1
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Yarawsky AE, Gough ES, Zai-Rose V, Figueroa NI, Cunningham HM, Burgner JW, DeLion MT, Paul LN. BASIS: BioAnalysis SEDFIT integrated software for cGMP analysis of SV-AUC data. Eur Biophys J 2024; 53:111-121. [PMID: 38329496 DOI: 10.1007/s00249-024-01700-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
Sedimentation velocity analytical ultracentrifugation (SV-AUC) has long been an important method for characterization of antibody therapeutics. Recently, SV-AUC has experienced a wave of new interest and usage from the gene and cell therapy industry, where SV-AUC has proven itself to be the "gold standard" analytical approach for determining capsid loading ratios for adeno-associated virus (AAV) and other viral vectors. While other more common approaches have existed in the realm of cGMP-compliant techniques for years, SV-AUC has long been used strictly for characterization, but not for release testing. This manuscript describes the challenges faced in bringing SV-AUC to a cGMP environment and describes a new program, "BASIS", which allows for 21 CFR Part 11-compliant data handling and data analysis using the well-known and frequently cited SEDFIT analysis software.
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Affiliation(s)
| | - Erik S Gough
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | - Valeria Zai-Rose
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | | | | | - John W Burgner
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | - Michael T DeLion
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | - Lake N Paul
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA.
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2
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Yarawsky AE, Zai-Rose V, Cunningham HM, Burgner JW, DeLion MT, Paul LN. AAV analysis by sedimentation velocity analytical ultracentrifugation: beyond empty and full capsids. Eur Biophys J 2023; 52:353-366. [PMID: 37037926 DOI: 10.1007/s00249-023-01646-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/13/2023] [Accepted: 03/22/2023] [Indexed: 04/12/2023]
Abstract
The recent surge of therapeutic interest in recombinant adeno-associated viral (AAV) vectors for targeted DNA delivery has brought analytical ultracentrifugation (AUC) into the spotlight. A major concern during formulation of AAV therapeutics is purity of the active species (DNA-containing capsid, or "filled capsids"). Insertion of DNA into AAV is not a highly efficient process; thus, a significant amount of empty and partial/intermediate AAV molecules may exist. Recent guidance from the FDA includes limiting the presence of empty AAV capsids and other impurities to reduce immunotoxicity. While chromatographic techniques (SEC, SEC-MALS, AEX) are often used for empty and full capsid quantitation due to the ease of accessibility and familiarity among most biochemists, the resolution and sensitivity attained by sedimentation velocity (SV-AUC) in the formulation buffer and purification buffers is unmatched. Approaches for using SV-AUC to determine the empty-to-full capsid ratio have already been discussed by others; however, in this report, we focus on the importance of characterizing other impurities, such as free DNA, partially filled capsids, and aggregates that are recognized as species of concern for immunotoxicity. We also demonstrate the usefulness of applying multiple analyses (e.g., c(s), g(s*), WDA) in confirming the presence of and determining the hydrodynamic parameters of these various species.
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Affiliation(s)
| | - Valeria Zai-Rose
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | | | - John W Burgner
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, 800 East Leigh Street, Richmond, VA, 23298, USA
| | - Michael T DeLion
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA
| | - Lake N Paul
- BioAnalysis, LLC, 3401 I Street Suite 206, Philadelphia, PA, 19134, USA.
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3
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Ayinuola YA, Tjia-Fleck S, Readnour BM, Liang Z, Ayinuola O, Paul LN, Lee SW, Fischetti VA, Ploplis VA, Castellino FJ. Relationships Between Plasminogen-Binding M-Protein and Surface Enolase for Human Plasminogen Acquisition and Activation in Streptococcus pyogenes. Front Microbiol 2022; 13:905670. [PMID: 35685926 PMCID: PMC9173704 DOI: 10.3389/fmicb.2022.905670] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Accepted: 04/19/2022] [Indexed: 02/03/2023] Open
Abstract
The proteolytic activity of human plasmin (hPm) is utilized by various cells to provide a surface protease that increases the potential of cells to migrate and disseminate. Skin-trophic Pattern D strains of Streptococcus pyogenes (GAS), e.g., GAS isolate AP53, contain a surface M-protein (PAM) that directly and strongly interacts (Kd ~ 1 nM) with human host plasminogen (hPg), after which it is activated to hPm by a specific coinherited bacterial activator, streptokinase (SK2b), or by host activators. Another ubiquitous class of hPg binding proteins on GAS cells includes "moonlighting" proteins, such as the glycolytic enzyme, enolase (Sen). However, the importance of Sen in hPg acquisition, especially when PAM is present, has not been fully developed. Sen forms a complex with hPg on different surfaces, but not in solution. Isogenic AP53 cells with a targeted deletion of PAM do not bind hPg, but the surface expression of Sen is also greatly diminished upon deletion of the PAM gene, thus confounding this approach for defining the role of Sen. However, cells with point deletions in PAM that negate hPg binding, but fully express PAM and Sen, show that hPg binds weakly to Sen on GAS cells. Despite this, Sen does not stimulate hPg activation by SK2b, but does stimulate tissue-type plasminogen activator-catalyzed activation of hPg. These data demonstrate that PAM plays the dominant role as a functional hPg receptor in GAS cells that also contain surface enolase.
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Affiliation(s)
- Yetunde A. Ayinuola
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Sheiny Tjia-Fleck
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States,Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Bradley M. Readnour
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States,Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Zhong Liang
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Olawole Ayinuola
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States
| | - Lake N. Paul
- BioAnalysis, LLC.Philadelphia, PA, United States
| | - Shaun W. Lee
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States
| | - Vincent A. Fischetti
- Laboratory of Bacterial Pathogenesis and Immunology, Rockefeller University, New York, NY, United States
| | - Victoria A. Ploplis
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States,Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
| | - Francis J. Castellino
- W.M. Keck Center for Transgene Research, University of Notre Dame, Notre Dame, IN, United States,Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States,*Correspondence: Francis J. Castellino,
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4
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Chen CL, Paul LN, Mermoud JC, Steussy CN, Stauffacher CV. Visualizing the enzyme mechanism of mevalonate diphosphate decarboxylase. Nat Commun 2020; 11:3969. [PMID: 32769976 PMCID: PMC7414129 DOI: 10.1038/s41467-020-17733-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 06/30/2020] [Indexed: 01/04/2023] Open
Abstract
Mevalonate diphosphate decarboxylases (MDDs) catalyze the ATP-dependent-Mg2+-decarboxylation of mevalonate-5-diphosphate (MVAPP) to produce isopentenyl diphosphate (IPP), which is essential in both eukaryotes and prokaryotes for polyisoprenoid synthesis. The substrates, MVAPP and ATP, have been shown to bind sequentially to MDD. Here we report crystals in which the enzyme remains active, allowing the visualization of conformational changes in Enterococcus faecalis MDD that describe sequential steps in an induced fit enzymatic reaction. Initial binding of MVAPP modulates the ATP binding pocket with a large loop movement. Upon ATP binding, a phosphate binding loop bends over the active site to recognize ATP and bring the molecules to their catalytically favored configuration. Positioned substrates then can chelate two Mg2+ ions for the two steps of the reaction. Closure of the active site entrance brings a conserved lysine to trigger dissociative phosphoryl transfer of γ-phosphate from ATP to MVAPP, followed by the production of IPP. Mevalonate diphosphate decarboxylase (MDD) is a key enzyme in the mevalonate pathway and catalyses the decarboxylation of mevalonate-5-diphosphate to isopentenyl diphosphate. Here, the authors provide insights into the conformational changes that occur during substrate binding of MDD and the subsequent enzymatic reaction steps by determining the substrate and intermediate bound crystal structures of Enterococcus faecalis MDD.
