scholarly journals Allosteric network in Ube2T drives specificity for RING E3 catalysed ubiquitin signals

2018 ◽  
Author(s):  
Viduth K Chaugule ◽  
Connor Arkinson ◽  
Rachel Toth ◽  
Helen Walden
Keyword(s):  
Dna Damage ◽  
Repair Pathway ◽  
Core Complex ◽  
Site Specific ◽  
E3 Ligases ◽  
Interstrand Crosslink ◽  
Damage Repair ◽  
Molecular Signals ◽  
Ring E3 Ligases ◽  
Ring E3

AbstractIn eukaryotes, DNA damage repair is implemented by a host of proteins that are coordinated by defined molecular signals. One such signal that transpires during the Fanconi Anemia (FA) - interstrand crosslink (ICL) repair pathway is the site-specific monoubiquitination of FANCD2 and FANCI proteins by a large, multi-protein FA core complex. The mechanics for this exquisitely specific monoubiquitin signal has been elusive. Here we show FANCL, the RING E3 module of the FA core complex, allosterically activates its cognate E2 Ube2T for monoubiquitination by a mechanism distinct from the typical RING-based catalysis. FANCL triggers intricate re-wiring of Ube2T’s intra-residue network thus activating the E2 for precision targeting. This network is intrinsically regulated by conserved gates and loops which can be engineered to yield Ube2T variants that enhance FANCD2 ubiquitination by ~30-fold without compromising on target specificity. Finally, we also uncover allosteric networks in other ubiquitin E2s that can be leveraged by RING E3 ligases to drive specific ubiquitination.

scholarly journals Arabidopsis DREB2A-Interacting Proteins Function as RING E3 Ligases and Negatively Regulate Plant Drought Stress–Responsive Gene Expression

2008 ◽  
Vol 20 (6) ◽  
pp. 1693-1707 ◽  
Author(s):  
Feng Qin ◽  
Yoh Sakuma ◽  
Lam-Son Phan Tran ◽  
Kyonoshin Maruyama ◽  
Satoshi Kidokoro ◽  
...  
Keyword(s):  
Gene Expression ◽  
Drought Stress ◽  
Interacting Proteins ◽  
E3 Ligases ◽  
Responsive Gene ◽  
Ring E3 Ligases ◽  
Ring E3

scholarly journals The Fanconi anemia DNA damage repair pathway in the spotlight for germline predisposition to colorectal cancer

2016 ◽  
Vol 24 (10) ◽  
pp. 1501-1505 ◽  
Author(s):  
Clara Esteban-Jurado ◽  
◽  
Sebastià Franch-Expósito ◽  
Jenifer Muñoz ◽  
Teresa Ocaña ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Damage ◽  
Fanconi Anemia ◽  
Dna Damage Repair ◽  
Repair Pathway ◽  
Damage Repair

scholarly journals MicroRNA-146a-5p enhances radiosensitivity in hepatocellular carcinoma through replication protein A3-induced activation of the DNA repair pathway

2019 ◽  
Vol 316 (3) ◽  
pp. C299-C311 ◽  
Author(s):  
Jing Luo ◽  
Zhong-Zhou Si ◽  
Ting Li ◽  
Jie-Qun Li ◽  
Zhong-Qiang Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Repair ◽  
Replication Protein ◽  
Repair Pathway ◽  
Related Factors ◽  
Damage Repair ◽  
Hcc Cells

Hepatocellular carcinoma (HCC) is known for its high mortality rate worldwide. Based on intensive studies, microRNA (miRNA) expression functions in tumor suppression. Therefore, we aimed to evaluate the contribution of miR-146a-5p to radiosensitivity in HCC through the activation of the DNA damage repair pathway by binding to replication protein A3 (RPA3). First, the limma package of R was performed to differentially analyze HCC expression chip, and regulative miRNA of RPA3 was predicted. Expression of miR-146a-5p, RPA3, and DNA damage repair pathway-related factors in tissues and cells was determined. The effects of radiotherapy on the expression of miR-146a-5p and RPA3 as well as on cell radiosensitivity, proliferation, cell cycle, and apoptosis were also assessed. The results showed that there exists a close correlation between miR-146a and the radiotherapy effect on HCC progression through regulation of RPA3 and the DNA repair pathway. The positive rate of ATM, pCHK2, and Rad51 in HCC tissues was higher when compared with that of the paracancerous tissues. SMMC-7721 and HepG2 cell proliferation were significantly inhibited following 8 Gy 6Mv dose. MiR-146a-5p restrained the expression of RPA3 and promoted the expression of relative genes associated with the DNA repair pathway. In addition, miR-146a-5p overexpression suppresses cell proliferation and enhances radiosensitivity and cell apoptosis in HCC cells. In conclusion, the present study revealed that miR-146a-5p could lead to the restriction of proliferation and the promotion of radiosensitivity and apoptosis in HCC cells through activation of DNA repair pathway and inhibition of RPA3.

