The Experts below are selected from a list of 24608466 Experts worldwide ranked by ideXlab platform
Jennifer Y. Zhang - One of the best experts on this subject based on the ideXlab platform.
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UBE2N promotes melanoma growth via mek fra1 sox10 signaling
Cancer Research, 2018Co-Authors: Anushka Dikshit, Yingai J. Jin, Simone Degan, Jihwan Hwang, Matthew W. Foster, Jennifer Y. ZhangAbstract:UBE2N is a K63-specific ubiquitin conjugase linked to various immune disorders and cancer. Here, we demonstrate that UBE2N and its partners UBE2V1 and UBE2V2 are highly expressed in malignant melanoma. Silencing of UBE2N and its partners significantly decreased melanoma cell proliferation and subcutaneous tumor growth. This was accompanied by increased expression of E-cadherin, p16, and MC1R and decreased expression of melanoma malignancy markers including SOX10, Nestin, and ABCB5. Mass spectrometry–based phosphoproteomic analysis revealed that UBE2N loss resulted in distinct alterations to the signaling landscape: MEK/ERK signaling was impaired, FRA1 and SOX10 gene regulators were downregulated, and p53 and p16 tumor suppressors were upregulated. Similar to inhibition of UBE2N and MEK, silencing FRA1 decreased SOX10 expression and cell proliferation. Conversely, exogenous expression of active FRA1 increased pMEK and SOX10 expression, and restored anchorage-independent cell growth of cells with UBE2N loss. Systemic delivery of NSC697923, a small-molecule inhibitor of UBE2N, significantly decreased melanoma xenograft growth. These data indicate that UBE2N is a novel regulator of the MEK/FRA1/SOX10 signaling cascade and is indispensable for malignant melanoma growth. Our findings establish the basis for targeting UBE2N as a potential treatment strategy for melanoma. Significance: These findings identify ubiquitin conjugase UBE2N and its variant partners as novel regulators of MAPK signaling and potential therapeutic targets in melanoma. Cancer Res; 78(22); 6462–72. ©2018 AACR .
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UBE2N Promotes Melanoma Growth via MEK/FRA1/SOX10 Signaling
Cancer research, 2018Co-Authors: Anushka Dikshit, Yingai J. Jin, Simone Degan, Jihwan Hwang, Matthew W. Foster, Jennifer Y. ZhangAbstract:UBE2N is a K63-specific ubiquitin conjugase linked to various immune disorders and cancer. Here, we demonstrate that UBE2N and its partners UBE2V1 and UBE2V2 are highly expressed in malignant melanoma. Silencing of UBE2N and its partners significantly decreased melanoma cell proliferation and subcutaneous tumor growth. This was accompanied by increased expression of E-cadherin, p16, and MC1R and decreased expression of melanoma malignancy markers including SOX10, Nestin, and ABCB5. Mass spectrometry–based phosphoproteomic analysis revealed that UBE2N loss resulted in distinct alterations to the signaling landscape: MEK/ERK signaling was impaired, FRA1 and SOX10 gene regulators were downregulated, and p53 and p16 tumor suppressors were upregulated. Similar to inhibition of UBE2N and MEK, silencing FRA1 decreased SOX10 expression and cell proliferation. Conversely, exogenous expression of active FRA1 increased pMEK and SOX10 expression, and restored anchorage-independent cell growth of cells with UBE2N loss. Systemic delivery of NSC697923, a small-molecule inhibitor of UBE2N, significantly decreased melanoma xenograft growth. These data indicate that UBE2N is a novel regulator of the MEK/FRA1/SOX10 signaling cascade and is indispensable for malignant melanoma growth. Our findings establish the basis for targeting UBE2N as a potential treatment strategy for melanoma. Significance: These findings identify ubiquitin conjugase UBE2N and its variant partners as novel regulators of MAPK signaling and potential therapeutic targets in melanoma. Cancer Res; 78(22); 6462–72. ©2018 AACR .
J Burn - One of the best experts on this subject based on the ideXlab platform.
