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Bo Wang, Li Zeng, Sean A Merillat, Svetlana Fischer, Joseph Ochaba, Leslie M Thompson, Sami J Barmada, Kenneth M Scaglione, Henry L Paulson
Huntington's disease (HD) is caused by a CAG repeat expansion that encodes a polyglutamine (polyQ) expansion in the HD disease protein, huntingtin (HTT). PolyQ expansion promotes misfolding and aggregation of mutant HTT (mHTT) within neurons. The cellular pathways, including ubiquitin-dependent processes, by which mHTT is regulated remain incompletely understood. Ube2W is the only ubiquitin conjugating enzyme (E2) known to ubiquitinate substrates at their amino (N)-termini, likely favoring substrates with disordered N-termini...
January 2018: Neurobiology of Disease
Jean-François Maure, Sandra C Moser, Ellis G Jaffray, Arno F Alpi, Ronald T Hay
SUMO and ubiquitin play important roles in the response of cells to DNA damage. These pathways are linked by the SUMO Targeted ubiquitin Ligase Rnf4 that catalyses transfer of ubiquitin from a ubiquitin loaded E2 conjugating enzyme to a polySUMO modified substrate. Rnf4 can functionally interact with multiple E2s, including Ube2w, in vitro. Chicken cells lacking Rnf4 are hypersensitive to hyroxyurea, DNA alkylating drugs and DNA crosslinking agents, but this sensitivity is suppressed by simultaneous depletion of Ube2w...
May 17, 2016: Scientific Reports
Bo Wang, Sean A Merillat, Michael Vincent, Amanda K Huber, Venkatesha Basrur, Doris Mangelberger, Li Zeng, Kojo Elenitoba-Johnson, Richard A Miller, David N Irani, Andrzej A Dlugosz, Santiago Schnell, Kenneth Matthew Scaglione, Henry L Paulson
UBE2W ubiquitinates N termini of proteins rather than internal lysine residues, showing a preference for substrates with intrinsically disordered N termini. The in vivo functions of this intriguing E2, however, remain unknown. We generated Ube2w germ line KO mice that proved to be susceptible to early postnatal lethality without obvious developmental abnormalities. Although the basis of early death is uncertain, several organ systems manifest changes in Ube2w KO mice. Newborn Ube2w KO mice often show altered epidermal maturation with reduced expression of differentiation markers...
February 5, 2016: Journal of Biological Chemistry
Chao Qi, De-Feng Li, Lei Feng, Yanjie Hou, Hui Sun, Da-Cheng Wang, Wei Liu
Ubiquitination is a post-translational modification that is involved in myriad cellar regulation and disease pathways. The ubiquitin-conjugating enzyme (E2) is an important player in the ubiquitin transfer pathway. Although many E2 structures are available, not all E2 families have known structures, and three-dimensional structures from fungal organisms other than yeast are lacking. We report here the crystal structure of UbcA1, which is a novel ubiquitin-conjugating enzyme identified from the edible and medicinal mushroom Agrocybe aegerita and displays potential antitumor properties...
November 3, 2015: Scientific Reports
Adam J Fletcher, Donna L Mallery, Ruth E Watkinson, Claire F Dickson, Leo C James
Tripartite motif (TRIM) 21 is a cytosolic antibody receptor that neutralizes antibody-coated viruses that penetrate the cell and simultaneously activates innate immunity. Here we show that the conjugation of TRIM21 with K63-linked ubiquitin (Ub-(63)Ub) catalyzed by the sequential activity of nonredundant E2 Ub enzymes is required for its dual antiviral functions. TRIM21 is first labeled with monoubiquitin (monoUb) by the E2 Ube2W. The monoUb is a substrate for the heterodimeric E2 Ube2N/Ube2V2, resulting in TRIM21-anchored Ub-(63)Ub...
August 11, 2015: Proceedings of the National Academy of Sciences of the United States of America
Andrew T Quaile, Malene L Urbanus, Peter J Stogios, Boguslaw Nocek, Tatiana Skarina, Alexander W Ensminger, Alexei Savchenko
LubX is part of the large arsenal of effectors in Legionella pneumophila that are translocated into the host cytosol during infection. Despite such unique features as the presence of two U-box motifs and its targeting of another effector SidH, the molecular basis of LubX activity remains poorly understood. Here we show that the N terminus of LubX is able to activate an extended number of ubiquitin-conjugating (E2) enzymes including UBE2W, UBEL6, and all tested members of UBE2D and UBE2E families. Crystal structures of LubX alone and in complex with UBE2D2 revealed drastic molecular diversification between the two U-box domains, with only the N-terminal U-box retaining E2 recognition features typical for its eukaryotic counterparts...
