scholarly journals The E3 Ubiquitin Ligases Hrd1 and gp78 Bind to and Promote Cholera Toxin Retro-Translocation

2010 ◽  
Vol 21 (1) ◽  
pp. 140-151 ◽  
Author(s):  
Kaleena M. Bernardi ◽  
Jeffrey M. Williams ◽  
Marjolein Kikkert ◽  
Sjaak van Voorden ◽  
Emmanuel J. Wiertz ◽  
...  
Keyword(s):  
Cholera Toxin ◽  
Ubiquitin Ligases ◽  
Dominant Negative ◽  
E3 Ubiquitin Ligases ◽  
Binding Studies ◽  
E3 Ligases ◽  
Sequence Of Events ◽  
Water Secretion ◽  
Protein Disulfide

To cause disease, cholera toxin (CT) is transported from the cell surface to the endoplasmic reticulum (ER) lumen where the catalytic CTA1 subunit retro-translocates to the cytosol to induce pathological water secretion. Two retro-translocon components are the Derlins and ER-associated multi-spanning E3 ubiquitin ligases including Hrd1 and gp78. We demonstrated previously that Derlin-1 facilitates CTA1 retro-translocation. However, as CTA1 is neither ubiquitinated on lysines nor at its N-terminus, the role of E3 ligases in toxin retro-translocation is unclear. Here, we show that expression of mutant Hrd1 and gp78 and a mutant E2-conjugating enzyme dedicated to retro-translocation (Ube2g2) decrease CTA1 retro-translocation. Hrd1 knockdown also attenuated toxin retro-translocation. Binding studies demonstrate that Hrd1 and gp78 interact with CT and protein disulfide isomerase, an ER chaperone that unfolds CTA1 to initiate translocation. Moreover, we find that the toxin's association with Hrd1 and gp78 is blocked by dominant-negative Derlin-1, suggesting that CT is targeted initially to Derlin-1 and then transferred to Hrd1 and gp78. These data demonstrate a role of the E3 ubiquitin ligases in CTA1 retro-translocation, implicate a sequence of events experienced by the toxin on the ER membrane, and raise the possibility that ubiquitination is involved in the transport process.

scholarly journals Comprehensive database of human E3 ubiquitin ligases: application to aquaporin-2 regulation

2016 ◽  
Vol 48 (7) ◽  
pp. 502-512 ◽  
Author(s):  
Barbara Medvar ◽  
Viswanathan Raghuram ◽  
Trairak Pisitkun ◽  
Abhijit Sarkar ◽  
Mark A. Knepper
Keyword(s):  
Human Genome ◽  
Large Scale ◽  
E3 Ligase ◽  
Ubiquitin Ligases ◽  
Bayes Rule ◽  
E3 Ubiquitin Ligases ◽  
E3 Ligases ◽  
Aquaporin 2 ◽  
Large Scale Data ◽  
Level Data

Aquaporin-2 (AQP2) is regulated in part via vasopressin-mediated changes in protein half-life that are in turn dependent on AQP2 ubiquitination. Here we addressed the question, “What E3 ubiquitin ligase is most likely to be responsible for AQP2 ubiquitination?” using large-scale data integration based on Bayes' rule. The first step was to bioinformatically identify all E3 ligase genes coded by the human genome. The 377 E3 ubiquitin ligases identified in the human genome, consisting predominant of HECT, RING, and U-box proteins, have been used to create a publically accessible and downloadable online database ( https://hpcwebapps.cit.nih.gov/ESBL/Database/E3-ligases/ ). We also curated a second database of E3 ligase accessory proteins that included BTB domain proteins, cullins, SOCS-box proteins, and F-box proteins. Using Bayes' theorem to integrate information from multiple large-scale proteomic and transcriptomic datasets, we ranked these 377 E3 ligases with respect to their probability of interaction with AQP2. Application of Bayes' rule identified the E3 ligases most likely to interact with AQP2 as (in order of probability): NEDD4 and NEDD4L (tied for first), AMFR, STUB1, ITCH, ZFPL1. Significantly, the two E3 ligases tied for top rank have also been studied extensively in the reductionist literature as regulatory proteins in renal tubule epithelia. The concordance of conclusions from reductionist and systems-level data provides strong motivation for further studies of the roles of NEDD4 and NEDD4L in the regulation of AQP2 protein turnover.

