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Basu R, Dambra R, Jiang D, Schätzlein SA, Njiyang S, Ashour J, Chiramel AI, Vigil A, Papov VV. Absolute quantification of viral proteins from pseudotyped VSV-GP using UPLC-MRM. Microbiol Spectr 2024; 12:e0365123. [PMID: 38916347 PMCID: PMC11302727 DOI: 10.1128/spectrum.03651-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 05/20/2024] [Indexed: 06/26/2024] Open
Abstract
The rapidly developing field of oncolytic virus (OV) therapy necessitates the development of new and improved analytical approaches for the characterization of the virus during production and development. Accurate monitoring and absolute quantification of viral proteins are crucial for OV product characterization and can facilitate the understanding of infection, immunogenicity, and development stages of viral replication. Targeted mass spectrometry methods like multiple reaction monitoring (MRM) offer a robust way to directly detect and quantify specific targeted proteins represented by surrogate peptides. We have leveraged the power of MRM by combining ultra-high performance liquid chromatography (UPLC) with a Sciex 6500 triple-stage quadrupole mass spectrometer to develop an assay that accurately and absolutely quantifies the structural proteins of a pseudotyped vesicular stomatitis virus (VSV) intended for use as a new biotherapeutic (designated hereafter as VSV-GP to differentiate it from native VSV). The new UPLC-MRM method provides absolute quantification with the use of heavy-labeled reference standard surrogate peptides. When added in known exact amounts to standards and samples, the reference standards normalize and account for any small perturbations during sample preparation and/or instrument performance, resulting in accurate and precise quantification. Because of the multiplexed nature of MRM, all targeted proteins are quantified at the same time. The optimized assay has been enhanced to quantify the ratios of the processed GP1 and GP2 proteins while simultaneously measuring any remaining or unprocessed form of the envelope protein GP complex (GPC; full-length GPC). IMPORTANCE The development of oncolytic viral therapy has gained considerable momentum in recent years. Vesicular stomatitis virus glycoprotein (VSV-GP) is a new biotherapeutic emerging in the oncolytic viral therapy platform. Novel analytical assays that can accurately and precisely quantify the viral proteins are a necessity for the successful development of viral vector as a biotherapeutic. We developed an ultra-high performance liquid chromatography multiple reaction monitoring-based assay to quantify the absolute concentrations of the different structural proteins of VSV-GP. The complete processing of GP complex (GPC) is a prerequisite for the infectivity of the virus. The assay extends the potential for quantifying full-length GPC, which provides an understanding of the processing of GPC (along with the quantification of GP1 and GP2 separately). We used this assay in tracking GPC processing in HEK-293-F production cell lines infected with VSV-GP.
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Affiliation(s)
- Rajeswari Basu
- Materials and Analytical Sciences, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut, USA
| | - Richard Dambra
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, Connecticut, USA
| | - Di Jiang
- Materials and Analytical Sciences, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut, USA
| | - Sophia A. Schätzlein
- Therapeutic Virus Development Group, Virus Therapeutic Center, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Shu Njiyang
- Therapeutic Virus Development Group, Virus Therapeutic Center, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Joseph Ashour
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, Connecticut, USA
| | - Abhilash I. Chiramel
- Therapeutic Virus Development Group, Virus Therapeutic Center, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Adam Vigil
- Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, Connecticut, USA
| | - Vladimir V. Papov
- Materials and Analytical Sciences, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut, USA
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2
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Joyce AW, Searle BC. Computational approaches to identify sites of phosphorylation. Proteomics 2024; 24:e2300088. [PMID: 37897210 DOI: 10.1002/pmic.202300088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/07/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023]
Abstract
Due to their oftentimes ambiguous nature, phosphopeptide positional isomers can present challenges in bottom-up mass spectrometry-based workflows as search engine scores alone are often not enough to confidently distinguish them. Additional scoring algorithms can remedy this by providing confidence metrics in addition to these search results, reducing ambiguity. Here we describe challenges to interpreting phosphoproteomics data and review several different approaches to determine sites of phosphorylation for both data-dependent and data-independent acquisition-based workflows. Finally, we discuss open questions regarding neutral losses, gas-phase rearrangement, and false localization rate estimation experienced by both types of acquisition workflows and best practices for managing ambiguity in phosphosite determination.
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Affiliation(s)
- Alex W Joyce
- Department of Biomedical Informatics, The Ohio State University Medical Center, Columbus, Ohio, USA
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, USA
| | - Brian C Searle
- Department of Biomedical Informatics, The Ohio State University Medical Center, Columbus, Ohio, USA
- Pelotonia Institute for Immuno-Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, Ohio, USA
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA
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3
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DeMarco AG, Hall MC. Phosphoproteomic Approaches for Identifying Phosphatase and Kinase Substrates. Molecules 2023; 28:3675. [PMID: 37175085 PMCID: PMC10180314 DOI: 10.3390/molecules28093675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023] Open
Abstract
Protein phosphorylation is a ubiquitous post-translational modification controlled by the opposing activities of protein kinases and phosphatases, which regulate diverse biological processes in all kingdoms of life. One of the key challenges to a complete understanding of phosphoregulatory networks is the unambiguous identification of kinase and phosphatase substrates. Liquid chromatography-coupled mass spectrometry (LC-MS/MS) and associated phosphoproteomic tools enable global surveys of phosphoproteome changes in response to signaling events or perturbation of phosphoregulatory network components. Despite the power of LC-MS/MS, it is still challenging to directly link kinases and phosphatases to specific substrate phosphorylation sites in many experiments. Here, we survey common LC-MS/MS-based phosphoproteomic workflows for identifying protein kinase and phosphatase substrates, noting key advantages and limitations of each. We conclude by discussing the value of inducible degradation technologies coupled with phosphoproteomics as a new approach that overcomes some limitations of current methods for substrate identification of kinases, phosphatases, and other regulatory enzymes.
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Affiliation(s)
- Andrew G. DeMarco
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Mark C. Hall
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
- Institute for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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4
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Liu X, Fields R, Schweppe DK, Paulo JA. Strategies for mass spectrometry-based phosphoproteomics using isobaric tagging. Expert Rev Proteomics 2021; 18:795-807. [PMID: 34652972 DOI: 10.1080/14789450.2021.1994390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Protein phosphorylation is a primary mechanism of signal transduction in cellular systems. Isobaric tagging can be used to investigate alterations in phosphorylation events in sample multiplexing experiments where quantification extends across all conditions. As such, innovations in tandem mass tag methods can facilitate the expansion of the depth and breadth of phosphoproteomic analyses. AREAS COVERED This review discusses the current state of tandem mass tag-centric phosphoproteomics and highlights advances in reagent chemistry, instrumentation, data acquisition, and data analysis. We stress that approaches for phosphoproteomic investigations require high-specificity enrichment, sensitive detection, and accurate phosphorylation site localization. EXPERT OPINION Tandem mass tag-centric phosphoproteomics will continue to be an important conduit for our understanding of signal transduction in living organisms. We anticipate that progress in phosphopeptide enrichment methodologies, enhancements in instrumentation and data acquisition technologies, and further refinements in analytical strategies will be key to the discovery of biologically relevant findings from phosphoproteomics studies.
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Affiliation(s)
- Xinyue Liu
- Department of Cell Biology, Harvard Medical School, Boston, USA
| | - Rose Fields
- Department of Genome Sciences, University of Washington, Seattle, USA
| | - Devin K Schweppe
- Department of Genome Sciences, University of Washington, Seattle, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, USA
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5
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Paulo JA, Schweppe DK. Advances in quantitative high-throughput phosphoproteomics with sample multiplexing. Proteomics 2021; 21:e2000140. [PMID: 33455035 DOI: 10.1002/pmic.202000140] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/18/2020] [Accepted: 12/04/2020] [Indexed: 02/06/2023]
Abstract
Eukaryotic protein phosphorylation modulates nearly every major biological process. Phosphorylation regulates protein activity, mediates cellular signal transduction, and manipulates cellular structure. Consequently, the dysregulation of kinase and phosphatase pathways has been linked to a multitude of diseases. Mass spectrometry-based proteomic techniques are increasingly used for the global interrogation of perturbations in phosphorylation-based cellular signaling. Strategies for studying phosphoproteomes require high-specificity enrichment, sensitive detection, and accurate localization of phosphorylation sites with advanced LC-MS/MS techniques and downstream informatics. Sample multiplexing with isobaric tags has also been integral to recent advancements in throughput and sensitivity for phosphoproteomic studies. Each of these facets of phosphoproteomics analysis present distinct challenges and thus opportunities for improvement and innovation. Here, we review current methodologies, explore persistent challenges, and discuss the outlook for isobaric tag-based quantitative phosphoproteomic analysis.