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Affiliation(s)
- Chun-Liang Chen
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Lake N Paul
- BioAnalysis, LLC, 1135 Dunton Street, Unit 2, Philadelphia, PA, 19123, USA.,Biophysical Analysis Laboratory, Bindley Bioscience Center, Purdue University, West Lafayette, IN, 47906, USA
| | - James C Mermoud
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | | | - Cynthia V Stauffacher
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA. .,Purdue University Center for Cancer Research (PUCCR), Purdue University, West Lafayette, IN, 47907, USA.
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5
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Chen CL, Mermoud JC, Paul LN, Steussy CN, Stauffacher CV. Mevalonate 5-diphosphate mediates ATP binding to the mevalonate diphosphate decarboxylase from the bacterial pathogen Enterococcus faecalis. J Biol Chem 2017; 292:21340-21351. [PMID: 29025876 PMCID: PMC5766736 DOI: 10.1074/jbc.m117.802223] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 09/23/2017] [Indexed: 01/07/2023] Open
Abstract
The mevalonate pathway produces isopentenyl diphosphate (IPP), a building block for polyisoprenoid synthesis, and is a crucial pathway for growth of the human bacterial pathogen Enterococcus faecalis The final enzyme in this pathway, mevalonate diphosphate decarboxylase (MDD), acts on mevalonate diphosphate (MVAPP) to produce IPP while consuming ATP. This essential enzyme has been suggested as a therapeutic target for the treatment of drug-resistant bacterial infections. Here, we report functional and structural studies on the mevalonate diphosphate decarboxylase from E. faecalis (MDDEF). The MDDEF crystal structure in complex with ATP (MDDEF-ATP) revealed that the phosphate-binding loop (amino acids 97-105) is not involved in ATP binding and that the phosphate tail of ATP in this structure is in an outward-facing position pointing away from the active site. This suggested that binding of MDDEF to MVAPP is necessary to guide ATP into a catalytically favorable position. Enzymology experiments show that the MDDEF performs a sequential ordered bi-substrate reaction with MVAPP as the first substrate, consistent with the isothermal titration calorimetry (ITC) experiments. On the basis of ITC results, we propose that this initial prerequisite binding of MVAPP enhances ATP binding. In summary, our findings reveal a substrate-induced substrate-binding event that occurs during the MDDEF-catalyzed reaction. The disengagement of the phosphate-binding loop concomitant with the alternative ATP-binding configuration may provide the structural basis for antimicrobial design against these pathogenic enterococci.
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Affiliation(s)
| | | | - Lake N. Paul
- the Biophysical Analysis Laboratory, Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47906
| | | | - Cynthia V. Stauffacher
- From the Department of Biological Sciences and ,Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907 and , To whom correspondence should be addressed:
Dept. of Biological Sciences, Purdue University, Hockmeyer Hall, Rm. 327, 240 South Martin Jischke Dr., West Lafayette, IN 47907. Tel.:
765-494-4937; Fax:
765-496-1189; E-mail:
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6
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Bueno AN, Shrestha RK, Ronau JA, Babar A, Sheedlo MJ, Fuchs JE, Paul LN, Das C. Dynamics of an Active-Site Flap Contributes to Catalysis in a JAMM Family Metallo Deubiquitinase. Biochemistry 2016; 54:6038-51. [PMID: 26368668 DOI: 10.1021/acs.biochem.5b00631] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endosome-associated deubiquitinase (DUB) AMSH is a member of the JAMM family of zinc-dependent metallo isopeptidases with high selectivity for Lys63-linked polyubiquitin chains, which play a key role in endosomal-lysosomal sorting of activated cell surface receptors. The catalytic domain of the enzyme features a flexible flap near the active site that opens and closes during its catalytic cycle. Structural analysis of its homologues, AMSH-LP (AMSH-like protein) and the fission yeast counterpart, Sst2, suggests that a conserved Phe residue in the flap may be critical for substrate binding and/or catalysis. To gain insight into the contribution of this flap in substrate recognition and catalysis, we generated mutants of Sst2 and characterized them using a combination of enzyme kinetics, X-ray crystallography, molecular dynamics simulations, and isothermal titration calorimetry (ITC). Our analysis shows that the Phe residue in the flap contributes key interactions during the rate-limiting step but not to substrate binding, since mutants of Phe403 exhibit a defect only in kcat but not in KM. Moreover, ITC studies show Phe403 mutants have similar KD for ubiquitin compared to the wild-type enzyme. The X-ray structures of both Phe403Ala and the Phe403Trp, in both the free and ubiquitin bound form, reveal no appreciable structural change that might impair substrate or alter product binding. We observed that the side chain of the Trp residue is oriented identically with respect to the isopeptide moiety of the substrate as the Phe residue in the wild-type enzyme, so the loss of activity seen in this mutant cannot be explained by the absence of a group with the ability to provide van der Waals interactions that facilitate the hyrdolysis of the Lys63-linked diubiquitin. Molecular dynamics simulations indicate that the flap in the Trp mutant is quite flexible, allowing almost free rotation of the indole side chain. Therefore, it is possible that these different dynamic properties of the flap in the Trp mutant, compared to the wild-type enzyme, manifest as a defect in interactions that facilitate the rate-limiting step. Consistent with this notion, the Trp mutant was able to cleave Lys48-linked and Lys11-linked diubiquitin better than the wild-type enzyme, indicating altered mobility and hence reduced selectivity.
