ABSTRACT: Cultured carcinoma cells were stimulated with growth factors and lysine acetylation and/or tyrosine phosphorylation dynamics were quantified.
Project description:Cultured carcinoma cells were stimulated with growth factors and lysine acetylation and/or tyrosine phosphorylation dynamics were quantified.
Project description:Post-translational modifications of proteins have emerged as a major mechanism for regulating gene expression. Yet our understanding of how histone modifications directly affect chromatin function remains limited. Here, we investigate acetylation of histone H3 at lysine 64 (H3K64ac), a previously uncharacterized acetylation site on the lateral surface of the histone octamer. We show that H3K64ac regulates nucleosome dynamics by (i) destabilizing nucleosomes, and (ii) regulating chromatin remodelling. Both of these functions have the potential to regulate gene expression. In line with this, we show that the p300 co-activator acetylates H3K64 both in vitro and in vivo. H3K64ac is enriched at the transcriptional start sites (TSS) of active genes and defines transcriptionally active chromatin in ES cells. Moreover, we find that H3K64ac is dynamic during developmental reprogramming, and during mammalian spermatogenesis where H3K64 hyperacetylation precedes histone replacement. Consistent with a function in transcriptional activation, H3K64ac opposes its repressive counterpart H3K64me3. Our findings reveal an important role for a histone modification within the nucleosome core as a regulator of chromatin function in vivo and they demonstrate that lateral surface modifications can define functionally opposing chromatin states. In this study, 2 biological replicate samples for H3K64ac ChIP and one sample of H3K9ac ChIP in mouse emryonic stem cells were analyzed using custom designed Nimblegen HD2.1oligonucleotide tiling arrays.
Project description:Bud dormancy in perennials in boreal and temperate ecosystems is crucial for survival in harsh winter. Dormancy is released by prolonged exposure to low temperatures and is followed by reactive growth in the spring. Lysine acetylation (Kac) is one of the major post-translational modifications (PTMs) involved in plant response to environment signals. However, little information is available on the effects of Kac modification on bud dormancy release. Here, we report the dynamics of lysine acetylome in hybrid poplar (Populus tremula x alba) dormant buds. A total number of 7,594 acetyl sites from 3,281 acetyl proteins were identified, representing the largest to date dataset of lysine acetylome in plants. Of them, 229 proteins were differentially acetylated during bud dormancy release and were involved mainly in the primary metabolism. Site-directed mutagenesis enzymatic assays showed that acetylation strongly modified the activities of two key enzymes of primary metabolism, pyruvate dehydrogenase (PDH) and isocitrate dehydrogenase (IDH). We thus propose that Kac of enzymes could be an important strategy for reconfiguration of metabolic processes during bud dormancy release. In all, our results reveal the importance of Kac in bud dormancy release and give a new perspective to understand the molecular mechanisms of tree’s seasonal growth.
Project description:Dynamics and functional interplay of histone lysine butyrylation, crotonylation, and acetylation in rice under starvation and submergence
Project description:Aspirin, or acetylsalicylic acid is widely used to control pain, inflammation and fever. Important to this function is its ability to irreversibly acetylate cyclooxygenases at active site serines. Aspirin has the potential to acetylate other amino-acid side-chains, leading to speculation that aspirin-mediated lysine acetylation could explain some of its drug actions or side-effects. Using a labeled form of aspirin, aspirin-d3, we identified over 12000 sites of lysine acetylation from cultured human cells. Although aspirin amplifies acetylation signals at thousands of sites, cells tolerate aspirin mediated acetylation very well unless endogenous deacetylases are inhibited. Apart from a limited number of cellular proteins that are substantially acetylated under endogenous conditions, aspirin mediated acetylation leads to a large increase in the acetylation of many proteins even although they remain at very low stoichiometry. This reinforces the idea that a major function of cellular deacetylases is the suppression of non-specific or non-enzymatic protein acetylation.
