Strukturelle und funktionelle Charakterisierung der Oligomerisierungsdomänen und c-terminalen Sequenzen in Mitgliedern der p53 Proteinfamilie
Zusammenfassung der Projektergebnisse
The aim of the project was to investigate the potential existence of secondary structure elements in the C-terminus of the two mammalian p53 homologs p63 and p73 by NMR spectroscopy and to investigate their functional relevance. We have determined the structure of the oligomerization domain of p73 and have shown that it contains an additional helix that is necessary to keep the protein in a tetrameric state. Based on chemical shifts we could also show that the oligomerization domain of p63 contains a similar helix as well. Transactivation experiments in SAOS2 cells revealed that the second helix is important for the transcriptional activity as well with mutants lacking this second helix only showing half of the transcriptional activity. We have identified a similar stabilizing second helix in the β-isoform of the p53-homolog of Ciona intestinalis, which is a model organism for understanding the evolution of vertebrates. In addition, we have revealed the regulatory mechanism that controls the transcriptional activity of TAp63α. This p63 isoform plays a major role as a quality control factor in female oocytes. In these cells TAp63α is highly expressed and kept in an inactive, dimeric conformation. Detection of double strand breaks activates p63 trough phosphorylation which triggers a major conformational switch from a dimeric and closed conformation to an open and tetrameric one. The active tetrameric state gets stabilized by the second helix that we identified in the oligomerization domain. A short interview focusing on the medical aspects of our results was published in the magazine “Der Spiegel”.
Projektbezogene Publikationen (Auswahl)
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(2009). Conformational stability and activity of p73 require a second helix in the tetramerization domain. Cell Death & Differentiation 16, 1582–1589
Coutandin D, Löhr F, Niesen FH, Ikeya T, Weber TA, Schäfer B, Zielonka EM, Bullock AN, Yang A, Güntert P, Knapp S, McKeon F, Ou HD, Dötsch V
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(2010). p63 and p73, the Ancestors of p53. Cold Spring Harbor Perspectives in Biology. Sep;2(9):a004887
Dötsch V, Bernassola F, Coutandin D, Candi E, Melino G
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(2010). Tracing the protectors path from the germ line to the genome. Proc Natl Acad Sci USA 107, 15318-25
Coutandin D, Der Ou H, Löhr F, Dötsch V.
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(2011). DNA damage in oocytes induces a switch of the quality control factor TAp63a from dimer to tetramer. Cell 144: 566-76
Deutsch GB, Zielonka EM, Coutandin D, Weber TA, Schäfer B, Hannewald J, Luh LM, Durst FG, Ibrahim M, Hoffmann J, Niesen FH, Sentürk A, Kunkel H, Brutschy B, Schleiff E, Knapp S, Acker-Palmer A, Grez M, McKeon F, Dötsch V
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(2011). Quality control in oocytes: Domain-domain interactions regulate the activity of p63. Cell Cycle 10: 1884-1885
Deutsch GB, Zielonka EM, Coutandin D, Dötsch V