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Affiliation(s)
- Amy N Bueno
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Rashmi K Shrestha
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Judith A Ronau
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Aditya Babar
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Michael J Sheedlo
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Julian E Fuchs
- Centre for Molecular Informatics, Department of Chemistry, University of Cambridge , Cambridge CB2 1EW, United Kingdom
| | - Lake N Paul
- Bindley Biosciences Center, Purdue University , West Lafayette, Indiana 47907, United States
| | - Chittaranjan Das
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
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7
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Narayanan A, Kumar S, Evrard AN, Paul LN, Yernool DA. An asymmetric heterodomain interface stabilizes a response regulator-DNA complex. Nat Commun 2015; 5:3282. [PMID: 24526190 DOI: 10.1038/ncomms4282] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 01/18/2014] [Indexed: 01/08/2023] Open
Abstract
Two-component signal transduction systems consist of pairs of histidine kinases and response regulators, which mediate adaptive responses to environmental cues. Most activated response regulators regulate transcription by binding tightly to promoter DNA via a phosphorylation-triggered inactive-to-active transition. The molecular basis for formation of stable response regulator-DNA complexes that precede the assembly of RNA polymerases is unclear. Here, we present structures of DNA complexed with the response regulator KdpE, a member of the OmpR/PhoB family. The distinctively asymmetric complex in an active-like conformation reveals a unique intramolecular interface between the receiver domain (RD) and the DNA-binding domain (DBD) of only one of the two response regulators in the complex. Structure-function studies show that this RD-DBD interface is necessary to form stable complexes that support gene expression. The conservation of sequence and structure suggests that these findings extend to a large group of response regulators that act as transcription factors.
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Affiliation(s)
- Anoop Narayanan
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2]
| | - Shivesh Kumar
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2] [3]
| | - Amanda N Evrard
- Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA
| | - Lake N Paul
- Bindley Bioscience Center, Purdue University, 1203 West State Street, West Lafayette, Indiana 47907, USA
| | - Dinesh A Yernool
- 1] Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, Indiana 47907, USA [2] Bindley Bioscience Center, Purdue University, 1203 West State Street, West Lafayette, Indiana 47907, USA
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8
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Affiliation(s)
- Victoria E. Hedrick
- Bindley Bioscience Center, Purdue Proteomics Facility, Purdue University; West Lafayette Indiana
| | - Mercedes N. LaLand
- Bindley Bioscience Center, Purdue Proteomics Facility, Purdue University; West Lafayette Indiana
| | - Ernesto S. Nakayasu
- Bindley Bioscience Center, Purdue Proteomics Facility, Purdue University; West Lafayette Indiana
| | - Lake N. Paul
- Bindley Bioscience Center, Purdue Proteomics Facility, Purdue University; West Lafayette Indiana
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9
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Tsai CJ, Aslam K, Drendel HM, Asiago JM, Goode KM, Paul LN, Rochet JC, Hazbun TR. Hsp31 Is a Stress Response Chaperone That Intervenes in the Protein Misfolding Process. J Biol Chem 2015; 290:24816-34. [PMID: 26306045 DOI: 10.1074/jbc.m115.678367] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Indexed: 12/17/2022] Open
Abstract
The Saccharomyces cerevisiae heat shock protein Hsp31 is a stress-inducible homodimeric protein that is involved in diauxic shift reprogramming and has glyoxalase activity. We show that substoichiometric concentrations of Hsp31 can abrogate aggregation of a broad array of substrates in vitro. Hsp31 also modulates the aggregation of α-synuclein (αSyn), a target of the chaperone activity of human DJ-1, an Hsp31 homolog. We demonstrate that Hsp31 is able to suppress the in vitro fibrillization or aggregation of αSyn, citrate synthase and insulin. Chaperone activity was also observed in vivo because constitutive overexpression of Hsp31 reduced the incidence of αSyn cytoplasmic foci, and yeast cells were rescued from αSyn-generated proteotoxicity upon Hsp31 overexpression. Moreover, we showed that Hsp31 protein levels are increased by H2O2, in the diauxic phase of normal growth conditions, and in cells under αSyn-mediated proteotoxic stress. We show that Hsp31 chaperone activity and not the methylglyoxalase activity or the autophagy pathway drives the protective effects. We also demonstrate reduced aggregation of the Sup35 prion domain, PrD-Sup35, as visualized by fluorescent protein fusions. In addition, Hsp31 acts on its substrates prior to the formation of large aggregates because Hsp31 does not mutually localize with prion aggregates, and it prevents the formation of detectable in vitro αSyn fibrils. These studies establish that the protective role of Hsp31 against cellular stress is achieved by chaperone activity that intervenes early in the protein misfolding process and is effective on a wide spectrum of substrate proteins, including αSyn and prion proteins.
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Affiliation(s)
- Chai-Jui Tsai
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Kiran Aslam
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Holli M Drendel
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Josephat M Asiago
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Kourtney M Goode
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Lake N Paul
- the Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907
| | - Jean-Christophe Rochet
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
| | - Tony R Hazbun
- From the Department of Medicinal Chemistry and Molecular Pharmacology and Purdue University Center for Cancer Research and
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10
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Li YH, Luo J, Mosley YYC, Hedrick VE, Paul LN, Chang J, Zhang G, Wang YK, Banko MR, Brunet A, Kuang S, Wu JL, Chang CJ, Scott MP, Yang JY. AMP-Activated Protein Kinase Directly Phosphorylates and Destabilizes Hedgehog Pathway Transcription Factor GLI1 in Medulloblastoma. Cell Rep 2015; 12:599-609. [PMID: 26190112 DOI: 10.1016/j.celrep.2015.06.054] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/11/2015] [Accepted: 06/15/2015] [Indexed: 12/25/2022] Open
Abstract
The Hedgehog (Hh) pathway regulates cell differentiation and proliferation during development by controlling the Gli transcription factors. Cell fate decisions and progression toward organ and tissue maturity must be coordinated, and how an energy sensor regulates the Hh pathway is not clear. AMP-activated protein kinase (AMPK) is an important sensor of energy stores and controls protein synthesis and other energy-intensive processes. AMPK is directly responsive to intracellular AMP levels, inhibiting a wide range of cell activities if ATP is low and AMP is high. Thus, AMPK can affect development by influencing protein synthesis and other processes needed for growth and differentiation. Activation of AMPK reduces GLI1 protein levels and stability, thus blocking Sonic-hedgehog-induced transcriptional activity. AMPK phosphorylates GLI1 at serines 102 and 408 and threonine 1074. Mutation of these three sites into alanine prevents phosphorylation by AMPK. This leads to increased GLI1 protein stability, transcriptional activity, and oncogenic potency.