scholarly journals Comprehensive Analysis of E3 Ubiquitin Ligases Reveals Ring Finger Protein 223 as a Novel Oncogene Activated by KLF4 in Pancreatic Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Lei Feng ◽  
Jieqing Wang ◽  
Jianmin Zhang ◽  
Jingfang Diao ◽  
Longguang He ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Transcriptional Activation ◽  
Prognostic Significance ◽  
Ring Finger ◽  
Ubiquitin Ligases ◽  
The Cancer Genome Atlas ◽  
Differentially Expressed ◽  
E3 Ubiquitin Ligases ◽  
E3 Ligases ◽  
Elevated Expression

Pancreatic cancer is one of the major malignancies and causes of mortality worldwide. E3 ubiquitin–protein ligases transfer activated ubiquitin from ubiquitin-conjugating enzymes to protein substrates and confer substrate specificity in cancer. In this study, we first downloaded data from The Cancer Genome Atlas pancreatic adenocarcinoma dataset, acquired all 27 differentially expressed genes (DEGs), and identified genomic alterations. Then, the prognostic significance of DEGs was analyzed, and eight DEGs (MECOM, CBLC, MARCHF4, RNF166, TRIM46, LONRF3, RNF39, and RNF223) and two clinical parameters (pathological N stage and T stage) exhibited prognostic significance. RNF223 showed independent significance as an unfavorable prognostic marker and was chosen for subsequent analysis. Next, the function of RNF223 in the pancreatic cancer cell lines ASPC-1 and PANC-1 was investigated, and RNF223 silencing promoted pancreatic cancer growth and migration. To explore the potential targets and pathways of RNF223 in pancreatic cancer, quantitative proteomics was applied to analyze differentially expressed proteins, and metabolism-related pathways were primarily enriched. Finally, the reason for the elevated expression of RNF223 was analyzed, and KLF4 was shown to contribute to the increased expression of RNF233. In conclusion, this study comprehensively analyzed the clinical significance of E3 ligases. Functional assays revealed that RNF223 promotes cancer by regulating cell metabolism. Finally, the elevated expression of RNF223 was attributed to KLF4-mediated transcriptional activation. This study broadens our knowledge regarding E3 ubiquitin ligases and signal transduction and provides novel markers and therapeutic targets in pancreatic cancer.

scholarly journals A Decoy Library Uncovers U-Box E3 Ubiquitin Ligases That Regulate Flowering Time in Arabidopsis

Genetics ◽  
2020 ◽  
Vol 215 (3) ◽  
pp. 699-712 ◽  
Author(s):  
Ann M. Feke ◽  
Jing Hong ◽  
Wei Liu ◽  
Joshua M. Gendron
Keyword(s):  
Flowering Time ◽  
Development Program ◽  
Reproductive Development ◽  
Ubiquitin Ligases ◽  
Dominant Negative ◽  
E3 Ubiquitin Ligases ◽  
Genetic Redundancy ◽  
Bona Fide ◽  
Reverse Genetic Screen

Targeted degradation of proteins is mediated by E3 ubiquitin ligases and is important for the execution of many biological processes. Redundancy has prevented the genetic characterization of many E3 ubiquitin ligases in plants. Here, we performed a reverse genetic screen in Arabidopsis using a library of dominant-negative U-box-type E3 ubiquitin ligases to identify their roles in flowering time and reproductive development. We identified five U-box decoy transgenic populations that have defects in flowering time or the floral development program. We used additional genetic and biochemical studies to validate PLANT U-BOX 14 (PUB14), MOS4-ASSOCIATED COMPLEX 3A (MAC3A), and MAC3B as bona fide regulators of flowering time. This work demonstrates the widespread importance of E3 ubiquitin ligases in floral reproductive development. Furthermore, it reinforces the necessity of dominant-negative strategies for uncovering previously unidentified regulators of developmental transitions in an organism with widespread genetic redundancy, and provides a basis on which to model other similar studies.

