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Homeodomain Interacting Protein Kinase 1 (HIPK1) Binds O‐GlcNAc Transferase and is O‐GlcNAcylated
Author(s) -
Copeland Ronald,
Hart Gerald
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1050.1
Subject(s) - kinase , serine , threonine , phosphorylation , transferase , chemistry , function (biology) , nuclear localization sequence , microbiology and biotechnology , biochemistry , cytoplasm , subcellular localization , protein kinase a , enzyme , biology
O‐linked β‐N‐acetylglucosamine (O‐GlcNAc) is a dynamic post‐translational modification consisting of the addition of a single N‐acetylglucosamine (GlcNAc) moiety to serine and/or threonine residues of numerous nuclear and cytoplasmic proteins. O‐GlcNAc is involved in various cellular processes by regulating aspects of a protein's function including affecting a protein's stability/activity, localization, and protein‐protein interactions. Using a Y2H screen with O‐GlcNAc transferase (OGT), the enzyme responsible for the O‐GlcNAc modification as bait, we have identified homeodomain‐interacting protein kinase 1 (HIPK1) among others as interacting with OGT. HIPK1, a nuclear protein kinase shown to be elevated in breast cancer cells, serves to phosphorylate various transcription factors including p53. Others have shown using HIPK1 −/− and +/+ MEFs that HIPK1 may play roles in cancer and tumorgenesis by regulating p53 and/or Mdm2 function. Herein, we begin to investigate what roles O‐GlcNAc may play regulating HIPK1 function. Y2H results were confirmed as HIPK1 co‐immunoprecipitates in both directions with OGT in vivo . We also demonstrate using an immunoblotting technique with an O‐GlcNAc specific antibody (110.6) and by an enzymatic labeling method that HIPK1 is O‐GlcNAc modified. Currently, we are working to map the O‐GlcNAc site(s) on HIPK1 and also map its OGT interacting domain. Results obtained will allow us to generate O‐GlcNAc site‐specific antibodies and begin to uncover the roles that O‐GlcNAc may play in regulating HIPK1 function, specifically as it relates to cancer and tumorgenesis. Supported by NIH NCI 42486 and DK 61671 to G.W.H. (Dr. Hart receives a share of the royalty received by the university on the sales of the 110.6 antibody. Terms of the arrangement are managed by JHU).