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Affiliation(s)
- Yen-Hsing Li
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Jia Luo
- Departments of Developmental Biology, Genetics, and Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yung-Yi C Mosley
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Victoria E Hedrick
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47906, USA
| | - Lake N Paul
- Bindley Bioscience Center, Purdue University, West Lafayette, IN 47906, USA
| | - Julia Chang
- Departments of Developmental Biology, Genetics, and Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - GuangJun Zhang
- Center for Cancer Research, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA; Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Yu-Kuo Wang
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu 300, Taiwan
| | - Max R Banko
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anne Brunet
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shihuan Kuang
- Center for Cancer Research, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA; Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Jen-Leih Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 115 Taiwan
| | - Chun-Ju Chang
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA; Center for Cancer Research, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA
| | - Matthew P Scott
- Departments of Developmental Biology, Genetics, and Bioengineering, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jer-Yen Yang
- Department of Basic Medical Sciences, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA; Center for Cancer Research, Purdue University College of Veterinary Medicine, West Lafayette, IN 47907, USA.
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11
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Tomar S, Johnston ML, St John SE, Osswald HL, Nyalapatla PR, Paul LN, Ghosh AK, Denison MR, Mesecar AD. Ligand-induced Dimerization of Middle East Respiratory Syndrome (MERS) Coronavirus nsp5 Protease (3CLpro): IMPLICATIONS FOR nsp5 REGULATION AND THE DEVELOPMENT OF ANTIVIRALS. J Biol Chem 2015; 290:19403-22. [PMID: 26055715 PMCID: PMC4528106 DOI: 10.1074/jbc.m115.651463] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Indexed: 12/20/2022] Open
Abstract
All coronaviruses, including the recently emerged Middle East respiratory
syndrome coronavirus (MERS-CoV) from the β-CoV subgroup, require the
proteolytic activity of the nsp5 protease (also known as 3C-like protease,
3CLpro) during virus replication, making it a high value target
for the development of anti-coronavirus therapeutics. Kinetic studies indicate
that in contrast to 3CLpro from other β-CoV 2c members,
including HKU4 and HKU5, MERS-CoV 3CLpro is less efficient at
processing a peptide substrate due to MERS-CoV 3CLpro being a weakly
associated dimer. Conversely, HKU4, HKU5, and SARS-CoV 3CLpro enzymes
are tightly associated dimers. Analytical ultracentrifugation studies support
that MERS-CoV 3CLpro is a weakly associated dimer
(Kd ∼52 μm) with a
slow off-rate. Peptidomimetic inhibitors of MERS-CoV 3CLpro were
synthesized and utilized in analytical ultracentrifugation experiments and
demonstrate that MERS-CoV 3CLpro undergoes significant ligand-induced
dimerization. Kinetic studies also revealed that designed reversible inhibitors
act as activators at a low compound concentration as a result of induced
dimerization. Primary sequence comparisons and x-ray structural analyses of two
MERS-CoV 3CLpro and inhibitor complexes, determined to 1.6 Å, reveal
remarkable structural similarity of the dimer interface with 3CLpro
from HKU4-CoV and HKU5-CoV. Despite this structural similarity, substantial
differences in the dimerization ability suggest that long range interactions by
the nonconserved amino acids distant from the dimer interface may control
MERS-CoV 3CLpro dimerization. Activation of MERS-CoV
3CLpro through ligand-induced dimerization appears to be unique
within the genogroup 2c and may potentially increase the complexity in the
development of MERS-CoV 3CLpro inhibitors as antiviral agents.
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Affiliation(s)
| | | | | | | | | | - Lake N Paul
- the Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, and
| | - Arun K Ghosh
- Chemistry, Purdue University, West Lafayette, Indiana 47907
| | - Mark R Denison
- the Departments of Pediatrics and Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Andrew D Mesecar
- From the Departments of Biological Sciences and Chemistry, Purdue University, West Lafayette, Indiana 47907,
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12
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D’Aquila T, Sirohi D, Grabowski JM, Hedrick VE, Paul LN, Greenberg AS, Kuhn RJ, Buhman KK. Characterization of the proteome of cytoplasmic lipid droplets in mouse enterocytes after a dietary fat challenge. PLoS One 2015; 10:e0126823. [PMID: 25992653 PMCID: PMC4436333 DOI: 10.1371/journal.pone.0126823] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 04/08/2015] [Indexed: 01/23/2023] Open
Abstract
Dietary fat absorption by the small intestine is a multistep process that regulates the uptake and delivery of essential nutrients and energy. One step of this process is the temporary storage of dietary fat in cytoplasmic lipid droplets (CLDs). The storage and mobilization of dietary fat is thought to be regulated by proteins that associate with the CLD; however, mechanistic details of this process are currently unknown. In this study we analyzed the proteome of CLDs isolated from enterocytes harvested from the small intestine of mice following a dietary fat challenge. In this analysis we identified 181 proteins associated with the CLD fraction, of which 37 are associated with known lipid related metabolic pathways. We confirmed the localization of several of these proteins on or around the CLD through confocal and electron microscopy, including perilipin 3, apolipoprotein A-IV, and acyl-CoA synthetase long-chain family member 5. The identification of the enterocyte CLD proteome provides new insight into potential regulators of CLD metabolism and the process of dietary fat absorption.
