bims-mascan Biomed News
on Mass spectrometry in cancer research
Issue of 2022–09–18
fifteen papers selected by
Giovanny Rodríguez Blanco, Uniklinikum Graz
  1. Optimized protocol to isolate primary mouse peritoneal macrophage metabolites.
  2. Molecular phenotyping approaches for the detection and monitoring of carbapenem-resistant Enterobacteriaceae by mass spectrometry.
  3. Lipid profiling analyses from mouse models and human infants.
  4. Isobaric labeling: Expanding the breadth, accuracy, depth, and diversity of sample multiplexing.
  5. Sex differences in brain tumor glutamine metabolism reveal sex-specific vulnerabilities to treatment.
  6. Novel Isobaric Tagging Reagent Enabled Multiplex Quantitative Glycoproteomics via Electron-Transfer/Higher-Energy Collisional Dissociation (EThcD) Mass Spectrometry.
  7. Fatty acid metabolism in aggressive B-cell lymphoma is inhibited by tetraspanin CD37.
  8. Metabolic reprogramming in the OPA1-deficient cells.
  9. N-Glycan Isomer Differentiation by Zero Flow Capillary Electrophoresis Coupled to Mass Spectrometry.
  10. Quantitative Analysis and Structural Elucidation of Fatty Acids by Isobaric Multiplex Labeling Reagents for Carbonyl-Containing Compound (SUGAR) Tags and m-CPBA Epoxidation.
  11. Recent advances and limitations of mTOR inhibitors in the treatment of cancer.
  12. Cytoskeletal vimentin regulates cell size and autophagy through mTORC1 signaling.
  13. DirectMS1Quant: Ultrafast Quantitative Proteomics with MS/MS-Free Mass Spectrometry.
  14. Physiological media advance cell culture experiments.
  15. JUMPptm: Integrated software for sensitive identification of post-translational modifications and its application in Alzheimer's disease study.
  1. STAR Protoc. 2022 Sep 13. pii: S2666-1667(22)00548-2. [Epub ahead of print]3(4): 101668
    Optimized protocol to isolate primary mouse peritoneal macrophage metabolites.
    Adam De Jesus, Carolina M Pusec, Tivoli Nguyen, Farnaz Keyhani-Nejad, Peng Gao, Samuel E Weinberg, Hossein Ardehali.
      Peritoneal macrophages (PMs) have been shown to have higher stability compared to other macrophage subtypes. However, obtaining enough PMs from a single mouse is often a limitation for metabolomics analysis. Here, we describe a protocol to isolate metabolites from a small number of mouse primary PMs for 13C-stable glucose tracing and metabolomics. Our protocol uses X for metabolite extraction instead of methanol. Our protocol can consistently extract metabolites from low cell number samples with fewer steps than methanol-based approaches. For complete details on the use and execution of this protocol, please refer to De Jesus et al., (2022).
    Keywords:  Cell isolation; Immunology; Mass spectrometry; Metabolism; Metabolomics
    DOI:  https://doi.org/10.1016/j.xpro.2022.101668
  2. J Mass Spectrom Adv Clin Lab. 2022 Nov;26 9-19
    Molecular phenotyping approaches for the detection and monitoring of carbapenem-resistant Enterobacteriaceae by mass spectrometry.
    Breanna Dixon, Waqar M Ahmed, Tim Felton, Stephen J Fowler.
      Antimicrobial resistance is increasing in prevalence and there is a clear need for the development of rapid detection methods in clinical diagnostics. This review explores -omics studies utilising mass spectrometry to investigate the molecular phenotype associated with carbapenem resistance. Whilst the specific mechanisms of carbapenem resistance are well characterised, the resistant phenotype is poorly understood. Understanding how the acquisition of resistance affects cellular physiology and cell metabolism through molecular phenotyping is a necessary step towards detecting resistance by diagnostic means. In addition, this article examines the potential of mass spectrometry for the identification of resistance biomarkers through molecular profiling of bacteria. Developments in mass spectrometry platforms are expanding the biomarker-based diagnostic landscape. Targeted measures, such as high-resolution mass spectrometry coupled with chromatographic separation show considerable promise for the identification of molecular signatures and the development of a rapid diagnostic assay for the detection of carbapenem resistance.
