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Dive into the research topics where Erik Björling is active.

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Featured researches published by Erik Björling.


Molecular & Cellular Proteomics | 2005

A Human Protein Atlas for Normal and Cancer Tissues Based on Antibody Proteomics

Mathias Uhlén; Erik Björling; Charlotta Agaton; Cristina Al-Khalili Szigyarto; Bahram Amini; Elisabet Andersen; Ann-Catrin Andersson; Pia Angelidou; Anna Asplund; Caroline Asplund; Lisa Berglund; Kristina Bergström; Harry Brumer; Dijana Cerjan; Marica Ekström; Adila El-Obeid; Cecilia Eriksson; Linn Fagerberg; Ronny Falk; Jenny Fall; Mattias Forsberg; Marcus Gry Björklund; Kristoffer Gumbel; Asif Halimi; Inga Hallin; Carl Hamsten; Marianne Hansson; My Hedhammar; Görel Hercules; Caroline Kampf

Antibody-based proteomics provides a powerful approach for the functional study of the human proteome involving the systematic generation of protein-specific affinity reagents. We used this strategy to construct a comprehensive, antibody-based protein atlas for expression and localization profiles in 48 normal human tissues and 20 different cancers. Here we report a new publicly available database containing, in the first version, ∼400,000 high resolution images corresponding to more than 700 antibodies toward human proteins. Each image has been annotated by a certified pathologist to provide a knowledge base for functional studies and to allow queries about protein profiles in normal and disease tissues. Our results suggest it should be possible to extend this analysis to the majority of all human proteins thus providing a valuable tool for medical and biological research.


Molecular & Cellular Proteomics | 2008

A Genecentric Human Protein Atlas for Expression Profiles Based on Antibodies

Lisa Berglund; Erik Björling; Per Oksvold; Linn Fagerberg; Anna Asplund; Cristina Al-Khalili Szigyarto; Anja Persson; Jenny Ottosson; Henrik Wernérus; Peter Nilsson; Emma Lundberg; Åsa Sivertsson; Sanjay Navani; Kenneth Wester; Caroline Kampf; Sophia Hober; Fredrik Pontén; Mathias Uhlén

An attractive path forward in proteomics is to experimentally annotate the human protein complement of the genome in a genecentric manner. Using antibodies, it might be possible to design protein-specific probes for a representative protein from every protein-coding gene and to subsequently use the antibodies for systematical analysis of cellular distribution and subcellular localization of proteins in normal and disease tissues. A new version (4.0) of the Human Protein Atlas has been developed in a genecentric manner with the inclusion of all human genes and splice variants predicted from genome efforts together with a visualization of each protein with characteristics such as predicted membrane regions, signal peptide, and protein domains and new plots showing the uniqueness (sequence similarity) of every fraction of each protein toward all other human proteins. The new version is based on tissue profiles generated from 6120 antibodies with more than five million immunohistochemistry-based images covering 5067 human genes, corresponding to ∼25% of the human genome. Version 4.0 includes a putative list of members in various protein classes, both functional classes, such as kinases, transcription factors, G-protein-coupled receptors, etc., and project-related classes, such as candidate genes for cancer or cardiovascular diseases. The exact antigen sequence for the internally generated antibodies has also been released together with a visualization of the application-specific validation performed for each antibody, including a protein array assay, Western blot analysis, immunohistochemistry, and, for a large fraction, immunofluorescence-based confocal microscopy. New search functionalities have been added to allow complex queries regarding protein expression profiles, protein classes, and chromosome location. The new version of the protein atlas thus is a resource for many areas of biomedical research, including protein science and biomarker discovery.


Molecular Systems Biology | 2009

A global view of protein expression in human cells, tissues, and organs

Fredrik Pontén; Marcus Gry; Linn Fagerberg; Emma Lundberg; Anna Asplund; Lisa Berglund; Per Oksvold; Erik Björling; Sophia Hober; Caroline Kampf; Sanjay Navani; Peter Nilsson; Jenny Ottosson; Anja Persson; Henrik Wernérus; Kenneth Wester; Mathias Uhlén

Defining the protein profiles of tissues and organs is critical to understanding the unique characteristics of the various cell types in the human body. In this study, we report on an anatomically comprehensive analysis of 4842 protein profiles in 48 human tissues and 45 human cell lines. A detailed analysis of over 2 million manually annotated, high‐resolution, immunohistochemistry‐based images showed a high fraction (>65%) of expressed proteins in most cells and tissues, with very few proteins (<2%) detected in any single cell type. Similarly, confocal microscopy in three human cell lines detected expression of more than 70% of the analyzed proteins. Despite this ubiquitous expression, hierarchical clustering analysis, based on global protein expression patterns, shows that the analyzed cells can be still subdivided into groups according to the current concepts of histology and cellular differentiation. This study suggests that tissue specificity is achieved by precise regulation of protein levels in space and time, and that different tissues in the body acquire their unique characteristics by controlling not which proteins are expressed but how much of each is produced.