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Affiliation(s)
- Joao A Paulo
- Harvard Medical School, Boston, Massachusetts, USA
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6
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Fagbohun OF, Olawoye B, Ademakinwa AN, Oriyomi OV, Fagbohun OS, Fadare OA, Msagati TAM. UHPLC/GC-TOF-MS metabolomics, MTT assay, and molecular docking studies reveal physostigmine as a new anticancer agent from the ethyl acetate and butanol fractions of Kigelia africana (Lam.) Benth. fruit extracts. Biomed Chromatogr 2020; 35:e4979. [PMID: 32895963 DOI: 10.1002/bmc.4979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 11/08/2022]
Abstract
Kigelia africana plant is widely used as a herbal remedy in preventing the onset and the treatment of cancer-related infections. With the increase in the research interest of the plant, the specific chemical compound or metabolite that confers its anticancer properties has not been adequately investigated. The ethyl acetate and butanol fractions of the fruit extracts were evaluated by 2-(4,5-dimethylthiazol-2-yl)-3,5-diphenyl-2H-tetrazolium bromide assay against four different cell lines, with the ethyl acetate fraction having inhibition concentration values of 0.53 and 0.42 μM against Hep G2 and HeLa cells, respectively. More than 235 phytoconstituents were profiled using UHPLC-TOF-MS, while more than 15 chemical compounds were identified using GC-MS from the fractions. Molecular docking studies revealed that physostigmine, fluazifop, dexamethasone, sulfisomidine, and desmethylmirtazapine could favorably bind at higher binding energies of -8.3, -8.6, -8.2, and -8.1 kcal/mol, respectively, better than camptothecin with a binding energy of -7.9 kcal/mol. The results of this study showed that physostigmine interacted well with topoisomerase IIα and had a high score of pharmacokinetic prediction using absorption, distribution, metabolism, excretion, and toxicity profiles, thereby suggesting that drug design using physostigmine as a base structure could serve as an alternative against the toxic side effects of doxorubicin and camptothecin.
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Affiliation(s)
- Oladapo F Fagbohun
- Department of Biomedical Engineering, First Technical University, Ibadan, Nigeria
| | - Babatunde Olawoye
- Department of Food Science and Technology, First Technical University, Ibadan, Nigeria
| | - Adedeji N Ademakinwa
- Department of Physical and Chemical Sciences, Elizade University, Ilara-Mokin, Nigeria
| | | | - Oladoyin S Fagbohun
- Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Olatomide A Fadare
- Organic Chemistry Research Laboratory, Department of Chemistry, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Titus A M Msagati
- Nanotechnology and Water Sustainability Research Unit, College of Science Engineering and Technology, University of South Africa (UNISA), Johannesburg, South Africa
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7
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Zeng WF, Zhou XX, Zhou WJ, Chi H, Zhan J, He SM. MS/MS Spectrum Prediction for Modified Peptides Using pDeep2 Trained by Transfer Learning. Anal Chem 2019; 91:9724-9731. [DOI: 10.1021/acs.analchem.9b01262] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Wen-Feng Zeng
- University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Xie-Xuan Zhou
- University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Wen-Jing Zhou
- University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Hao Chi
- University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Jianfeng Zhan
- University of Chinese Academy of Sciences, 100190 Beijing, China
| | - Si-Min He
- University of Chinese Academy of Sciences, 100190 Beijing, China
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8
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Liu S, Yu F, Hu Q, Wang T, Yu L, Du S, Yu W, Li N. Development of in Planta Chemical Cross-Linking-Based Quantitative Interactomics in Arabidopsis. J Proteome Res 2018; 17:3195-3213. [DOI: 10.1021/acs.jproteome.8b00320] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Shichang Liu
- Division of Life Science, Energy Institute, Institute for the Environment, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Fengchao Yu
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Qin Hu
- Division of Life Science, Energy Institute, Institute for the Environment, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Tingliang Wang
- Tsinghua-Peking Joint Center for Life Sciences, Center for Structural Biology, School of Life Sciences and School of Medicine, Tsinghua University, Beijing 100084, China
| | - Lujia Yu
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Shengwang Du
- Department of Physics, The Hong Kong University of Science and Technology, Hong Kong SAR, China
- Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Weichuan Yu
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
- Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
| | - Ning Li
- Division of Life Science, Energy Institute, Institute for the Environment, The Hong Kong University of Science and Technology, Hong Kong SAR, China
- Division of Biomedical Engineering, The Hong Kong University of Science and Technology, Hong Kong SAR, China
- The Hong Kong University of Science and Technology, Shenzhen Research Institute, Shenzhen Guangdong 518057, China
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9
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Abstract
Most pathogenic bacteria deliver virulence factors into host cytosol through type III secretion systems (T3SS) to perturb host immune responses. The expression of T3SS is often repressed in rich medium but is specifically induced in the host environment. The molecular mechanisms underlying host-specific induction of T3SS expression is not completely understood. Here we demonstrate in Xanthomonas citri that host-induced phosphorylation of the ATP-dependent protease Lon stabilizes HrpG, the master regulator of T3SS, conferring bacterial virulence. Ser/Thr/Tyr phosphoproteome analysis revealed that phosphorylation of Lon at serine 654 occurs in the citrus host. In rich medium, Lon represses T3SS by degradation of HrpG via recognition of its N terminus. Genetic and biochemical data indicate that phosphorylation at serine 654 deactivates Lon proteolytic activity and attenuates HrpG proteolysis. Substitution of alanine for Lon serine 654 resulted in repression of T3SS gene expression in the citrus host through robust degradation of HrpG and reduced bacterial virulence. Our work reveals a novel mechanism for distinct regulation of bacterial T3SS in different environments. Additionally, our data provide new insight into the role of protein posttranslational modification in the regulation of bacterial virulence.IMPORTANCE Type III secretion systems (T3SS) are an essential virulence trait of many bacterial pathogens because of their indispensable role in the delivery of virulence factors. However, expression of T3SS in the noninfection stage is energy consuming. Here, we established a model to explain the differential regulation of T3SS in host and nonhost environments. When Xanthomonas cells are grown in rich medium, the T3SS regulator HrpG is targeted by Lon protease for proteolysis. The degradation of HrpG leads to downregulated expression of HrpX and the hrp/hrc genes. When Xanthomonas cells infect the host, specific plant stimuli can be perceived and induce Lon phosphorylation at serine 654. Phosphorylation on Lon attenuates its proteolytic activity and protects HrpG from degradation. Consequently, enhanced stability of HrpG activates HrpX and turns on bacterial T3SS in the host. Our work provides a novel molecular mechanism underlying host-dependent activation of bacterial T3SS.
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10
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Hauser A, Penkert M, Hackenberger CPR. Chemical Approaches to Investigate Labile Peptide and Protein Phosphorylation. Acc Chem Res 2017; 50:1883-1893. [PMID: 28723107 DOI: 10.1021/acs.accounts.7b00170] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protein phosphorylation is by far the most abundant and most studied post-translational modification (PTM). For a long time, phosphate monoesters of serine (pSer), threonine (pThr), and tyrosine (pTyr) have been considered as the only relevant forms of phosphorylation in organisms. Recently, several research groups have dedicated their efforts to the investigation of other, less characterized phosphoamino acids as naturally occurring PTMs. Such apparent peculiar phosphorylations include the phosphoramidates of histidine (pHis), arginine (pArg), and lysine (pLys), the phosphorothioate of cysteine (pCys), and the anhydrides of pyrophosphorylated serine (ppSer) and threonine (ppThr). Almost all of these phosphorylated amino acids show higher lability under physiological conditions than those of phosphate monoesters. Furthermore, they are prone to hydrolysis under acidic and sometimes basic conditions as well as at elevated temperatures, which renders their synthetic accessibility and proteomic analysis particularly challenging. In this Account, we illustrate recent chemical approaches to probe the occurrence and function of these labile phosphorylation events. Within these endeavors, the synthesis of site-selectively phosphorylated peptides, in particular in combination with chemoselective phosphorylation strategies, was crucial. With these well-defined standards in hand, the appropriate proteomic mass spectrometry-based analysis protocols for the characterization of labile phosphosites in biological samples could be developed. Another successful approach in this research field includes the design and synthesis of stable analogues of these labile PTMs, which were used for the generation of pHis- and pArg-specific antibodies for the detection and enrichment of endogenous phosphorylated samples. Finally, other selective enrichment techniques are described, which rely for instance on the unique chemical environment of a pyrophosphate or the selective interaction between a phosphoamino acid and its phosphatase. It is worth noting that many of those studies are still in their early stages, which is also reflected in the small number of identified phosphosites compared to that of phosphate monoesters. Thus, many challenges need to be mastered to fully understand the biological role of these poorly characterized and rather uncommon phosphorylations. Taken together, this overview exemplifies recent efforts in a flourishing field of functional proteomic analysis and furthermore manifests the power of modern peptide synthesis to address unmet questions in the life sciences.
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Affiliation(s)
- Anett Hauser
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Institute
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße
2, 12489 Berlin, Germany
| | - Martin Penkert
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Institute
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße
2, 12489 Berlin, Germany
| | - Christian P. R. Hackenberger
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Roessle-Straße 10, 13125 Berlin, Germany
- Institute
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße
2, 12489 Berlin, Germany
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11
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Abstract
Kinase-mediated phosphorylation is a pivotal regulatory process in stomatal responses to stresses. Through a redox proteomics study, a sucrose non-fermenting 1-related protein kinase (SnRK2.4) was identified to be redox-regulated in Brassica napus guard cells upon abscisic acid treatment. There are six genes encoding SnRK2.4 paralogs in B. napus Here, we show that recombinant BnSnRK2.4-1C exhibited autophosphorylation activity and preferentially phosphorylated the N-terminal region of B. napus slow anion channel (BnSLAC1-NT) over generic substrates. The in vitro activity of BnSnRK2.4-1C requires the presence of manganese (Mn2+). Phosphorylation sites of autophosphorylated BnSnRK2.4-1C were mapped, including serine and threonine residues in the activation loop. In vitro BnSnRK2.4-1C autophosphorylation activity was inhibited by oxidants such as H2O2 and recovered by active thioredoxin isoforms, indicating redox regulation of BnSnRK2.4-1C. Thiol-specific isotope tagging followed by mass spectrometry analysis revealed specific cysteine residues responsive to oxidant treatments. The in vivo activity of BnSnRK2.4-1C is inhibited by 15 min of H2O2 treatment. Taken together, these data indicate that BnSnRK2.4-1C, an SnRK preferentially expressed in guard cells, is redox-regulated with potential roles in guard cell signal transduction.
