| 1. |
- Aebersold, Ruedi, et al.
(författare)
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How many human proteoforms are there?
- 2018
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Ingår i: Nature Chemical Biology. - : NATURE PUBLISHING GROUP. - 1552-4450 .- 1552-4469. ; 14:3, s. 206-214
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Tidskriftsartikel (refereegranskat)abstract
- Despite decades of accumulated knowledge about proteins and their post-translational modifications (PTMs), numerous questions remain regarding their molecular composition and biological function. One of the most fundamental queries is the extent to which the combinations of DNA-, RNA-and PTM-level variations explode the complexity of the human proteome. Here, we outline what we know from current databases and measurement strategies including mass spectrometry-based proteomics. In doing so, we examine prevailing notions about the number of modifications displayed on human proteins and how they combine to generate the protein diversity underlying health and disease. We frame central issues regarding determination of protein-level variation and PTMs, including some paradoxes present in the field today. We use this framework to assess existing data and to ask the question, "How many distinct primary structures of proteins (proteoforms) are created from the 20,300 human genes?" We also explore prospects for improving measurements to better regularize protein-level biology and efficiently associate PTMs to function and phenotype.
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| 2. |
- Wang, Harris H., et al.
(författare)
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Multiplexed in Vivo His-Tagging of Enzyme Pathways for in Vitro Single-Pot Multienzyme Catalysis
- 2012
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Ingår i: ACS Synthetic Biology. - : American Chemical Society (ACS). - 2161-5063. ; 1:2, s. 43-52
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Tidskriftsartikel (refereegranskat)abstract
- Protein pathways are dynamic and highly coordinated spatially and temporally, capable of performing a diverse range of complex chemistries and enzymatic reactions with precision and at high efficiency. Biotechnology aims to harvest these natural systems to construct more advanced in vitro reactions, capable of new chemistries and operating at high yield. Here, we present an efficient Multiplex Automated Genome Engineering (MAGE) strategy to simultaneously modify and co-purify large protein complexes and pathways from the model organism Escherichia coli to reconstitute functional synthetic proteomes in vitro. By application of over 110 MAGE cycles, we successfully inserted hexa-histidine sequences into 38 essential genes in vivo that encode for the entire translation machinery. Streamlined co-purification and reconstitution of the translation, protein complex enabled protein synthesis in vitro. Our approach can be applied to a growing area of applications in in vitro one-pot multienzyme catalysis (MEC) to manipulate or enhance in vitro pathways such as natural product or carbohydrate biosynthesis.
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| 3. |
- Fazio, Allessandro, et al.
(författare)
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Transcription factor control of growth rate dependent genes in Saccharomyces cerevisiae: A three factor design
- 2008
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Ingår i: BMC Genomics. ; 9:341
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Tidskriftsartikel (refereegranskat)abstract
- Background: Characterization of cellular growth is central to understanding living systems. Here, we applied a three-factor design to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostate cultures of Saccharomyces cerevisiae. The three factors we considered were specific growth rate, nutrient limitation, and oxygen availability.Results: We identified 268 growth rate dependent genes, independent of nutrient limitation and oxygen availability. The transcriptional response was used to identify key areas in metabolism around which mRNA expression changes are significantly associated. Among key metabolic pathways, this analysis revealed de novo synthesis of pyrimidine ribonucleotides and ATP producing and consuming reactions at fast cellular growth. By scoring the significance of overlap between growth rate dependent genes and known transcription factor target sets, transcription factors that coordinate balanced growth were also identified. Our analysis shows that Fhl I, Rap I, and Sfp I, regulating protein biosynthesis, have significantly enriched target sets for genes up-regulated with increasing growth rate. Cell cycle regulators, such as Ace2 and Swi6, and stress response regulators, such as Yap I, were also shown to have significantly enriched target sets.Conclusion: Our work, which is the first genome-wide gene expression study to investigate specific growth rate and consider the impact of oxygen availability, provides a more conservative estimate of growth rate dependent genes than previously reported. We also provide a global view of how a small set of transcription factors, 13 in total, contribute to control of cellular growth rate. We anticipate that multi-factorial designs will play an increasing role in elucidating cellular regulation.
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| 4. |
- Jimenez-Ferrer, Itzia, et al.
