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- Muthukrishnan, Uma, 1984-, et al.
(författare)
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The exosome membrane localization of histones is independent of DNA and upregulated in response to stress
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Extracellular histones contribute to many acute and chronic diseases but also populate the secretomes of healthy cells and biofluids. However, a secretory pathway for histones has not been described. Here we report that core and linker histones localize to multivesicular bodies and are secreted via exosomes. Histones are tightly associated with the exosome membrane, with N-terminal domains exposed, in a DNA-independent manner. Furthermore, rapid upregulation of exosomal histones occurs following heat stress, accompanied by enhanced vesicle secretion and a shift towards a population of smaller vesicles. Proteomic analyses identified the downregulation of endosomal sorting complex required for transport (ESCRT) complex as a possible mechanism underlying increased histone secretion.We show for the first time that membrane-associated histones are actively secreted from intact cells via the multivesicular body/exosomal pathway. We demonstrate a novel pathway for extracellular histone release that may have a role in both health and disease.
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| 2. |
- Boström, Tove, et al.
(författare)
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Investigating the correlation of protein and mRNA levels in human cell lines using quantitative proteomics and transcriptomics
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- An important topic of discussion in proteomics is the degree of correlation of RNA and protein levels in cells, tissues and organs. In this study, the difference in protein and mRNA levels for a number of selected gene targets were investigated across six human cell lines using quantitative proteomics and next generation sequencing-based transcriptomics. The copy numbers of 32 proteins were determined using an absolute quantitative proteomics approach (PrEST-SILAC), where heavy isotope-labeled protein fragments were used as internal standards. A cross evaluation of protein copy numbers determined by mass spectrometry and staining profiles using immunohistochemistry showed good correlation. The mRNA levels were determined using RNA sequencing based on digital counting of sequencing reads and the levels determined as FPKM values. Comparison of the relative variations in mRNA and protein levels for individual genes across the six cell lines showed correlation between protein and mRNA levels, including six genes with high variability in expression levels in the six cell lines resulting in an average correlation of 0.9 (Spearman's rank coefficient). In summary, the analysis of the selected protein targets supports the conclusion that the translation rate across cell lines correlates for a particular gene, suggesting that individual protein levels can be predicted from the respective mRNA levels by defining the relation between protein and mRNA, specific for each human gene.
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