Coupling Computational and Intracellular Screening and Selection Toward Co-compatible cJun and cFos Antagonists

Area of Science:

• Molecular Biology
• Biochemistry
• Drug Discovery

Background:

• Basic leucine-zipper (bZIP) proteins are key regulators of cellular processes like proliferation and apoptosis.
• Activator protein-1 (AP-1) dimers, particularly cFos-cJun, are implicated in disease progression.
• Targeting bZIP proteins is challenging due to their central role in cell signaling.

Purpose of the Study:

• To demonstrate a novel combined in silico/in cellulo peptide-library screening platform.
• To derive a peptide with high selectivity for cJun over cFos, avoiding homodimerization.
• To develop compatible peptide antagonists for multiple AP-1 family members.

Main Methods:

• Computational screening of over 60 million peptides to predict stability and off-target effects.
• Intracellular selection to refine the peptide library and validate candidate sequences.
• Designing peptides with minimal cross-talk between cFos and cJun antagonists.

Main Results:

• Successfully derived a peptide sequence with high selectivity for cJun relative to cFos.
• The derived peptide avoids homodimerization, enhancing specificity.
• The new peptide shows predicted limited cross-talk with a previously identified cFos-selective peptide.

Conclusions:

• The combined in silico/in cellulo screening platform is effective for evolving compatible peptides with specific targeting capabilities.
• This approach offers a powerful strategy for developing modulators of complex protein-protein interactions, like those in the AP-1 family.
• The findings provide new insights into multistate screening for designing peptides that meet conflicting requirements.