    Keywords:  AMR, antimicrobial resistance; Antimicrobial resistance; CP, carbapenemase-producing; CR, carbapenem-resistance; CRE, carbapenem-resistant Enterobacteriaceae; CRO, carbapenem-resistant organism; DI, direct infusion; Enterobacteriaceae; FAME, fatty acid methyl ester; FTIR, Fourier-transform infrared spectroscopy; GC, gas chromatography; HILIC, hydrophilic interaction liquid chromatography; IM, ion mobility; KPC, Klebsiella pneumoniae carbapenemase; LC, liquid chromatography; Lipidomics; MALDI-TOF MS, matrix-assister laser desorption/ionisation-time of flight mass spectrometry; MIC, minimum inhibitory concentration; MOLI, metal oxide laser ionisation; MOS, metal oxide sensor; MRSA, methicillin-resistant Staphylococcus aureus; MS, mass spectrometry; Mass spectrometry; Metabolomics; NMR, nuclear magnetic resonance; OMV, outer membrane vesicle; PTM, post-translational modification; Proteomics; SESI, secondary electrospray ionisation; SIFT, selected-ion flow-tube; SPME, solid phase microextraction; TOF, time of flight
    DOI:  https://doi.org/10.1016/j.jmsacl.2022.09.001
  3. STAR Protoc. 2022 Sep 15. pii: S2666-1667(22)00559-7. [Epub ahead of print]3(4): 101679
    Lipid profiling analyses from mouse models and human infants.
    Laurentya Olga, Ivana Bobeldijk-Pastorova, Richard C Bas, Florine Seidel, Stuart G Snowden, Samuel Furse, Ken K Ong, Robert Kleemann, Albert Koulman.
      This protocol outlines a translational lipidomic approach to discover lipid biomarkers that could predict morphometric body and histological organ measurements (e.g., weight and adiposity gains) during specific stages of life (e.g., early life). We describe procedures ranging from animal experimentation and histological analyses to downstream analytical steps through lipid profiling, both in mice and humans. This protocol represents a reliable and versatile approach to translate and validate candidate lipid biomarkers from animal models to a human cohort. For complete details on the use and execution of this protocol, please refer to Olga et al. (2021).
    Keywords:  Clinical protocol; Health sciences; Mass spectrometry; Metabolism; Metabolomics; Systems biology
    DOI:  https://doi.org/10.1016/j.xpro.2022.101679
  4. Proteomics. 2022 Sep 11. e2200328
    Isobaric labeling: Expanding the breadth, accuracy, depth, and diversity of sample multiplexing.
    Joao A Paulo.
      Isobaric labeling has rapidly become a predominant strategy for proteome-wide abundance measurements. Coupled to mass spectrometry, sample multiplexing techniques using isobaric labeling are unparalleled for profiling proteins and posttranslational modifications across multiple samples in a single experiment. Here, I highlight aspects of isobaric labeling in the context of expanding the breadth of multiplexing, improving quantitative accuracy and proteome depth, and developing a wide range of diverse applications. I underscore two facets that enhance quantitative accuracy and reproducibility, specifically the availability of quality control standards for isobaric labeling experiments and the evolution of data acquisition methods. I also emphasize the necessity for standardized methodologies, particularly for emerging high-throughput workflows. Future developments in sample multiplexing will further strengthen the importance of isobaric labeling for comprehensive proteome profiling. This article is protected by copyright. All rights reserved.
    Keywords:  RTS-MS3; SPS-MS3; TMT; interference; isobaric tag; multiplexing
    DOI:  https://doi.org/10.1002/pmic.202200328
  5. Med (N Y). 2022 Sep 08. pii: S2666-6340(22)00365-8. [Epub ahead of print]
    Sex differences in brain tumor glutamine metabolism reveal sex-specific vulnerabilities to treatment.
    Jasmin Sponagel, Jill K Jones, Cheryl Frankfater, Shanshan Zhang, Olivia Tung, Kevin Cho, Kelsey L Tinkum, Hannah Gass, Elena Nunez, Douglas R Spitz, Prakash Chinnaiyan, Jacob Schaefer, Gary J Patti, Maya S Graham, Audrey Mauguen, Milan Grkovski, Mark P Dunphy, Simone Krebs, Jingqin Luo, Joshua B Rubin, Joseph E Ippolito.
       BACKGROUND: Brain cancer incidence and mortality rates are greater in males. Understanding the molecular mechanisms that underlie those sex differences could improve treatment strategies. Although sex differences in normal metabolism are well described, it is currently unknown whether they persist in cancerous tissue.