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12
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Penkert M, Yates LM, Schümann M, Perlman D, Fiedler D, Krause E. Unambiguous Identification of Serine and Threonine Pyrophosphorylation Using Neutral-Loss-Triggered Electron-Transfer/Higher-Energy Collision Dissociation. Anal Chem 2017; 89:3672-3680. [DOI: 10.1021/acs.analchem.6b05095] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Martin Penkert
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle Str. 10, 13125 Berlin, Germany
- Humboldt Universität zu Berlin, Department
of Chemistry, Brook-Taylor-Straße
2, 12489 Berlin, Germany
| | - Lisa M. Yates
- Princeton University, Department of Chemistry, Frick Chemistry Building, Washington
Road, Princeton, New Jersey 08544, United States
| | - Michael Schümann
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle Str. 10, 13125 Berlin, Germany
| | - David Perlman
- Princeton University, Department of Molecular Biology, 119 Lewis Thomas Laboratory, Washington
Road, Princeton, New Jersey 08544, United States
| | - Dorothea Fiedler
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle Str. 10, 13125 Berlin, Germany
- Humboldt Universität zu Berlin, Department
of Chemistry, Brook-Taylor-Straße
2, 12489 Berlin, Germany
| | - Eberhard Krause
- Leibniz Institut für Molekulare Pharmakologie (FMP), Robert-Rössle Str. 10, 13125 Berlin, Germany
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Cutillas PR. Targeted In-Depth Quantification of Signaling Using Label-Free Mass Spectrometry. Methods Enzymol 2016; 585:245-268. [PMID: 28109432 DOI: 10.1016/bs.mie.2016.09.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Protein phosphorylation encodes information on the activity of kinase-driven signaling pathways that regulate cell biology. This chapter discusses an approach, named TIQUAS (targeted in-depth quantification of signaling), to quantify cell signaling comprehensively and without bias. The workflow-based on mass spectrometry (MS) and computational science-consists of targeting the analysis of phosphopeptides previously identified by shotgun liquid chromatography tandem MS (LC-MS/MS) across the samples that are being compared. TIQUAS therefore takes advantage of concepts derived from both targeted (data-independent) and data-dependent acquisition methods; phosphorylation sites are quantified in all experimental samples regardless of whether or not these phosphopeptides were identified by MS/MS in all runs. As a result, datasets are obtained containing quantitative information on several thousand phosphorylation sites in as many samples and replicates as required in the experimental design, and these rich datasets are devoid of a significant number of missing data points. This chapter discussed the biochemical, analytical, and computational procedures required to apply the approach and for obtaining a biological interpretation of the data in the context of our understanding of cell signaling regulation and kinase-substrate relationships.
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Affiliation(s)
- P R Cutillas
- Barts Cancer Institute, Queen Mary University of London, John Vane Science Centre, London, United Kingdom.
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14
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Ubiquitin-Like Proteasome System Represents a Eukaryotic-Like Pathway for Targeted Proteolysis in Archaea. mBio 2016; 7:mBio.00379-16. [PMID: 27190215 PMCID: PMC4895103 DOI: 10.1128/mbio.00379-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The molecular mechanisms of targeted proteolysis in archaea are poorly understood, yet they may have deep evolutionary roots shared with the ubiquitin-proteasome system of eukaryotic cells. Here, we demonstrate in archaea that TBP2, a TATA-binding protein (TBP) modified by ubiquitin-like isopeptide bonds, is phosphorylated and targeted for degradation by proteasomes. Rapid turnover of TBP2 required the functions of UbaA (the E1/MoeB/ThiF homolog of archaea), AAA ATPases (Cdc48/p97 and Rpt types), a type 2 JAB1/MPN/MOV34 metalloenzyme (JAMM/MPN+) homolog (JAMM2), and 20S proteasomes. The ubiquitin-like protein modifier small archaeal modifier protein 2 (SAMP2) stimulated the degradation of TBP2, but SAMP2 itself was not degraded. Analysis of the TBP2 fractions that were not modified by ubiquitin-like linkages revealed that TBP2 had multiple N termini, including Met1-Ser2, Ser2, and Met1-Ser2(p) [where (p) represents phosphorylation]. The evidence suggested that the Met1-Ser2(p) form accumulated in cells that were unable to degrade TBP2. We propose a model in archaea in which the attachment of ubiquitin-like tags can target proteins for degradation by proteasomes and be controlled by N-terminal degrons. In support of a proteolytic mechanism that is energy dependent and recycles the ubiquitin-like protein tags, we find that a network of AAA ATPases and a JAMM/MPN+ metalloprotease are required, in addition to 20S proteasomes, for controlled intracellular proteolysis. This study advances the fundamental knowledge of signal-guided proteolysis in archaea and sheds light on components that are related to the ubiquitin-proteasome system of eukaryotes. In archaea, the ubiquitin-like proteasome system is found to require function of an E1/MoeB/ThiF homolog, a type 2 JAMM/MPN+ metalloprotease, and a network of AAA ATPases for the targeted destruction of proteins. We provide evidence that the attachment of the ubiquitin-like protein is controlled by an N-terminal degron and stimulates proteasome-mediated proteolysis.
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15
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Ning DL, Liu KH, Liu CC, Liu JW, Qian CR, Yu Y, Wang YF, Wang YC, Wang BC. Large-scale comparative phosphoprotein analysis of maize seedling leaves during greening. PLANTA 2016; 243:501-517. [PMID: 26497871 DOI: 10.1007/s00425-015-2420-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 10/06/2015] [Indexed: 06/05/2023]
Abstract
MAIN CONCLUSION : Large-scale comparative phosphoprotein analysis in maize seedlings reveals a complicated molecular regulation mechanism at the phosphoproteomic level during de-etiolation. In the present study we report a phosphoproteomic study conducted on Zea mays etiolated leaves harvested at three time points during greening (etiolated seedlings and seedlings exposed to light for 6 or 12 h). We identified a total of 2483 phosphopeptides containing 2389 unambiguous phosphosites from 1339 proteins. The abundance of nearly 692 phosphorylated peptides containing 783 phosphosites was reproducible and profiled with high confidence among treatments. Comparisons with other large-scale phosphoproteomic studies revealed that 473 of the phosphosites are novel to this study. Of the 783 phosphosites identified, 171, 79, and 138 were identified in 0, 6, and 12 h samples, respectively, which suggest that regulation of phosphorylation plays important roles during maize seedling de-etiolation. Our experimental methods included enrichment of phosphoproteins, allowing the identification of a great number of low abundance proteins, such as transcription factors, protein kinases, and photoreceptors. Most of the identified phosphoproteins were involved in gene transcription, post-transcriptional regulation, or signal transduction, and only a few were involved in photosynthesis and carbon metabolism. It is noteworthy that tyrosine phosphorylation and calcium signaling pathways might play important roles during maize seedling de-etiolation. Taken together, we have elucidated a new level of complexity in light-induced reversible protein phosphorylation during maize seedling de-etiolation.
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16
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Brown R, Stuart SA, Houel S, Ahn NG, Old WM. Large-Scale Examination of Factors Influencing Phosphopeptide Neutral Loss during Collision Induced Dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2015; 26:1128-42. [PMID: 25851653 PMCID: PMC4509682 DOI: 10.1007/s13361-015-1109-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/18/2015] [Accepted: 02/18/2015] [Indexed: 05/14/2023]
Abstract
Collision-induced dissociation (CID) remains the predominant mass spectrometry-based method for identifying phosphorylation sites in complex mixtures. Unfortunately, the gas-phase reactivity of phosphoester bonds results in MS/MS spectra dominated by phosphoric acid (H3PO4) neutral loss events, suppressing informative peptide backbone cleavages. To understand the major drivers of H3PO4 neutral loss, we performed robust nonparametric statistical analysis of local and distal sequence effects on the magnitude and variability of neutral loss, using a collection of over 35,000 unique phosphopeptide MS/MS spectra. In contrast to peptide amide dissociation pathways, which are strongly influenced by adjacent amino acid side chains, we find that neutral loss of H3PO4 is affected by both proximal and distal sites, most notably basic residues and the peptide N-terminal primary amine. Previous studies have suggested that protonated basic residues catalyze neutral loss through direct interactions with the phosphate. In contrast, we find that nearby basic groups decrease neutral loss regardless of mobility class, an effect only seen by stratifying spectra by charge-mobility. The most inhibitory bases are those immediately N-terminal to the phosphate, presumably because of steric hindrances in catalyzing neutral loss. Further evidence of steric effects is shown by the presence of proline, which can dramatically reduce the presence of neutral loss when between the phosphate and a possible charge donor. In mobile proton spectra, the N-terminus is the strongest predictor of high neutral loss, with proximity to the N-terminus essential for peptides to exhibit the highest levels of neutral loss.
