FOXO4

The FOXO4 peptide (standard L-amino acid configuration) is designed to engage the same FOXO4–p53 nuclear interaction as its D-retro-inverso (DRI) analog, but it is composed of conventional L-amino acids arranged in the forward sequence. 

While the intended molecular target remains the same, the difference lies in stability: L-form peptides are rapidly degraded by endogenous proteases in biological environments, typically within minutes to hours.

Functionally, the peptide is used to compete with endogenous FOXO4 for binding to p53, thereby disrupting the nuclear complex that helps senescent cells evade apoptosis. 

Once p53 is released from FOXO4-mediated sequestration, it can activate the intrinsic, p53-dependent apoptotic pathway in senescent cells. This effect is considered more selective in senescent cells due to their higher FOXO4 expression and increased nuclear localization compared to non-senescent cells.

Research applications:

• Cellular senescence research
• In vitro senolysi
• Structural pharmacology
• Comparative stereochemistry
• Aging biology