1
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Safa N, Pettigrew JH, Gauthier TJ, Melvin AT. Direct measurement of deubiquitinating enzyme activity in intact cells using a protease-resistant, cell-permeable, peptide-based reporter. Biochem Eng J 2019; 151. [PMID: 32831622 DOI: 10.1016/j.bej.2019.107320] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Deubiquitinating enzymes (DUBs) regulate the removal of the polyubiquitin chain from proteins targeted for degradation. Current approaches to quantify DUB activity are limited to test tube-based assays that incorporate enzymes or cell lysates, but not intact cells. The goal of this work was to develop a novel peptide-based biosensor of DUB activity that is cell permeable, protease-resilient, fluorescent, and specific to DUBs. The biosensor consists of an N-terminal β-hairpin motif that acts as both a 'protectide' to increase intracellular stability and a cell penetrating peptide (CPP) to facilitate the uptake into intact cells. The β-hairpin was conjugated to a C-terminal substrate consisting of the last four amino acids in ubiquitin (LRGG) to facilitate DUB mediated cleavage of a C-terminal fluorophore (AFC). The kinetics of the peptide reporter were characterized in cell lysates by dose response and inhibition enzymology studies. Inhibition studies with an established DUB inhibitor (PR-619) confirmed the specificity of both reporters to DUBs. Fluorometry and fluorescent microscopy experiments followed by mathematical modeling established the capability of the biosensor to measure DUB activity in intact cells while maintaining cellular integrity. The novel reporter introduced here is compatible with high-throughput single cell analysis platforms such as FACS and droplet microfluidics facilitating direct quantification of DUB activity in single intact cells with direct application in point-of-care cancer diagnostics and drug discovery.
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Affiliation(s)
- Nora Safa
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803
| | - Jacob H Pettigrew
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803
| | - Ted J Gauthier
- LSU AgCenter Biotechnology Lab, Louisiana State University, Baton Rouge, LA, 70803
| | - Adam T Melvin
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA, 70803
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2
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Huang CJ, Lu MY, Chang YW, Li WH. Experimental Evolution of Yeast for High-Temperature Tolerance. Mol Biol Evol 2019; 35:1823-1839. [PMID: 29684163 DOI: 10.1093/molbev/msy077] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Thermotolerance is a polygenic trait that contributes to cell survival and growth under unusually high temperatures. Although some genes associated with high-temperature growth (Htg+) have been identified, how cells accumulate mutations to achieve prolonged thermotolerance is still mysterious. Here, we conducted experimental evolution of a Saccharomyces cerevisiae laboratory strain with stepwise temperature increases for it to grow at 42 °C. Whole genome resequencing of 14 evolved strains and the parental strain revealed a total of 153 mutations in the evolved strains, including single nucleotide variants, small INDELs, and segmental duplication/deletion events. Some mutations persisted from an intermediate temperature to 42 °C, so they might be Htg+ mutations. Functional categorization of mutations revealed enrichment of exonic mutations in the SWI/SNF complex and F-type ATPase, pointing to their involvement in high-temperature tolerance. In addition, multiple mutations were found in a general stress-associated signal transduction network consisting of Hog1 mediated pathway, RAS-cAMP pathway, and Rho1-Pkc1 mediated cell wall integrity pathway, implying that cells can achieve Htg+ partly through modifying existing stress regulatory mechanisms. Using pooled segregant analysis of five Htg+ phenotype-orientated pools, we inferred causative mutations for growth at 42 °C and identified those mutations with stronger impacts on the phenotype. Finally, we experimentally validated a number of the candidate Htg+ mutations. This study increased our understanding of the genetic basis of yeast tolerance to high temperature.