Project description:Mutant isocitrate dehydrogenase (IDH) 1 and 2 play a pathogenic role in cancers including acute myeloid leukemia (AML) by producing oncometabolite 2- hydroxyglutarate (2-HG) . We recently reported that tyrosine phosphorylation activates IDH1 R132H mutant in AML cells. Here we show that, surprisingly, mutant IDH2 (mIDH2) R140Q commonly has K413-acetylation, which negatively regulates mIDH2 activity in human AML cells by attenuating dimerization and blocking binding of substrate (α-ketoglutarate) and cofactor (NADPH). Mechanistically, K413-acetylation of mitochondrial mIDH2 is achieved through a series of hierarchical phosphorylation events mediated by tyrosine kinase FLT3, which phosphorylates mIDH2 to recruit upstream mitochondrial acetyltransferase ACAT1 and simultaneously activates ACAT1 and inhibits upstream mitochondrial deacetylase SIRT3 through tyrosine- phosphorylation. Moreover, we found that the intrinsic enzyme activity of mIDH2 is much higher than mIDH1, thus the inhibitory K413-acetylation optimizes leukemogenic ability of mIDH2 in AML cells by both producing sufficient 2-HG for transformation and avoiding cytotoxic accumulation of intracellular 2-HG.
Project description:Oxidative stress adaptation strategies are important to cell function and are linked to cardiac, neurodegenerative disease and cancer. Representatives of the domain Archaea are used as model organisms based on their extreme tolerance to oxidants and close evolutionary relationship with eukaryotes. Study of the halophilic archaeon Haloferax volcanii reveals lysine acetylation to be associated with oxidative stress responses. The strong oxidant hypochlorite: i) stimulates an increase in lysine acetyltransferase HvPat2 to HvPat1 abundance ratios and ii) selects for lysine deacetylase sir2 mutants. Here we report the dynamic occupancy of the lysine acetylome of glycerol-grown H. volcanii as it shifts in profile in response to hypochlorite. These findings are revealed by the: 1) quantitative multiplex LC-MS/MS analysis of the SILAC-compatible parent and Δsir2 mutant strains and 2) label free LC-MS/MS analysis of H26 ‘wild type’ cells. The results show that lysine acetylation is associated with key biological processes including DNA topology, central metabolism, cobalamin biosynthesis and translation. Lysine acetylation targets are found conserved across species. Moreover, lysine residues modified by acetylation and ubiquitin-like sampylation are identified suggesting post-translational modification (PTM) crosstalk. Overall, the results of this study expand the current knowledge of lysine acetylation in Archaea, with the long-term goal to provide a balanced evolutionary perspective of PTM systems in living organisms.
Project description:Nucleosome mapping and histone H3 lysine 14 acetylation chromatin immuno-precipitation in two unrelated strains of yeast (BY and RM).
Project description:Aspirin, or acetylsalicylic acid is widely used to control pain, inflammation and fever. Important to this function is its ability to irreversibly acetylate cyclooxygenases at active site serines. Aspirin has the potential to acetylate other amino-acid side-chains, leading to speculation that aspirin-mediated lysine acetylation could explain some of its drug actions or side-effects. Using a labeled form of aspirin, aspirin-d3, we identified over 12000 sites of lysine acetylation from cultured human cells. Although aspirin amplifies acetylation signals at thousands of sites, cells tolerate aspirin mediated acetylation very well unless endogenous deacetylases are inhibited. Apart from a limited number of cellular proteins that are substantially acetylated under endogenous conditions, aspirin mediated acetylation leads to a large increase in the acetylation of many proteins even although they remain at very low stoichiometry. This reinforces the idea that a major function of cellular deacetylases is the suppression of non-specific or non-enzymatic protein acetylation.
Project description:Aspirin, or acetylsalicylic acid is widely used to control pain, inflammation and fever. Important to this function is its ability to irreversibly acetylate cyclooxygenases at active site serines. Aspirin has the potential to acetylate other amino-acid side-chains, leading to speculation that aspirin-mediated lysine acetylation could explain some of its drug actions or side-effects. Using a labeled form of aspirin, aspirin-d3, we identified over 12000 sites of lysine acetylation from cultured human cells. Although aspirin amplifies acetylation signals at thousands of sites, cells tolerate aspirin mediated acetylation very well unless endogenous deacetylases are inhibited. Apart from a limited number of cellular proteins that are substantially acetylated under endogenous conditions, aspirin mediated acetylation leads to a large increase in the acetylation of many proteins even although they remain at very low stoichiometry. This reinforces the idea that a major function of cellular deacetylases is the suppression of non-specific or non-enzymatic protein acetylation.