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Dobson L, Gerdán C, Tusnády S, Szekeres L, Kuffa K, Langó T, Zeke A, Tusnády GE. UniTmp: unified resources for transmembrane proteins. Nucleic Acids Res 2024; 52:D572-D578. [PMID: 37870462 PMCID: PMC10767979 DOI: 10.1093/nar/gkad897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/24/2023] Open
Abstract
The UNIfied database of TransMembrane Proteins (UniTmp) is a comprehensive and freely accessible resource of transmembrane protein structural information at different levels, from localization of protein segments, through the topology of the protein to the membrane-embedded 3D structure. We not only annotated tens of thousands of new structures and experiments, but we also developed a new system that can serve these resources in parallel. UniTmp is a unified platform that merges TOPDB (Topology Data Bank of Transmembrane Proteins), TOPDOM (database of conservatively located domains and motifs in proteins), PDBTM (Protein Data Bank of Transmembrane Proteins) and HTP (Human Transmembrane Proteome) databases and provides interoperability between the incorporated resources and an easy way to keep them regularly updated. The current update contains 9235 membrane-embedded structures, 9088 sequences with 536 035 topology-annotated segments and 8692 conservatively localized protein domains or motifs as well as 5466 annotated human transmembrane proteins. The UniTmp database can be accessed at https://www.unitmp.org.
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Affiliation(s)
- László Dobson
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
- Department of Bioinformatics, Semmelweis University, Budapest, Tűzoltó u. 7, H-1094, Hungary
| | - Csongor Gerdán
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
| | - Simon Tusnády
- Department of Bioinformatics, Semmelweis University, Budapest, Tűzoltó u. 7, H-1094, Hungary
| | - Levente Szekeres
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
| | - Katalin Kuffa
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Pázmány P. stny. 1/C, H-1117, Hungary
| | - Tamás Langó
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
| | - András Zeke
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
| | - Gábor E Tusnády
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Budapest, Magyar Tudósok körútja 2, H-1117, Hungary
- Department of Bioinformatics, Semmelweis University, Budapest, Tűzoltó u. 7, H-1094, Hungary
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Kirsch ZJ, Blake JM, Huynh U, Agrohia DK, Tremblay CY, Graban EM, Vaughan RC, Vachet RW. Membrane Protein Binding Interactions Studied in Live Cells via Diethylpyrocarbonate Covalent Labeling Mass Spectrometry. Anal Chem 2023; 95:7178-7185. [PMID: 37102678 PMCID: PMC10350911 DOI: 10.1021/acs.analchem.2c05616] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
Membrane proteins are vital in the human proteome for their cellular functions and make up a majority of drug targets in the U.S. However, characterizing their higher-order structures and interactions remains challenging. Most often membrane proteins are studied in artificial membranes, but such artificial systems do not fully account for the diversity of components present in cell membranes. In this study, we demonstrate that diethylpyrocarbonate (DEPC) covalent labeling mass spectrometry can provide binding site information for membrane proteins in living cells using membrane-bound tumor necrosis factor α (mTNFα) as a model system. Using three therapeutic monoclonal antibodies that bind TNFα, our results show that residues that are buried in the epitope upon antibody binding generally decrease in DEPC labeling extent. Additionally, serine, threonine, and tyrosine residues on the periphery of the epitope increase in labeling upon antibody binding because of a more hydrophobic microenvironment that is created. We also observe changes in labeling away from the epitope, indicating changes to the packing of the mTNFα homotrimer, compaction of the mTNFα trimer against the cell membrane, and/or previously uncharacterized allosteric changes upon antibody binding. Overall, DEPC-based covalent labeling mass spectrometry offers an effective means of characterizing structure and interactions of membrane proteins in living cells.
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Affiliation(s)
- Zachary J. Kirsch
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Jeanna M. Blake
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Uyen Huynh
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Dheeraj K. Agrohia
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Catherine Y. Tremblay
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Eric M. Graban
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Robert C. Vaughan
- QuarryBio, Collins Building, 2051 East Paul Dirac Dr., Tallahassee, FL 32310
| | - Richard W. Vachet
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States
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Langó T, Kuffa K, Tóth G, Turiák L, Drahos L, Tusnády GE. Comprehensive Discovery of the Accessible Primary Amino Group-Containing Segments from Cell Surface Proteins by Fine-Tuning a High-Throughput Biotinylation Method. Int J Mol Sci 2022; 24:ijms24010273. [PMID: 36613715 PMCID: PMC9820203 DOI: 10.3390/ijms24010273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
Cell surface proteins, including transmembrane and other surface-anchored proteins, play a key role in several critical cellular processes and have a strong diagnostic value. The development of quick and robust experimental methods remains vital for the accurate and comprehensive characterization of the cell surface subproteome of individual cells. Here we present a high-throughput technique which relies on the biotinylation of the accessible primary amino groups in the extracellular segments of the proteins, using HL60 as a model cell line. Several steps of the method have been thoroughly optimized to capture labeled surface proteins selectively and in larger quantities. These include the following: improving the efficiency of the cell surface biotinylation; reducing the endogen protease activity; applying an optimal amount of affinity column and elution steps for labeled peptide enrichment; and examining the effect of various solid-phase extraction methods, different HPLC gradients, and various tandem mass spectrometry settings. Using the optimized workflow, we identified at least 1700 surface-associated individual labeled peptides (~6000-7000 redundant peptides) from the model cell surface in a single nanoHPLC-MS/MS run. The presented method can provide a comprehensive and specific list of the cell surface available protein segments that could be potential targets in various bioinformatics and molecular biology research.