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Affiliation(s)
- Robert Brown
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | - Scott A. Stuart
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
| | | | - Natalie G. Ahn
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
- Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80309
| | - William M. Old
- Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309
- Corresponding author: William M. Old, Department of Molecular Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309, Phone: 303-492-5519, Fax: 303-492-2439,
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17
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Lee DCH, Jones AR, Hubbard SJ. Computational phosphoproteomics: from identification to localization. Proteomics 2015; 15:950-63. [PMID: 25475148 PMCID: PMC4384807 DOI: 10.1002/pmic.201400372] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 10/31/2014] [Accepted: 11/26/2014] [Indexed: 01/08/2023]
Abstract
Analysis of the phosphoproteome by MS has become a key technology for the characterization of dynamic regulatory processes in the cell, since kinase and phosphatase action underlie many major biological functions. However, the addition of a phosphate group to a suitable side chain often confounds informatic analysis by generating product ion spectra that are more difficult to interpret (and consequently identify) relative to unmodified peptides. Collectively, these challenges have motivated bioinformaticians to create novel software tools and pipelines to assist in the identification of phosphopeptides in proteomic mixtures, and help pinpoint or "localize" the most likely site of modification in cases where there is ambiguity. Here we review the challenges to be met and the informatics solutions available to address them for phosphoproteomic analysis, as well as highlighting the difficulties associated with using them and the implications for data standards.
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Affiliation(s)
- Dave C H Lee
- Faculty of Life Sciences, University of ManchesterManchester, UK
| | - Andrew R Jones
- Institute of Integrative Biology, University of LiverpoolLiverpool, UK
| | - Simon J Hubbard
- Faculty of Life Sciences, University of ManchesterManchester, UK
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18
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Fischer JDSDG, Dos Santos MDM, Marchini FK, Barbosa VC, Carvalho PC, Zanchin NIT. A scoring model for phosphopeptide site localization and its impact on the question of whether to use MSA. J Proteomics 2015; 129:42-50. [PMID: 25623781 DOI: 10.1016/j.jprot.2015.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 01/03/2015] [Accepted: 01/16/2015] [Indexed: 01/04/2023]
Abstract
The production of structurally significant product ions during the dissociation of phosphopeptides is a key to the successful determination of phosphorylation sites. These diagnostic ions can be generated using the widely adopted MS/MS approach, MS3 (Data Dependent Neutral Loss - DDNL), or by multistage activation (MSA). The main purpose of this work is to introduce a false-localization rate (FLR) probabilistic model to enable unbiased phosphoproteomics studies. Briefly, our algorithm infers a probabilistic function from the distribution of the identified phosphopeptides' XCorr Delta scores (XD-Scores) in the current experiment. Our module infers p-values by relying on Gaussian mixture models and a logistic function. We demonstrate the usefulness of our probabilistic model by revisiting the "to MSA, or not to MSA" dilemma. For this, we use human leukemia-derived cells (K562) as a study model and enriched for phosphopeptides using the hydroxyapatite (HAP) chromatography. The aliquots were analyzed with and without MSA on an Orbitrap-XL. Our XD-Scoring analysis revealed that the MS/MS approach provides more identifications because of its faster scan rate, but that for the same given scan rate higher-confidence spectra can be achieved with MSA. Our software is integrated into the PatternLab for proteomics freely available for academic community at http://www.patternlabforproteomics.org. Biological significance Assigning statistical confidence to phosphorylation sites is necessary for proper phosphoproteomic assessment. Here we present a rigorous statistical model, based on Gaussian mixture models and a logistic function, which overcomes shortcomings of previous tools. The algorithm described herein is made readily available to the scientific community by integrating it into the widely adopted PatternLab for proteomics. This article is part of a Special Issue entitled: Computational Proteomics.
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Affiliation(s)
| | - Marlon D M Dos Santos
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz, Paraná, Brazil
| | - Fabricio K Marchini
- Functional Genomics Laboratory, Carlos Chagas Institute, Fiocruz, Paraná, Brazil
| | - Valmir C Barbosa
- Systems Engineering and Computer Science Program, COPPE, Federal University of Rio de Janeiro, Brazil
| | - Paulo C Carvalho
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz, Paraná, Brazil.
| | - Nilson I T Zanchin
- Laboratory for Proteomics and Protein Engineering, Carlos Chagas Institute, Fiocruz, Paraná, Brazil.
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19
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Silva-Sanchez C, Li H, Chen S. Recent advances and challenges in plant phosphoproteomics. Proteomics 2015; 15:1127-41. [PMID: 25429768 DOI: 10.1002/pmic.201400410] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 09/29/2014] [Accepted: 11/24/2014] [Indexed: 12/13/2022]
Abstract
Plants are sessile organisms that need to respond to environmental changes quickly and efficiently. They can accomplish this by triggering specialized signaling pathways often mediated by protein phosphorylation and dephosphorylation. Phosphorylation is a fast response that can switch on or off a myriad of biological pathways and processes. Proteomics and MS are the main tools employed in the study of protein phosphorylation. Advances in the technologies allow simultaneous identification and quantification of thousands of phosphopeptides and proteins that are essential to understanding the sophisticated biological systems and regulations. In this review, we summarize the advances in phosphopeptide enrichment and quantitation, MS for phosphorylation site mapping and new data acquisition methods, databases and informatics, interpretation of biological insights and crosstalk with other PTMs, as well as future directions and challenges in the field of phosphoproteomics.
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Affiliation(s)
- Cecilia Silva-Sanchez
- Proteomics and Mass Spectrometry, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, USA
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20
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Sugden C, Urbaniak MD, Araki T, Williams JG. The Dictyostelium prestalk inducer differentiation-inducing factor-1 (DIF-1) triggers unexpectedly complex global phosphorylation changes. Mol Biol Cell 2014; 26:805-20. [PMID: 25518940 PMCID: PMC4325849 DOI: 10.1091/mbc.e14-08-1319] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Differentiation-inducing factor-1 (DIF-1) is a polyketide that induces Dictyostelium amoebae to differentiate as prestalk cells. We performed a global quantitative screen for phosphorylation changes that occur within the first minutes after addition of DIF-1, using a triple-label SILAC approach. This revealed a new world of DIF-1-controlled signaling, with changes in components of the MAPK and protein kinase B signaling pathways, components of the actinomyosin cytoskeletal signaling networks, and a broad range of small GTPases and their regulators. The results also provide evidence that the Ca(2+)/calmodulin-dependent phosphatase calcineurin plays a role in DIF-1 signaling to the DimB prestalk transcription factor. At the global level, DIF-1 causes a major shift in the phosphorylation/dephosphorylation equilibrium toward net dephosphorylation. Of interest, many of the sites that are dephosphorylated in response to DIF-1 are phosphorylated in response to extracellular cAMP signaling. This accords with studies that suggest an antagonism between the two inducers and also with the rapid dephosphorylation of the cAMP receptor that we observe in response to DIF-1 and with the known inhibitory effect of DIF-1 on chemotaxis to cAMP. All MS data are available via ProteomeXchange with identifier PXD001555.
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Affiliation(s)
- Chris Sugden
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Michael D Urbaniak
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster LA1 4YG, United Kingdom
| | - Tsuyoshi Araki
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Jeffrey G Williams
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
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21
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Yang C, Zhong X, Li L. Recent advances in enrichment and separation strategies for mass spectrometry-based phosphoproteomics. Electrophoresis 2014; 35:3418-29. [PMID: 24687451 PMCID: PMC4849134 DOI: 10.1002/elps.201400017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 03/21/2014] [Accepted: 03/21/2014] [Indexed: 12/29/2022]
Abstract
Due to the significance of protein phosphorylation in various biological processes and signaling events, new analytical techniques for enhanced phosphoproteomics have been rapidly introduced in the recent years. The combinatorial use of the phospho-specific enrichment techniques and prefractionation methods prior to MS analysis enable comprehensive profiling of the phosphoproteome and facilitate deciphering the critical roles that phosphorylation plays in signaling pathways in various biological systems. This review places special emphasis on the recent five-year (2009-2013) advances for enrichment and separation techniques that have been utilized for phosphopeptides prior to MS analysis.