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Affiliation(s)
- Chih-Jen Huang
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan.,Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan
| | - Mei-Yeh Lu
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Ya-Wen Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Wen-Hsiung Li
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, Taiwan.,Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan.,Department of Ecology and Evolution, University of Chicago, Chicago, IL
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3
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Meng Y, Zhang C, Yi J, Zhou Z, Fa Z, Zhao J, Yang Y, Fang W, Wang Y, Liao WQ. Deubiquitinase Ubp5 Is Required for the Growth and Pathogenicity of Cryptococcus gattii. PLoS One 2016; 11:e0153219. [PMID: 27049762 PMCID: PMC4822882 DOI: 10.1371/journal.pone.0153219] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/24/2016] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus gattii is a resurgent fungal pathogen that primarily infects immunocompetent hosts. Thus, it poses an increasingly significant impact on global public health; however, the mechanisms underlying its pathogenesis remain largely unknown. We conducted a detailed characterization of the deubiquitinase Ubp5 in the biology and virulence of C. gattii using the hypervirulent strain R265, and defined its properties as either distinctive or shared with C. neoformans. Deletion of the C. gattii Ubp5 protein by site-directed disruption resulted in a severe growth defect under both normal and stressful conditions (such as high temperature, high salt, cell wall damaging agents, and antifungal agents), similar to the effects observed in C. neoformans. However, unlike C. neoformans, the C. gattii ubp5Δ mutant displayed a slight enhancement of capsule and melanin production, indicating the evolutionary convergence and divergence of Ubp5 between these two sibling species. Attenuated virulence of the Cg-ubp5Δ mutant was not solely due to its reduced thermotolerance at 37°C, as shown in both worm and mouse survival assays. In addition, the assessment of fungal burden in mammalian organs further indicated that Ubp5 was required for C. gattii pulmonary survival and, consequently, extrapulmonary dissemination. Taken together, our work highlights the importance of deubiquitinase Ubp5 in the virulence composite of both pathogenic cryptococcal species, and it facilitates a better understanding of C. gattii virulence mechanisms.
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Affiliation(s)
- Yunfang Meng
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Second Military Medical University, Shanghai, China.,Department of Dermatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Chao Zhang
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Jiu Yi
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Zhaojing Zhou
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Zhenzong Fa
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Jingyu Zhao
- Shanghai Dermatology Hospital, Shanghai, China
| | - Yali Yang
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Wei Fang
- PLA Key Laboratory of Mycosis, Department of Dermatology and Venereology, Changzheng Hospital, Shanghai, China
| | - Yan Wang
- Department of Pharmacology, School of Pharmacy, Second Military Medical University, Shanghai, China
| | - Wan-Qing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, Shanghai Institute of Medical Mycology, Second Military Medical University, Shanghai, China
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4
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Ostapenko D, Burton JL, Solomon MJ. The Ubp15 deubiquitinase promotes timely entry into S phase in Saccharomyces cerevisiae. Mol Biol Cell 2015; 26:2205-16. [PMID: 25877870 PMCID: PMC4462939 DOI: 10.1091/mbc.e14-09-1400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 12/22/2022] Open
Abstract
The anaphase-promoting complex in partnership with its activator, Cdh1, is an E3 ubiquitin ligase responsible for targeting cell cycle proteins during G1 phase. In the budding yeast Saccharomyces cerevisiae, Cdh1 associates with the deubiquitinating enzyme Ubp15, but the significance of this interaction is unclear. To better understand the physiological role(s) of Ubp15, we examined cell cycle phenotypes of cells lacking Ubp15. We found that ubp15∆ cells exhibited delayed progression from G1 into S phase and increased sensitivity to the DNA synthesis inhibitor hydroxyurea. Both phenotypes of ubp15∆ cells were rescued by additional copies of the S-phase cyclin gene CLB5. Clb5 is an unstable protein targeted for proteasome-mediated degradation by several pathways. We found that during G1 phase, the APC(Cdh1)-mediated degradation of Clb5 was accelerated in ubp15∆ cells. Ubp15 interacted with Clb5 independent of Cdh1 and deubiquitinated Clb5 in a reconstituted system. Thus deubiquitination by Ubp15 counteracts APC activity toward cyclin Clb5 to allow Clb5 accumulation and a timely entry into S phase.