scholarly journals Identification of a PGXPP degron motif in dishevelled and structural basis for its binding to the E3 ligase KLHL12

Open Biology ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 200041 ◽  
Author(s):  
Zhuoyao Chen ◽  
Gregory A. Wasney ◽  
Sarah Picaud ◽  
Panagis Filippakopoulos ◽  
Masoud Vedadi ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Molecular Mechanisms ◽  
Hydrophobic Interactions ◽  
E3 Ubiquitin Ligase ◽  
Structural Basis ◽  
E3 Ligases ◽  
Kelch Domain ◽  
Ring E3 Ligases ◽  
Ring E3 ◽  
New Protein

Wnt signalling is dependent on dishevelled proteins (DVL1-3), which assemble an intracellular Wnt signalosome at the plasma membrane. The levels of DVL1-3 are regulated by multiple Cullin-RING E3 ligases that mediate their ubiquitination and degradation. The BTB-Kelch protein KLHL12 was the first E3 ubiquitin ligase to be identified for DVL1-3, but the molecular mechanisms determining its substrate interactions have remained unknown. Here, we mapped the interaction of DVL1-3 to a ‘PGXPP' motif that is conserved in other known partners and substrates of KLHL12, including PLEKHA4, PEF1, SEC31 and DRD4. To determine the binding mechanism, we solved a 2.4 Å crystal structure of the Kelch domain of KLHL12 in complex with a DVL1 peptide that bound with low micromolar affinity. The DVL1 substrate adopted a U-shaped turn conformation that enabled hydrophobic interactions with all six blades of the Kelch domain β-propeller. In cells, the mutation or deletion of this motif reduced the binding and ubiquitination of DVL1 and increased its stability confirming this sequence as a degron motif for KLHL12 recruitment. These results define the molecular mechanisms determining DVL regulation by KLHL12 and establish the KLHL12 Kelch domain as a new protein interaction module for a novel proline-rich motif.

Designing active RNF4 monomers by introducing a tryptophan: avidity towards E2∼Ub conjugates dictates the activity of ubiquitin RING E3 ligases

2019 ◽  
Vol 476 (10) ◽  
pp. 1465-1482 ◽  
Author(s):  
Sayani Sarkar ◽  
Adaitya Prasad Behera ◽  
Prateeka Borar ◽  
Prerana Agarwal Banka ◽  
Ajit B. Datta
Keyword(s):  
Enzymatic Activity ◽  
Tryptophan Residue ◽  
Amino Acid Residues ◽  
Binding Studies ◽  
E3 Ligases ◽  
Ring Domains ◽  
Biochemical Analyses ◽  
Ring E3 Ligases ◽  
Ring E3 ◽  
Existing Data

Abstract Ubiquitin RING E3 ligases (E3s) catalyze ubiquitin (Ub) transfer to their substrates by engaging E2∼Ub intermediates with the help of their RING domains. Different E3s have been found to contain a conserved tryptophan residue in their RING that plays an essential role in E2 binding and, hence, enzymatic activity. Many active E3s, however, lack this specific residue. We mined through the existing data to observe that the conservation of the tryptophan and quaternary organization of the RING domains are remarkably correlated. Monomeric RINGs possess the tryptophan while all well-characterized dimeric RINGs, except RNF8, contain other amino acid residues. Biochemical analyses on representative E3s and their mutants reveal that the tryptophan is essential for optimal enzymatic activity of monomeric RINGs whereas dimeric E3s with tryptophan display hyperactivity. Most critically, the introduction of the tryptophan restores the activity of inactive monomeric RNF4 mutants, an obligatory dimeric E3. Binding studies indicate that monomeric RINGs retained the tryptophan for their optimal functionality to compensate for weak Ub binding. On the other hand, tryptophan was omitted from dimeric RINGs during the course of evolution to prevent unwanted modifications and allow regulation of their activity through oligomerization.

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