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Affiliation(s)
- Chenxi Yang
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Xuefei Zhong
- School of Pharmacy, University of Wisconsin, 777 Highland Avenue, Madison, Wisconsin 53705, United States
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
- School of Pharmacy, University of Wisconsin, 777 Highland Avenue, Madison, Wisconsin 53705, United States
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22
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Bauer M, Ahrné E, Baron AP, Glatter T, Fava LL, Santamaria A, Nigg EA, Schmidt A. Evaluation of Data-Dependent and -Independent Mass Spectrometric Workflows for Sensitive Quantification of Proteins and Phosphorylation Sites. J Proteome Res 2014; 13:5973-88. [DOI: 10.1021/pr500860c] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Manuel Bauer
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Erik Ahrné
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Anna P. Baron
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Timo Glatter
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Luca L. Fava
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Anna Santamaria
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Erich A. Nigg
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
| | - Alexander Schmidt
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland
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23
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Hao P, Ren Y, Tam JP, Sze SK. Correction of Errors in Tandem Mass Spectrum Extraction Enhances Phosphopeptide Identification. J Proteome Res 2013; 12:5548-57. [DOI: 10.1021/pr4004486] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Piliang Hao
- School of Biological Sciences and ‡Singapore Centre
on Environmental Life Sciences
Engineering, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Yan Ren
- School of Biological Sciences and ‡Singapore Centre
on Environmental Life Sciences
Engineering, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - James P. Tam
- School of Biological Sciences and ‡Singapore Centre
on Environmental Life Sciences
Engineering, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Siu Kwan Sze
- School of Biological Sciences and ‡Singapore Centre
on Environmental Life Sciences
Engineering, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
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24
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Engholm-Keller K, Larsen MR. Technologies and challenges in large-scale phosphoproteomics. Proteomics 2013; 13:910-31. [PMID: 23404676 DOI: 10.1002/pmic.201200484] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 01/18/2013] [Accepted: 01/31/2013] [Indexed: 12/23/2022]
Abstract
Phosphorylation, the reversible addition of a phosphate group to amino acid side chains of proteins, is a fundamental regulator of protein activity, stability, and molecular interactions. Most cellular processes, such as inter- and intracellular signaling, protein synthesis, degradation, and apoptosis, rely on phosphorylation. This PTM is thus involved in many diseases, rendering localization and assessment of extent of phosphorylation of major scientific interest. MS-based phosphoproteomics, which aims at describing all phosphorylation sites in a specific type of cell, tissue, or organism, has become the main technique for discovery and characterization of phosphoproteins in a nonhypothesis driven fashion. In this review, we describe methods for state-of-the-art MS-based analysis of protein phosphorylation as well as the strategies employed in large-scale phosphoproteomic experiments with focus on the various challenges and limitations this field currently faces.
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Affiliation(s)
- Kasper Engholm-Keller
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
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25
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Meijer LAT, Zhou H, Chan OYA, Altelaar AFM, Hennrich ML, Mohammed S, Bos JL, Heck AJR. Quantitative global phosphoproteomics of human umbilical vein endothelial cells after activation of the Rap signaling pathway. MOLECULAR BIOSYSTEMS 2013; 9:732-49. [PMID: 23403867 DOI: 10.1039/c3mb25524g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The small GTPase Rap1 is required for proper cell-cell junction formation and also plays a key role in mediating cAMP-induced tightening of adherens junctions and subsequent increased barrier function of endothelial cells. To further study how Rap1 controls barrier function, we performed quantitative global phosphoproteomics in human umbilical vein endothelial cells (HUVECs) prior to and after Rap1 activation by the Epac-selective cAMP analog 8-pCPT-2'-O-Me-cAMP-AM (007-AM). Tryptic digests were labeled using stable isotope dimethyl labeling, enriched with phosphopeptides by strong cation exchange (SCX), followed by titanium(iv) immobilized metal affinity chromatography (Ti(4+)-IMAC) and analyzed by high resolution mass spectrometry. We identified 19 859 unique phosphopeptides containing 17 278 unique phosphosites on 4594 phosphoproteins, providing the largest HUVEC phosphoproteome to date. Of all identified phosphosites, 220 (∼1%) were more than 1.5-fold up- or downregulated upon Rap activation, in two independent experiments. Compatible with the function of Rap1, these alterations were found predominantly in proteins regulating the actin cytoskeleton, cell-cell junctions and cell adhesion.
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Affiliation(s)
- Lars A T Meijer
- Molecular Cancer Research, Centre for Biomedical Genetics and Cancer Genomics Centre, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, The Netherlands.
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26
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Kweon HK, Andrews PC. Quantitative analysis of global phosphorylation changes with high-resolution tandem mass spectrometry and stable isotopic labeling. Methods 2013; 61:251-9. [PMID: 23611819 PMCID: PMC3700606 DOI: 10.1016/j.ymeth.2013.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 03/05/2013] [Accepted: 04/13/2013] [Indexed: 11/23/2022] Open
Abstract
Quantitative measurement of specific protein phosphorylation sites is a primary interest of biologists, as site-specific phosphorylation information provides insights into cell signaling networks and cellular dynamics at a system level. Over the last decade, selective phosphopeptide enrichment methods including IMAC and metal oxides (TiO₂ and ZrO₂) have been developed and greatly facilitate large scale phosphoproteome analysis of various cells, tissues and living organisms, in combination with modern mass spectrometers featuring high mass accuracy and high mass resolution. Various quantification strategies have been applied to detecting relative changes in expression of proteins, peptides, and specific modifications between samples. The combination of mass spectrometry-based phosphoproteome analysis with quantification strategies provides a straightforward and unbiased method to identify and quantify site-specific phosphorylation. We describe common strategies for mass spectrometric analysis of stable isotope labeled samples, as well as two widely applied phosphopeptide enrichment methods based on IMAC(NTA-Fe³⁺) and metal oxide (ZrO₂). Instrumental configurations for on-line LC-tandem mass spectrometric analysis and parameters of conventional bioinformatic analysis of large data sets are also considered for confident identification, localization, and reliable quantification of site-specific phosphorylation.
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Affiliation(s)
- Hye Kyong Kweon
- Department of Biological Chemistry, University of Michigan, USA.
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27
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Zhang Y, Fonslow BR, Shan B, Baek MC, Yates JR. Protein analysis by shotgun/bottom-up proteomics. Chem Rev 2013; 113:2343-94. [PMID: 23438204 PMCID: PMC3751594 DOI: 10.1021/cr3003533] [Citation(s) in RCA: 979] [Impact Index Per Article: 89.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yaoyang Zhang
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bryan R. Fonslow
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Bing Shan
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Moon-Chang Baek
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Department of Molecular Medicine, Cell and Matrix Biology Research Institute, School of Medicine, Kyungpook National University, Daegu 700-422, Republic of Korea
| | - John R. Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA
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28
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Analysis of human serum phosphopeptidome by a focused database searching strategy. J Proteomics 2013; 78:389-97. [DOI: 10.1016/j.jprot.2012.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 07/17/2012] [Accepted: 10/08/2012] [Indexed: 12/20/2022]
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29
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Multiple phosphorylable sites in the Zaire Ebolavirus nucleoprotein evidenced by high resolution tandem mass spectrometry. J Virol Methods 2013; 187:159-65. [DOI: 10.1016/j.jviromet.2012.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 09/04/2012] [Accepted: 10/03/2012] [Indexed: 11/18/2022]
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30
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Vandenbogaert M, Hourdel V, Jardin-Mathé O, Bigeard J, Bonhomme L, Legros V, Hirt H, Schwikowski B, Pflieger D. Automated Phosphopeptide Identification Using Multiple MS/MS Fragmentation Modes. J Proteome Res 2012; 11:5695-703. [DOI: 10.1021/pr300507j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | - Véronique Hourdel
- Plate-forme de Protéomique, Institut Pasteur, 28 rue du Docteur Roux, 75015 Paris,
France
| | - Olivia Jardin-Mathé
- Systems Biology Lab, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Jean Bigeard
- URGV Plant Genomics, INRA/CNRS/Université d’Evry Val d’Essonne, 2 rue Gaston Crémieux, 91057 Evry, France
| | - Ludovic Bonhomme
- Université Evry Val d’Essonne (UEVE), LAMBE, bd François Mitterrand, 91025
Evry, France
- CNRS, UMR 8587, bd François Mitterrand, 91025
Evry, France
| | - Véronique Legros
- Université Evry Val d’Essonne (UEVE), LAMBE, bd François Mitterrand, 91025
Evry, France
- CNRS, UMR 8587, bd François Mitterrand, 91025
Evry, France
| | - Heribert Hirt
- URGV Plant Genomics, INRA/CNRS/Université d’Evry Val d’Essonne, 2 rue Gaston Crémieux, 91057 Evry, France
- College of Science, King Saud University, P.O. Box 2455, Riyadh 11451,
Saudi Arabia
| | - Benno Schwikowski
- Systems Biology Lab, Institut Pasteur, 25 rue du Docteur Roux, 75015 Paris, France
| | - Delphine Pflieger
- Université Evry Val d’Essonne (UEVE), LAMBE, bd François Mitterrand, 91025
Evry, France
- CNRS, UMR 8587, bd François Mitterrand, 91025
Evry, France
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31
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Sun Z, Hamilton KL, Reardon KF. Phosphoproteomics and molecular cardiology: Techniques, applications and challenges. J Mol Cell Cardiol 2012; 53:354-68. [DOI: 10.1016/j.yjmcc.2012.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 05/26/2012] [Accepted: 06/03/2012] [Indexed: 12/16/2022]
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32
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Abstract
eEF2K [eEF2 (eukaryotic elongation factor 2) kinase] phosphorylates and inactivates the translation elongation factor eEF2. eEF2K is not a member of the main eukaryotic protein kinase superfamily, but instead belongs to a small group of so-called α-kinases. The activity of eEF2K is normally dependent upon Ca2+ and calmodulin. eEF2K has previously been shown to undergo autophosphorylation, the stoichiometry of which suggested the existence of multiple sites. In the present study we have identified several autophosphorylation sites, including Thr348, Thr353, Ser366 and Ser445, all of which are highly conserved among vertebrate eEF2Ks. We also identified a number of other sites, including Ser78, a known site of phosphorylation, and others, some of which are less well conserved. None of the sites lies in the catalytic domain, but three affect eEF2K activity. Mutation of Ser78, Thr348 and Ser366 to a non-phosphorylatable alanine residue decreased eEF2K activity. Phosphorylation of Thr348 was detected by immunoblotting after transfecting wild-type eEF2K into HEK (human embryonic kidney)-293 cells, but not after transfection with a kinase-inactive construct, confirming that this is indeed a site of autophosphorylation. Thr348 appears to be constitutively autophosphorylated in vitro. Interestingly, other recent data suggest that the corresponding residue in other α-kinases is also autophosphorylated and contributes to the activation of these enzymes [Crawley, Gharaei, Ye, Yang, Raveh, London, Schueler-Furman, Jia and Cote (2011) J. Biol. Chem. 286, 2607–2616]. Ser366 phosphorylation was also detected in intact cells, but was still observed in the kinase-inactive construct, demonstrating that this site is phosphorylated not only autocatalytically but also in trans by other kinases.