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Affiliation(s)
- Tamás Langó
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
- Correspondence:
| | - Katalin Kuffa
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány P. stny. 1/C, H-1117 Budapest, Hungary
| | - Gábor Tóth
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
| | - Lilla Turiák
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
| | - László Drahos
- MS Proteomics Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
| | - Gábor E. Tusnády
- Protein Bioinformatics Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok krt 2, H-1117 Budapest, Hungary
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Dafun AS, Marcoux J. Structural mass spectrometry of membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140813. [PMID: 35750312 DOI: 10.1016/j.bbapap.2022.140813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/10/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
The analysis of proteins and protein complexes by mass spectrometry (MS) has come a long way since the invention of electrospray ionization (ESI) in the mid 80s. Originally used to characterize small soluble polypeptide chains, MS has progressively evolved over the past 3 decades towards the analysis of samples of ever increasing heterogeneity and complexity, while the instruments have become more and more sensitive and resolutive. The proofs of concepts and first examples of most structural MS methods appeared in the early 90s. However, their application to membrane proteins, key targets in the biopharma industry, is more recent. Nowadays, a wealth of information can be gathered from such MS-based methods, on all aspects of membrane protein structure: sequencing (and more precisely proteoform characterization), but also stoichiometry, non-covalent ligand binding (metals, drug, lipids, carbohydrates), conformations, dynamics and distance restraints for modelling. In this review, we present the concept and some historical and more recent applications on membrane proteins, for the major structural MS methods.
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Affiliation(s)
- Angelique Sanchez Dafun
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Julien Marcoux
- Institut de Pharmacologie et de Biologie Structurale (IPBS), Université de Toulouse, CNRS, UPS, Toulouse, France.
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Pan X, Kirsch ZJ, Vachet RW. Distinguishing Histidine Tautomers in Proteins Using Covalent Labeling-Mass Spectrometry. Anal Chem 2022; 94:1003-1010. [PMID: 34962759 PMCID: PMC8787799 DOI: 10.1021/acs.analchem.1c03902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In this work, we use diethylpyrocarbonate (DEPC)-based covalent labeling together with LC-MS/MS analysis to distinguish the two sidechain tautomers of histidine residues in peptides and proteins. From labeling experiments on model peptides, we demonstrate that DEPC reacts equally with both tautomeric forms to produce chemically different products with distinct dissociation patterns and LC retention times, allowing the ratios of the two tautomers to be determined in peptides and proteins. Upon measuring the tautomer ratios of several histidine residues in myoglobin, we find good agreement with previous 2D NMR data on this protein. Because our DEPC labeling/MS approach is simpler, faster, and more precise than 2D NMR, our method will be a valuable way to determine how protein structure enforces histidine sidechain tautomerization. Because the tautomeric state of histidine residues is often important for protein structure and function, the ability of DEPC labeling/MS to distinguish histidine tautomers should equip researchers with a tool to understand the histidine residue structure and function more deeply in proteins.
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Liu G, Choi MH, Ma H, Guo X, Lo PC, Kim J, Zhang L. Bioorthogonal Conjugation-Assisted Purification Method for Profiling Cell Surface Proteome. Anal Chem 2022; 94:1901-1909. [PMID: 35019258 DOI: 10.1021/acs.analchem.1c05187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Surface biotinylation has been widely adapted in profiling the cellular proteome associated with the plasma membrane. However, the workflow is subject to interference from the cytoplasmic biotin-associated proteins that compete for streptavidin-binding during purification. Here we established a bioorthogonal conjugation-assisted purification (BCAP) workflow that utilizes the Staudinger chemoselective ligation to label and isolate surface-associated proteins while minimizing the binding of endogenous biotin-associated proteins. Label-free quantitative proteomics demonstrated that BCAP is efficient in isolating cell surface proteins with excellent reproducibility. Subsequently, we applied BCAP to compare the surface proteome of proliferating and senescent mouse embryonic fibroblasts (MEFs). Among the results, EHD2 was identified and validated as a novel protein that is enhanced at the cell surface of senescent MEFs. We expect that BCAP will have broad applications in profiling cell surface proteomes in the future.