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identification of stk6 stk15 as a candidate low penetrance tumor susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewarttoland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Lucy Maccarthymorrogh, Bruce A J Ponder, Hiroki Nagase, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses (Mus musculus × Mus spretus) identified the gene encoding Aurora2 (Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
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Identification of Stk6/STK15 as a candidate low-penetrance tumor-susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewart-toland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Bruce A J Ponder, Hiroki Nagase, Jian-hua Mao, Lucy Maccarthy-morrogh, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses ( Mus musculus × Mus spretus ) identified the gene encoding Aurora2 ( Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F_1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
Zhao-qing Luo - One of the best experts on this subject based on the ideXlab platform.
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Legionella effector MavC targets the UBE2N~Ub conjugate for noncanonical ubiquitination.
Nature communications, 2020Co-Authors: Kedar Puvar, Rachel E. Klevit, Zhao-qing Luo, Shalini Iyer, Sebastian Kenny, Kristos I. Negrón Terón, Peter S. Brzovic, Chittaranjan DasAbstract:The bacterial effector MavC modulates the host immune response by blocking UBE2N activity employing an E1-independent ubiquitin ligation, catalyzing formation of a γ-glutamyl-e-Lys (Gln40Ub-Lys92UBE2N) isopeptide crosslink using a transglutaminase mechanism. Here we provide biochemical evidence in support of MavC targeting the activated, thioester-linked UBE2N~ubiquitin conjugate, catalyzing an intramolecular transglutamination reaction, covalently crosslinking the UBE2N and Ub subunits effectively inactivating the E2~Ub conjugate. Ubiquitin exhibits weak binding to MavC alone, but shows an increase in affinity when tethered to UBE2N in a disulfide-linked substrate that mimics the charged E2~Ub conjugate. Crystal structures of MavC in complex with the substrate mimic and crosslinked product provide insights into the reaction mechanism and underlying protein dynamics that favor transamidation over deamidation, while revealing a crucial role for the structurally unique insertion domain in substrate recognition. This work provides a structural basis of ubiquitination by transglutamination and identifies this enzyme’s true physiological substrate. The Legionella pneumophila effector MavC inhibits the human ubiquitin-conjugating enzyme UBE2N. Here, the authors combine NMR, X-ray crystallography and biochemical assays and show that MavC catalyses the intramolecular transglutaminase reaction between the UBE2N and Ub subunits of the UBE2N∼Ub conjugate and present the substrate- and product-bound MavC crystal structures.
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legionella effector mavc targets the UBE2N ub conjugate for noncanonical ubiquitination
Nature Communications, 2020Co-Authors: Kedar Puvar, Rachel E. Klevit, Zhao-qing Luo, Shalini Iyer, Sebastian Kenny, Kristos I. Negrón Terón, Peter S. Brzovic, Chittaranjan DasAbstract:The bacterial effector MavC modulates the host immune response by blocking UBE2N activity employing an E1-independent ubiquitin ligation, catalyzing formation of a γ-glutamyl-e-Lys (Gln40Ub-Lys92UBE2N) isopeptide crosslink using a transglutaminase mechanism. Here we provide biochemical evidence in support of MavC targeting the activated, thioester-linked UBE2N~ubiquitin conjugate, catalyzing an intramolecular transglutamination reaction, covalently crosslinking the UBE2N and Ub subunits effectively inactivating the E2~Ub conjugate. Ubiquitin exhibits weak binding to MavC alone, but shows an increase in affinity when tethered to UBE2N in a disulfide-linked substrate that mimics the charged E2~Ub conjugate. Crystal structures of MavC in complex with the substrate mimic and crosslinked product provide insights into the reaction mechanism and underlying protein dynamics that favor transamidation over deamidation, while revealing a crucial role for the structurally unique insertion domain in substrate recognition. This work provides a structural basis of ubiquitination by transglutamination and identifies this enzyme’s true physiological substrate. The Legionella pneumophila effector MavC inhibits the human ubiquitin-conjugating enzyme UBE2N. Here, the authors combine NMR, X-ray crystallography and biochemical assays and show that MavC catalyses the intramolecular transglutaminase reaction between the UBE2N and Ub subunits of the UBE2N∼Ub conjugate and present the substrate- and product-bound MavC crystal structures.
