Interaction between the transactivation domain of p53 and PC4 exemplifies acidic activation domains as single-stranded DNA mimics.
The tumor suppressor p53 regulates cell cycle arrest and apoptosis by transactivating several genes that are critical for these processes. The transcriptional activity of p53 is often regulated by post-translational modifications and its interactions with various transcriptional coactivators. Here we report a physical interaction between the N-terminal transactivation domain (TAD) of p53 and the C-terminal DNA-binding domain of positive cofactor 4 (PC4(CTD)). Using NMR spectroscopy, we showed that residues 35-57 (TAD2) interact with PC4. (15)N,(1)H HSQC and fluorescence competition experiments indicated that TAD binds to the DNA-binding site of PC4. Hepta-phosphorylation of the TAD peptide increased its binding affinity. Computer modeling of the p53N-PC4 complex revealed several important interactions that are reminiscent of those in the single-stranded DNA-PC4 complex. The ubiquitous nature of the acidic transactivation domain of p53 in mediating interactions with several transcription cofactors is also manifested as a DNA mimetic.
Rajagopalan
Sridharan
S
MRC Centre for Protein Engineering, Cambridge, United Kingdom.
Andreeva
Antonina
A
Teufel
Daniel P
DP
Freund
Stefan M
SM
Fersht
Alan R
AR
D000595:Amino Acid Sequence; D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013050:Spectrometry, Fluorescence / Q000379:methods; D014157:Transcription Factors / Q000737:chemistry*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C509201:SUB1 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D004247:DNA