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Affiliation(s)
- Guopan Liu
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China.,Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Ming Ho Choi
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China
| | - Haiying Ma
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China
| | - Xuejiao Guo
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China
| | - Pui-Chi Lo
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China
| | - Jinyong Kim
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China
| | - Liang Zhang
- Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon 999077, Hong Kong China.,Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
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Pan X, Vachet RW. MEMBRANE PROTEIN STRUCTURES AND INTERACTIONS FROM COVALENT LABELING COUPLED WITH MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2022; 41:51-69. [PMID: 33145813 PMCID: PMC8093322 DOI: 10.1002/mas.21667] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 05/31/2023]
Abstract
Membrane proteins are incredibly important biomolecules because they mediate interactions between a cell's external and internal environment. Obtaining information about membrane protein structure and interactions is thus important for understanding these essential biomolecules. Compared with the analyses of water-soluble proteins, the structural analysis of membrane proteins is more challenging owing to their unique chemical properties and the presence of lipid components that are necessary to solubilize them. The combination of covalent labeling (CL) and mass spectrometry (MS) has recently been applied with great success to study membrane protein structure and interactions. These studies have demonstrated the many advantages that CL-MS methods have over other traditional biophysical techniques. In this review, we discuss both amino acid-specific and non-specific labeling approaches and the special considerations needed to address the unique challenges associated with interrogating membrane proteins. This review highlights the aspects of this approach that require special care to be applied correctly and provides a comprehensive review of the membrane protein systems that have been studied by CL-MS. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
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Dobson L, Zeke A, Tusnády GE. PolarProtPred: Predicting apical and basolateral localization of transmembrane proteins using putative short linear motifs and deep learning. Bioinformatics 2021; 37:4328-4335. [PMID: 34185052 PMCID: PMC8384406 DOI: 10.1093/bioinformatics/btab480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 06/03/2021] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
Motivation Cell polarity refers to the asymmetric organization of cellular components in various cells. Epithelial cells are the best-known examples of polarized cells, featuring apical and basolateral membrane domains. Mounting evidence suggests that short linear motifs play a major role in protein trafficking to these domains, although the exact rules governing them are still elusive. Results In this study we prepared neural networks that capture recurrent patterns to classify transmembrane proteins localizing into apical and basolateral membranes. Asymmetric expression of drug transporters results in vectorial drug transport, governing the pharmacokinetics of numerous substances, yet the data on how proteins are sorted in epithelial cells is very scattered. The provided method may offer help to experimentalists to identify or better characterize molecular networks regulating the distribution of transporters or surface receptors (including viral entry receptors like that of COVID-19). Availability The prediction server PolarProtPred is available at http://polarprotpred.ttk.hu. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Laszlo Dobson
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, Budapest, 1117, Hungary.,Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, Heidelberg, 69117, Germany
| | - András Zeke
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, Budapest, 1117, Hungary
| | - Gábor E Tusnády
- Institute of Enzymology, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, Budapest, 1117, Hungary
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Roy S, Cha JN, Goodwin AP. Nongenetic Bioconjugation Strategies for Modifying Cell Membranes and Membrane Proteins: A Review. Bioconjug Chem 2020; 31:2465-2475. [PMID: 33146010 DOI: 10.1021/acs.bioconjchem.0c00529] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The cell membrane possesses an extensive library of proteins, carbohydrates, and lipids that control a significant portion of inter- and intracellular functions, including signaling, proliferation, migration, and adhesion, among others. Augmenting the cell surface composition would open possibilities for advances in therapy, tissue engineering, and probing fundamental cell processes. While genetic engineering has proven effective for many in vitro applications, these techniques result in irreversible changes to cells and are difficult to apply in vivo. Another approach is to instead attach exogenous functional groups to the cell membrane without changing the genetic nature of the cell. This review focuses on more recent approaches of nongenetic methods of cell surface modification through metabolic pathways, anchorage by hydrophobic interactions, and chemical conjugation. Benefits and drawbacks of each approach are considered, followed by a discussion of potential applications for nongenetic cell surface modification and an outlook on the future of the field.
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Partial proteolysis improves the identification of the extracellular segments of transmembrane proteins by surface biotinylation. Sci Rep 2020; 10:8880. [PMID: 32483232 PMCID: PMC7264363 DOI: 10.1038/s41598-020-65831-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/08/2020] [Indexed: 01/11/2023] Open
Abstract
Transmembrane proteins (TMP) play a crucial role in several physiological processes. Despite their importance and diversity, only a few TMP structures have been determined by high-resolution protein structure characterization methods so far. Due to the low number of determined TMP structures, the parallel development of various bioinformatics and experimental methods was necessary for their topological characterization. The combination of these methods is a powerful approach in the determination of TMP topology as in the Constrained Consensus TOPology prediction. To support the prediction, we previously developed a high-throughput topology characterization method based on primary amino group-labelling that is still limited in identifying all TMPs and their extracellular segments on the surface of a particular cell type. In order to generate more topology information, a new step, a partial proteolysis of the cell surface has been introduced to our method. This step results in new primary amino groups in the proteins that can be biotinylated with a membrane-impermeable agent while the cells still remain intact. Pre-digestion also promotes the emergence of modified peptides that are more suitable for MS/MS analysis. The modified sites can be utilized as extracellular constraints in topology predictions and may contribute to the refined topology of these proteins.
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