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Pattern recognition and classification of images are key challenges throughout the life sciences. We combined two approaches for large-scale classification of fluorescence microscopy images. First, using the publicly available data set from the Cell Atlas of the Human Protein Atlas (HPA), we integrated an image-classification task into a mainstream video game (EVE Online) as a mini-game, named Project Discovery. Participation by 322,006 gamers over 1 year provided nearly 33 million classifications of subcellular localization patterns, including patterns that were not previously annotated by the HPA. Second, we used deep learning to build an automated Localization Cellular Annotation Tool (Loc-CAT). This tool classifies proteins into 29 subcellular localization patterns and can deal efficiently with multi-localization proteins, performing robustly across different cell types. Combining the annotations of gamers and deep learning, we applied transfer learning to create a boosted learner that can characterize subcellular protein distribution with F1 score of 0.72. We found that engaging players of commercial computer games provided data that augmented deep learning and enabled scalable and readily improved image classification., QC 20181001

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QC 20150512

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., QC 20130305

The complexity of tissue and the alterations that distinguish normal from cancer remain a challenge for translating results from tumor biological studies into clinical medicine. This has generated an unmet need to exploit the findings from studies based on cell lines and model organisms to develop, validate and clinically apply novel diagnostic, prognostic and treatment predictive markers. As one step to meet this challenge, the Human Protein Atlas project has been set up to produce antibodies towards human protein targets corresponding to all human protein coding genes and to map protein expression in normal human tissues, cancer and cells. Here, we present a dictionary based on microscopy images created as an amendment to the Human Protein Atlas. The aim of the dictionary is to facilitate the interpretation and use of the image-based data available in the Human Protein Atlas, but also to serve as a tool for training and understanding tissue histology, pathology and cell biology. The dictionary contains three main parts, normal tissues, cancer tissues and cells, and is based on high-resolution images at different magnifications of full tissue sections stained with H & E. The cell atlas is centered on immunofluorescence and confocal microscopy images, using different color channels to highlight the organelle structure of a cell. Here, we explain how this dictionary can be used as a tool to aid clinicians and scientists in understanding the use of tissue histology and cancer pathology in diagnostics and biomarker studies.

Microtubules are filamentous structures that are involved in several important cellular processes, including cell division, cellular structure and mechanics, and intracellular transportation. Little is known about potential differences in microtubule distributions within and across cell lines. Here we describe a method to estimate information pertaining to 3D microtubule distributions from 2D fluorescence images. Our method allows for quantitative comparisons of microtubule distribution parameters (number of microtubules, mean length) between different cell lines. Among eleven cell lines compared, some showed differences that could be accounted for by differences in the total amount of tubulin per cell while others showed statistically significant differences in the balance between number and length of microtubules. We also observed that some cell lines that visually appear different in their microtubule distributions are quite similar when the model parameters are considered. The method is expected to be generally useful for comparing microtubule distributions between cell lines and for a given cell line after various perturbations. The results are also expected to enable analysis of the differences in gene expression underlying the observed differences in microtubule distributions among cell types., QC 20130111

The subcellular locations of proteins are closely related to their function and constitute an essential aspect for understanding the complex machinery of living cells. A systematic effort has been initiated to map the protein distribution in three functionally different cell lines with the aim to provide a subcellular localization index for at least one representative protein from all human protein-encoding genes. Here, we present the results of over 4,000 proteins mapped to 16 subcellular compartments. The results indicate a ubiquitous protein expression with a majority of the proteins found in all three cell lines and a large portion localized to two or more compartments. The inter-relationships between the subcellular compartments are visualized in a protein-compartment network based on all detected proteins. Hierarchical clustering was performed to determine how closely related the organelles are in terms of protein constituents and compare the proteins detected in each cell type. Our results show distinct organelle proteomes, well conserved across the cell types, and demonstrate that biochemically similar organelles are grouped together., QC 20110905

Mitochondria are involved in a wide range of cellular functions beyond their role in energy metabolism. Defining the human mitochondrial proteome is crucial to understand the mitochondria’s diverse functions and role in disease. Here, we present an image-based map of the human mitochondrial proteome containing 1,121 proteins with subcellular resolution. Our analysis shows that 48.3% (n=542) of the proteins localize to additional cellular compartments, further contributing to the diverse cellular functions of mitochondria and connectivity to other organelles. Furthermore, the mitochondrial proteome reveals tissue specific clustering, suggesting tissue specific functions and physiology. Strikingly, the single cell resolution of our dataset revealed extensive heterogeneity for as much as 33.5% (n=376) of the mitochondrial proteome which could not be explained by cell cycle progression. By performing a high throughput immunofluorescence screen, we conclude that heterogeneity in mitochondria protein expression can establish metabolic states in cell populations. This map of the mitochondrial proteome, part of the Human Protein Atlas database (www.proteinatlas.org), provides a valuable knowledge resource for studies of mitochondria function, dysfunction and disease., QC 20240405

Mitochondria is involved in a numerous variety of cellular functions beyond its role in energy metabolism. Defining the human mitochondrial proteome is crucial to understand the mitochondria’s diverse functions and role in disease. Here, we present an image-based map of the human mitochondrial proteome containing 1,098 proteins. The single cell resolution revealed extensive heterogeneity for as much as 20% (n=226) of the mitochondrial proteome. These variations are independent of cell cycle position and likely represent metabolic fluctuations in the cell. Our analysis shows that 48% (n=524) of the proteins localize to additional cellular compartments, further contributing to the diverse cellular functions of mitochondria. This map of the mitochondrial proteome, part of the Cell Atlas of the Human Protein Atlas database (www.proteinatlas.org), provides a valuable knowledge resource for studies of mitochondria function, dysfunction and disease., QC 20191007

QC 20170512

Defining the human mitochondrial proteome is crucial to understand the mitochondria’s diverse functions and role in disease. Here, we present an image-based map of the human mitochondrial proteome containing 1,070 proteins, of which 376 have previously not been reported to localize to the mitochondria. Our analysis shows that approximately 50% (n=493) of the proteins localize to additional cellular compartments, likely contributing to the diverse cellular functions of mitochondria. This map of the mitochondrial proteome, part of the Cell Atlas of the Human Protein Atlas database (www.proteinatlas.org), provides a valuable knowledge resource for studies of mitochondria function, dysfunction and disease., QC 20170512