Molecular & Cellular Proteomics | 2008

Toward a Confocal Subcellular Atlas of the Human Proteome

Laurent Barbe; Emma Lundberg; Per Oksvold; Anna Stenius; Erland Lewin; Erik Björling; Anna Asplund; Fredrik Pontén; Hjalmar Brismar; Mathias Uhlén; Helene Andersson-Svahn

Information on protein localization on the subcellular level is important to map and characterize the proteome and to better understand cellular functions of proteins. Here we report on a pilot study of 466 proteins in three human cell lines aimed to allow large scale confocal microscopy analysis using protein-specific antibodies. Approximately 3000 high resolution images were generated, and more than 80% of the analyzed proteins could be classified in one or multiple subcellular compartment(s). The localizations of the proteins showed, in many cases, good agreement with the Gene Ontology localization prediction model. This is the first large scale antibody-based study to localize proteins into subcellular compartments using antibodies and confocal microscopy. The results suggest that this approach might be a valuable tool in conjunction with predictive models for protein localization.


Molecular & Cellular Proteomics | 2008

Antibodypedia, a Portal for Sharing Antibody and Antigen Validation Data

Erik Björling; Mathias Uhlén

Antibodies are useful tools to characterize the components of the human proteome and to validate potential protein biomarkers discovered through various clinical proteomics efforts. The lack of validation results across various applications for most antibodies often makes it necessary to perform cumbersome investigations to ensure specificity of a particular antibody in a certain application. A need therefore exists for a standardized system for sharing validation data about publicly available antibodies and to allow antibody providers as well as users to contribute and edit experimental evidence data, including data also on the antigen. Here we describe a new publicly available portal called Antibodypedia, which has been developed to allow sharing of information regarding validation of antibodies in which providers can submit their own validation results and reliability scores. We report standardized validation criteria and submission rules for applications such as Western blots, protein arrays, immunohistochemistry, and immunofluorescence. The contributor is expected to provide experimental evidence and a validation score for each antibody, and the users can subsequently provide feedback and comments on the use of the antibody. The database thus provides a virtual resource of publicly available antibodies toward human proteins with accompanying experimental evidence supporting an individual validation score for each antibody in an application-specific manner.


Molecular & Cellular Proteomics | 2008

A Web-based Tool for in Silico Biomarker Discovery Based on Tissue-specific Protein Profiles in Normal and Cancer Tissues

Erik Björling; Cecilia Lindskog; Per Oksvold; Jerker Linné; Caroline Kampf; Sophia Hober; Mathias Uhlén; Fredrik Pontén

Here we report the dev elopment of a publicly available Web-based analysis tool for exploring proteins expressed in a tissue- or cancer-specific manner. The search queries are based on the human tissue profiles in normal and cancer cells in the Human Protein Atlas portal and rely on the individual annotation performed by pathologists of images representing immunohistochemically stained tissue sections. Approximately 1.8 million images representing more than 3000 antibodies directed toward human proteins were used in the study. The search tool allows for the systematic exploration of the protein atlas to discover potential protein biomarkers. Such biomarkers include tissue-specific markers, cell type-specific markers, tumor type-specific markers, markers of malignancy, and prognostic or predictive markers of cancers. Here we show examples of database queries to generate sets of candidate biomarker proteins for several of these different categories. Expression profiles of candidate proteins can then subsequently be validated by examination of the underlying high resolution images. The present study shows examples of search strategies revealing several potential protein biomarkers, including proteins specifically expressed in normal cells and in cancer cells from specified tumor types. The lists of candidate proteins can be used as a starting point for further validation in larger patient cohorts using both immunological approaches and technologies utilizing more classical proteomics tools.


Clinical Proteomics | 2004

Antibody-based tissue profiling as a tool for clinical proteomics

Caroline Kampf; Ann-Catrin Andersson; Kenneth Wester; Erik Björling; Mathias Uhlén; Fredrik Pontén

Here, we show a strategy for high-throughput antibody-based tissue profiling with the aim to create an atlas of protein expression patterns in normal human tissues and cancer tissues representing the 20 most prevalent cancer types. A set of standardized tissue microarrays (TMAs) was produced to allow for rapid screening of a multitude of different cells and tissues using immunohistochemistry. Eight TMA blocks were produced containing 48 different normal human tissues in triplicate and cancer tissue from 216 individually different tumors in duplicate. Sections from these blocks were immunohistochemically stained using five commercial and five in-house generated antibodies. Digital images for annotation of expression profiles were generated using a semiautomated approach. Five hundred seventy-six images and annotation data corresponding to a total of 30 Gbytes of data were collected for each antibody. The data presented here suggest that antibody-based profiling of protein expression in tissues can be used as a valuable tool in clinical proteomics.


