore, inhibition of the SUMO pathway phenocopies disruption of the Hedgehog (Hh) pathway, and can block the proliferation of CySCs induced by Hh activation. Importantly, the SUMO pathway directly regulates the SUMOylation of Hh pathway transcription factor Cubitus interruptus (Ci), which is required for promoting CySC proliferation. Thus, we conclude that SUMO directly targets the Hh pathway and regulates CySC maintenance in adult Drosophila testis.

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Activation of Smurf E3 Ligase Promoted by Smoothened Regulates Hedgehog Signaling through Targeting Patched Turnover

Abstract: Protein turnover of Patched, the Hedgehog receptor and key negative regulator of Hedgehog signaling, is controlled by the ubiquitin E3 ligase, Smurf, in a manner that depends on activation of signal transducer, Smoothened.

Cited by 43 publications

References 52 publications

Activities of the Cytoplasmic Domains of Patched-1 Modulate but Are Not Essential for the Regulation of Canonical Hedgehog Signaling

Activities of the Cytoplasmic Domains of Patched-1 Modulate but Are Not Essential for the Regulation of Canonical Hedgehog Signaling

Patched-1 Proapoptotic Activity Is Downregulated by Modification of K1413 by the E3 Ubiquitin-Protein Ligase Itchy Homolog

SUMO regulates somatic cyst stem cells maintenance and directly targets hedgehog pathway in adult Drosophila testis

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