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Molecular Basis of Ubiquitination Catalyzed by the Bacterial Transglutaminase MavC
Advanced science (Weinheim Baden-Wurttemberg Germany), 2020Co-Authors: Hongxin Guan, Yini Huang, Zhao-xi Wang, Zhao-qing Luo, Ninghai Gan, Vanja Perčulija, Songying OuyangAbstract:The Legionella pneumophila effector MavC is a transglutaminase that carries out atypical ubiquitination of the host ubiquitin (Ub)-conjugation enzyme UBE2N by catalyzing the formation of an isopeptide bond between Gln40Ub and Lys92UBE2N, which leads to inhibition of signaling in the NF-κB pathway. In the absence of UBE2N, MavC deamidates Ub at Gln40 or catalyzes self-ubiquitination. However, the mechanisms underlying these enzymatic activities of MavC are poorly understood at the molecular level. This study reports the structure of the MavC-UBE2N-Ub ternary complex representing a snapshot of MavC-catalyzed crosslinking of UBE2N and Ub, which reveals the way by which UBE2N-Ub binds to the Insertion and Tail domains of MavC. Based on the structural and experimental data, the catalytic mechanism for the deamidase and transglutaminase activities of MavC is proposed. Finally, by comparing the structures of MavC and MvcA, the homologous protein that reverses MavC-induced UBE2N ubiquitination, several essential regions and two key residues (Trp255MavC and Phe268MvcA) responsible for their respective enzymatic activities are identified. The results provide insights into the mechanisms for substrate recognition and ubiquitination mediated by MavC as well as explanations for the opposite activity of MavC and MvcA in terms of regulation of UBE2N ubiquitination.
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Molecular basis of ubiquitination catalyzed by the bacterial transglutaminase MavC
2020Co-Authors: Hongxin Guan, Zhao-xi Wang, Zhao-qing Luo, Songying OuyangAbstract:The Legionella pneumophila effector MavC is a transglutaminase that carries out atypical ubiquitination of the ubiquitin (Ub) E2 conjugation enzyme UBE2N by catalyzing the formation of an isopeptide bond between Gln40 of Ub and Lys92 (or to a less extent, Lys94) of UBE2N, which results in inhibition of UBE2N signaling in the NF-{kappa}B pathway. In the absence of UBE2N, MavC deamidates Ub at Gln40 or catalyzes self-ubiquitination. However, the mechanisms underlying these enzymatic activities of MavC are not fully understood at molecular level. In this study, we obtained the structure of the MavC-UBE2N-Ub ternary complex that represents a snapshot of covalent cross-linking of UBE2N and Ub catalyzed by MavC. The structure reveals the unique way by which the cross-linked catalytic product UBE2N-Ub binds mainly to the Insertion and the Tail domains of MavC prior to its release. Based on our structural, biochemical and mutational analyses, we proposed the catalytic mechanism for both the deamidase and the transglutaminase activities of MavC. Finally, by comparing the structures of MavC and MvcA, the homologous protein that reverses MavC-induced UBE2N ubiquitination, we identified several key regions of the two proteins responsible for their opposite enzymatic activity. Our results provide insights into the mechanisms for substrate recognition and ubiquitination mediated by MavC as well as explanation for the opposite activities of MavC and MvcA in terms of regulation of UBE2N ubiquitination.
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Legionella pneumophila inhibits immune signalling via MavC-mediated transglutaminase-induced ubiquitination of UBE2N
Nature microbiology, 2018Co-Authors: Ninghai Gan, Ernesto S Nakayasu, Peter J. Hollenbeck, Zhao-qing LuoAbstract:The bacterial pathogen Legionella pneumophila modulates host immunity using effectors translocated by its Dot/Icm transporter to facilitate its intracellular replication. A number of these effectors employ diverse mechanisms to interfere with protein ubiquitination, a post-translational modification essential for immunity. Here, we have found that L. pneumophila induces monoubiquitination of the E2 enzyme UBE2N by its Dot/Icm substrate MavC(Lpg2147). We demonstrate that MavC is a transglutaminase that catalyses covalent linkage of ubiquitin to Lys92 and Lys94 of UBE2N via Gln40. Similar to canonical transglutaminases, MavC possess deamidase activity that targets ubiquitin at Gln40. We identified Cys74 as the catalytic residue for both ubiquitination and deamidation activities. Furthermore, ubiquitination of UBE2N by MavC abolishes its activity in the formation of K63-type polyubiquitin chains, which dampens NF-κB signalling in the initial phase of bacterial infection. Our results reveal an unprecedented mechanism of modulating host immunity by modifying a key ubiquitination enzyme by ubiquitin transglutamination.