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Affiliation(s)
- Denis Ostapenko
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114
| | - Janet L Burton
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114
| | - Mark J Solomon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114
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5
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Sahtoe DD, Sixma TK. Layers of DUB regulation. Trends Biochem Sci 2015; 40:456-67. [PMID: 26073511 DOI: 10.1016/j.tibs.2015.05.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/06/2015] [Accepted: 05/11/2015] [Indexed: 11/15/2022]
Abstract
Proteolytic enzymes, such as (iso-)peptidases, are potentially hazardous for cells. To neutralize their potential danger, tight control of their activities has evolved. Deubiquitylating enzymes (DUBs) are isopeptidases involved in eukaryotic ubiquitylation. They reverse ubiquitin signals by hydrolyzing ubiquitin adducts, giving them control over all aspects of ubiquitin biology. The importance of DUB function is underscored by their frequent deregulation in human disease, making these enzymes potential drug targets. Here, we review the different layers of DUB enzyme regulation. We discuss how post-translational modification (PTM), regulatory domains within DUBs, and incorporation of DUBs into macromolecular complexes contribute to their activity. We conclude that most DUBs are likely to use a combination of these basic regulatory mechanisms.
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Affiliation(s)
- Danny D Sahtoe
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Titia K Sixma
- Division of Biochemistry and Cancer Genomics Center, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
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6
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Fukuoh A, Cannino G, Gerards M, Buckley S, Kazancioglu S, Scialo F, Lihavainen E, Ribeiro A, Dufour E, Jacobs HT. Screen for mitochondrial DNA copy number maintenance genes reveals essential role for ATP synthase. Mol Syst Biol 2014; 10:734. [PMID: 24952591 PMCID: PMC4265055 DOI: 10.15252/msb.20145117] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The machinery of mitochondrial DNA (mtDNA) maintenance is only partially characterized and is of wide interest due to its involvement in disease. To identify novel components of this machinery, plus other cellular pathways required for mtDNA viability, we implemented a genome-wide RNAi screen in Drosophila S2 cells, assaying for loss of fluorescence of mtDNA nucleoids stained with the DNA-intercalating agent PicoGreen. In addition to previously characterized components of the mtDNA replication and transcription machineries, positives included many proteins of the cytosolic proteasome and ribosome (but not the mitoribosome), three proteins involved in vesicle transport, some other factors involved in mitochondrial biogenesis or nuclear gene expression, > 30 mainly uncharacterized proteins and most subunits of ATP synthase (but no other OXPHOS complex). ATP synthase knockdown precipitated a burst of mitochondrial ROS production, followed by copy number depletion involving increased mitochondrial turnover, not dependent on the canonical autophagy machinery. Our findings will inform future studies of the apparatus and regulation of mtDNA maintenance, and the role of mitochondrial bioenergetics and signaling in modulating mtDNA copy number.
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Affiliation(s)
- Atsushi Fukuoh
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland Department of Clinical Chemistry and Laboratory Medicine, Kyushu University Graduate school of Medical Sciences, Fukuoka, Japan Department of Medical Laboratory Science, Junshin Gakuen University, Fukuoka, Japan
| | - Giuseppe Cannino
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Mike Gerards
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Suzanne Buckley
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Selena Kazancioglu
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Filippo Scialo
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Eero Lihavainen
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland
| | - Andre Ribeiro
- Department of Signal Processing, Tampere University of Technology, Tampere, Finland
| | - Eric Dufour
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland
| | - Howard T Jacobs
- BioMediTech and Tampere University Hospital, University of Tampere, Tampere, Finland Research Program of Molecular Neurology, University of Helsinki, Helsinki, Finland
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7
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Bozza WP, Liang Q, Gong P, Zhuang Z. Transient kinetic analysis of USP2-catalyzed deubiquitination reveals a conformational rearrangement in the K48-linked diubiquitin substrate. Biochemistry 2012; 51:10075-86. [PMID: 23211065 DOI: 10.1021/bi3009104] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Deubiquitination has emerged as an essential regulatory mechanism of a number of cellular processes. An in-depth understanding of deubiquitinating enzyme (DUB) catalysis, particularly the mode of ubiquitin binding and the individual steps in the DUB catalytic turnover, is imperative for exploiting DUBs for therapeutic intervention. In this work, we present a transient kinetic study of USP2 in hydrolyzing a model substrate Ub-AMC and a physiological substrate K48-linked diubiquitin. We conducted stopped-flow fluorescence analyses of the binding of mono- and diubiquitin to an inactive USP2 mutant and unveiled interesting differences in the binding kinetics between the two substrates. While a simple one-step binding of monoubiquitin to USP2 was observed, a biphasic binding was evident for diubiquitin. We further followed the deubiquitination reaction of Ub-AMC and K48-linked IQF-diubiquitin by USP2 using stopped-flow florescence under a single-turnover condition. Global fitting of the reaction traces revealed differences in the microscopic rate constants between Ub-AMC and the physiological diubiquitin substrate. Our binding and single-turnover data support a conformational rearrangement of the diubiquitin substrate in USP2-catalyzed deubiquitination. This finding is significant given the recent finding that the K48-linked diubiquitin is dynamic in its conformation. Our results provide useful insights into the mechanism of how USP recognizes ubiquitin moieties in a chain structure, which is important for understanding USP catalysis and developing inhibitors against USPs.
