{"id":{"repo_id":"uthsc","oai_identifier":"oai:digitalcommons.library.tmc.edu:utgsbs_dissertations-1125"},"canonical_url":"https://search.dev.ndltd.org/etd/uthsc/oai:digitalcommons.library.tmc.edu:utgsbs_dissertations-1125","repository":{"repo_id":"uthsc","name":"University of Texas Health Science Center at Houston","base_url":"https://digitalcommons.library.tmc.edu/do/oai/"},"display":{"title":"14-3-3Sigma Negatively Regulates The Stability and Subcellular Localization of Cop1","abstract":"Mammalian constitutive photomorphogenic 1 (COP1), a p53 E3 ubiquitin ligase, is a key negative regulator for p53. DNA damage leads to the translocation of COP1 to the cytoplasm, but the underlying mechanism remains unknown. We discovered that 14-3-3σ controlled COP1 subcellular localization and protein stability. Investigation of the underlying mechanism suggested that, upon DNA damage, 14-3-3σ bound to phosphorylated COP1 at S387, resulting in COP1 translocation to the cytoplasm and cytoplasmic COP1 ubiquitination and proteasomal degradation. 14-3-3σ targeted COP1 for degradation to prevent COP1-mediated p53 degradation, p53 ubiquitination, and p53 transcription repression. COP1 expression promoted cell proliferation, cell transformation, and tumor progression, attesting to its role in cancer promotion. 14-3-3σ negatively regulated COP1 function and prevented tumor growth in cancer xenografts. COP1 protein levels were inversely correlated with 14-3-3σ protein levels in human breast and pancreatic cancer specimens. Together, these results define a novel, detailed mechanism for the posttranslational regulation of COP1 upon DNA damage and provide a mechanistic explanation of the correlation of COP1 overexpression with 14-3-3σ downregulation during tumorigenesis.","abstract_html":"Mammalian constitutive photomorphogenic 1 (COP1), a p53 E3 ubiquitin ligase, is a key negative regulator for p53. DNA damage leads to the translocation of COP1 to the cytoplasm, but the underlying mechanism remains unknown. We discovered that 14-3-3σ controlled COP1 subcellular localization and protein stability. Investigation of the underlying mechanism suggested that, upon DNA damage, 14-3-3σ bound to phosphorylated COP1 at S387, resulting in COP1 translocation to the cytoplasm and cytoplasmic COP1 ubiquitination and proteasomal degradation. 14-3-3σ targeted COP1 for degradation to prevent COP1-mediated p53 degradation, p53 ubiquitination, and p53 transcription repression. COP1 expression promoted cell proliferation, cell transformation, and tumor progression, attesting to its role in cancer promotion. 14-3-3σ negatively regulated COP1 function and prevented tumor growth in cancer xenografts. COP1 protein levels were inversely correlated with 14-3-3σ protein levels in human breast and pancreatic cancer specimens. Together, these results define a novel, detailed mechanism for the posttranslational regulation of COP1 upon DNA damage and provide a mechanistic explanation of the correlation of COP1 overexpression with 14-3-3σ downregulation during tumorigenesis.","abstract_has_math":false,"creators":["Su, Chun-Hui"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation (PhD)","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Mong-Hong Lee, Ph.D.","Randy J. Legerski, Ph.D.","Pierre D. McCrea, Ph.D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2010,"date_issued":"2010-12-01T08:00:00Z","date_published":"2010-12-01T08:00:00Z","updated_at":"2026-07-24T05:50:16Z","subjects":["COP1","p53","14-3-3sigma","ubiquitination","Biology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.library.tmc.edu/utgsbs_dissertations/101","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Mong-Hong Lee, Ph.D.","Randy J. Legerski, Ph.D.","Pierre D. 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DNA damage leads to the translocation of COP1 to the cytoplasm, but the underlying mechanism remains unknown. We discovered that 14-3-3σ controlled COP1 subcellular localization and protein stability. Investigation of the underlying mechanism suggested that, upon DNA damage, 14-3-3σ bound to phosphorylated COP1 at S387, resulting in COP1 translocation to the cytoplasm and cytoplasmic COP1 ubiquitination and proteasomal degradation. 14-3-3σ targeted COP1 for degradation to prevent COP1-mediated p53 degradation, p53 ubiquitination, and p53 transcription repression. COP1 expression promoted cell proliferation, cell transformation, and tumor progression, attesting to its role in cancer promotion. 14-3-3σ negatively regulated COP1 function and prevented tumor growth in cancer xenografts. COP1 protein levels were inversely correlated with 14-3-3σ protein levels in human breast and pancreatic cancer specimens. Together, these results define a novel, detailed mechanism for the posttranslational regulation of COP1 upon DNA damage and provide a mechanistic explanation of the correlation of COP1 overexpression with 14-3-3σ downregulation during tumorigenesis."]},{"key":"dc:title","label":"Title","values":["14-3-3Sigma Negatively Regulates The Stability and Subcellular Localization of Cop1"]}]}],"canonical_facts":{"dc:contributor":["Mong-Hong Lee, Ph.D.","Randy J. Legerski, Ph.D.","Pierre D. McCrea, Ph.D."],"dc:creator":["Su, Chun-Hui"],"dc:date.available":["2010-12-15T08:00:00Z"],"dc:description.abstract":["Mammalian constitutive photomorphogenic 1 (COP1), a p53 E3 ubiquitin ligase, is a key negative regulator for p53. DNA damage leads to the translocation of COP1 to the cytoplasm, but the underlying mechanism remains unknown. We discovered that 14-3-3σ controlled COP1 subcellular localization and protein stability. Investigation of the underlying mechanism suggested that, upon DNA damage, 14-3-3σ bound to phosphorylated COP1 at S387, resulting in COP1 translocation to the cytoplasm and cytoplasmic COP1 ubiquitination and proteasomal degradation. 14-3-3σ targeted COP1 for degradation to prevent COP1-mediated p53 degradation, p53 ubiquitination, and p53 transcription repression. COP1 expression promoted cell proliferation, cell transformation, and tumor progression, attesting to its role in cancer promotion. 14-3-3σ negatively regulated COP1 function and prevented tumor growth in cancer xenografts. COP1 protein levels were inversely correlated with 14-3-3σ protein levels in human breast and pancreatic cancer specimens. Together, these results define a novel, detailed mechanism for the posttranslational regulation of COP1 upon DNA damage and provide a mechanistic explanation of the correlation of COP1 overexpression with 14-3-3σ downregulation during tumorigenesis."],"dc:identifier":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/101"],"dc:subject":["COP1","p53","14-3-3sigma","ubiquitination","Biology"],"dc:title":["14-3-3Sigma Negatively Regulates The Stability and Subcellular Localization of Cop1"],"thesis:degree_level":["Dissertation (PhD)"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T05:50:16Z"}