August 4, 2015: Structure
Adam J Fletcher, Devin E Christensen, Chad Nelson, Choon Ping Tan, Torsten Schaller, Paul J Lehner, Wesley I Sundquist, Greg J Towers
TRIM5α is an antiviral, cytoplasmic, E3 ubiquitin (Ub) ligase that assembles on incoming retroviral capsids and induces their premature dissociation. It inhibits reverse transcription of the viral genome and can also synthesize unanchored polyubiquitin (polyUb) chains to stimulate innate immune responses. Here, we show that TRIM5α employs the E2 Ub-conjugating enzyme Ube2W to anchor the Lys63-linked polyUb chains in a process of TRIM5α auto-ubiquitination. Chain anchoring is initiated, in cells and in vitro, through Ube2W-catalyzed monoubiquitination of TRIM5α...
August 4, 2015: EMBO Journal
Sarah E Soss, Kristie L Rose, Salisha Hill, Sophie Jouan, Walter J Chazin
The E3 ubiquitin ligase CHIP is involved in protein triage, serving as a co-chaperone for refolding as well as catalyzing ubiquitination of substrates. CHIP functions with both the stress induced Hsp70 and constitutive Hsc70 chaperones, and also plays a role in maintaining their balance in the cell. When the chaperones carry no client proteins, CHIP catalyzes their polyubiquitination and subsequent proteasomal degradation. Although Hsp70 and Hsc70 are highly homologous in sequence and similar in structure, CHIP mediated ubiquitination promotes degradation of Hsp70 with a higher efficiency than for Hsc70...
2015: PloS One
John S Bett, Maria Stella Ritorto, Richard Ewan, Ellis G Jaffray, Satpal Virdee, Jason W Chin, Axel Knebel, Thimo Kurz, Matthias Trost, Michael H Tatham, Ronald T Hay
Modification of proteins with ubiquitin (Ub) occurs through a variety of topologically distinct Ub linkages, including Ube2W-mediated monoubiquitylation of N-terminal alpha amines to generate peptide-linked linear mono-Ub fusions. Protein ubiquitylation can be reversed by the action of deubiquitylating enzymes (DUBs), many of which show striking preference for particular Ub linkage types. Here, we have screened for DUBs that preferentially cleave N-terminal Ub from protein substrates but do not act on Ub homopolymers...
March 15, 2015: Biochemical Journal
Vinayak Vittal, Lei Shi, Dawn M Wenzel, K Matthew Scaglione, Emily D Duncan, Venkatesha Basrur, Kojo S J Elenitoba-Johnson, David Baker, Henry L Paulson, Peter S Brzovic, Rachel E Klevit
Ubiquitination of the αN-terminus of protein substrates has been reported sporadically since the early 1980s. However, the identity of an enzyme responsible for this unique ubiquitin (Ub) modification has only recently been elucidated. We show the Ub-conjugating enzyme (E2) Ube2w uses a unique mechanism to facilitate the specific ubiquitination of the α-amino group of its substrates that involves recognition of backbone atoms of intrinsically disordered N termini. We present the NMR-based solution ensemble of full-length Ube2w that reveals a structural architecture unlike that of any other E2 in which its C terminus is partly disordered and flexible to accommodate variable substrate N termini...
January 2015: Nature Chemical Biology
Vinayak Vittal, Dawn M Wenzel, Peter S Brzovic, Rachel E Klevit
The biochemical and structural characterization of ubiquitin-conjugating enzymes (E2s) over the past 30 years has fostered important insights into ubiquitin transfer mechanisms. Although many of these enzymes share high sequence and structural conservation, their functional roles in the cell are decidedly diverse. Here, we report that the mono-ubiquitinating E2 UBE2W forms a homodimer using two distinct protein surfaces. Dimerization is primarily driven by residues in the ß-sheet region and Loops 4 and 7 of the catalytic domain...
September 2013: Cell Biochemistry and Biophysics
Kenneth Matthew Scaglione, Venkatesha Basrur, Naila S Ashraf, John R Konen, Kojo S J Elenitoba-Johnson, Sokol V Todi, Henry L Paulson
Attachment of ubiquitin to substrate is typically thought to occur via formation of an isopeptide bond between the C-terminal glycine residue of ubiquitin and a lysine residue in the substrate. In vitro, Ube2w is nonreactive with free lysine yet readily ubiquitinates substrate. Ube2w also contains novel residues within its active site that are important for its ability to ubiquitinate substrate. To identify the site of modification, we analyzed ubiquitinated substrates by mass spectrometry and found the N-terminal -NH2 group as the site of conjugation...
