| 31. |
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| 32. |
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| 33. |
- Danielsson, Frida, et al.
(författare)
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RNA Deep Sequencing as a Tool for Selection of Cell Lines for Systematic Subcellular Localization of All Human Proteins
- 2013
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 12:1, s. 231-239
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Tidskriftsartikel (refereegranskat)abstract
- One of the major challenges of a chromosome-centric proteome project is to explore in a systematic manner the potential proteins identified from the chromosomal genome sequence, but not yet characterized on a protein level. Here, we describe the use of RNA deep sequencing to screen human cell lines for RNA profiles and to use this information to select cell lines suitable for characterization of the corresponding gene product. In this manner, the subcellular localization of proteins can be analyzed systematically using antibody-based confocal microscopy. We demonstrate the usefulness of selecting cell lines with high expression levels of RNA transcripts to increase the likelihood of high quality immunofluorescence staining and subsequent successful subcellular localization of the corresponding protein. The results show a path to combine transcriptomics with affinity proteomics to characterize the proteins in a gene- or chromosome-centric manner.
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| 34. |
- Danielsson, Frida, et al.
(författare)
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Spatial Characterization of the Human Centrosome Proteome Opens Up New Horizons for a Small but Versatile Organelle
- 2020
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Ingår i: Proteomics. - : Wiley-VCH Verlag. - 1615-9853 .- 1615-9861.
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Tidskriftsartikel (refereegranskat)abstract
- After a century of research, the human centrosome continues to fascinate. Based on immunofluorescence and confocal microscopy, an extensive inventory of the protein components of the human centrosome, and the centriolar satellites, with the important contribution of over 300 novel proteins localizing to these compartments is presented. A network of candidate centrosome proteins involved in ubiquitination, including six interaction partners of the Kelch-like protein 21, and an additional network of protein phosphatases, together supporting the suggested role of the centrosome as an interactive hub for cell signaling, is identified. Analysis of multi-localization across cellular organelles analyzed within the Human Protein Atlas (HPA) project shows how multi-localizing proteins are particularly overrepresented in centriolar satellites, supporting the dynamic nature and wide range of functions for this compartment. In summary, the spatial dissection of the human centrosome and centriolar satellites described here provides a comprehensive knowledgebase for further exploration of their proteomes.
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| 35. |
- Danielsson, Frida, et al.
(författare)
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Transcriptome profiling of the interconnection of pathways involved in malignant transformation and response to hypoxia
- 2018
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Ingår i: Oncotarget. - : Impact Journals LLC. - 1949-2553. ; 9:28, s. 19730-19744
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Tidskriftsartikel (refereegranskat)abstract
- In tumor tissues, hypoxia is a commonly observed feature resulting from rapidly proliferating cancer cells outgrowing their surrounding vasculature network. Transformed cancer cells are known to exhibit phenotypic alterations, enabling continuous proliferation despite a limited oxygen supply. The four-step isogenic BJ cell model enables studies of defined steps of tumorigenesis: the normal, immortalized, transformed, and metastasizing stages. By transcriptome profiling under atmospheric and moderate hypoxic (3% O2) conditions, we observed that despite being highly similar, the four cell lines of the BJ model responded strikingly different to hypoxia. Besides corroborating many of the known responses to hypoxia, we demonstrate that the transcriptome adaptation to moderate hypoxia resembles the process of malignant transformation. The transformed cells displayed a distinct capability of metabolic switching, reflected in reversed gene expression patterns for several genes involved in oxidative phosphorylation and glycolytic pathways. By profiling the stage-specific responses to hypoxia, we identified ASS1 as a potential prognostic marker in hypoxic tumors. This study demonstrates the usefulness of the BJ cell model for highlighting the interconnection of pathways involved in malignant transformation and hypoxic response.
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| 36. |
- Edfors, Fredrik, et al.
(författare)
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Gene-specific correlation of RNA and protein levels in human cells and tissues
- 2016
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Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292 .- 1744-4292. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- An important issue for molecular biology is to establish whether transcript levels of a given gene can be used as proxies for the corresponding protein levels. Here, we have developed a targeted proteomics approach for a set of human non-secreted proteins based on parallel reaction monitoring to measure, at steady-state conditions, absolute protein copy numbers across human tissues and cell lines and compared these levels with the corresponding mRNA levels using transcriptomics. The study shows that the transcript and protein levels do not correlate well unless a gene-specific RNA-to-protein (RTP) conversion factor independent of the tissue type is introduced, thus significantly enhancing the predictability of protein copy numbers from RNA levels. The results show that the RTP ratio varies significantly with a few hundred copies per mRNA molecule for some genes to several hundred thousands of protein copies per mRNA molecule for others. In conclusion, our data suggest that transcriptome analysis can be used as a tool to predict the protein copy numbers per cell, thus forming an attractive link between the field of genomics and proteomics.
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| 37. |
- Edfors, Fredrik, et al.