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Affiliation(s)
- William P Bozza
- Department of Chemistry and Biochemistry, 214A Drake Hall, University of Delaware, Newark, DE 19716, USA
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8
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Villamil MA, Liang Q, Chen J, Choi YS, Hou S, Lee KH, Zhuang Z. Serine phosphorylation is critical for the activation of ubiquitin-specific protease 1 and its interaction with WD40-repeat protein UAF1. Biochemistry 2012; 51:9112-23. [PMID: 23116119 DOI: 10.1021/bi300845s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Deubiquitinating enzymes (DUBs) are important for the normal function of a number of cellular processes, including transcriptional regulation, cell cycle control, and DNA damage response. The enzymatic activity of DUB is regulated by different mechanisms. DUBs in several different families are post-translationally modified by phosphorylation. Large-scale phosphoproteomic studies of human DUBs revealed that a majority of ubiquitin-specific proteases (USPs) are phosphorylated. USP1 is a prototypical DUB that requires a specific interaction with a WD40-repeat protein, UAF1, for its catalytic activity. In this study, we show that Ser313 phosphorylation in USP1 is required for its interaction with UAF1 and for the stimulation of USP1's activity. In contrast, two other known USP1 serine phosphorylations (Ser42 and Ser67) are dispensable with respect to the activity of the USP1/UAF1 complex. An S313D phosphomimetic mutation in USP1 can substitute for Ser313 phosphorylation in promoting the formation of the USP1/UAF1 complex. We further demonstrated that CDK1 is responsible for Ser313 phosphorylation, and protein phosphatase treatment of USP1 can lead to inactivation of USP1/UAF1. An inserted domain in USP1 (amino acids 235-408) was found to interact with UAF1, and this interaction is mediated by Ser313 phosphorylation. Our findings revealed an intriguing mechanism of regulating USP1 activity that combines phosphorylation of a key serine residue in USP1 and the specific interaction of USP1 with a WD40-repeat protein UAF1. The pSer313-dependent formation of the USP1/UAF1 complex points to a new approach for inhibiting USP1 activity by disrupting the interaction between the UAF1's WD40-repeat domain and the Ser313-containing phosphopeptide in USP1.
