Development of a p62 biodegrader for autophagy targeted degradation

Area of Science:

• Cellular Biology
• Molecular Biology
• Biochemistry

Background:

• Autophagy complements proteasomal degradation for complex cellular waste removal.
• The optimal components of the autophagy-lysosomal pathway for targeted degradation remain unidentified.
• Targeted degradation strategies are crucial for understanding and treating various diseases.

Purpose of the Study:

• To identify effective autophagy components for targeted degradation of organelles and soluble proteins.
• To explore induced-proximity strategies for manipulating the autophagy-lysosomal pathway.
• To develop novel heterobifunctional degraders for specific cellular targets.

Main Methods:

• Utilized two orthogonal induced-proximity strategies to screen autophagy effectors.
• Investigated the role of autophagy cargo receptors, ATG8-like proteins, ULK1, and TBK1 in targeted degradation.
• Developed and tested a single-domain antibody against p62 for heterobifunctional degrader applications.

Main Results:

• Recruitment of autophagy cargo receptors, ATG8-like proteins, ULK1, or TBK1 induced mitophagy.
• Only self-oligomerizing autophagy cargo receptors degraded soluble cytosolic proteins.
• A p62-targeting single-domain antibody fused to PINK1 selectively cleared damaged mitochondria.

Conclusions:

• Autophagy cargo receptors are essential for degrading both organelles and soluble proteins via targeted autophagy.
• Avidity plays a critical role in the efficacy of targeted autophagy.
• Autophagy cargo receptors represent promising platforms for developing heterobifunctional degraders against organelles and protein aggregates.