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Affiliation(s)
- Theresa D’Aquila
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Devika Sirohi
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America
| | - Jeffrey M. Grabowski
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
| | - Victoria E. Hedrick
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America
| | - Lake N. Paul
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America
| | - Andrew S. Greenberg
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, United States of America
| | - Richard J. Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana, United States of America
| | - Kimberly K. Buhman
- Department of Nutrition Science, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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13
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Ronau J, Paul LN, Fuchs JE, Liedl K, Abu-Omar MM, Das C. A conserved acidic residue in phenylalanine hydroxylase contributes to cofactor affinity and catalysis. Biochemistry 2014; 53:6834-48. [PMID: 25295853 PMCID: PMC4222540 DOI: 10.1021/bi500734h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/22/2014] [Indexed: 01/19/2023]
Abstract
The catalytic domains of aromatic amino acid hydroxylases (AAAHs) contain a non-heme iron coordinated to a 2-His-1-carboxylate facial triad and two water molecules. Asp139 from Chromobacterium violaceum PAH (cPAH) resides within the second coordination sphere and contributes key hydrogen bonds with three active site waters that mediate its interaction with an oxidized form of the cofactor, 7,8-dihydro-l-biopterin, in crystal structures. To determine the catalytic role of this residue, various point mutants were prepared and characterized. Our isothermal titration calorimetry (ITC) analysis of iron binding implies that polarity at position 139 is not the sole criterion for metal affinity, as binding studies with D139E suggest that the size of the amino acid side chain also appears to be important. High-resolution crystal structures of the mutants reveal that Asp139 may not be essential for holding the bridging water molecules together, because many of these waters are retained even in the Ala mutant. However, interactions via the bridging waters contribute to cofactor binding at the active site, interactions for which charge of the residue is important, as the D139N mutant shows a 5-fold decrease in its affinity for pterin as revealed by ITC (compared to a 16-fold loss of affinity in the case of the Ala mutant). The Asn and Ala mutants show a much more pronounced defect in their kcat values, with nearly 16- and 100-fold changes relative to that of the wild type, respectively, indicating a substantial role of this residue in stabilization of the transition state by aligning the cofactor in a productive orientation, most likely through direct binding with the cofactor, supported by data from molecular dynamics simulations of the complexes. Our results indicate that the intervening water structure between the cofactor and the acidic residue masks direct interaction between the two, possibly to prevent uncoupled hydroxylation of the cofactor before the arrival of phenylalanine. It thus appears that the second-coordination sphere Asp residue in cPAH, and, by extrapolation, the equivalent residue in other AAAHs, plays a role in fine-tuning pterin affinity in the ground state via deformable interactions with bridging waters and assumes a more significant role in the transition state by aligning the cofactor through direct hydrogen bonding.
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Affiliation(s)
- Judith
A. Ronau
- Department
of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
- Department
of Molecular Biophysics and Biochemistry, Yale University, 266
Whitney Avenue, New Haven, Connecticut 06520, United States
| | - Lake N. Paul
- Bindley
Biosciences Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Julian E. Fuchs
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences Innsbruck (CMBI), University
of Innsbruck, Innrain
80/82, 6020 Innsbruck, Austria
- Centre
for Molecular Informatics, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Klaus
R. Liedl
- Institute
of General, Inorganic and Theoretical Chemistry and Center for Molecular
Biosciences Innsbruck (CMBI), University
of Innsbruck, Innrain
80/82, 6020 Innsbruck, Austria
| | - Mahdi M. Abu-Omar
- Department
of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Chittaranjan Das
- Department
of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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14
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Abstract
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The X-ray structure of benzoylformate
decarboxylase (BFDC) from Pseudomonas putida ATCC
12633 shows it to be a tetramer.
This was believed to be typical of all thiamin diphosphate-dependent
decarboxylases until recently when the structure of KdcA, a branched-chain
2-keto acid decarboxylase from Lactococcus lactis, showed it to be a homodimer. This lent credence to earlier unfolding
experiments on pyruvate decarboxylase from Saccharomyces cerevisiae that indicated that it might be active as a dimer. To investigate
this possibility in BFDC, we sought to shift the equilibrium toward
dimer formation. Point mutations were made in the noncatalytic monomer–monomer
interfaces, but these had a minimal effect on both tetramer formation
and catalytic activity. Subsequently, the R141E/Y288A/A306F variant
was shown by analytical ultracentrifugation to be partially dimeric.
It was also found to be catalytically inactive. Further experiments
revealed that just two mutations, R141E and A306F, were sufficient
to markedly alter the dimer–tetramer equilibrium and to provide
an ∼450-fold decrease in kcat.
Equilibrium denaturation studies suggested that the residual activity
was possibly due to the presence of residual tetramer. The structures
of the R141E and A306F variants, determined to <1.5 Å resolution,
hinted that disruption of the monomer interfaces will be accompanied
by movement of a loop containing Leu109 and Leu110. As these residues
contribute to the hydrophobicity of the active site and the correct
positioning of the substrate, it seems that tetramer formation may
well be critical to the catalytic activity of BFDC.
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Affiliation(s)
- Forest H Andrews
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana 46202, United States
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15
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Olek AT, Rayon C, Makowski L, Kim HR, Ciesielski P, Badger J, Paul LN, Ghosh S, Kihara D, Crowley M, Himmel ME, Bolin JT, Carpita NC. The structure of the catalytic domain of a plant cellulose synthase and its assembly into dimers. Plant Cell 2014; 26:2996-3009. [PMID: 25012190 PMCID: PMC4145127 DOI: 10.1105/tpc.114.126862] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 06/08/2014] [Accepted: 06/17/2014] [Indexed: 05/03/2023]
Abstract
Cellulose microfibrils are para-crystalline arrays of several dozen linear (1→4)-β-d-glucan chains synthesized at the surface of the cell membrane by large, multimeric complexes of synthase proteins. Recombinant catalytic domains of rice (Oryza sativa) CesA8 cellulose synthase form dimers reversibly as the fundamental scaffold units of architecture in the synthase complex. Specificity of binding to UDP and UDP-Glc indicates a properly folded protein, and binding kinetics indicate that each monomer independently synthesizes single glucan chains of cellulose, i.e., two chains per dimer pair. In contrast to structure modeling predictions, solution x-ray scattering studies demonstrate that the monomer is a two-domain, elongated structure, with the smaller domain coupling two monomers into a dimer. The catalytic core of the monomer is accommodated only near its center, with the plant-specific sequences occupying the small domain and an extension distal to the catalytic domain. This configuration is in stark contrast to the domain organization obtained in predicted structures of plant CesA. The arrangement of the catalytic domain within the CesA monomer and dimer provides a foundation for constructing structural models of the synthase complex and defining the relationship between the rosette structure and the cellulose microfibrils they synthesize.