June 28, 2013: Journal of Biological Chemistry
Michael H Tatham, Anna Plechanovová, Ellis G Jaffray, Helena Salmen, Ronald T Hay
The covalent attachment of the protein ubiquitin to intracellular proteins by a process known as ubiquitylation regulates almost all major cellular systems, predominantly by regulating protein turnover. Ubiquitylation requires the co-ordinated action of three enzymes termed E1, E2 and E3, and typically results in the formation of an isopeptide bond between the C-terminal carboxy group of ubiquitin and the ϵ-amino group of a target lysine residue. However, ubiquitin is also known to conjugate to the thiol of cysteine residue side chains and the α-amino group of protein N-termini, although the enzymes responsible for discrimination between different chemical groups have not been defined...
July 1, 2013: Biochemical Journal
Lea M Starita, Jonathan N Pruneda, Russell S Lo, Douglas M Fowler, Helen J Kim, Joseph B Hiatt, Jay Shendure, Peter S Brzovic, Stanley Fields, Rachel E Klevit
Although ubiquitination plays a critical role in virtually all cellular processes, mechanistic details of ubiquitin (Ub) transfer are still being defined. To identify the molecular determinants within E3 ligases that modulate activity, we scored each member of a library of nearly 100,000 protein variants of the murine ubiquitination factor E4B (Ube4b) U-box domain for auto-ubiquitination activity in the presence of the E2 UbcH5c. This assay identified mutations that enhance activity both in vitro and in cellular p53 degradation assays...
April 2, 2013: Proceedings of the National Academy of Sciences of the United States of America
K Matthew Scaglione, Eszter Zavodszky, Sokol V Todi, Srikanth Patury, Ping Xu, Edgardo Rodríguez-Lebrón, Svetlana Fischer, John Konen, Ana Djarmati, Junmin Peng, Jason E Gestwicki, Henry L Paulson
The mechanisms by which ubiquitin ligases are regulated remain poorly understood. Here we describe a series of molecular events that coordinately regulate CHIP, a neuroprotective E3 implicated in protein quality control. Through their opposing activities, the initiator E2, Ube2w, and the specialized deubiquitinating enzyme (DUB), ataxin-3, participate in initiating, regulating, and terminating the CHIP ubiquitination cycle. Monoubiquitination of CHIP by Ube2w stabilizes the interaction between CHIP and ataxin-3, which through its DUB activity limits the length of chains attached to CHIP substrates...
August 19, 2011: Molecular Cell
Yingying Zhang, Xiaowei Zhou, Lixia Zhao, Chao Li, Hengqi Zhu, Long Xu, Liran Shan, Xiang Liao, Zekun Guo, Peitang Huang
Fanconi anemia (FA) is a rare cancer-predisposing genetic disease mostly caused by improper regulation of the monoubiquitination of Fanconi anemia complementation group D2 (FANCD2). Genetic studies have indicated that ubiquitin conjugating enzyme UBE2T and HHR6 could regulate FANCD2 monoubiquitination through distinct mechanisms. However, the exact regulation mechanisms of FANCD2 monoubiquitination in response to different DNA damages remain unclear. Here we report that UBE2W, a new ubiquitin conjugating enzyme, could regulate FANCD2 monoubiquitination by mechanisms different from UBE2T or HHR6...
February 2011: Molecules and Cells
Yingying Zhang, Hengqi Zhu, Lixia Zhao, Xiaowei Zhou, Peitang Huang
Ubiquitin conjugating enzyme functions as the second enzyme required for protein ubiquitination and plays an important role in ubiquitin transferring and substrate specific recognition. UBE2W, a newly described member of E2 family, was formerly reported probably involving in phototransduction or retinal degeneration in Drosophila. In this study, we report that murine UBE2W harbors a typical UBC domain and is highly conserved in different vertebrate homologues. GST-tagged UBE2W was expressed in E. coli BL21 (DE3) and purified with GST affinity chromatography...
April 2008: Sheng Wu Gong Cheng Xue Bao, Chinese Journal of Biotechnology
Devin E Christensen, Peter S Brzovic, Rachel E Klevit
An E3 ubiquitin ligase mediates the transfer of activated ubiquitin from an E2 ubiquitin-conjugating enzyme to its substrate lysine residues. Using a structure-based, yeast two-hybrid strategy, we discovered six previously unidentified interactions between the human heterodimeric RING E3 BRCA1-BARD1 and the human E2s UbcH6, Ube2e2, UbcM2, Ubc13, Ube2k and Ube2w. All six E2s bind directly to the BRCA1 RING motif and are active with BRCA1-BARD1 for autoubiquitination in vitro. Four of the E2s direct monoubiquitination of BRCA1...
October 2007: Nature Structural & Molecular Biology
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