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Bonet-Costa C, Vilaseca M, Diema C, Vujatovic O, Vaquero A, Omeñaca N, Castejón L, Bernués J, Giralt E, Azorín F. Combined bottom-up and top-down mass spectrometry analyses of the pattern of post-translational modifications of Drosophila melanogaster linker histone H1. J Proteomics 2012; 75:4124-38. [PMID: 22647927 DOI: 10.1016/j.jprot.2012.05.034] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/18/2012] [Accepted: 05/20/2012] [Indexed: 12/27/2022]
Abstract
Linker histone H1 is a major chromatin component that binds internucleosomal DNA and mediates the folding of nucleosomes into a higher-order structure, namely the 30-nm chromatin fiber. Multiple post-translational modifications (PTMs) of core histones H2A, H2B, H3 and H4 have been identified and their important contribution to the regulation of chromatin structure and function is firmly established. In contrast, little is known about histone H1 modifications and their function. Here we address this question in Drosophila melanogaster, which, in contrast to most eukaryotic species, contains a single histone H1 variant, dH1. For this purpose, we combined bottom-up and top-down mass-spectrometry strategies. Our results indicated that dH1 is extensively modified by phosphorylation, methylation, acetylation and ubiquitination, with most PTMs falling in the N-terminal domain. Interestingly, several dH1 N-terminal modifications have also been reported in specific human and/or mouse H1 variants, suggesting that they have conserved functions. In this regard, we also provide evidence for the contribution of one of such conserved PTMs, dimethylation of K27, to heterochromatin organization during mitosis. Furthermore, our results also identified multiple dH1 isoforms carrying several phosphorylations and/or methylations, illustrating the high structural heterogeneity of dH1. In particular, we identified several non-CDK sites at the N-terminal domain that appear to be hierarchically phosphorylated. This study provides the most comprehensive PTM characterization of any histone H1 variant to date.
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Affiliation(s)
- Carles Bonet-Costa
- Institute of Molecular Biology of Barcelona, CSIC, 08028 Barcelona, Spain
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34
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Fonslow BR, Niessen SM, Singh M, Wong CCL, Xu T, Carvalho PC, Choi J, Park SK, Yates JR. Single-step inline hydroxyapatite enrichment facilitates identification and quantitation of phosphopeptides from mass-limited proteomes with MudPIT. J Proteome Res 2012; 11:2697-709. [PMID: 22509746 DOI: 10.1021/pr300200x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Herein we report the characterization and optimization of single-step inline enrichment of phosphopeptides directly from small amounts of whole cell and tissue lysates (100-500 μg) using a hydroxyapatite (HAP) microcolumn and Multidimensional Protein Identification Technology (MudPIT). In comparison to a triplicate HILIC-IMAC phosphopeptide enrichment study, ∼80% of the phosphopeptides identified using HAP-MudPIT were unique. Similarly, analysis of the consensus phosphorylation motifs between the two enrichment methods illustrates the complementarity of calcium- and iron-based enrichment methods and the higher sensitivity and selectivity of HAP-MudPIT for acidic motifs. We demonstrate how the identification of more multiply phosphorylated peptides from HAP-MudPIT can be used to quantify phosphorylation cooperativity. Through optimization of HAP-MudPIT on a whole cell lysate we routinely achieved identification and quantification of ca. 1000 phosphopeptides from a ∼1 h enrichment and 12 h MudPIT analysis on small quantities of material. Finally, we applied this optimized method to identify phosphorylation sites from a mass-limited mouse brain region, the amygdala (200-500 μg), identifying up to 4000 phosphopeptides per run.
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Affiliation(s)
- Bryan R Fonslow
- Department of Chemical Physiology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, California 92037, USA
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35
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Lu Y, Zhou X, Stemmer PM, Reid GE. Sulfonium ion derivatization, isobaric stable isotope labeling and data dependent CID- and ETD-MS/MS for enhanced phosphopeptide quantitation, identification and phosphorylation site characterization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:577-93. [PMID: 21952753 PMCID: PMC4228788 DOI: 10.1007/s13361-011-0190-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 06/03/2011] [Accepted: 06/03/2011] [Indexed: 05/12/2023]
Abstract
An amine specific peptide derivatization strategy involving the use of novel isobaric stable isotope encoded 'fixed charge' sulfonium ion reagents, coupled with an analysis strategy employing capillary HPLC, ESI-MS, and automated data dependent ion trap CID-MS/MS, -MS(3), and/or ETD-MS/MS, has been developed for the improved quantitative analysis of protein phosphorylation, and for identification and characterization of their site(s) of modification. Derivatization of 50 synthetic phosphopeptides with S,S'-dimethylthiobutanoylhydroxysuccinimide ester iodide (DMBNHS), followed by analysis using capillary HPLC-ESI-MS, yielded an average 2.5-fold increase in ionization efficiencies and a significant increase in the presence and/or abundance of higher charge state precursor ions compared to the non-derivatized phosphopeptides. Notably, 44% of the phosphopeptides (22 of 50) in their underivatized states yielded precursor ions whose maximum charge states corresponded to +2, while only 8% (4 of 50) remained at this maximum charge state following DMBNHS derivatization. Quantitative analysis was achieved by measuring the abundances of the diagnostic product ions corresponding to the neutral losses of 'light' (S(CH(3))(2)) and 'heavy' (S(CD(3))(2)) dimethylsulfide exclusively formed upon CID-MS/MS of isobaric stable isotope labeled forms of the DMBNHS derivatized phosphopeptides. Under these conditions, the phosphate group stayed intact. Access for a greater number of peptides to provide enhanced phosphopeptide sequence identification and phosphorylation site characterization was achieved via automated data-dependent CID-MS(3) or ETD-MS/MS analysis due to the formation of the higher charge state precursor ions. Importantly, improved sequence coverage was observed using ETD-MS/MS following introduction of the sulfonium ion fixed charge, but with no detrimental effects on ETD fragmentation efficiency.
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Affiliation(s)
- Yali Lu
- Department of Chemistry, Michigan State University, 229 Chemistry Building, Michigan State University, East Lansing, MI, 48824, USA
| | - Xiao Zhou
- Department of Chemistry, Michigan State University, 229 Chemistry Building, Michigan State University, East Lansing, MI, 48824, USA
| | - Paul M. Stemmer
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI, USA
| | - Gavin E. Reid
- Department of Chemistry, Michigan State University, 229 Chemistry Building, Michigan State University, East Lansing, MI, 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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36
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Han D, Moon S, Kim Y, Ho WK, Kim K, Kang Y, Jun H, Kim Y. Comprehensive phosphoproteome analysis of INS-1 pancreatic β-cells using various digestion strategies coupled with liquid chromatography-tandem mass spectrometry. J Proteome Res 2012; 11:2206-23. [PMID: 22276854 DOI: 10.1021/pr200990b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Type 2 diabetes results from aberrant regulation of the phosphorylation cascade in beta-cells. Phosphorylation in pancreatic beta-cells has not been examined extensively, except with regard to subcellular phosphoproteomes using mitochondria. Thus, robust, comprehensive analytical strategies are needed to characterize the many phosphorylated proteins that exist, because of their low abundance, the low stoichiometry of phosphorylation, and the dynamic regulation of phosphoproteins. In this study, we attempted to generate data on a large-scale phosphoproteome from the INS-1 rat pancreatic beta-cell line using linear ion trap MS/MS. To profile the phosphoproteome in-depth, we used comprehensive phosphoproteomic strategies, including detergent-based protein extraction (SDS and SDC), differential sample preparation (in-gel, in-solution digestion, and FASP), TiO2 enrichment, and MS replicate analyses (MS2-only and multiple-stage activation). All spectra were processed and validated by stringent multiple filtering using target and decoy databases. We identified 2467 distinct phosphorylation sites on 1419 phosphoproteins using 4 mg of INS-1 cell lysate in 24 LC-MS/MS runs, of which 683 (27.7%) were considered novel phosphorylation sites that have not been characterized in human, mouse, or rat homologues. Our informatics data constitute a rich bioinformatics resource for investigating the function of reversible phosphorylation in pancreatic beta-cells. In particular, novel phosphorylation sites on proteins that mediate the pathology of type 2 diabetes, such as Pdx-1, Nkx.2, and Srebf1, will be valuable targets in ongoing phosphoproteomics studies.
