Chemically Induced Nuclear Pore Complex Protein Degradation via TRIM21

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• Bifunctional degrader molecules, like proteolysis-targeting chimeras (PROTACs), show promise but are limited by a scarcity of E3 ligase ligands.
• TRIM21 is an E3 ligase with potential therapeutic applications.

Purpose of the Study:

• To identify novel small-molecule ligands for the E3 ligase TRIM21.
• To investigate the mechanism of action and cellular effects of these TRIM21 ligands.

Main Methods:

• DNA-Encoded Library (DEL) technology for ligand discovery.
• Crystallography to confirm ligand-TRIM21 interaction.
• Proteomic studies to identify protein targets.
• Immunofluorescence assays to assess cellular effects.

Main Results:

• Identified novel small-molecule ligands for TRIM21.
• Demonstrated antiproliferative effects of ligands across cancer cell types.
• Discovered that ligands downregulate Nuclear Pore Complex Protein NUP155 and mRNA Export Factor GLE1 in a TRIM21-dependent, ubiquitin-proteasome pathway.
• Showed NUP155 is the primary target, with GLE1 as a passenger target.
• Confirmed degradation of NUP155 and GLE1 disrupts nuclear envelope integrity, causing cell death.

Conclusions:

• Novel TRIM21 ligands were discovered using DEL technology.
• TRIM21 ligands act as monovalent degraders, inducing degradation of NUP155 and GLE1.
• Degradation of these proteins leads to nuclear envelope disruption and cell death, revealing a new mode of action for TRIM21 ligands.