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Affiliation(s)
- Anna T Olek
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054
| | - Catherine Rayon
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054
| | - Lee Makowski
- Department of Bioengineering, Northeastern University, Boston, Massachusetts 02115 Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115
| | - Hyung Rae Kim
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971
| | - Peter Ciesielski
- National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305
| | - John Badger
- DeltaG Technologies, San Diego, California 92122
| | - Lake N Paul
- Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2057
| | - Subhangi Ghosh
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971
| | - Daisuke Kihara
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971 Department of Computer Science, Purdue University, West Lafayette, Indiana 47907-2107
| | - Michael Crowley
- National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305
| | - Michael E Himmel
- National Renewable Energy Laboratory, Biomolecular Science Group, Golden, Colorado 80401-3305
| | - Jeffrey T Bolin
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971
| | - Nicholas C Carpita
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054 Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1971 Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907-2057
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16
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Shrestha RK, Ronau JA, Davies CW, Guenette RG, Strieter ER, Paul LN, Das C. Insights into the mechanism of deubiquitination by JAMM deubiquitinases from cocrystal structures of the enzyme with the substrate and product. Biochemistry 2014; 53:3199-217. [PMID: 24787148 PMCID: PMC4033627 DOI: 10.1021/bi5003162] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
AMSH, a conserved zinc metallo deubiquitinase,
controls downregulation
and degradation of cell-surface receptors mediated by the endosomal
sorting complexes required for transport (ESCRT) machinery. It displays
high specificity toward the Lys63-linked polyubiquitin chain, which
is used as a signal for ESCRT-mediated endosomal–lysosomal
sorting of receptors. Herein, we report the crystal structures of
the catalytic domain of AMSH orthologue Sst2 from fission yeast, its
ubiquitin (product)-bound form, and its Lys63-linked diubiquitin (substrate)-bound
form at 1.45, 1.7, and 2.3 Å, respectively. The structures reveal
that the P-side product fragment maintains nearly all the contacts
with the enzyme as seen with the P portion (distal ubiquitin) of the
Lys63-linked diubiquitin substrate, with additional coordination of
the Gly76 carboxylate group of the product with the active-site Zn2+. One of the product-bound structures described herein is
the result of an attempt to cocrystallize the diubiquitin substrate
bound to an active site mutant presumed to render the enzyme inactive,
instead yielding a cocrystal structure of the enzyme bound to the
P-side ubiquitin fragment of the substrate (distal ubiquitin). This
fragment was generated in situ from the residual
activity of the mutant enzyme. In this structure, the catalytic water
is seen placed between the active-site Zn2+ and the carboxylate
group of Gly76 of ubiquitin, providing what appears to be a snapshot
of the active site when the product is about to depart. Comparison
of this structure with that of the substrate-bound form suggests the
importance of dynamics of a flexible flap near the active site in
catalysis. The crystal structure of the Thr319Ile mutant of the catalytic
domain of Sst2 provides insight into structural basis of microcephaly
capillary malformation syndrome. Isothermal titration calorimetry
yields a dissociation constant (KD) of
10.2 ± 0.6 μM for the binding of ubiquitin to the enzyme,
a value comparable to the KM of the enzyme
catalyzing hydrolysis of the Lys63-linked diubiquitin substrate (∼20
μM). These results, together with the previously reported observation
that the intracellular concentration of free ubiquitin (∼20
μM) exceeds that of Lys63-linked polyubiquitin chains, imply
that the free, cytosolic form of the enzyme remains inhibited by being
tightly bound to free ubiquitin. We propose that when AMSH associates
with endosomes, inhibition would be relieved because of ubiquitin
binding domains present on its endosomal binding partners that would
shift the balance toward better recognition of polyubiquitin chains
via the avidity effect.
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Affiliation(s)
- Rashmi K Shrestha
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47907, United States
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17
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Phoon PY, Paul LN, Burgner JW, San Martin-Gonzalez MF, Narsimhan G. Effect of cross-linking of interfacial sodium caseinate by natural processing on the oxidative stability of oil-in-water (o/w) emulsions. J Agric Food Chem 2014; 62:2822-2829. [PMID: 24606400 DOI: 10.1021/jf403285z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This study investigated how enzymatic cross-linking of interfacial sodium caseinate and emulsification, via high-pressure homogenization, influenced the intrinsic oxidative stability of 4% (w/v) menhaden oil-in-water emulsions stabilized by 1% (w/v) caseinate at pH 7. Oil oxidation was monitored by the ferric thiocyanate perioxide value assay. Higher homogenization pressure resulted in improved intrinsic emulsion oxidative stability, which is attributed to increased interfacial cross-linking as indicated by higher weighted average sedimentation coefficients of interfacial protein species (from 11.2 S for 0 kpsi/0.1 MPa to 18 S for 20 kpsi/137.9 MPa). Moderate dosage of transglutaminase at 0.5-1.0 U/mL emulsion enhanced intrinsic emulsion oxidative stability further, despite a contradictory reduction in the antioxidant property of cross-linked caseinate as tested by the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. This implied the prominent role of cross-linked interfacial caseinate as a physical barrier for oxygen transfer, hence its efficacy in retarding oil oxidation.
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Affiliation(s)
- Pui Yeu Phoon
- Department of Food Science, 745 Agricultural Mall Drive, Purdue University , West Lafayette, Indiana 47907, United States
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18
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Abstract
AMSH, a deubiquitinating enzyme (DUB) with exquisite specificity for Lys63-linked polyubiquitin chains, is an endosome-associated DUB that regulates sorting of activated cell-surface signaling receptors to the lysosome, a process mediated by the members of the endosomal sorting complexes required for transport (ESCRT) machinery. Whole-exome sequencing of DNA samples from children with microcephaly capillary malformation (MIC-CAP) syndrome identified recessive mutations encoded in the AMSH gene causatively linked to the disease. Herein, we report a number of important observations that significantly advance our understanding of AMSH within the context of the ESCRT machinery. First, we performed mutational and kinetic analysis of the putative residues involved in diubiquitin recognition and catalysis with a view of better understanding the catalytic mechanism of AMSH. Our mutational and kinetic analysis reveals that recognition of the proximal ubiquitin is imperative for the linkage specificity and catalytic efficiency of the enzyme. The MIC-CAP disease mutation, Thr313Ile, yields a substantial loss of catalytic activity without any significant change in the thermodynamic stability of the protein, indicating that its perturbed catalytic activity is the basis of the disease. The catalytic activity of AMSH is stimulated upon binding to the ESCRT-0 member STAM; however, the precise mechanism and its significance are not known. On the basis of a number of biochemical and biophysical analyses, we are able to propose a model for activation according to which activation of AMSH is allowed by facile, simultaneous binding to two ubiquitin groups in a polyubiquitin substrate, one by the catalytic domain of the DUB (binding to the distal ubiquitin) and the other (the proximal ubiquitin) by the ubiquitin interacting motif (UIM) from STAM. Such a mode of binding would stabilize the ubiquitin chain in a productive orientation, resulting in an enhancement of the activity of the enzyme. These data together provide a mechanism for understanding the recruitment and activation of AMSH at ESCRT-0, providing biochemical and biophysical evidence that supports a role for AMSH when it is recruited to the initial ESCRT complex: it functions to facilitate the transfer of ubiquitinated receptors (cargo) from one ESCRT member to the next by disassembling the polyubiquitin chain while leaving some ubiquitin groups still attached to the cargo.