    METHODS: Using positron emission tomography (PET) imaging and mass spectrometry, we assessed sex differences in glioma metabolism in samples from affected individuals. We assessed the role of glutamine metabolism in male and female murine transformed astrocytes using isotope labeling, metabolic rescue experiments, and pharmacological and genetic perturbations to modulate pathway activity.
    FINDINGS: We found that male glioblastoma surgical specimens are enriched for amino acid metabolites, including glutamine. Fluoroglutamine PET imaging analyses showed that gliomas in affected male individuals exhibit significantly higher glutamine uptake. These sex differences were well modeled in murine transformed astrocytes, in which male cells imported and metabolized more glutamine and were more sensitive to glutaminase 1 (GLS1) inhibition. The sensitivity to GLS1 inhibition in males was driven by their dependence on glutamine-derived glutamate for α-ketoglutarate synthesis and tricarboxylic acid (TCA) cycle replenishment. Females were resistant to GLS1 inhibition through greater pyruvate carboxylase (PC)-mediated TCA cycle replenishment, and knockdown of PC sensitized females to GLS1 inhibition.
    CONCLUSION: Our results show that clinically important sex differences exist in targetable elements of metabolism. Recognition of sex-biased metabolism may improve treatments through further laboratory and clinical research.
    FUNDING: This work was supported by NIH grants, Joshua's Great Things, the Siteman Investment Program, and the Barnard Research Fund.
    Keywords:  TCA cycle; Translation to patients; cancer metabolism; glioma; glutaminase; glutamine metabolism; glutathione; pyruvate carboxylase; sex differences; solid-state NMR; α-ketoglutarate
    DOI:  https://doi.org/10.1016/j.medj.2022.08.005
  6. J Am Soc Mass Spectrom. 2022 Sep 12.
    Novel Isobaric Tagging Reagent Enabled Multiplex Quantitative Glycoproteomics via Electron-Transfer/Higher-Energy Collisional Dissociation (EThcD) Mass Spectrometry.
    Miyang Li, Xiaofang Zhong, Yu Feng, Lingjun Li.
      Protein glycosylation, covalent attachment of carbohydrates to polypeptide chains, is a highly important post-translational modification involved in many essential physiological processes. Comprehensive site-specific and quantitative analysis is crucial for revealing the diverse functions and dynamics of glycosylation. To characterize intact glycopeptides, mass spectrometry (MS)-based glycoproteomics employs versatile fragmentation methods, among which electron-transfer/higher-energy collision dissociation (EThcD) has gained great popularity. However, the inherent limitation of EThcD in fragmenting low-charge ions has prevented its widespread applications. Furthermore, there is a need to develop a high-throughput strategy for comparative glycoproteomics with a large cohort of samples. Herein, we developed isobaric N,N-dimethyl leucine-derivatized ethylenediamine (DiLeuEN) tags to increase the charge states of glycopeptides, thereby improving the fragmentation efficiency and allowing for in-depth intact glycopeptide analysis, especially for sialoglycopeptides. Moreover, the unique reporter ions of DiLeuEN-labeled glycopeptides generated in tandem MS spectra enable relative quantification of up to four samples in a single analysis, which represents a new high-throughput method for quantitative glycoproteomics.
    Keywords:  DiLeuEN; EThcD; isobaric labeling; mass spectrometry; quantitative glycoproteomics
    DOI:  https://doi.org/10.1021/jasms.2c00177
  7. Nat Commun. 2022 Sep 13. 13(1): 5371
    Fatty acid metabolism in aggressive B-cell lymphoma is inhibited by tetraspanin CD37.
    Rens Peeters, Jorge Cuenca-Escalona, Esther A Zaal, Anna T Hoekstra, Anouk C G Balvert, Marcos Vidal-Manrique, Niek Blomberg, Sjoerd J van Deventer, Rinke Stienstra, Julia Jellusova, Martin Giera, Luciana Hannibal, Ute Spiekerkoetter, Martin Ter Beest, Celia R Berkers, Annemiek B van Spriel.