scholarly journals Establishment of a Wheat Cell-Free Synthesized Protein Array Containing 250 Human and Mouse E3 Ubiquitin Ligases to Identify Novel Interaction between E3 Ligases and Substrate Proteins

PLoS ONE ◽  
2016 ◽  
Vol 11 (6) ◽  
pp. e0156718 ◽  
Author(s):  
Hirotaka Takahashi ◽  
Atsushi Uematsu ◽  
Satoshi Yamanaka ◽  
Mei Imamura ◽  
Tatsuro Nakajima ◽  
...  
Keyword(s):  
Ubiquitin Ligases ◽  
Protein Array ◽  
E3 Ubiquitin Ligases ◽  
E3 Ligases ◽  
Substrate Proteins ◽  
Human And Mouse

scholarly journals Potential of E3 Ubiquitin Ligases in Cancer Immunity: Opportunities and Challenges

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3309
Author(s):  
Peng Ye ◽  
Xiaoxia Chi ◽  
Jong-Ho Cha ◽  
Shahang Luo ◽  
Guanghui Yang ◽  
...  
Keyword(s):  
Checkpoint Inhibitors ◽  
Ubiquitin Ligases ◽  
Immune Checkpoints ◽  
E3 Ubiquitin Ligases ◽  
E3 Ligases ◽  
Beneficial Effects ◽  
Clinical Strategies ◽  
Immune Pathway ◽  
Future Direction ◽  
Cancer Immunotherapies

Cancer immunotherapies, including immune checkpoint inhibitors and immune pathway–targeted therapies, are promising clinical strategies for treating cancer. However, drug resistance and adverse reactions remain the main challenges for immunotherapy management. The future direction of immunotherapy is mainly to reduce side effects and improve the treatment response rate by finding new targets and new methods of combination therapy. Ubiquitination plays a crucial role in regulating the degradation of immune checkpoints and the activation of immune-related pathways. Some drugs that target E3 ubiquitin ligases have exhibited beneficial effects in preclinical and clinical antitumor treatments. In this review, we discuss mechanisms through which E3 ligases regulate tumor immune checkpoints and immune-related pathways as well as the opportunities and challenges for integrating E3 ligases targeting drugs into cancer immunotherapy.

scholarly journals Functional Significance of the E3 Ubiquitin Ligases in Disease and Therapeutics

2021 ◽  
Author(s):  
Julius Tieroyaare Dongdem ◽  
Cletus Adiyaga Wezena
Keyword(s):  
Therapeutic Potential ◽  
Protein Complexes ◽  
Ring Finger ◽  
Ubiquitin Ligases ◽  
E3 Ubiquitin Ligases ◽  
Phd Finger ◽  
E3 Ligases ◽  
Cellular Processes ◽  
Future Drug ◽  
Ubiquitin Conjugating Enzyme

E3 ubiquitin ligases of which there are >600 putative in humans, constitute a family of highly heterogeneous proteins and protein complexes that are the ultimate enzymes responsible for the recruitment of an ubiquitin loaded E2 ubiquitin-conjugating enzyme, recognise the appropriate protein substrate and directly or indirectly transfer the ubiquitin load onto the substrate. The aftermath of an E3 ligase activity is usually the formation of an isopeptide bond between the free carboxylate group of ubiquitin’s C-terminal Gly76 and an ε-amino group of the substrate’s Lys, even though non-canonical ubiquitylation on non-amine groups of target proteins have been observed. E3 ligases are grouped into four distinct families: HECT, RING-finger/U-box, RBR and PHD-finger. E3 ubiquitin ligases play critical roles in subcellular signalling cascades in eukaryotes. Dysfunctional E3 ubiquitin ligases therefore tend to inflict dramatic effects on human health and may result in the development of various diseases including Parkinson’s, Amyotrophic Lateral Sclerosis, Alzheimer’s, cancer, etc. Being regulators of numerous cellular processes, some E3 ubiquitin ligases have become potential targets for therapy. This chapter will present a comprehensive review of up-to-date findings in E3 ligases, their role in the pathology of disease and therapeutic potential for future drug development.