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Affiliation(s)
- Christopher W Davies
- Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States
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19
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Ronau JA, Paul LN, Fuchs JE, Corn IR, Wagner KT, Liedl KR, Abu-Omar MM, Das C. An additional substrate binding site in a bacterial phenylalanine hydroxylase. Eur Biophys J 2013; 42:691-708. [PMID: 23860686 PMCID: PMC3972754 DOI: 10.1007/s00249-013-0919-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/20/2013] [Accepted: 06/26/2013] [Indexed: 01/07/2023]
Abstract
Phenylalanine hydroxylase (PAH) is a non-heme iron enzyme that catalyzes oxidation of phenylalanine to tyrosine, a reaction that must be kept under tight regulatory control. Mammalian PAH has a regulatory domain in which binding of the substrate leads to allosteric activation of the enzyme. However, the existence of PAH regulation in evolutionarily distant organisms, for example some bacteria in which it occurs, has so far been underappreciated. In an attempt to crystallographically characterize substrate binding by PAH from Chromobacterium violaceum, a single-domain monomeric enzyme, electron density for phenylalanine was observed at a distal site 15.7 Å from the active site. Isothermal titration calorimetry (ITC) experiments revealed a dissociation constant of 24 ± 1.1 μM for phenylalanine. Under the same conditions, ITC revealed no detectable binding for alanine, tyrosine, or isoleucine, indicating the distal site may be selective for phenylalanine. Point mutations of amino acid residues in the distal site that contact phenylalanine (F258A, Y155A, T254A) led to impaired binding, consistent with the presence of distal site binding in solution. Although kinetic analysis revealed that the distal site mutants suffer discernible loss of their catalytic activity, X-ray crystallographic analysis of Y155A and F258A, the two mutants with the most noticeable decrease in activity, revealed no discernible change in the structure of their active sites, suggesting that the effect of distal binding may result from protein dynamics in solution.
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Affiliation(s)
- Judith A. Ronau
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Lake N. Paul
- Bindley Biosciences Center, Purdue University, West Lafayette, IN 47907, USA
| | - Julian E. Fuchs
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Isaac R. Corn
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Kyle T. Wagner
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Klaus R. Liedl
- Institute of General, Inorganic and Theoretical Chemistry, and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80/82, A-6020 Innsbruck, Austria
| | - Mahdi M. Abu-Omar
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA
| | - Chittaranjan Das
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN-47907, USA,To whom correspondence should be addressed: Chittaranjan Das, Brown Laboratory of Chemistry, 560 Oval Drive, West Lafayette, IN, 47907, (765)-494-5478, Fax: (765)-494-0239,
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20
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Morrow ME, Kim MI, Ronau JA, Sheedlo MJ, White RR, Chaney J, Paul LN, Lill MA, Artavanis-Tsakonas K, Das C. Stabilization of an unusual salt bridge in ubiquitin by the extra C-terminal domain of the proteasome-associated deubiquitinase UCH37 as a mechanism of its exo specificity. Biochemistry 2013; 52:3564-78. [PMID: 23617878 PMCID: PMC3898853 DOI: 10.1021/bi4003106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ubiquitination is countered by a group of enzymes collectively called deubiquitinases (DUBs); ∼100 of them can be found in the human genome. One of the most interesting aspects of these enzymes is the ability of some members to selectively recognize specific linkage types between ubiquitin in polyubiquitin chains and their endo and exo specificity. The structural basis of exo-specific deubiquitination catalyzed by a DUB is poorly understood. UCH37, a cysteine DUB conserved from fungi to humans, is a proteasome-associated factor that regulates the proteasome by sequentially cleaving polyubiquitin chains from their distal ends, i.e., by exo-specific deubiquitination. In addition to the catalytic domain, the DUB features a functionally uncharacterized UCH37-like domain (ULD), presumed to keep the enzyme in an inhibited state in its proteasome-free form. Herein we report the crystal structure of two constructs of UCH37 from Trichinella spiralis in complex with a ubiquitin-based suicide inhibitor, ubiquitin vinyl methyl ester (UbVME). These structures show that the ULD makes direct contact with ubiquitin stabilizing a highly unusual intramolecular salt bridge between Lys48 and Glu51 of ubiquitin, an interaction that would be favored only with the distal ubiquitin but not with the internal ones in a Lys48-linked polyubiquitin chain. An inspection of 39 DUB-ubiquitin structures in the Protein Data Bank reveals the uniqueness of the salt bridge in ubiquitin bound to UCH37, an interaction that disappears when the ULD is deleted, as revealed in the structure of the catalytic domain alone bound to UbVME. The structural data are consistent with previously reported mutational data on the mammalian enzyme, which, together with the fact that the ULD residues that bind to ubiquitin are conserved, points to a similar mechanism behind the exo specificity of the human enzyme. To the best of our knowledge, these data provide the only structural example so far of how the exo specificity of a DUB can be determined by its noncatalytic domain. Thus, our data show that, contrary to its proposed inhibitory role, the ULD actually contributes to substrate recognition and could be a major determinant of the proteasome-associated function of UCH37. Moreover, our structures show that the unproductively oriented catalytic cysteine in the free enzyme is aligned correctly when ubiquitin binds, suggesting a mechanism for ubiquitin selectivity.
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Affiliation(s)
- Marie E. Morrow
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Myung-Il Kim
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Judith A. Ronau
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Michael J. Sheedlo
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Rhiannon R. White
- Division of Cell and Molecular Biology, Imperial College London, Sir Alexander Fleming Bldg, Imperial College Road, London, SW7 2AZ, UK
| | - Joseph Chaney
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA
| | - Lake N. Paul
- Bindley Biosciences Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Markus A. Lill
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907, USA
| | - Katerina Artavanis-Tsakonas
- Division of Cell and Molecular Biology, Imperial College London, Sir Alexander Fleming Bldg, Imperial College Road, London, SW7 2AZ, UK
| | - Chittaranjan Das
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907, USA,To whom correspondence should be addressed: Chittaranjan Das, Brown Laboratory of Chemistry, 560 Oval Drive, West Lafayette, IN, 47907, (765)-494-5478, Fax: (765)-494-0239,
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21
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Collins CJ, McCauliff LA, Hyun SH, Zhang Z, Paul LN, Kulkarni A, Zick K, Wirth M, Storch J, Thompson DH. Synthesis, characterization, and evaluation of pluronic-based β-cyclodextrin polyrotaxanes for mobilization of accumulated cholesterol from Niemann-Pick type C fibroblasts. Biochemistry 2013; 52:3242-53. [PMID: 23560535 DOI: 10.1021/bi3010889] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several lines of evidence suggest that β-cyclodextrin (β-CD) derivatives initiate the efflux of accumulated, unesterified cholesterol from the late endosomal/lysosomal compartment in Niemann Pick C (NPC) disease models. Unfortunately, repeated injections or continuous infusions of current β-CD therapies are required to sustain suppression of symptoms and prolong life. In an effort to make CD treatment a more viable option by boosting efficacy and improving pharmacokinetics, a library of Pluronic surfactant-based β-CD polyrotaxanes has been developed using biocompatible poly(ethylene glycol) (PEG)-polypropylene glycol (PPG)-PEG triblock copolymers. These compounds carry multiple copies of β-CD as shown by (1)H NMR, 2D nuclear Overhouser effect spectroscopy, gel permeation chromatography/multiangle light scattering, analytical ultracentrifugation analysis, matrix assisted laser desorption/ionization mass spectrometry, and diffusion-ordered spectroscopy. Analyses of free β-cyclodextrin contamination in the compounds were made by reverse phase high pressure liquid chromatography and hydrophilic interaction liquid chromatography. Dethreading kinetics were studied by reverse phase high pressure liquid chromatography, UV/vis, and (1)H NMR analysis. Filipin staining studies using npc2(-/-) fibroblasts show significant reversal of cholesterol accumulation after treatment with polyrotaxane compounds. The rate and efficacy of reversal is similar to that achieved by equivalent amounts of monomeric β-CD alone.