      The importance of fatty acid (FA) metabolism in cancer is well-established, yet the mechanisms underlying metabolic reprogramming remain elusive. Here, we identify tetraspanin CD37, a prognostic marker for aggressive B-cell lymphoma, as essential membrane-localized inhibitor of FA metabolism. Deletion of CD37 on lymphoma cells results in increased FA oxidation shown by functional assays and metabolomics. Furthermore, CD37-negative lymphomas selectively deplete palmitate from serum in mouse studies. Mechanistically, CD37 inhibits the FA transporter FATP1 through molecular interaction. Consequently, deletion of CD37 induces uptake and processing of exogenous palmitate into energy and essential building blocks for proliferation, and inhibition of FATP1 reverses this phenotype. Large lipid deposits and intracellular lipid droplets are observed in CD37-negative lymphoma tissues of patients. Moreover, inhibition of carnitine palmitoyl transferase 1 A significantly compromises viability and proliferation of CD37-deficient lymphomas. Collectively, our results identify CD37 as a direct gatekeeper of the FA metabolic switch in aggressive B-cell lymphoma.
    DOI:  https://doi.org/10.1038/s41467-022-33138-7
  8. Cell Mol Life Sci. 2022 Sep 14. 79(10): 517
    Metabolic reprogramming in the OPA1-deficient cells.
    Wenting Dai, Zhichao Wang, Qiong A Wang, David Chan, Lei Jiang.
      OPA1, a dynamin-related GTPase mutated in autosomal dominant optic atrophy, is essential for the fusion of the inner mitochondrial membrane. Although OPA1 deficiency leads to impaired mitochondrial morphology, the role of OPA1 in central carbon metabolism remains unclear. Here, we aim to explore the functional role and metabolic mechanism of OPA1 in cell fitness beyond the control of mitochondrial fusion. We applied [U-13C]glucose and [U-13C]glutamine isotope tracing techniques to OPA1-knockout (OPA1-KO) mouse embryonic fibroblasts (MEFs) compared to OPA1 wild-type (OPA1-WT) controls. Furthermore, the resulting tracing data were integrated by metabolic flux analysis to understand the underlying metabolic mechanism through which OPA1 deficiency reprograms cellular metabolism. OPA1-deficient MEFs were depleted of intracellular citrate, which was consistent with the decreased oxygen consumption rate in these cells with mitochondrial fission that is not balanced by mitochondrial fusion. Whereas oxidative glucose metabolism was impaired, OPA1-deficient cells activated glutamine-dependent reductive carboxylation and subsequently relied on this reductive metabolism to produce cytosolic citrate as a predominant acetyl-CoA source for de novo fatty acid synthesis. Prevention of cytosolic glutamine reductive carboxylation by GSK321, an inhibitor of isocitrate dehydrogenase 1 (IDH1), largely repressed lipid synthesis and blocked cell proliferation in OPA1-deficient MEFs. Our data support that, when glucose oxidation failed to support lipogenesis and proliferation in cells with unbalanced mitochondrial fission, OPA1 deficiency stimulated metabolic anaplerosis into glutamine-dependent reductive carboxylation in an IDH1-mediated manner.
    Keywords:  Cell growth; Citrate; De novo lipogenesis; OPA1 dysfunction; Oxidative metabolism; Reductive carboxylation
    DOI:  https://doi.org/10.1007/s00018-022-04542-5
  9. Anal Chem. 2022 Sep 13.
    N-Glycan Isomer Differentiation by Zero Flow Capillary Electrophoresis Coupled to Mass Spectrometry.
    Sander Wagt, Noortje de Haan, Wenjun Wang, Tao Zhang, Manfred Wuhrer, Guinevere S M Lageveen-Kammeijer.
      Isomeric N-glycans often vastly differ in their biological activities, hence the need for methods that allow resolving and structurally characterizing them in biological material. Here, we established a zero flow approach using capillary electrophoresis in combination with (tandem) mass spectrometry to allow structural characterization of isomeric N-glycans at high sensitivity. Additionally, diagnostic fragment ion ratios were identified, indicative for the antenna carrying specifically linked sialic acids. In total, 208 N-glycans were characterized in human plasma, with 57 compositions showing multiple isomers.
    DOI:  https://doi.org/10.1021/acs.analchem.2c02840
  10. Anal Chem. 2022 Sep 13.
    Quantitative Analysis and Structural Elucidation of Fatty Acids by Isobaric Multiplex Labeling Reagents for Carbonyl-Containing Compound (SUGAR) Tags and m-CPBA Epoxidation.
    Yu Feng, Yanni Lv, Ting-Jia Gu, Bingming Chen, Lingjun Li.