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Affiliation(s)
- Dohyun Han
- Department of Biomedical Engineering, Institute of Medical & Biological Engineering, Medical Research Center, College of Medicine, Yongon-Dong, Seoul, 110-799 Korea
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37
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Huang Y, Thelen JJ. KiC assay: a quantitative mass spectrometry-based approach for kinase client screening and activity analysis [corrected]. Methods Mol Biol 2012; 893:359-70. [PMID: 22665311 DOI: 10.1007/978-1-61779-885-6_22] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein phosphorylation is one of the most important posttranslational modifications (PTMs) involved in the transduction of cellular signals. The number of kinases in eukaryotic genomes ranges from several hundred to over one thousand. And with rapidly evolving mass spectrometry (MS)-based approaches, thousands to tens of thousands of phosphorylation sites (phosphosites) have been reported from various eukaryotic organisms, from man to plants. In this relative context, few bona fide kinase-client relationships have been identified to date. To merge the gap between these phosphosites and the cognate kinases that beget these events, comparable large-scale methodologies are required. We describe in detail a MS-based method for identifying kinase-client interactions and quantifying kinase activity. We term this novel Kinase-Client assay, the KiC assay. The KiC assay relies upon the fact that substrate specificities of many kinases are largely determined by primary amino acid sequence or phosphorylation motifs, which consist of key amino acids surrounding the phosphorylation sites. The workflow for detecting kinase-substrate interactions includes four major steps: (1) preparation of purified kinases and synthetic peptide library, (2) in vitro kinase peptide library assay, (3) liquid chromatography (LC)-tandem MS (MS/MS) analysis, and (4) data processing and interpretation. Kinase activity is quantified with the KiC assay by monitoring spectral counts of phosphorylated and unphosphorylated peptides as the readout from LC-tandem mass spectrometry. The KiC assay can be applied as a discovery assay to screen kinases against a synthetic peptide library to find kinase-client relationships or as a targeted assay to characterize kinase kinetics.
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Affiliation(s)
- Yadong Huang
- Interdisciplinary Plant Group, Department of Biochemistry, University of Missouri-Columbia, Columbia, MO, USA
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38
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Comparative analysis of Erk phosphorylation suggests a mixed strategy for measuring phospho-form distributions. Mol Syst Biol 2011; 7:482. [PMID: 21487401 PMCID: PMC3097084 DOI: 10.1038/msb.2011.15] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 03/15/2011] [Indexed: 01/21/2023] Open
Abstract
The functional impact of multisite protein phosphorylation can depend on both the numbers and the positions of phosphorylated sites-the global pattern of phosphorylation or 'phospho-form'-giving biological systems profound capabilities for dynamic information processing. A central problem in quantitative systems biology, therefore, is to measure the 'phospho-form distribution': the relative amount of each of the 2(n) phospho-forms of a protein with n-phosphorylation sites. We compared four potential methods-western blots with phospho-specific antibodies, peptide-based liquid chromatography (LC) and mass spectrometry (MS; pepMS), protein-based LC/MS (proMS) and nuclear magnetic resonance spectroscopy (NMR)-on differentially phosphorylated samples of the well-studied mitogen-activated protein kinase Erk2, with two phosphorylation sites. The MS methods were quantitatively consistent with each other and with NMR to within 10%, but western blots, while highly sensitive, showed significant discrepancies with MS. NMR also uncovered two additional phosphorylations, for which a combination of pepMS and proMS yielded an estimate of the 16-member phospho-form distribution. This combined MS strategy provides an optimal mixture of accuracy and coverage for quantifying distributions, but positional isomers remain a challenging problem.
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39
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Leitner A, Sturm M, Lindner W. Tools for analyzing the phosphoproteome and other phosphorylated biomolecules: a review. Anal Chim Acta 2011; 703:19-30. [PMID: 21843671 DOI: 10.1016/j.aca.2011.07.012] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 07/07/2011] [Accepted: 07/10/2011] [Indexed: 11/28/2022]
Abstract
Enrichment, separation and mass spectrometric analysis of biomolecules carrying a phosphate group plays an important role in current analytical chemistry. Application areas range from the preparative enrichment of phospholipids for biotechnological purposes and the separation and purification of plasmid DNA or mRNA to the specific preconcentration of phosphoproteins and -peptides to facilitate their later identification and characterization by mass spectrometry. Most of the recent improvements in this field were triggered by the need for phosphopeptide enrichment technology for the analysis of cellular protein phosphorylation events with the help of liquid chromatography-mass spectrometry. The high sensitivity of mass spectrometry and the possibility to combine this technique with different separation modes in liquid chromatography have made it the method of choice for proteome analysis. However, in the case of phosphoprotein analysis, the low abundance of the resulting phosphopeptides and their low quality fragment spectra interfere with the identification of phosphorylation events. Recent developments in phosphopeptide enrichment and fragmentation technologies successfully helped to overcome these limitations. In this review, we will focus on sample preparation techniques in the field of phosphoproteomics, but also highlight recent advancements for the analysis of other phosphorylated biomolecules.
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40
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Meléndez LM, Colon K, Rivera L, Rodriguez-Franco E, Toro-Nieves D. Proteomic analysis of HIV-infected macrophages. J Neuroimmune Pharmacol 2011; 6:89-106. [PMID: 21153888 PMCID: PMC3028070 DOI: 10.1007/s11481-010-9253-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 11/23/2010] [Indexed: 12/21/2022]
Abstract
Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate immunity against pathogens including HIV. These cells are also important viral reservoirs in the central nervous system and secrete inflammatory mediators and toxins that affect the tissue environment and function of surrounding cells. In the era of antiretroviral therapy, there are fewer of these inflammatory mediators. Proteomic approaches including surface enhancement laser desorption ionization, one- and two-dimensional difference in gel electrophoresis, and liquid chromatography tandem mass spectrometry have been used to uncover the proteins produced by in vitro HIV-infected monocytes, macrophages, and microglia. These approaches have advanced the understanding of novel mechanisms for HIV replication and neuronal damage. They have also been used in tissue macrophages that restrict HIV replication to understand the mechanisms of restriction for future therapies. In this review, we summarize the proteomic studies on HIV-infected mononuclear phagocytes and discuss other recent proteomic approaches that are starting to be applied to this field. As proteomic instruments and methods evolve to become more sensitive and quantitative, future studies are likely to identify more proteins that can be targeted for diagnosis or therapy and to uncover novel disease mechanisms.
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Affiliation(s)
- Loyda M Meléndez
- Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San Juan 00935, Puerto Rico.
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41
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Eyrich B, Sickmann A, Zahedi RP. Catch me if you can: mass spectrometry-based phosphoproteomics and quantification strategies. Proteomics 2011; 11:554-70. [PMID: 21226000 DOI: 10.1002/pmic.201000489] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2010] [Revised: 09/13/2010] [Accepted: 09/21/2010] [Indexed: 01/16/2023]
Abstract
Phosphorylation of proteins is one of the most prominent PTMs and for instance a key regulator of signal transduction. In order to improve our understanding of cellular phosphorylation events, considerable effort has been devoted to improving the analysis of phosphorylation by MS-based proteomics. Different enrichment strategies for phosphorylated peptides/proteins, such as immunoaffinity chromatography (IMAC) or titanium dioxide, have been established and constantly optimized for subsequent MS analysis. Concurrently, specific MS techniques were developed for more confident identification and phosphorylation site localization. In addition, more attention is paid to the LC-MS instrumentation to avoid premature loss of phosphorylated peptides within the analytical system. Despite major advances in all of these fields, the analysis of phosphopeptides still remains far from being routine in proteomics. However, to reveal cellular regulation by phosphorylation events, not only qualitative information about the phosphorylation status of proteins but also, in particular, quantitative information about distinct changes in phosphorylation patterns upon specific stimulation is mandatory. Thus, yielded insights are of outstanding importance for the emerging field of systems biology. In this review, we will give an insight into the historical development of phosphoproteome analysis and discuss its recent progress particularly regarding phosphopeptide quantification and assessment of phosphorylation stoichiometry.
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Affiliation(s)
- Beate Eyrich
- Leibniz-Institut für Analytische Wissenschaften-ISAS-eV, Dortmund, Germany
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42
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Rosenqvist H, Ye J, Jensen ON. Analytical strategies in mass spectrometry-based phosphoproteomics. Methods Mol Biol 2011; 753:183-213. [PMID: 21604124 DOI: 10.1007/978-1-61779-148-2_13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Phosphoproteomics, the systematic study of protein phosphorylation events and cell signaling networks in cells and tissues, is a rapidly evolving branch of functional proteomics. Current phosphoproteomics research provides a large toolbox of strategies and protocols that may assist researchers to reveal key regulatory events and phosphorylation-mediated processes in the cell and in whole organisms. We present an overview of sensitive and robust analytical methods for phosphopeptide analysis, including calcium phosphate precipitation and affinity enrichment methods such as IMAC and TiO(2). We then discuss various tandem mass spectrometry approaches for phosphopeptide sequencing and quantification, and we consider aspects of phosphoproteome data analysis and interpretation. Efficient integration of these stages of phosphoproteome analysis is highly important to ensure a successful outcome of large-scale experiments for studies of phosphorylation-mediated protein regulation.