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Affiliation(s)
- Christopher J Collins
- Department of Chemistry, Purdue University , 560 Oval Drive, West Lafayette, Indiana 47904, United States
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Davies CW, Paul LN, Das C. Mechanism for recruitment of the endosome‐associated deubiquitinating enzyme, AMSH. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.782.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Lake N Paul
- Bindley Biosciences CenterPurdue UniversityWest LafayetteIN
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Bajaj R, Park MI, Paul LN, Klug CS, Davidson AL. Structural Mechanism of Action of Binding Protein Independent Mutant MalG511 of Escherichia Coli Maltose Transporter. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Davies CW, Kim MI, Paul LN, Das C. Mutational and kinetic analysis of the endosome‐associated deubiquitinating enzyme, AMSH. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.754.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Lake N Paul
- Bindley Biosciences CenterPurdue UniversityWest LafayetteIN
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Davies CW, Paul LN, Kim MI, Das C. Structural and thermodynamic comparison of the catalytic domain of AMSH and AMSH-LP: nearly identical fold but different stability. J Mol Biol 2011; 413:416-29. [PMID: 21888914 DOI: 10.1016/j.jmb.2011.08.029] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 08/08/2011] [Accepted: 08/12/2011] [Indexed: 01/05/2023]
Abstract
AMSH plays a critical role in the ESCRT (endosomal sorting complexes required for transport) machinery, which facilitates the down-regulation and degradation of cell-surface receptors. It displays a high level of specificity toward cleavage of Lys63-linked polyubiquitin chains, the structural basis of which has been understood recently through the crystal structure of a highly related, but ESCRT-independent, protein AMSH-LP (AMSH-like protein). We have determined the X-ray structure of two constructs representing the catalytic domain of AMSH: AMSH244, the JAMM (JAB1/MPN/MOV34)-domain-containing polypeptide segment from residues 244 to 424, and AMSH219(E280A), an active-site mutant, Glu280 to Ala, of the segment from 219 to 424. In addition to confirming the expected zinc coordination in the protein, the structures reveal that the catalytic domains of AMSH and AMSH-LP are nearly identical; however, guanidine-hydrochloride-induced unfolding studies show that the catalytic domain of AMSH is thermodynamically less stable than that of AMSH-LP, indicating that the former is perhaps structurally more plastic. Much to our surprise, in the AMSH219(E280A) structure, the catalytic zinc was still held in place, by the compensatory effect of an aspartate from a nearby loop moving into a position where it could coordinate with the zinc, once again suggesting the plasticity of AMSH. Additionally, a model of AMSH244 bound to Lys63-linked diubiquitin reveals a type of interface for the distal ubiquitin significantly different from that seen in AMSH-LP. Altogether, we believe that our data provide important insight into the structural difference between the two proteins that may translate into the difference in their biological function.
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Affiliation(s)
- Christopher W Davies
- Brown Laboratory of Chemistry, Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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Loaiza A, Ronau JA, Ribbe A, Stanciu L, Burgner JW, Paul LN, Abu-Omar MM. Folding dynamics of phenylalanine hydroxylase depends on the enzyme’s metallation state: the native metal, iron, protects against aggregate intermediates. Eur Biophys J 2011; 40:959-68. [DOI: 10.1007/s00249-011-0711-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 04/07/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
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Balasubramaniam D, Paul LN, Homan KT, Hall MC, Stauffacher CV. Specificity of HCPTP variants toward EphA2 tyrosines by quantitative selected reaction monitoring. Protein Sci 2011; 20:1172-81. [PMID: 21538645 DOI: 10.1002/pro.646] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Revised: 04/09/2011] [Accepted: 04/20/2011] [Indexed: 11/08/2022]
Abstract
EphA2 receptor tyrosine kinase and the human cytoplasmic protein tyrosine phosphatase (HCPTP) are overexpressed in a number of epithelial cancers. Overexpressed EphA2 in these cancers shows a significant decrease in phosphotyrosine content which results in suppression of receptor signaling and endocytosis and an increase in metastatic potential. The decreased phosphotyrosine content of EphA2 has been associated with decreased contact with its ligand, ephrin A1 and dephosphorylation by HCPTP. Potential specificity of the two HCPTP variants for tyrosines on EphA2 has not been investigated. We have used a mass spectrometry assay to measure relative rates of dephosphorylation for the two HCPTP variants at phosphotyrosine sites associated with control of the EphA2 kinase activity or interaction with downstream targets. Our results suggest that although both variants dephosphorylate the EphA2 receptor, the rate and specificity of dephosphorylation for specific tyrosines are different for HCPTP-A and HCPTP-B. The SAM domain tyrosine Y960 which has been implicated in downstream PI3K signaling is dephosphorylated exclusively by HCPTP-B. The activation loop tyrosine (Y772) which directly controls kinase activity is dephosphorylated about six times faster by HCPTP-A. In contrast, the juxtamembrane tyrosines (Y575, Y588 and Y594) which are implicated in both control of kinase activity and downstream signaling are dephosphorylated by both variants with similar rates. This difference in preference for dephosphorylation sites on EphA2 not only illuminates the different roles of the two variants of the phosphatase in EphA2 signaling, but also explains why both HCPTP variants are highly conserved in most mammals.
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Affiliation(s)
- Deepa Balasubramaniam
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA
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