      In this study, a novel analytical method was developed to investigate fatty acids (FAs) for relative quantification, carbon-carbon double-bond localization, and cis-/trans-geometry differentiation by isobaric multiplex labeling reagents for carbonyl-containing compound (SUGAR) tag conjugation and meta-chloroperoxybenzoic acid (m-CPBA) epoxidation. FAs are essential components of cells and have diverse functions in energy storage and as complex lipid constituents. It has been reported that FAs play different roles in various biological processes such as the functional development of the brain. The comprehensive characterization and quantification of FAs are crucial to further elucidate their biological roles. However, it is challenging to perform relative quantification and structural elucidation of FAs using integrated mass spectrometry (MS)-based methods. Recently, our group developed isobaric multiplex SUGAR tags for quantitative glycomics. Besides aldehyde/ketone groups on glycans, hydrazide groups also possess reactivity toward carboxylic acids on FAs. In this study, we extended SUGAR tag labeling with FAs for the quantitative analysis by liquid chromatography (LC)-MS/MS in the positive ion mode and applied this strategy for the comparative analysis of FAs hydrolyzed from oil samples. In addition, to comprehensively elucidate the structures of unsaturated FAs, epoxidation by m-CPBA was performed before SUGAR tag labeling to enable carbon-carbon double-bond localization. Moreover, the cis- and trans-geometries of carbon-carbon double bonds in multiple pairs of monounsaturated FAs could also be differentiated in higher-energy collisional dissociation (HCD)-MS/MS. This study developed a high-throughput comprehensive FA analysis platform, which could be widely applied and utilized in biological and clinical studies.
    DOI:  https://doi.org/10.1021/acs.analchem.2c01917
  11. Cancer Cell Int. 2022 Sep 15. 22(1): 284
    Recent advances and limitations of mTOR inhibitors in the treatment of cancer.
    Eunus S Ali, Kangkana Mitra, Shamima Akter, Sarker Ramproshad, Banani Mondal, Ishaq N Khan, Muhammad Torequl Islam, Javad Sharifi-Rad, Daniela Calina, William C Cho.
      The PI3K-Akt-mechanistic (formerly mammalian) target of the rapamycin (mTOR) signaling pathway is important in a variety of biological activities, including cellular proliferation, survival, metabolism, autophagy, and immunity. Abnormal PI3K-Akt-mTOR signalling activation can promote transformation by creating a cellular environment conducive to it. Deregulation of such a system in terms of genetic mutations and amplification has been related to several human cancers. Consequently, mTOR has been recognized as a key target for the treatment of cancer, especially for treating cancers with elevated mTOR signaling due to genetic or metabolic disorders. In vitro and in vivo, rapamycin which is an immunosuppressant agent actively suppresses the activity of mTOR and reduces cancer cell growth. As a result, various sirolimus-derived compounds have now been established as therapies for cancer, and now these medications are being investigated in clinical studies. In this updated review, we discuss the usage of sirolimus-derived compounds and other drugs in several preclinical or clinical studies as well as explain some of the challenges involved in targeting mTOR for treating various human cancers.
    Keywords:  Cancer; Rapamycin; Targeted therapy; mTOR inhibitors; mTOR pathway; mTORC1; mTORC2
    DOI:  https://doi.org/10.1186/s12935-022-02706-8
  12. PLoS Biol. 2022 Sep;20(9): e3001737
    Cytoskeletal vimentin regulates cell size and autophagy through mTORC1 signaling.
    Ponnuswamy Mohanasundaram, Leila S Coelho-Rato, Mayank Kumar Modi, Marta Urbanska, Franziska Lautenschläger, Fang Cheng, John E Eriksson.
      The nutrient-activated mTORC1 (mechanistic target of rapamycin kinase complex 1) signaling pathway determines cell size by controlling mRNA translation, ribosome biogenesis, protein synthesis, and autophagy. Here, we show that vimentin, a cytoskeletal intermediate filament protein that we have known to be important for wound healing and cancer progression, determines cell size through mTORC1 signaling, an effect that is also manifested at the organism level in mice. This vimentin-mediated regulation is manifested at all levels of mTOR downstream target activation and protein synthesis. We found that vimentin maintains normal cell size by supporting mTORC1 translocation and activation by regulating the activity of amino acid sensing Rag GTPase. We also show that vimentin inhibits the autophagic flux in the absence of growth factors and/or critical nutrients, demonstrating growth factor-independent inhibition of autophagy at the level of mTORC1. Our findings establish that vimentin couples cell size and autophagy through modulating Rag GTPase activity of the mTORC1 signaling pathway.
