scholarly journals Positive feedback of SuFu negating protein 1 on Hedgehog signaling promotes colorectal tumor growth

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Zhengwei Yan ◽  
Minzhang Cheng ◽  
Guohui Hu ◽  
Yao Wang ◽  
Shaopeng Zeng ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Tumor Growth ◽  
Ubiquitin Ligase ◽  
Hedgehog Signaling ◽  
Nuclear Translocation ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
Hh Signaling ◽  
Proliferation Regulation ◽  
Feedback Regulator

AbstractHedgehog (Hh) signaling plays a critical role in embryogenesis and tissue homeostasis, and its deregulation has been associated with tumor growth. The tumor suppressor SuFu inhibits Hh signaling by preventing the nuclear translocation of Gli and suppressing cell proliferation. Regulation of SuFu activity and stability is key to controlling Hh signaling. Here, we unveil SuFu Negating Protein 1 (SNEP1) as a novel Hh target, that enhances the ubiquitination and proteasomal degradation of SuFu and thus promotes Hh signaling. We further show that the E3 ubiquitin ligase LNX1 plays a critical role in the SNEP1-mediated degradation of SuFu. Accordingly, SNEP1 promotes colorectal cancer (CRC) cell proliferation and tumor growth. High levels of SNEP1 are detected in CRC tissues and are well correlated with poor prognosis in CRC patients. Moreover, SNEP1 overexpression reduces sensitivity to anti-Hh inhibitor in CRC cells. Altogether, our findings demonstrate that SNEP1 acts as a novel feedback regulator of Hh signaling by destabilizing SuFu and promoting tumor growth and anti-Hh resistance.

scholarly journals HELZ2 Promotes K63-Linked Polyubiquitination of c-Myc to Induce Retinoblastoma Tumorigenesis

2021 ◽  
Author(s):  
Hanjun Dai ◽  
wen ZENG ◽  
WEIJUAN ZENG ◽  
MING YAN ◽  
ping jiang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Zinc Finger ◽  
Ubiquitin Ligase ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
Transcriptional Regulators ◽  
Zinc Finger Domain ◽  
Retinoblastoma Cell ◽  
Animal Survival

Abstract Retinoblastoma is a rare ocular tumor in children that originates in the retina. Several core transcriptional regulators maintain the expansion of retinoblastoma tumors, including c-Myc. Here, we demonstrated that Helicase with zinc finger domain 2 (HELZ2) promoted retinoblastoma tumorigenesis by targeting c-Myc. HELZ2-deficient inhibited retinoblastoma cell proliferation, whereas overexpression of HELZ2 promoted retinoblastoma cell proliferation. In addition, high levels of HELZ2 promoted xenograft retinoblastoma tumorigenesis and inhibited animal survival. Mechanistically, HELZ2 interacted with c-Myc and promoted its K63-linked polyubiquitination. We indicated that HELZ2 promoted the interaction between E3 ubiquitin ligase HUWE1 and c-Myc, and HELZ2-mediated K63-linked polyubiquitination and activation of c-Myc were dependent on HUWE1. Taken together, HELZ2 plays a critical role in the regulation of retinoblastoma tumorigenesis by enhancing the activity of c-Myc.

scholarly journals Herpes Simplex Virus 1 E3 Ubiquitin Ligase ICP0 Protein Inhibits Tumor Necrosis Factor Alpha-Induced NF-κB Activation by Interacting with p65/RelA and p50/NF-κB1

2013 ◽  
Vol 87 (23) ◽  
pp. 12935-12948 ◽  
Author(s):  
Jie Zhang ◽  
Kezhen Wang ◽  
Shuai Wang ◽  
Chunfu Zheng
Keyword(s):  
Tumor Necrosis Factor ◽  
Ubiquitin Ligase ◽  
Tumor Necrosis ◽  
Nuclear Translocation ◽  
E3 Ubiquitin Ligase ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Necrosis Factor ◽  
Hsv 1

NF-κB plays central roles in regulation of diverse biological processes, including innate and adaptive immunity and inflammation. HSV-1 is the archetypal member of the alphaherpesviruses, with a large genome encoding over 80 viral proteins, many of which are involved in virus-host interactions and show immune modulatory capabilities. In this study, we demonstrated that the HSV-1 ICP0 protein, a viral E3 ubiquitin ligase, was shown to significantly suppress tumor necrosis factor alpha (TNF-α)-mediated NF-κB activation. ICP0 was demonstrated to bind to the NF-κB subunits p65 and p50 by coimmunoprecipitation analysis. ICP0 bound to the Rel homology domain (RHD) of p65. Fluorescence microscopy demonstrated that ICP0 abolished nuclear translocation of p65 upon TNF-α stimulation. Also, ICP0 degraded p50 via its E3 ubiquitin ligase activity. The RING finger (RF) domain mutant ICP0 (ICP0-RF) lost its ability to inhibit TNF-α-mediated NF-κB activation and p65 nuclear translocation and degrade p50. Notably, the RF domain of ICP0 was sufficient to interact with p50 and abolish NF-κB reporter gene activity. Here, it is for the first time shown that HSV-1 ICP0 interacts with p65 and p50, degrades p50 through the ubiquitin-proteasome pathway, and prevents NF-κB-dependent gene expression, which may contribute to immune evasion and pathogenesis of HSV-1.