(författare)
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The MHC class II transactivator modulates seeded alpha-synuclein pathology and dopaminergic neurodegeneration in an in vivo rat model of Parkinson's disease
- 2021
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Ingår i: Brain, Behavior, and Immunity. - : Elsevier BV. - 0889-1591. ; 91, s. 369-382
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Tidskriftsartikel (refereegranskat)abstract
- Background: Abnormal folding, aggregation and spreading of alpha-synuclein (αsyn) is a mechanistic hypothesis for the progressive neuropathology in Parkinson's disease (PD). Spread of αsyn between cells is supported by clinical, neuropathological and experimental evidence. It has been proposed that a pro-inflammatory micro-environment in response to αsyn can promote its aggregation. We have previously shown that allelic differences in the major histocompatibility complex class two transactivator (Mhc2ta) gene, located in the VRA4 locus, alter MHCII expression levels, microglial activation and antigen presentation capacity in rats upon human αsyn over-expression. In addition, Mhc2ta regulated dopaminergic neurodegeneration and the extent of motor impairment. The purpose of this study was to determine whether Mhc2ta regulates αsyn aggregation, propagation and dopaminergic pathology in an αsyn pre-formed fibril (PFF)-seeded in vivo model of PD. Methods: The DA and DA.VRA4 congenic rat strains share background genome but display differential microglial antigen presenting capacity due to different Mhc2ta alleles in the VRA4 locus. PFFs of human αsyn or BSA solution were injected unilaterally to the striatum of DA and DA.VRA4 rats two weeks after ipsilateral administration of recombinant adeno-associated virus (rAAV) vectors carrying human αsyn or GFP to the substantia nigra pars compacta. Behavioural assessment was performed at 2, 5 and 8 weeks while histological evaluation of αsyn pathology, inflammation and neurodegeneration as well as determination of serum cytokine profiles were performed at 8 weeks. Results: rAAV-mediated expression of human αsyn in nigral dopaminergic neurons combined with striatal PFF administration induced enhanced αsyn pathology in DA.VRA4 compared to DA rats. Mhc2ta thus significantly regulated the seeding, propagation and toxicity of αsyn in vivo. This was reflected in terms of wider extent and anatomical distribution of αsyn inclusions, ranging from striatum to the forebrain, midbrain, hindbrain and cerebellum in DA.VRA4. Compared to DA rats, DA.VRA4 also displayed enhanced motor impairment and dopaminergic neurodegeneration as well as higher levels of the proinflammatory cytokines IL-2 and TNFα in serum. Conclusions: We conclude that the key regulator of MHCII expression, Mhc2ta, modulates neuroinflammation, αsyn-seeded Lewy-like pathology, dopaminergic neurodegeneration and motor impairment. This makes Mhc2ta and microglial antigen presentation promising therapeutic targets for reducing the progressive neuropathology and clinical manifestations in PD.
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| 5. |
- Nookaew, Intawat, 1977, et al.
(författare)
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The genome-scale metabolic model ilN800 of Saccharomyces cerevisiae and its validation: a scaffold to query lipid metabolism
- 2008
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Ingår i: BMC Systems Biology. - : Springer Science and Business Media LLC. - 1752-0509. ; 2:71
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Tidskriftsartikel (refereegranskat)abstract
- Background: Up to now, there have been three published versions of a yeast genome-scale metabolic model: iFF708, iND750 and iLL672. All three models, however, lack a detailed description of lipid metabolism and thus are unable to be used as integrated scaffolds for gaining insights into lipid metabolism from multilevel omic measurement technologies (e.g. genome-wide mRNA levels). To overcome this limitation, we reconstructed a new version of the Saccharomyces cerevisiae genome-scale model, ilN800 that includes a more rigorous and detailed descrition of lipid metabolism. Results: The reconstructed metabolic model comprises 1446 reactions and 1013 metabolites. Beyond incorporating new reactions involved in lipid metabolism, we also present new biomass equations that improve the predictive power of flux balance analysis simulations. Predictions of both growth capability and large scale in silico single gene deletions by ilN800 were consistent with experimental data. In addition, 13C-labeling experiments validated the new biomass equations and calculated intracellular fluxes. To demonstrate the applicability of ilN800, we show that the model can be used as a scaffold to reveal the regulatory importance of lipid metabolism precursors and intermediates that would have been missed in previous models from transcriptome datasets. Conclusions: Performing integrated analyses using ilN800 as a network scaffold is shown to be a valuable tool for elucidating the behavior of complex metabolic networks, particularly for identifying regulatory targets in lipid metabolism that can be used for industrial applications or for understanding lipid disease states.
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| 6. |
- Usaite, Renata, et al.
(författare)
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Reconstruction of the yeast Snf1 kinase regulatory network reveals its role as a global energy regulator
- 2009
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Ingår i: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 5:319, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Highly conserved among eukaryotic cells, ghe AMP-activated kinase (AMPK) is a central regulator of carbon metabolism. To map the complete network of interactions around AMPK in yeast (Snf1) and to evaluate the role of its regulatory subunit Snf4, we measured global mRNA, protein and metabolite levels in wild type, ∆snf1, ∆snf4, and ∆snf1∆snf4 knockout strains. Using four newly developed computional tools, including novel DOGMA sub-network analysis, we showed the benefits of three-level ome-data integration to uncover the global Snf1 kinase role in yeast. We for the first time identified Snf1's global regulation on gene and protein expression levels, and showed that yeast Snf1 has a far more extensive function in controlling energy metabolism that reported earlier. Additionally, we identified complementary roles of Snf1 and Snf4. Similar to the function of AMPK in humans, our findings showed that Snf1 is a low-energy checkpoint and that yeast can be used more extensively as a model system for studying the molecular mechanisms underlying the global regulation of AMPK in mammals, failure of which leads to metabolic diseases.
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