    DOI:  https://doi.org/10.1371/journal.pbio.3001737
  13. Anal Chem. 2022 Sep 12.
    DirectMS1Quant: Ultrafast Quantitative Proteomics with MS/MS-Free Mass Spectrometry.
    Mark V Ivanov, Julia A Bubis, Vladimir Gorshkov, Irina A Tarasova, Lev I Levitsky, Elizaveta M Solovyeva, Anastasiya V Lipatova, Frank Kjeldsen, Mikhail V Gorshkov.
      Recently, we presented the DirectMS1 method of ultrafast proteome-wide analysis based on minute-long LC gradients and MS1-only mass spectra acquisition. Currently, the method provides the depth of human cell proteome coverage of 2500 proteins at a 1% false discovery rate (FDR) when using 5 min LC gradients and 7.3 min runtime in total. While the standard MS/MS approaches provide 4000-5000 protein identifications within a couple of hours of instrumentation time, we advocate here that the higher number of identified proteins does not always translate into better quantitation quality of the proteome analysis. To further elaborate on this issue, we performed a one-on-one comparison of quantitation results obtained using DirectMS1 with three popular MS/MS-based quantitation methods: label-free (LFQ) and tandem mass tag quantitation (TMT), both based on data-dependent acquisition (DDA) and data-independent acquisition (DIA). For comparison, we performed a series of proteome-wide analyses of well-characterized (ground truth) and biologically relevant samples, including a mix of UPS1 proteins spiked at different concentrations into an Echerichia coli digest used as a background and a set of glioblastoma cell lines. MS1-only data was analyzed using a novel quantitation workflow called DirectMS1Quant developed in this work. The results obtained in this study demonstrated comparable quantitation efficiency of 5 min DirectMS1 with both TMT and DIA methods, yet the latter two utilized a 10-20-fold longer instrumentation time.
    DOI:  https://doi.org/10.1021/acs.analchem.2c02255
  14. Trends Biochem Sci. 2022 Sep 13. pii: S0968-0004(22)00232-8. [Epub ahead of print]
    Physiological media advance cell culture experiments.
    Martin Fischer.
      The metabolism plays a fundamental role in cellular signaling pathways, but commonly used cell culture media do not reflect physiological metabolite concentrations. The metabolic control hub mammalian target of rapamycin complex 1 (mTORC1) kinase is an illuminating example that it is about time to advance our cell culture to become more physiological and relevant.
    Keywords:  RFX7; cancer research; cell culture media; mTOR; metabolism; p53
    DOI:  https://doi.org/10.1016/j.tibs.2022.08.007
  15. Proteomics. 2022 Sep 12. e2100369
    JUMPptm: Integrated software for sensitive identification of post-translational modifications and its application in Alzheimer's disease study.
    Suresh Poudel, David Vanderwall, Zuo-Fei Yuan, Zhiping Wu, Junmin Peng, Yuxin Li.
      Mass spectrometry (MS)-based proteomic analysis of posttranslational modifications (PTMs) usually requires the pre-enrichment of modified proteins or peptides. However, recent ultra-deep whole proteome profiling generates millions of spectra in a single experiment, leaving many unassigned spectra, some of which may be derived from PTM peptides. Here we present JUMPptm, an integrative computational pipeline, to extract PTMs from unenriched whole proteome. JUMPptm combines the advantages of JUMP, MSFragger and Comet search engines, and includes de novo tags, customized database search and peptide filtering, which iteratively analyzes each PTM by a multi-stage strategy to improve sensitivity and specificity. We applied JUMPptm to the deep brain proteome of Alzheimer's disease (AD), and identified 34,954 unique peptides with phosphorylation, methylation, acetylation, ubiquitination, and others. The phosphorylated peptides were validated by enriched phosphoproteome from the same sample. TMT-based quantification revealed 482 PTM peptides dysregulated at different stages during AD progression. For example, the acetylation of numerous mitochondrial proteins is significantly decreased in AD. A total of 60 PTM sites are found in the pan-PTM map of the Tau protein. The JUMPptm program is an effective tool for pan-PTM analysis and the resulting AD pan-PTM profile serves as a valuable resource for AD research. This article is protected by copyright. All rights reserved.
    Keywords:  Alzheimer's disease; acetylation; mass spectrometry; oxidation; phosphorylation; posttranslational modification; proteomics; tau; ubiquitination
    DOI:  https://doi.org/10.1002/pmic.202100369
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