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Browsing by Author "Dreyton, Christina J."

Now showing 1 - 3 of 3
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    Chemical Proteomic Platform To Identify Citrullinated Proteins
    Lewallen, Daniel M.; Bicker, Kevin L.; Subramanian, Venkataraman; Clancy, Kathleen W.; Slade, Daniel J.; Martell, Julianne; Dreyton, Christina J.; Sokolove, Jeremy; Weerapana, Eranthie; Thompson, Paul R. (2015-11-20)
    Anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA) and are routinely used for disease diagnosis. Protein citrullination is also increased in cancer and other autoimmune disorders, suggesting that citrullinated proteins may serve as biomarkers for diseases beyond RA. To identify these citrullinated proteins, we developed biotin-conjugated phenylglyoxal (biotin-PG). Using this probe and our platform technology, we identified >50 intracellular citrullinated proteins. More than 20 of these are involved in RNA splicing, suggesting, for the first time, that citrullination modulates RNA biology. Overall, this chemical proteomic platform will play a key role in furthering ourunderstanding of protein citrullination in rheumatoid arthritis and potentially a wider spectrum of inflammatory diseases.
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    Peptidylarginine deiminase 2-catalyzed histone H3 arginine 26 citrullination facilitates estrogen receptor alpha target gene activation
    Zhang, Xuesen; Bolt, Michael; Guertin, Michael J.; Chen, Wei; Zhang, Sheng; Cherrington, Brian D.; Slade, Daniel J.; Dreyton, Christina J.; Subramanian, Venkataraman; Bicker, Kevin L.; Thompson, Paul R.; Mancini, Michael A.; Lis, John T.; Coonrod, Scott A. (2012-08-14)
    Cofactors for estrogen receptor α (ERα) can modulate gene activity by posttranslationally modifying histone tails at target promoters. Here, we found that stimulation of ERα-positive cells with 17β-estradiol (E2) promotes global citrullination of histone H3 arginine 26 (H3R26) on chromatin. Additionally, we found that the H3 citrulline 26 (H3Cit26) modification colocalizes with ERα at decondensed chromatin loci surrounding the estrogen-response elements of target promoters. Surprisingly, we also found that citrullination of H3R26 is catalyzed by peptidylarginine deiminase (PAD) 2 and not by PAD4 (which citrullinates H4R3). Further, we showed that PAD2 interacts with ERα after E2 stimulation and that inhibition of either PAD2 or ERα strongly suppresses E2-induced H3R26 citrullination and ERα recruitment at target gene promoters. Collectively, our data suggest that E2 stimulation induces the recruitment of PAD2 to target promoters by ERα, whereby PAD2 then citrullinates H3R26, which leads to local chromatin decondensation and transcriptional activation.
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    Protein Arginine Deiminase 2 Binds Calcium in an Ordered Fashion: Implications for Inhibitor Design
    Slade, Daniel J.; Fang, Pengfei; Dreyton, Christina J.; Zhang, Ying; Fuhrmann, Jakob; Rempel, Don; Bax, Benjamin D.; Coonrod, Scott A.; Lewis, Huw D.; Guo, Min; Gross, Michael L.; Thompson, Paul R. (American Chemical Society, 2015-04-01)
    Protein arginine deiminases (PADs) are calcium-dependent histone-modifying enzymes whose activity is dysregulated in inflammatory diseases and cancer. PAD2 functions as an Estrogen Receptor (ER) coactivator in breast cancer cells via the citrullination of histone tail arginine residues at ER binding sites. Although an attractive therapeutic target, the mechanisms that regulate PAD2 activity are largely unknown, especially the detailed role of how calcium facilitates enzyme activation. To gain insights into these regulatory processes, we determined the first structures of PAD2 (27 in total), and through calcium-titrations by X-ray crystallography, determined the order of binding and affinity for the six calcium ions that bind and activate this enzyme. These structures also identified several PAD2 regulatory elements, including a calcium switch that controls proper positioning of the catalytic cysteine residue, and a novel active site shielding mechanism. Additional biochemical and mass-spectrometry-based hydrogen/deuterium exchange studies support these structural findings. The identification of multiple intermediate calcium-bound structures along the PAD2 activation pathway provides critical insights that will aid the development of allosteric inhibitors targeting the PADs.