scholarly journals The ubiquitin ligase HERC4 mediates c-Maf ubiquitination and delays the growth of multiple myeloma xenografts in nude mice

Blood ◽  
2016 ◽  
Vol 127 (13) ◽  
pp. 1676-1686 ◽  
Author(s):  
Zubin Zhang ◽  
Jiefei Tong ◽  
Xiaowen Tang ◽  
Jiaxiang Juan ◽  
Biyin Cao ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Ubiquitin Ligase ◽  
Nude Mice ◽  
Key Points

Key Points HERC4 is the first identified ubiquitin ligase that mediates c-Maf ubiquitination and degradation. HERC4 suppresses MM cell proliferation and delays MM tumor growth.

scholarly journals Cul4-Ddb1 ubiquitin ligases facilitate DNA replication-coupled sister chromatid cohesion through regulation of cohesin acetyltransferase Esco2

2018 ◽  
Author(s):  
Haitao Sun ◽  
Jiaxin Zhang ◽  
Jingjing Zhang ◽  
Zhen Li ◽  
Qinhong Cao ◽  
...  
Keyword(s):  
Dna Replication ◽  
Ubiquitin Ligase ◽  
Sister Chromatid ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Ligases ◽  
Sister Chromatid Cohesion ◽  
Vital Role ◽  
Chromatid Cohesion ◽  
Evolutionarily Conserved

AbstractCohesin acetyltransferases Esco1 and Esco2 play a vital role in establishing sister chromatid cohesion. How Esco1 and Esco2 are controlled to achieve this in a DNA replication-coupled manner remains unclear in higher eukaryotes. Here we show that Cul4-RING ligases (CRL4s) play a critical role in sister chromatid cohesion in human cells. Depletion of Cul4A, Cul4B or Ddb1 subunits substantially reduces normal cohesion efficiency. We also show that Mms22L, a vertebrate ortholog of yeast Mms22, is one of Ddb1 and Cul4-associated factors (DCAFs) involved in cohesion. Several lines of evidence suggest a selective interaction of CRL4s with Esco2, but not Esco1. Depletion of either CRL4s or Esco2 causes a defect in Smc3 acetylation which can be rescued by HDAC8 inhibition. More importantly, both CRL4s and PCNA act as mediators for efficiently stabilizing Esco2 on chromatin and catalyzing Smc3 acetylation. Taken together, we propose an evolutionarily conserved mechanism in which CRL4s and PCNA regulate Esco2-dependent establishment of sister chromatid cohesion.Author summaryWe identified human Mms22L as a substrate specific adaptor of Cul4-Ddb1 E3 ubiquitin ligase. Downregulation of Cul4A, Cul4B or Ddb1 subunit causes reduction of acetylated Smc3, via interaction with Esco2 acetyltransferase, and then impairs sister chromatid cohesion in 293T cells. We found functional complementation between Cul4-Ddb1-Mms22L E3 ligase and Esco2 in Smc3 acetylation and sister chromatid cohesion. Interestingly, both Cul4-Ddb1 E3 ubiquitin ligase and PCNA contribute to Esco2 mediated Smc3 acetylation. To summarise, we demonstrated an evolutionarily conserved mechanism in which Cul4-Ddb1 E3 ubiquitin ligases and PCNA regulate Esco2-dependent establishment of sister chromatid cohesion.

scholarly journals A means to an end: ubiquitination of Mpl

Blood ◽  
2010 ◽  
Vol 115 (6) ◽  
pp. 1111-1112
Author(s):  
Wei Tong
Keyword(s):  
Cell Proliferation ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Down Regulation

Abstract In this issue of Blood, Saur and colleagues report that ubiquitin-mediated degradation of the Mpl receptor constrains Tpo-mediated cell proliferation, highlighting the importance of the E3 ubiquitin ligase c-Cbl in rapid down-regulation of Tpo/Mpl signaling.

scholarly journals The sterol-responsive RNF145 E3 ubiquitin ligase mediates the degradation of HMG-CoA reductase together with gp78 and Hrd1

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Sam A Menzies ◽  
Norbert Volkmar ◽  
Dick JH van den Boomen ◽  
Richard T Timms ◽  
Anna S Dickson ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Critical Role ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligase ◽  
Editorial Note ◽  
Hmg Coa Reductase ◽  
Genome Wide ◽  
Cholesterol Biosynthetic Pathway ◽  
Coa Reductase ◽  
Rate Limiting

