• Login
    View Item 
    •   Home
    • Theses and Dissertations
    • Theses and Dissertations
    • View Item
    •   Home
    • Theses and Dissertations
    • Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarly CommonsCommunitiesTitleAuthorsIssue DateSubmit DateSubjectsThis CollectionTitleAuthorsIssue DateSubmit DateSubjects

    My Account

    LoginRegister

    About

    AboutCreative CommonsAugusta University LibrariesUSG Copyright Policy

    Statistics

    Display statistics

    Novel Role of Heat Shock Protein (HSP) 90 in Regulating ATR-CHK1 DNA Damage Response Pathway in Cancer Cells

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Ha_Kyungsoo_PhD_2011.pdf
    Size:
    2.789Mb
    Format:
    PDF
    Download
    Authors
    Ha, Kyungsoo
    Issue Date
    2011-10
    URI
    http://hdl.handle.net/10675.2/345985
    
    Metadata
    Show full item record
    Abstract
    DNA damage caused by environmental mutagens or reactive metabolic byproducts induces DNA damage response (DDR), which regulates cell cycle transit, DNA repair and apoptosis. DDR involves the phosphorylation and activation of Ataxia Telangiectasia Mutated (ATM) and ATM and RAD3-related (ATR) proteins. ATR regulates the firing of the replication forks during S phase, and the repair of damaged replication forks to prevent premature onset of mitosis. ATR phosphorylates and activates CHK1 which phosphorylates and inactivates CDC25, thereby inhibiting CDK1 activation and cell cycle progression. In the present studies, we determined that treatment with an hsp90 inhibitor AUY922, without affecting the mRNA levels, dose-dependently depletes the protein levels of p-ATR (Ser 428), ATR and CHK1 in human breast and cervical cancer cells. Additionally, treatment with the pan-histone deacetylase inhibitor panobinostat (PS), which is known to induce hyperacetylation and inhibition of hsp90 function, also depleted ATR and CHK1 levels in cancer cells. Co-treatment with the proteasome inhibitor bortezomib (BZ) partially reversed AUY922- or PS-mediated depletion of ATR and CHK1 expression, indicating proteasome-mediated degradation of ATR and CHK1. Treatment with either AUY922 or PS markedly inhibited the binding of ATR with hsp90, induced polyubiquitylation of ATR, and decreased the half-life of both ATR and CHK1 proteins. Treatment with AUY922 also abrogated ionizing radiation (IR)-induced cell cycle arrest and increased the amount of DNA damage in the cancer cells following IR. Treatment with AUY922 also inhibited the recruitment of p-ATR, ATR and 53BP1 to the site of DNA damage. In addition, HDAC3 binds to and deacetylates hsp90 in the nucleus. Depletion of HDAC3 by either short hairpin RNA or genetic knockout induced hyperacetylation of nuclear hsp90, resulting in the inhibition of chaperone association of ATR with hsp90 and depletion of ATR. These findings demonstrate that 1) ATR is chaperoned by hsp90, 2) Inhibition of chaperone function of hsp90 results in proteasomal degradation of ATR and inhibition of DDR, 3) pan-HDAC inhibitors abrogate ATRCHK1 cell cycle checkpoint pathway by modulating chaperone activity of hsp90 and 4) HD AC3 plays a critical role in the regulation of DNA damage response by stabilizing the chaperone activity of nuclear hsp90.
    Affiliation
    Institute of Molecular Medicine and Genetics
    Description
    The file you are attempting to access is currently restricted to Augusta University. Please log in with your NetID if off campus.
    Collections
    Theses and Dissertations
    Institute of Molecular Medicine and Genetics Theses and Dissertations

    entitlement

     
    DSpace software (copyright © 2002 - 2022)  DuraSpace
    Quick Guide | Contact Us
    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.