Proteomics | 2008

A whole‐genome bioinformatics approach to selection of antigens for systematic antibody generation

Lisa Berglund; Erik Björling; Kalle Jonasson; Johan Rockberg; Linn Fagerberg; Cristina Al-Khalili Szigyarto; Åsa Sivertsson; Mathias Uhlén

Here, we present an antigen selection strategy based on a whole‐genome bioinformatics approach, which is facilitated by an interactive visualization tool displaying protein features from both public resources and in‐house generated data. The web‐based bioinformatics platform has been designed for selection of multiple, non‐overlapping recombinant protein epitope signature tags by display of predicted information relevant for antigens, including domain‐ and epitope sized sequence similarities to other proteins, transmembrane regions and signal peptides. The visualization tool also displays shared and exclusive protein regions for genes with multiple splice variants. A genome‐wide analysis demonstrates that antigens for approximately 80% of the human protein‐coding genes can be selected with this strategy.


Molecular & Cellular Proteomics | 2010

A Community Standard Format for the Representation of Protein Affinity Reagents

David E. Gloriam; Sandra Orchard; Daniela Bertinetti; Erik Björling; Erik Bongcam-Rudloff; Carl Borrebaeck; Julie Bourbeillon; Andrew Bradbury; Antoine de Daruvar; Stefan Duebel; Ronald Frank; Toby J. Gibson; Larry Gold; Niall J. Haslam; Friedrich W. Herberg; Tara Hiltke; Joerg D. Hoheisel; Samuel Kerrien; Manfred Koegl; Zoltán Konthur; Bernhard Korn; Ulf Landegren; Luisa Montecchi-Palazzi; Sandrine Palcy; Henry Rodriguez; Sonja Schweinsberg; Volker Sievert; Oda Stoevesandt; Michael J. Taussig; Marius Ueffing

Protein affinity reagents (PARs), most commonly antibodies, are essential reagents for protein characterization in basic research, biotechnology, and diagnostics as well as the fastest growing class of therapeutics. Large numbers of PARs are available commercially; however, their quality is often uncertain. In addition, currently available PARs cover only a fraction of the human proteome, and their cost is prohibitive for proteome scale applications. This situation has triggered several initiatives involving large scale generation and validation of antibodies, for example the Swedish Human Protein Atlas and the German Antibody Factory. Antibodies targeting specific subproteomes are being pursued by members of Human Proteome Organisation (plasma and liver proteome projects) and the United States National Cancer Institute (cancer-associated antigens). ProteomeBinders, a European consortium, aims to set up a resource of consistently quality-controlled protein-binding reagents for the whole human proteome. An ultimate PAR database resource would allow consumers to visit one on-line warehouse and find all available affinity reagents from different providers together with documentation that facilitates easy comparison of their cost and quality. However, in contrast to, for example, nucleotide databases among which data are synchronized between the major data providers, current PAR producers, quality control centers, and commercial companies all use incompatible formats, hindering data exchange. Here we propose Proteomics Standards Initiative (PSI)-PAR as a global community standard format for the representation and exchange of protein affinity reagent data. The PSI-PAR format is maintained by the Human Proteome Organisation PSI and was developed within the context of ProteomeBinders by building on a mature proteomics standard format, PSI-molecular interaction, which is a widely accepted and established community standard for molecular interaction data. Further information and documentation are available on the PSI-PAR web site.


Biotechnology Journal | 2014

Antibody performance in western blot applications is context- dependent

Cajsa Älgenäs; Charlotta Agaton; Linn Fagerberg; Anna Asplund; Lisa Björling; Erik Björling; Caroline Kampf; Emma Lundberg; Peter Nilsson; Anja Persson; Kenneth Wester; Fredrik Pontén; Henrik Wernérus; Mathias Uhlén; Jenny Ottosson Takanen; Sophia Hober

An important concern for the use of antibodies in various applications, such as western blot (WB) or immunohistochemistry (IHC), is specificity. This calls for systematic validations using well-designed conditions. Here, we have analyzed 13 000 antibodies using western blot with lysates from human cell lines, tissues, and plasma. Standardized stratification showed that 45% of the antibodies yielded supportive staining, and the rest either no staining (12%) or protein bands of wrong size (43%). A comparative study of WB and IHC showed that the performance of antibodies is application-specific, although a correlation between no WB staining and weak IHC staining could be seen. To investigate the influence of protein abundance on the apparent specificity of the antibody, new WB analyses were performed for 1369 genes that gave unsupportive WBs in the initial screening using cell lysates with overexpressed full-length proteins. Then, more than 82% of the antibodies yielded a specific band corresponding to the full-length protein. Hence, the vast majority of the antibodies (90%) used in this study specifically recognize the target protein when present at sufficiently high levels. This demonstrates the context- and application-dependence of antibody validation and emphasizes that caution is needed when annotating binding reagents as specific or cross-reactive. WB is one of the most commonly used methods for validation of antibodies. Our data implicate that solely using one platform for antibody validation might give misleading information and therefore at least one additional method should be used to verify the achieved data.

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Mathias Uhlén

Royal Institute of Technology

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Sophia Hober

Royal Institute of Technology

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Henrik Wernérus

Royal Institute of Technology

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Anja Persson

Royal Institute of Technology

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Peter Nilsson

Royal Institute of Technology

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