Mammalian HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the cholesterol biosynthetic pathway and the therapeutic target of statins, is post-transcriptionally regulated by sterol-accelerated degradation. Under cholesterol-replete conditions, HMGCR is ubiquitinated and degraded, but the identity of the E3 ubiquitin ligase(s) responsible for mammalian HMGCR turnover remains controversial. Using systematic, unbiased CRISPR/Cas9 genome-wide screens with a sterol-sensitive endogenous HMGCR reporter, we comprehensively map the E3 ligase landscape required for sterol-accelerated HMGCR degradation. We find that RNF145 and gp78 independently co-ordinate HMGCR ubiquitination and degradation. RNF145, a sterol-responsive ER-resident E3 ligase, is unstable but accumulates following sterol depletion. Sterol addition triggers RNF145 recruitment to HMGCR via Insigs, promoting HMGCR ubiquitination and proteasome-mediated degradation. In the absence of both RNF145 and gp78, Hrd1, a third UBE2G2-dependent E3 ligase, partially regulates HMGCR activity. Our findings reveal a critical role for the sterol-responsive RNF145 in HMGCR regulation and elucidate the complexity of sterol-accelerated HMGCR degradation.Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (<xref ref-type="decision-letter" rid="SA1">see decision letter</xref>).

scholarly journals Oestrogen causes ATBF1 protein degradation through the oestrogen-responsive E3 ubiquitin ligase EFP

2012 ◽  
Vol 444 (3) ◽  
pp. 581-590 ◽  
Author(s):  
Xue-Yuan Dong ◽  
Xiaoying Fu ◽  
Songqing Fan ◽  
Peng Guo ◽  
Dan Su ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Degradation ◽  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
E3 Ubiquitin Ligase ◽  
Breast Development ◽  
Protein Levels ◽  
Ubiquitin Proteasome ◽  
Dependent Cell ◽  
Proteasome Pathway

We reported previously that the tumour suppressor ATBF1 (AT motif-binding factor 1) formed an autoregulatory feedback loop with oestrogen–ERα (oestrogen receptor α) signalling to regulate oestrogen-dependent cell proliferation in breast cancer cells. In this loop ATBF1 inhibits the function of oestrogen–ERα signalling, whereas ATBF1 protein levels are fine-tuned by oestrogen-induced transcriptional up-regulation as well as UPP (ubiquitin–proteasome pathway)-mediated protein degradation. In the present study we show that EFP (oestrogen-responsive finger protein) is an E3 ubiquitin ligase mediating oestrogen-induced ATBF1 protein degradation. Knockdown of EFP increases ATBF1 protein levels, whereas overexpression of EFP decreases ATBF1 protein levels. EFP interacts with and ubiquitinates ATBF1 protein. Furthermore, we show that EFP is an important factor in oestrogen-induced ATBF1 protein degradation in which some other factors are also involved. In human primary breast tumours the levels of ATBF1 protein are positively correlated with the levels of EFP protein, as both are directly up-regulated ERα target gene products. However, the ratio of ATBF1 protein to EFP protein is negatively correlated with EFP protein levels. Functionally, ATBF1 antagonizes EFP-mediated cell proliferation. These findings not only establish EFP as the E3 ubiquitin ligase for oestrogen-induced ATBF1 protein degradation, but further support the autoregulatory feedback loop between ATBF1 and oestrogen–ERα signalling and thus implicate ATBF1 in oestrogen-dependent breast development and carcinogenesis.

scholarly journals RPRD1A stabilizes NRF2 and aggravates HCC progression through competing with p62 for TRIM21 binding

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiaofan Feng ◽  
Tianyi Jiang ◽  
Chun Yang ◽  
Shujie Pang ◽  
Zhiwen Ding ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Nuclear Translocation ◽  
Redox Homeostasis ◽  
E3 Ubiquitin Ligase ◽  
Related Sequence ◽  
Therapeutic Benefits ◽  
Oxidative Stress Defense ◽  
Oncogenic Protein

AbstractNRF2 is the master transcriptional activator of cytoprotective genes and Kelch-like ECH-associated protein 1 (Keap1), a biosensor for electrophiles and oxidation, promotes NRF2 degradation in unstressed conditions. SQSTM1/p62, an oncogenic protein aberrantly accumulated in hepatocellular carcinoma (HCC), binds and sequestrates Keap1, leading to the prevention of NRF2 degradation. Here, we show that p15INK4b-related sequence/regulation of nuclear pre-mRNA domain-containing protein 1A (RPRD1A) is highly expressed in HCC tumors and correlated with aggressive clinicopathological features. RPRD1A competitively interacts with TRIM21, an E3 ubiquitin ligase of p62, resulting in the decrease of p62 ubiquitination and the increased sequestration for Keap1. Therefore, RPRD1A enhances the nuclear translocation of NRF2, which induces gene expression for counteracting oxidative stress, maintaining cancer cells survival, and promoting HCC development. Moreover, disturbing the redox homeostasis of cancer cells by genetic knockdown of RPRD1A sensitizes cancer cells to platinum-induced cell death. Our study reveals RPRD1A is involved in the oxidative stress defense program and highlights the therapeutic benefits of targeting pathways that support antioxidation.

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