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Affiliation(s)
- Mark A Villamil
- Department of Chemistry and Biochemistry, 214A Drake Hall, University of Delaware, Newark, Delaware 19716, United States
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9
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Fang W, Price MS, Toffaletti DL, Tenor J, Betancourt-Quiroz M, Price JL, Pan WH, Liao WQ, Perfect JR. Pleiotropic effects of deubiquitinating enzyme Ubp5 on growth and pathogenesis of Cryptococcus neoformans. PLoS One 2012; 7:e38326. [PMID: 22719877 PMCID: PMC3375289 DOI: 10.1371/journal.pone.0038326] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 05/03/2012] [Indexed: 12/16/2022] Open
Abstract
Ubiquitination is a reversible protein modification that influences various cellular processes in eukaryotic cells. Deubiquitinating enzymes remove ubiquitin, maintain ubiquitin homeostasis and regulate protein degradation via the ubiquitination pathway. Cryptococcus neoformans is an important basidiomycete pathogen that causes life-threatening meningoencephalitis primarily in the immunocompromised population. In order to understand the possible influence deubiquitinases have on growth and virulence of the model pathogenic yeast Cryptococcus neoformans, we generated deletion mutants of seven putative deubiquitinase genes. Compared to other deubiquitinating enzyme mutants, a ubp5Δ mutant exhibited severely attenuated virulence and many distinct phenotypes, including decreased capsule formation, hypomelanization, defective sporulation, and elevated sensitivity to several external stressors (such as high temperature, oxidative and nitrosative stresses, high salts, and antifungal agents). Ubp5 is likely the major deubiquitinating enzyme for stress responses in C. neoformans, which further delineates the evolutionary divergence of Cryptococcus from the model yeast S. cerevisiae, and provides an important paradigm for understanding the potential role of deubiquitination in virulence by other pathogenic fungi. Other putative deubiquitinase mutants (doa4Δ and ubp13Δ) share some phenotypes with the ubp5Δ mutant, illustrating functional overlap among deubiquitinating enzymes in C. neoformans. Therefore, deubiquitinating enzymes (especially Ubp5) are essential for the virulence composite of C. neoformans and provide an additional yeast survival and propagation advantage in the host.
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Affiliation(s)
- Wei Fang
- Shanghai Key Laboratory of Molecular Medical Mycology, PLA Key Laboratory of Mycosis, Institute of Dermatology and Mycosis of Changzheng Hospital, Second Military Medical University, Shanghai, China
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Michael S. Price
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Dena L. Toffaletti
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jennifer Tenor
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Marisol Betancourt-Quiroz
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jennifer L. Price
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Wei-hua Pan
- Shanghai Key Laboratory of Molecular Medical Mycology, PLA Key Laboratory of Mycosis, Institute of Dermatology and Mycosis of Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Wan-qing Liao
- Shanghai Key Laboratory of Molecular Medical Mycology, PLA Key Laboratory of Mycosis, Institute of Dermatology and Mycosis of Changzheng Hospital, Second Military Medical University, Shanghai, China
- * E-mail: (JRP); (W-QL)
| | - John R. Perfect
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail: (JRP); (W-QL)
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10
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Villamil MA, Chen J, Liang Q, Zhuang Z. A Noncanonical Cysteine Protease USP1 Is Activated through Active Site Modulation by USP1-Associated Factor 1. Biochemistry 2012; 51:2829-39. [DOI: 10.1021/bi3000512] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark A. Villamil
- Department
of Chemistry and Biochemistry, 214A Drake
Hall, University of Delaware, Newark, Delaware
19716, United States
| | - Junjun Chen
- Department
of Chemistry and Biochemistry, 214A Drake
Hall, University of Delaware, Newark, Delaware
19716, United States
| | - Qin Liang
- Department
of Chemistry and Biochemistry, 214A Drake
Hall, University of Delaware, Newark, Delaware
19716, United States
| | - Zhihao Zhuang
- Department
of Chemistry and Biochemistry, 214A Drake
Hall, University of Delaware, Newark, Delaware
19716, United States
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11
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Schaefer JB, Morgan DO. Protein-linked ubiquitin chain structure restricts activity of deubiquitinating enzymes. J Biol Chem 2011; 286:45186-96. [PMID: 22072716 DOI: 10.1074/jbc.m111.310094] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The attachment of lysine 48 (Lys(48))-linked polyubiquitin chains to proteins is a universal signal for degradation by the proteasome. Here, we report that long Lys(48)-linked chains are resistant to many deubiquitinating enzymes (DUBs). Representative enzymes from this group, Ubp15 from yeast and its human ortholog USP7, rapidly remove mono- and diubiquitin from substrates but are slow to remove longer Lys(48)-linked chains. This resistance is lost if the structure of Lys(48)-linked chains is disrupted by mutation of ubiquitin or if chains are linked through Lys(63). In contrast to Ubp15 and USP7, Ubp12 readily cleaves the ends of long chains, regardless of chain structure. We propose that the resistance to many DUBs of long, substrate-attached Lys(48)-linked chains helps ensure that proteins are maintained free from ubiquitin until a threshold of ubiquitin ligase activity enables degradation.
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Affiliation(s)
- Jonathan B Schaefer
- Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA
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