A small-molecule degron with a phenylpropionic acid scaffold

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Targeted protein degradation (TPD) is a promising drug discovery strategy utilizing proteolysis-targeting chimeras (PROTACs).
• The limited repertoire of E3 ligase ligands restricts the scope of current PROTAC technology.
• The ubiquitin-proteasome system (UPS) is a key cellular machinery for protein turnover.

Purpose of the Study:

• To discover novel small-molecule degrons for PROTAC development.
• To investigate the mechanism of action for newly designed PROTACs.
• To expand the toolkit for targeted protein degradation.

Main Methods:

• Design and synthesis of PROTACs incorporating a novel phenylpropionic acid-derived degron.
• Utilizing HaloTag-fused proteins as targets for degradation.
• Mechanistic studies to elucidate the E3 ligase recruitment pathway.

Main Results:

• A novel small-molecule degron was identified, derived from a ligand of S-phase kinase-interacting protein 2 (Skp2).
• PROTACs utilizing this degron successfully induced proteasomal degradation of HaloTag-fused proteins.
• Structural-activity relationships for the PROTACs were established.
• Mechanistic studies indicated that the degron does not engage Skp2, but rather other UPS components.

Conclusions:

• A novel degron expands the utility of PROTACs in targeted protein degradation.
• The identified degron recruits alternative UPS machinery, distinct from Skp2.
• This discovery offers new avenues for developing TPD-based therapeutics.