1 / 11

Post-transcriptional modifications of p53

Post-transcriptional modifications of p53. Ubiquitin mediated Protealysis. CSN Phosphorylation. Ubiquitin mediated Protealysis. ATM etc Phosphorylation. Mdm2 interaction. O-GlcNac. P53. Ser149. Ser15. Thr18. Ser20. Ser155. Mdm2 binding region.

derora
Download Presentation

Post-transcriptional modifications of p53

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Post-transcriptional modifications of p53 Ubiquitin mediated Protealysis CSN Phosphorylation Ubiquitin mediated Protealysis ATM etc Phosphorylation Mdm2 interaction O-GlcNac P53 Ser149 Ser15 Thr18 Ser20 Ser155 Mdm2 binding region Mdm2: a member of E3 ubiquitin-ligase CSN(COP9 signalosome) : a conserved protein complex that evolved in parallel with the ubiquitin-proteasome system

  2. Two chemicals used • Dox(doxorubicin): a DNA-damaging agent that is known to stabilize p53 • STZ(streptozotocin): an O-GlacNacase inhibitor.

  3. Effiect of Dox/STZ treatment on accumulation and O-GlcNAcylation of p53

  4. Effiect of Dox/STZ treatment on accumulation and O-GlcNAcylation of p53 Transcriptional level?

  5. O-GlcNAcylation of p53 by STZ treatment reduces p53 ubiquitination and p53–Mdm2 interactions in MCF-7 cells Total ubiquitin level ALLN: a proteasome inhibitor

  6. O-GlcNAcylation of p53 by STZ treatment inhibitsphosphorylation of p53 at Thr 155 in MCF-7 cells CNS-p53 interaction CNS levels Thr 155 CNS Kinase activity Thr 155 In-vitro assay: IP CNS His-tag purify p53 as substrate

  7. p53 is modified by O-GlcNAc at Ser 149 bn= residue masses+1 yn=residue masses+H2O+1

  8. Mutation of the p53 O-GlcNAcylation site (Ser 149) abrogates STZ induced p53 accumulation ?

  9. Mutation of the Ser 149 abrogates STZ induced p53 accumulation in p53-knockout H1299 cells Exogenously expressed p53 retains biological activity ?

  10. Conclusions • Ser 149 of p53 is O-GlcNAcylated • This modification associated decreased phosphorylation at Thr 155, which is a site of COP9 signalsome. • Thus stabilize p53 by blocking ubiquitin-dependent proteolysis

More Related