Grapevine U-Box E3 Ubiquitin Ligase VlPUB38 Negatively Regulates Fruit Ripening by Facilitating Abscisic-Aldehyde Oxidase Degradation

2020 ◽  
Author(s):  
Yihe Yu ◽  
Xiangxuan Meng ◽  
Dalong Guo ◽  
Shengdi Yang ◽  
Guohai Zhang ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Fruit Ripening ◽  
Ectopic Expression ◽  
E3 Ubiquitin Ligase ◽  
Aldehyde Oxidase ◽  
26S Proteasome ◽  
Dependent Manner ◽  
Proteasome Degradation ◽  
Key Factor ◽  
Aba Synthesis

Abstract The plant U-box E3 ubiquitin ligase-mediated ubiquitin/26S proteasome degradation system plays a key role in plant growth and development. Previously screened from the grape PUB gene family, PUB38 was shown to participate in the berry-ripening progress. Here, we demonstrate that the E3 ligase VlPUB38 mediates abscisic acid (ABA) synthesis via 26S proteasome degradation and its involvement in regulating fruit-ripening processes. Strawberry-overexpressing VlPUB38 lines displayed obvious inhibition of mature phenotype, and this was rescued by exogenous ABA treatment and MG132. Post-ABA treatment, expression levels of ABA response-related genes in VlPUB38-overexpressed Arabidopsis significantly exceeded controls. Strawberry and Arabidopsis ectopic expression assays suggest that VlPUB38 negatively regulates fruit ripening in an ABA-dependent manner. Moreover, VlPUB38 has ubiquitin ligase activity, which depends on the U-box-conserved domain. VlPUB38 interacts with abscisic-aldehyde oxidase (VlAAO), targeting VlAAO proteolysis via the 26S proteasome system. These results indicate that VlPUB38 negatively regulates grape fruit ripening by mediating the degradation of key factor VlAAO in the ABA synthesis pathway.

scholarly journals RNF125 is a Ubiquitin-Protein Ligase that Promotes p53 Degradation

2015 ◽  
Vol 35 (1) ◽  
pp. 237-245 ◽  
Author(s):  
Liuzhong Yang ◽  
Bing Zhou ◽  
Xiaorui Li ◽  
Zhihong Lu ◽  
Weiwei Li ◽  
...  
Keyword(s):  
Rna Interference ◽  
Growth Inhibition ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Physical Interaction ◽  
Dependent Manner ◽  
Ubiquitin Protein Ligase ◽  
Proteasome Degradation ◽  
Dose Dependent

Background/Aims: Although early studies show that Mdm2 is the primary E3 ubiquitin ligase for the p53 tumor suppressor, an increasing amount of data suggests that p53 ubiquitination and degradation are more complex than once thought. Here, we investigated the role of RNF125, a non-Mdm2 ubiquitin-protein ligase, in the regulation of p53. Methods and Results: RNF125 physically interacted with p53 in exogenous/endogenous co-immunoprecipitation (IP) and GST-pull down assay, and a C72/75A mutation of RNF125 did not interfere with this interaction. Expression of RNF125 decreased the level of p53 in a dose-dependent manner, whereas knockdown of RNF125 by RNA interference increased the level of p53. As shown by Western blotting and ubiquitin assay, RNF125 ubiquitinated p53 and targeted it for proteasome degradation. Furthermore, RNF125 repressed p53 functions including p53-dependent transactivation and growth inhibition. Conclusion: Our data suggest that RNF125 negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation.

scholarly journals A Noncanonical Mechanism of Nrf2 Activation by Autophagy Deficiency: Direct Interaction between Keap1 and p62

2010 ◽  
Vol 30 (13) ◽  
pp. 3275-3285 ◽  
Author(s):  
Alexandria Lau ◽  
Xiao-Jun Wang ◽  
Fei Zhao ◽  
Nicole F. Villeneuve ◽  
Tongde Wu ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Defense Mechanism ◽  
Ectopic Expression ◽  
E3 Ubiquitin Ligase ◽  
Direct Interaction ◽  
Degradation Pathway ◽  
26S Proteasome ◽  
Ubiquitin Ligase Complex ◽  
Subsequent Degradation ◽  
Kelch Domain