(författare)
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Immunoproteomics using polyclonal antibodies and stable isotope-labeled affinity-purified recombinant proteins
- 2014
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 13:6, s. 1611-1624
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Tidskriftsartikel (refereegranskat)abstract
- AThe combination of immuno-based methods and mass spectrometry detection has great potential in the field of quantitative proteomics. Here, we describe a new method (immuno-SILAC) for the absolute quantification of proteins in complex samples based on polyclonal antibodies and stable isotope-labeled recombinant protein fragments to allow affinity enrichment prior to mass spectrometry analysis and accurate quantification. We took advantage of the antibody resources publicly available from the Human Protein Atlas project covering more than 80% of all human protein-coding genes. Epitope mapping revealed that a majority of the polyclonal antibodies recognized multiple linear epitopes, and based on these results, a semi-automated method was developed for peptide enrichment using polyclonal antibodies immobilized on protein A-coated magnetic beads. A protocol based on the simultaneous multiplex capture of more than 40 protein targets showed that approximately half of the antibodies enriched at least one functional peptide detected in the subsequent mass spectrometry analysis. The approach was further developed to also generate quantitative data via the addition of heavy isotope-labeled recombinant protein fragment standards prior to trypsin digestion. Here, we show that we were able to use small amounts of antibodies (50 ng per target) in this manner for efficient multiplex analysis of quantitative levels of proteins in a human HeLa cell lysate. The results suggest that polyclonal antibodies generated via immunization of recombinant protein fragments could be used for the enrichment of target peptides to allow for rapid mass spectrometry analysis taking advantage of a substantial reduction in sample complexity. The possibility of building up a proteome-wide resource for immuno-SILAC assays based on publicly available antibody resources is discussed.
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| 38. |
- Edfors, Fredrik, 1988-, et al.
(författare)
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Validation of antibodies for Western blot applications using orthogonal methods
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- There is a great need for standardized validation methods for antibody specificity and selectivity. Here, we describe the use of orthogonal methods in which the specificity of an antibody in a particular application is determined based on correlation of protein abundance across several samples using an antibody-independent method. We show that pair-wise correlation between orthogonal samples can be used to score the specificity of antibodies in a standardized manner using a test panel of human cell lines. Here, we investigated two independent methods for validation of antibodies in Western blot applications, namely transcriptomics and targeted proteomics and we show that the two methods yield similar, but not identical results. The orthogonal methods can also be used to investigate on- and off- target binding for antibodies with multiple bands in the Western blot assay. In conclusion, orthogonal methods for antibody validation provide an attractive strategy for systematic validation of antibodies in a quantitative manner.
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| 39. |
- Engen, Kristine, et al.
(författare)
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Autoantibodies to the N-Methyl-D-Aspartate Receptor in Adolescents With Early Onset Psychosis and Healthy Controls
- 2020
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Ingår i: Frontiers in Psychiatry. - : Frontiers Media SA. - 1664-0640. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background Autoantibodies to theN-methyl-D-aspartate receptor (NMDAR-Abs) in autoimmune encephalitis have been associated with prominent psychiatric symptoms. The aims of the present study are to identify the prevalence of NMDAR-Abs in adolescents with early onset psychosis disorders (EOP) and healthy controls (HC) and examine its clinical significance. Method Plasma samples were acquired from 46 adolescent EOP patients and 69 age- and sex matched HC, and assessed for the presence of immunoglobulin G NMDAR-Abs. All participants underwent psychiatric evaluation, neurological examination and head magnetic resonance imaging. Results NMDAR-Abs were detected in three of 46 (6.5%) EOP patients and in two of 69 (2.9%) HC. One NMDAR-Abs EOP patient presented with unusual psychopathology and minor T1 weighted lesions of vasculopathological origin located bi-frontally and in the basal ganglia, and had a recent diagnosis of a separate autoimmune disease. One NMDAR-Ab HC displayed a T2 weighted FLAIR hyperintensity lesion in the left frontal lobe. The remaining three NMDAR-Ab participants were two EOP patients without neurological or radiological findings, and one HC without any clinical findings. Conclusions We report that a small number of EOP patients and HC have NMDAR-Abs with a similar frequency in both groups. The presence of the antibodies was not associated with any distinctive clinical or radiological features. Detection of the antibodies had no diagnostic implication, and a positive NMDAR antibody test must be carefully interpreted and reviewed within the individual clinical context.
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| 40. |
- Fagerberg, Linn, et al.
(författare)
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Analysis of the human tissue-specific expression by genome-wide integration of transcriptomics and antibody-based proteomics
- 2014
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 13:2, s. 397-406
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Tidskriftsartikel (refereegranskat)abstract
- Global classification of the human proteins with regards to spatial expression patterns across organs and tissues is important for studies of human biology and disease. Here, we used a quantitative transcriptomics analysis (RNA-Seq) to classify the tissue-specific expression of genes across a representative set of all major human organs and tissues and combined this analysis with antibody- based profiling of the same tissues. To present the data, we launch a new version of the Human Protein Atlas that integrates RNA and protein expression data corresponding to 80% of the human protein-coding genes with access to the primary data for both the RNA and the protein analysis on an individual gene level. We present a classification of all human protein-coding genes with regards to tissue-specificity and spatial expression pattern. The integrative human expression map can be used as a starting point to explore the molecular constituents of the human body.
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