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Affiliation(s)
- Heidi Rosenqvist
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, Scotland, UK
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43
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Ledvina AR, Beauchene NA, McAlister GC, Syka JEP, Schwartz JC, Griep-Raming J, Westphall MS, Coon JJ. Activated-ion electron transfer dissociation improves the ability of electron transfer dissociation to identify peptides in a complex mixture. Anal Chem 2010; 82:10068-74. [PMID: 21062032 DOI: 10.1021/ac1020358] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Using a modified electron transfer dissociation (ETD)-enabled quadrupole linear ion trap (QLT) mass spectrometer, we demonstrate the utility of IR activation concomitant with ETD ion-ion reactions (activated-ion ETD, AI-ETD). Analyzing 12 strong cation exchanged (SCX) fractions of a LysC digest of human cell protein extract using ETD, collision-activated dissociation (CAD), and AI-ETD, we find that AI-ETD generates 13 405 peptide spectral matches (PSMs) at a 1% false-discovery rate (1% FDR), surpassing both ETD (7 968) and CAD (10 904). We also analyze 12 SCX fractions of a tryptic digest of human cell protein extract and find that ETD produces 6 234 PSMs, AI-ETD 9 130 PSMs, and CAD 15 209 PSMs. Compared to ETD with supplemental collisional activation (ETcaD), AI-ETD generates ∼80% more PSMs for the whole cell lysate digested with trypsin and ∼50% more PSMs for the whole cell lysate digested with LysC.
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Affiliation(s)
- Aaron R Ledvina
- Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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44
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Savitski MM, Lemeer S, Boesche M, Lang M, Mathieson T, Bantscheff M, Kuster B. Confident phosphorylation site localization using the Mascot Delta Score. Mol Cell Proteomics 2010; 10:M110.003830. [PMID: 21057138 DOI: 10.1074/mcp.m110.003830] [Citation(s) in RCA: 223] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Large scale phosphorylation analysis is more and more getting into focus of proteomic research. Although it is now possible to identify thousands of phosphorylated peptides in a biological system, confident site localization remains challenging. Here we validate the Mascot Delta Score (MD-score) as a simple method that achieves similar sensitivity and specificity for phosphosite localization as the published Ascore, which is mainly used in conjunction with Sequest. The MD-score was evaluated using liquid chromatography-tandem MS data of 180 individually synthesized phosphopeptides with precisely known phosphorylation sites. We tested the MD-score for a wide range of commonly available fragmentation methods and found it to be applicable throughout with high statistical significance. However, the different fragmentation techniques differ strongly in their ability to localize phosphorylation sites. At 1% false localization rate, the highest number of correctly assigned phosphopeptides was achieved by higher energy collision induced dissociation in combination with an Orbitrap mass analyzer followed very closely by low resolution ion trap spectra obtained after electron transfer dissociation. Both these methods are significantly better than low resolution spectra acquired after collision induced dissociation and multi stage activation. Score thresholds determined from simple calibration functions for each fragmentation method were stable over replicate analyses of the phosphopeptide set. The MD-score outperforms the Ascore for tyrosine phosphorylated peptides and we further show that the ability to call sites correctly increases with increasing distance of two candidate sites within a peptide sequence. The MD-score does not require complex computational steps which makes it attractive in terms of practical utility. We provide all mass spectra and the synthetic peptides to the community so that the development of present and future localization software can be benchmarked and any laboratory can determine MD-scores and localization probabilities for their individual analytical set up.
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45
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Trost M, Bridon G, Desjardins M, Thibault P. Subcellular phosphoproteomics. MASS SPECTROMETRY REVIEWS 2010; 29:962-90. [PMID: 20931658 DOI: 10.1002/mas.20297] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Protein phosphorylation represents one of the most extensively studied post-translational modifications, primarily due to the emergence of sensitive methods enabling the detection of this modification both in vitro and in vivo. The availability of enrichment methods combined with sensitive mass spectrometry instrumentation has played a crucial role in uncovering the dynamic changes and the large expanding repertoire of this reversible modification. The structural changes imparted by the phosphorylation of specific residues afford exquisite mechanisms for the regulation of protein functions by modulating new binding sites on scaffold proteins or by abrogating protein-protein interactions. However, the dynamic interplay of protein phosphorylation is not occurring randomly within the cell but is rather finely orchestrated by specific kinases and phosphatases that are unevenly distributed across subcellular compartments. This spatial separation not only regulates protein phosphorylation but can also control the activity of other enzymes and the transfer of other post-translational modifications. While numerous large-scale phosphoproteomics studies highlighted the extent and diversity of phosphoproteins present in total cell lysates, the further understanding of their regulation and biological activities require a spatio-temporal resolution only achievable through subcellular fractionation. This review presents a first account of the emerging field of subcellular phosphoproteomics where cell fractionation approaches are combined with sensitive mass spectrometry methods to facilitate the identification of low abundance proteins and to unravel the intricate regulation of protein phosphorylation.
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Affiliation(s)
- Matthias Trost
- Institute for Research in Immunology and Cancer, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, Québec, Canada H3C 3J7
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46
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Savitski MM, Scholten A, Sweetman G, Mathieson T, Bantscheff M. Evaluation of Data Analysis Strategies for Improved Mass Spectrometry-Based Phosphoproteomics. Anal Chem 2010; 82:9843-9. [DOI: 10.1021/ac102083q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
| | - Arjen Scholten
- Cellzome AG, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | - Toby Mathieson
- Cellzome AG, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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47
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Nesvizhskii AI. A survey of computational methods and error rate estimation procedures for peptide and protein identification in shotgun proteomics. J Proteomics 2010; 73:2092-123. [PMID: 20816881 DOI: 10.1016/j.jprot.2010.08.009] [Citation(s) in RCA: 358] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 08/25/2010] [Accepted: 08/25/2010] [Indexed: 12/18/2022]
Abstract
This manuscript provides a comprehensive review of the peptide and protein identification process using tandem mass spectrometry (MS/MS) data generated in shotgun proteomic experiments. The commonly used methods for assigning peptide sequences to MS/MS spectra are critically discussed and compared, from basic strategies to advanced multi-stage approaches. A particular attention is paid to the problem of false-positive identifications. Existing statistical approaches for assessing the significance of peptide to spectrum matches are surveyed, ranging from single-spectrum approaches such as expectation values to global error rate estimation procedures such as false discovery rates and posterior probabilities. The importance of using auxiliary discriminant information (mass accuracy, peptide separation coordinates, digestion properties, and etc.) is discussed, and advanced computational approaches for joint modeling of multiple sources of information are presented. This review also includes a detailed analysis of the issues affecting the interpretation of data at the protein level, including the amplification of error rates when going from peptide to protein level, and the ambiguities in inferring the identifies of sample proteins in the presence of shared peptides. Commonly used methods for computing protein-level confidence scores are discussed in detail. The review concludes with a discussion of several outstanding computational issues.
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48
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Przybylski C, Jünger MA, Aubertin J, Radvanyi F, Aebersold R, Pflieger D. Quantitative Analysis of Protein Complex Constituents and Their Phosphorylation States on a LTQ-Orbitrap Instrument. J Proteome Res 2010; 9:5118-32. [DOI: 10.1021/pr1003888] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Cédric Przybylski
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
| | - Martin A. Jünger
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
| | - Johannes Aubertin
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
| | - François Radvanyi
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
| | - Ruedi Aebersold
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
| | - Delphine Pflieger
- Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, CNRS UMR 8587, Laboratoire d’Analyse et de Modélisation pour la Biologie et l’Environnement, Université d’Evry-Val-d’Essonne, 91025 Evry, France, Institute for Molecular Systems Biology, ETH, Zürich, Switzerland and Faculty of Science, University of Zurich, Zurich, Switzerland, and Équipe Oncologie Moléculaire, UMR 144 - CNRS, Institut Curie, 75248 Paris, France
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Gloeckner CJ, Boldt K, von Zweydorf F, Helm S, Wiesent L, Sarioglu H, Ueffing M. Phosphopeptide analysis reveals two discrete clusters of phosphorylation in the N-terminus and the Roc domain of the Parkinson-disease associated protein kinase LRRK2. J Proteome Res 2010; 9:1738-45. [PMID: 20108944 DOI: 10.1021/pr9008578] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) that increase its kinase activity associate with familial forms of Parkinson disease (PD). As phosphorylation determines the functional state of most protein kinases, we systematically mapped LRRK2 phosphorylation sites by mass spectrometry. Our analysis revealed a high degree of constitutive phosphorylation in a narrow serine-rich region preceding the LRR-domain. Allowing de novo autophosphorylation of purified LRRK2 in an in vitro autokinase assay prior to mass spectrometric analysis, we discovered multiple sites of autophosphorylation. Solely serine and threonine residues were found phosphorylated suggesting LRRK2 as a true serine threonine kinase. Autophosphorylation mainly targets the ROC GTPase domain and its clustering around the GTP binding pocket of ROC suggests cross-regulatory activity between kinase and Roc domain. In conclusion, the phosphoprotein LRRK2 functions as an autocatalytically active serine threonine kinase. Clustering of phosphosites within two discrete domains suggest that phosphorylation may regulate its biological functions in a yet unknown fashion.
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Affiliation(s)
- Christian Johannes Gloeckner
- Helmholtz Zentrum München-German Research Center for Environmental Health, Department of Protein Science, Neuherberg, Germany
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50
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Jiang X, Ye M, Han G, Dong X, Zou H. Classification Filtering Strategy to Improve the Coverage and Sensitivity of Phosphoproteome Analysis. Anal Chem 2010; 82:6168-75. [DOI: 10.1021/ac100975t] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xinning Jiang
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Mingliang Ye
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Guanghui Han
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Xiaoli Dong
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hanfa Zou
- CAS Key Laboratory of Separation Sciences for Analytical Chemistry, National Chromatographic R&A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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