ABSTRACT In response to stress, cells can utilize several cellular processes, such as autophagy, which is a bulk-lysosomal degradation pathway, to mitigate damages and increase the chances of cell survival. Deregulation of autophagy causes upregulation of p62 and the formation of p62-containing aggregates, which are associated with neurodegenerative diseases and cancer. The Nrf2-Keap1 pathway functions as a critical regulator of the cell's defense mechanism against oxidative stress by controlling the expression of many cellular protective proteins. Under basal conditions, Nrf2 is ubiquitinated by the Keap1-Cul3-E3 ubiquitin ligase complex and targeted to the 26S proteasome for degradation. Upon induction, the activity of the E3 ubiquitin ligase is inhibited through the modification of cysteine residues in Keap1, resulting in the stabilization and activation of Nrf2. In this current study, we identified the direct interaction between p62 and Keap1 and the residues required for the interaction have been mapped to 349-DPSTGE-354 in p62 and three arginines in the Kelch domain of Keap1. Accumulation of endogenous p62 or ectopic expression of p62 sequesters Keap1 into aggregates, resulting in the inhibition of Keap1-mediated Nrf2 ubiquitination and its subsequent degradation by the proteasome. In contrast, overexpression of mutated p62, which loses its ability to interact with Keap1, had no effect on Nrf2 stability, demonstrating that p62-mediated Nrf2 upregulation is Keap1 dependent. These findings demonstrate that autophagy deficiency activates the Nrf2 pathway in a noncanonical cysteine-independent mechanism.

scholarly journals The mitochondrial E3 ubiquitin ligase MARCH5 is required for Drp1 dependent mitochondrial division

2007 ◽  
Vol 178 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Mariusz Karbowski ◽  
Albert Neutzner ◽  
Richard J. Youle
Keyword(s):  
Rna Interference ◽  
Ubiquitin Ligase ◽  
Molecular Interactions ◽  
Mitochondrial Fission ◽  
Ectopic Expression ◽  
E3 Ubiquitin Ligase ◽  
Dependent Manner ◽  
Wild Type ◽  
Subcellular Trafficking ◽  
Mitochondrial Division

We identify a mitochondrial E3 ubiquitin ligase, MARCH5, as a critical regulator of mitochondrial fission. MARCH5 RING mutants and MARCH5 RNA interference induce an abnormal elongation and interconnection of mitochondria indicative of an inhibition of mitochondrial division. The aberrant mitochondrial phenotypes in MARCH5 RING mutant–expressing cells are reversed by ectopic expression of Drp1, but not another mitochondrial fission protein Fis1. Moreover, as indicated by abnormal clustering and mitochondrial accumulation of Drp1, as well as decreased cellular mobility of YFP-Drp1 in cells expressing MARCH5 RING mutants, MARCH5 activity regulates the subcellular trafficking of Drp1, likely by impacting the correct assembly at scission sites or the disassembly step of fission complexes. Loss of this activity may account for the observed mitochondrial division defects. Finally, MARCH5 RING mutants and endogenous Drp1, but not wild-type MARCH5 or Fis1, co-assemble into abnormally enlarged clusters in a Drp1 GTPase-dependent manner, suggesting molecular interactions among these proteins. Collectively, our data suggest a model in which mitochondrial division is regulated by a MARCH5 ubiquitin-dependent switch.

scholarly journals The p73 Tumor Suppressor Is Targeted by Pirh2 RING Finger E3 Ubiquitin Ligase for the Proteasome-dependent Degradation

2011 ◽  
Vol 286 (41) ◽  
pp. 35388-35395 ◽  
Author(s):  
Yong-Sam Jung ◽  
Yingjuan Qian ◽  
Xinbin Chen
Keyword(s):  
Tumor Suppressor ◽  
Ubiquitin Ligase ◽  
Human Cancer ◽  
Ectopic Expression ◽  
E3 Ubiquitin Ligase ◽  
Ring Finger ◽  
Growth Suppression ◽  
Dependent Manner

The p73 gene, a homologue of the p53 tumor suppressor, is expressed as TA and ΔN isoforms. TAp73 has similar activity as p53 and functions as a tumor suppressor whereas ΔNp73 has both pro- and anti-survival functions. While p73 is rarely mutated in spontaneous tumors, the expression status of p73 is linked to the sensitivity of tumor cells to chemotherapy and prognosis for many types of human cancer. Thus, uncovering its regulators in tumors is of great interest. Here, we found that Pirh2, a RING finger E3 ubiquitin ligase, promotes the proteasome-dependent degradation of p73. Specifically, we showed that knockdown of Pirh2 up-regulates, whereas ectopic expression of Pirh2 down-regulates, expression of endogenous and exogenous p73. In addition, Pirh2 physically associates with and promotes TAp73 polyubiquitination both in vivo and in vitro. Moreover, we found that p73 can be degraded by both 20 S and 26 S proteasomes. Finally, we showed that Pirh2 knockdown leads to growth suppression in a TAp73-dependent manner. Taken together, our findings indicate that Pirh2 promotes the proteasomal turnover of TAp73, and thus targeting Pirh2 to restore TAp73-mediated growth suppression in p53-deficient tumors may be developed as a novel anti-cancer strategy.