The regulation of E3 ubiquitin ligases Cbl and its cross talking in bone homeostasis

2020 ◽  
Vol 15 ◽  
Author(s):  
Xiaobin Yang ◽  
Dingjun Hao ◽  
Baorong He
Keyword(s):  
Cellular Proliferation ◽  
Bone Matrix ◽  
Osteoclast Differentiation ◽  
Ubiquitin Ligases ◽  
E3 Ubiquitin Ligases ◽  
Bone Homeostasis ◽  
And Migration ◽  
First Time ◽  
Definite Role

: The E3 ubiquitin ligases Cbl has been found play an important role in regulating cellular proliferation and migration. Whereas the excessive differentiation of osteoclast and/or its over expressing of resorptive functions could lead the pathological bone homeostasis by overly bone matrix degradation. Since the first time of the important role of Cbl in the regulating osteoclast differentiation (also named osteoclastogenesis) has been reported in decades ago. The extensively studies have been conducted for in-depth exploring the Cbl’s definite role during osteoclastogenesis, as well as its cross talking with other signaling pathways (such as: Src and PI3K signaling) in bone homeostasis. Herein, our current study aim to briefly conclude the current studies of osteoclastogenesis and the regulatory role of Cbl, as well as its cross-talking in bone homeostasis.

scholarly journals The nucleotide exchange factors Grp170 and Sil1 induce cholera toxin release from BiP to enable retrotranslocation

2015 ◽  
Vol 26 (12) ◽  
pp. 2181-2189 ◽  
Author(s):  
Jeffrey M. Williams ◽  
Takamasa Inoue ◽  
Grace Chen ◽  
Billy Tsai
Keyword(s):  
Cholera Toxin ◽  
Ubiquitin Ligase ◽  
Protein Disulfide Isomerase ◽  
Nucleotide Exchange ◽  
Binding Studies ◽  
Disulfide Isomerase ◽  
Binding Partner ◽  
Nucleotide Exchange Factors ◽  
Protein Disulfide ◽  
J Protein

Cholera toxin (CT) intoxicates cells by trafficking from the cell surface to the endoplasmic reticulum (ER), where the catalytic CTA1 subunit hijacks components of the ER-associated degradation (ERAD) machinery to retrotranslocate to the cytosol and induce toxicity. In the ER, CT targets to the ERAD machinery composed of the E3 ubiquitin ligase Hrd1-Sel1L complex, in part via the activity of the Sel1L-binding partner ERdj5. This J protein stimulates BiP's ATPase activity, allowing BiP to capture the toxin. Presumably, toxin release from BiP must occur before retrotranslocation. Here, using loss-and gain-of-function approaches coupled with binding studies, we demonstrate that the ER-resident nucleotide exchange factors (NEFs) Grp170 and Sil1 induce CT release from BiP in order to promote toxin retrotranslocation. In addition, we find that after NEF-dependent release from BiP, the toxin is transferred to protein disulfide isomerase; this ER redox chaperone is known to unfold CTA1, which allows the toxin to cross the Hrd1-Sel1L complex. Our data thus identify two NEFs that trigger toxin release from BiP to enable successful retrotranslocation and clarify the fate of the toxin after it disengages from BiP.

scholarly journals Inhibition of Xanthine Oxidase by Allopurinol Prevents Skeletal Muscle Atrophy: Role of p38 MAPKinase and E3 Ubiquitin Ligases

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e46668 ◽  
Author(s):  
Frederic Derbre ◽  
Beatriz Ferrando ◽  
Mari Carmen Gomez-Cabrera ◽  
Fabian Sanchis-Gomar ◽  
Vladimir E. Martinez-Bello ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Xanthine Oxidase ◽  
Muscle Atrophy ◽  
Ubiquitin Ligases ◽  
Skeletal Muscle Atrophy ◽  
E3 Ubiquitin Ligases
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