Transcription factor p53 protects cells against tumorigenesis when subjected to various cellular stresses. Under these conditions, p53 interacts with transcription factor Forkhead box O (FOXO) 4, thereby inducing cellular senescence by upregulating the transcription of senescence-associated protein p21. However, the structural details of this interaction remain unclear. Here, we characterize the interaction between p53 and FOXO4 by NMR, chemical cross-linking, and analytical ultracentrifugation. Our results reveal that the interaction between p53 TAD and the FOXO4 Forkhead domain is essential for the overall stability of the p53:FOXO4 complex. Furthermore, contacts involving the N-terminal segment of FOXO4, the C-terminal negative regulatory domain of p53 and the DNA-binding domains of both proteins stabilize the complex, whose formation blocks p53 binding to DNA but without affecting the DNA-binding properties of FOXO4. Therefore, our structural findings may help to understand the intertwined functions of p53 and FOXO4 in cellular homeostasis, longevity, and stress response.

• Klíčová slova
• DNA binding, Forkhead box O 4, nuclear magnetic resonance, protein-protein interaction, senescence, transcription factor p53,
• MeSH
• DNA chemie   MeSH
• forkhead transkripční faktory * chemie   genetika   metabolismus   MeSH
• nádorový supresorový protein p53 * genetika   metabolismus   MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA MeSH
• forkhead transkripční faktory * MeSH
• nádorový supresorový protein p53 * MeSH
• proteiny buněčného cyklu MeSH

FOXO transcription factors regulate cellular homeostasis, longevity and response to stress. FOXO1 (also known as FKHR) is a key regulator of hepatic glucose production and lipid metabolism, and its specific inhibition may have beneficial effects on diabetic hyperglycemia by reducing hepatic glucose production. Moreover, all FOXO proteins are considered potential drug targets for drug resistance prevention in cancer therapy. However, the development of specific FOXO inhibitors requires a detailed understanding of structural differences between individual FOXO DNA-binding domains. The high-resolution structure of the DNA-binding domain of FOXO1 reported in this study and its comparison with structures of other FOXO proteins revealed differences in both their conformation and flexibility. These differences are encoded by variations in protein sequences and account for the distinct functions of FOXO proteins. In particular, the positions of the helices H1, H2 and H3, whose interface form the hydrophobic core of the Forkhead domain, and the interactions between hydrophobic residues located on the interface between the N-terminal segment, the H2-H3 loop, and the recognition helix H3 differ among apo FOXO1, FOXO3 and FOXO4 proteins. Therefore, the availability of apo structures of DNA-binding domains of all three major FOXO proteins will support the development of FOXO-type-specific inhibitors.

• Klíčová slova
• DNA-binding domain, FOXO1, Forkhead domain, nuclear magnetic resonance, structure,
• MeSH
• forkhead box protein O1 chemie   genetika   metabolismus   MeSH
• forkhead transkripční faktory chemie   genetika   metabolismus   MeSH
• hydrofobní a hydrofilní interakce MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• molekulární modely MeSH
• myši MeSH
• protein FOXO3 chemie   genetika   metabolismus   MeSH
• proteinové domény MeSH
• sekundární struktura proteinů MeSH
• sekvenční analýza proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• forkhead box protein O1 MeSH
• forkhead transkripční faktory MeSH
• protein FOXO3 MeSH