scholarly journals Hect E3 ubiquitin ligase Tom1 controls Dia2 degradation during the cell cycle

2012 ◽  
Vol 23 (21) ◽  
pp. 4203-4211 ◽  
Author(s):  
Dong-Hwan Kim ◽  
Deanna M. Koepp
Keyword(s):  
Cell Cycle ◽  
Protein Degradation ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
S Phase ◽  
Temperature Sensitive ◽  
Dependent Manner ◽  
Charged Residues ◽  
Phase Progression ◽  
Positively Charged

The ubiquitin proteasome system plays a pivotal role in controlling the cell cycle. The budding yeast F-box protein Dia2 is required for genomic stability and is targeted for ubiquitin-dependent degradation in a cell cycle–dependent manner, but the identity of the ubiquitination pathway is unknown. We demonstrate that the Hect domain E3 ubiquitin ligase Tom1 is required for Dia2 protein degradation. Deletion of DIA2 partially suppresses the temperature-sensitive phenotype of tom1 mutants. Tom1 is required for Dia2 ubiquitination and degradation during G1 and G2/M phases of the cell cycle, whereas the Dia2 protein is stabilized during S phase. We find that Tom1 binding to Dia2 is enhanced in G1 and reduced in S phase, suggesting a mechanism for this proteolytic switch. Tom1 recognizes specific, positively charged residues in a Dia2 degradation/NLS domain. Loss of these residues blocks Tom1-mediated turnover of Dia2 and causes a delay in G1–to–S phase progression. Deletion of DIA2 rescues a delay in the G1–to–S phase transition in the tom1Δ mutant. Together our results suggest that Tom1 targets Dia2 for degradation during the cell cycle by recognizing positively charged residues in the Dia2 degradation/NLS domain and that Dia2 protein degradation contributes to G1–to–S phase progression.

E3 ubiquitin ligase CHIP interacts with C-type lectin-like receptor CLEC-2 and promotes its ubiquitin-proteasome degradation

2016 ◽  
Vol 28 (10) ◽  
pp. 1530-1536 ◽  
Author(s):  
Miaomiao Shao ◽  
Lili Li ◽  
Shushu Song ◽  
Weicheng Wu ◽  
Peike Peng ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
Proteasome Degradation ◽  
Ubiquitin Proteasome

scholarly journals Proteomic analysis identifies the E3 ubiquitin ligase Pdzrn3 as a regulatory target of Wnt5a-Ror signaling

2021 ◽  
Vol 118 (25) ◽  
pp. e2104944118
Author(s):  
Sara E. Konopelski Snavely ◽  
Michael W. Susman ◽  
Ryan C. Kunz ◽  
Jia Tan ◽  
Srisathya Srinivasan ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Large Scale ◽  
Glycogen Synthase ◽  
E3 Ubiquitin Ligase ◽  
Ubiquitin Proteasome System ◽  
Dependent Manner ◽  
Casein Kinase 1 ◽  
Downstream Signaling ◽  
Proteomic Screen ◽  
Responsive Element

Wnt5a-Ror signaling is a conserved pathway that regulates morphogenetic processes during vertebrate development [R. T. Moon et al., Development 119, 97–111 (1993); I. Oishi et al., Genes Cells 8, 645–654 (2003)], but its downstream signaling events remain poorly understood. Through a large-scale proteomic screen in mouse embryonic fibroblasts, we identified the E3 ubiquitin ligase Pdzrn3 as a regulatory target of the Wnt5a-Ror pathway. Upon pathway activation, Pdzrn3 is degraded in a β-catenin–independent, ubiquitin-proteasome system–dependent manner. We developed a flow cytometry-based reporter to monitor Pdzrn3 abundance and delineated a signaling cascade involving Frizzled, Dishevelled, Casein kinase 1, and Glycogen synthase kinase 3 that regulates Pdzrn3 stability. Epistatically, Pdzrn3 is regulated independently of Kif26b, another Wnt5a-Ror effector. Wnt5a-dependent degradation of Pdzrn3 requires phosphorylation of three conserved amino acids within its C-terminal LNX3H domain [M. Flynn, O. Saha, P. Young, BMC Evol. Biol. 11, 235 (2011)], which acts as a bona fide Wnt5a-responsive element. Importantly, this phospho-dependent degradation is essential for Wnt5a-Ror modulation of cell migration. Collectively, this work establishes a Wnt5a-Ror cell morphogenetic cascade involving Pdzrn3 phosphorylation and degradation.

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