A CRISPR activation screen identifies FBXO22 supporting targeted protein degradation.

in Nature chemical biology by Ananya A Basu, Chenlu Zhang, Isabella A Riha, Assa Magassa, Miguel A Campos, Alana G Caldwell, Felicia Ko, Xiaoyu Zhang

TLDR

  • The study is looking for ways to get rid of specific proteins in the body. They are using a special tool called CRISPR to find proteins that can help get rid of these specific proteins. They found a protein called 22-SLF that can help get rid of a protein called FK506-binding protein 12. They also found that this protein can be used to get rid of other proteins in the body. This study could help with finding new ways to get rid of specific proteins in the body.

Abstract

Targeted protein degradation (TPD) represents a potent chemical biology paradigm that leverages the cellular degradation machinery to pharmacologically eliminate specific proteins of interest. Although multiple E3 ligases have been discovered to facilitate TPD, there exists a compelling requirement to diversify the pool of E3 ligases available for such applications. Here we describe a clustered regularly interspaced short palindromic repeats (CRISPR)-based transcriptional activation screen focused on human E3 ligases, with the goal of identifying E3 ligases that can facilitate heterobifunctional compound-mediated target degradation. Through this approach, we identified a candidate proteolysis-targeting chimera (PROTAC), 22-SLF, that induces the degradation of FK506-binding protein 12 when the transcription of FBXO22 gene is activated. Subsequent mechanistic investigations revealed that 22-SLF interacts with C227 and/or C228 in F-box protein 22 (FBXO22) to achieve target degradation. Lastly, we demonstrated the versatility of FBXO22-based PROTACs by effectively degrading additional endogenous proteins, including bromodomain-containing protein 4 and the echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase fusion protein.

Overview

  • The study aims to identify E3 ligases that can facilitate heterobifunctional compound-mediated target degradation using a CRISPR-based transcriptional activation screen. The study focuses on human E3 ligases and uses a candidate protein, 22-SLF, to induce the degradation of FK506-binding protein 12 when the transcription of FBXO22 gene is activated. The study also investigates the mechanism of action of 22-SLF and demonstrates the versatility of FBXO22-based PROTACs by effectively degrading additional endogenous proteins.

Comparative Analysis & Findings

  • The study identifies a candidate protein, 22-SLF, that induces the degradation of FK506-binding protein 12 when the transcription of FBXO22 gene is activated. The study also investigates the mechanism of action of 22-SLF and demonstrates the versatility of FBXO22-based PROTACs by effectively degrading additional endogenous proteins.

Implications and Future Directions

  • The study's findings highlight the potential of using CRISPR-based transcriptional activation screens to identify E3 ligases that can facilitate heterobifunctional compound-mediated target degradation. The study also demonstrates the versatility of FBXO22-based PROTACs, which could be used for the targeted elimination of specific proteins of interest. Future research could focus on optimizing the design of PROTACs for specific targets or exploring the use of PROTACs in combination with other therapeutic approaches.
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