Paraskevi Briassouli - One of the best experts on this subject based on the ideXlab platform.
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The N-terminal domain of the Aurora-A Phe-31 variant encodes an E3 ubiquitin ligase and mediates ubiquitination of IκBα
Human molecular genetics, 2006Co-Authors: Paraskevi Briassouli, Florence Chan, Spiros LinardopoulosAbstract:The N-terminal domain of the Aurora-A Phe-31 variant encodes an E3 ubiquitin ligase and mediates ubiquitination of I kappa B alpha Aurora-A is an important regulator of mitosis and is frequently amplified in human cancer. Ectopic expression of Aurora-A in mammalian cells induces centrosome amplification, genomic instability and transformation. A common genetic variant in Aurora-A (F31I) is preferentially amplified and is associated with the occurrence and the status of colon, oesophageal and breast cancers. Here we demonstrate that the N-terminal domain of Aurora-A Phe-31 variant exhibits an intrinsic ubiquitin ligase activity. Mutation of cysteines 8, 33 and 49 of Aurora-A abolishes the ubiquitin ligase activity of the protein. Aurora-A in a complex with UBE2N/MMS2 catalyses polyubiquitination of I kappa B alpha in vitro and in vivo.
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identification of stk6 stk15 as a candidate low penetrance tumor susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewarttoland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Lucy Maccarthymorrogh, Bruce A J Ponder, Hiroki Nagase, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses (Mus musculus × Mus spretus) identified the gene encoding Aurora2 (Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
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Identification of Stk6/STK15 as a candidate low-penetrance tumor-susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewart-toland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Bruce A J Ponder, Hiroki Nagase, Jian-hua Mao, Lucy Maccarthy-morrogh, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses ( Mus musculus × Mus spretus ) identified the gene encoding Aurora2 ( Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F_1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
John P De Koning - One of the best experts on this subject based on the ideXlab platform.
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identification of stk6 stk15 as a candidate low penetrance tumor susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewarttoland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Lucy Maccarthymorrogh, Bruce A J Ponder, Hiroki Nagase, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses (Mus musculus × Mus spretus) identified the gene encoding Aurora2 (Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
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Identification of Stk6/STK15 as a candidate low-penetrance tumor-susceptibility gene in mouse and human
Nature Genetics, 2003Co-Authors: Amanda Ewart-toland, Paraskevi Briassouli, John P De Koning, Jinwei Yuan, Florence Chan, Bruce A J Ponder, Hiroki Nagase, Jian-hua Mao, Lucy Maccarthy-morrogh, J BurnAbstract:Linkage analysis and haplotype mapping in interspecific mouse crosses ( Mus musculus × Mus spretus ) identified the gene encoding Aurora2 ( Stk6 in mouse and STK15 in human) as a candidate skin tumor susceptibility gene. The Stk6 allele inherited from the susceptible M. musculus parent was overexpressed in normal cells and preferentially amplified in tumor cells from F_1 hybrid mice. We identified a common genetic variant in STK15 (resulting in the amino acid substitution F31I) that is preferentially amplified and associated with the degree of aneuploidy in human colon tumors. The Ile31 variant transforms rat1 cells more potently than the more common Phe31 variant. The E2 ubiquitin-conjugating enzyme UBE2N was a preferential binding partner of the 'weak' STK15 Phe31 variant form in yeast two-hybrid screens and in human cells. This interaction results in colocalization of UBE2N with STK15 at the centrosomes during mitosis. These results are consistent with an important role for the Ile31 variant of STK15 in human cancer susceptibility.
