PFI-7
 Chemical probe for GID4, substrate-recognition subunit of the CTLH E3 ubiquitin-protein ligase complex
  
  
        
      The probe PFI-7 (hydrochloride) is available at Sigma and Tocris.
The inactive control PFI-7N (hydrochloride) is available at Sigma.
     
                
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        overview
      
 
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        in vitro potency
      
 
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        cell based assay data
      
 
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        references
      
 
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        co-crystal structures
      
 
                      
       
    
    
      
        overview
        
      
      
        | Probe |   | Negative control | 
  |    |   | 
PFI-7  |    | PFI-7N  | 
Pfizer in collaboration with the SGC have developed PFI-7, a potent, cell active chemical probe for the E3 ligase GID4. PFI-7 binds potently to GID4 with KD = 0.08 μM (SPR) and displaces the known degron1 peptide in a NanoBRETTM assay with EC50 = 0.6 μM. PFI-7N is a closely related negative control with KD = 5 μM (SPR). A co-crystal structure has been deposited.
We have further developed a handle PFI-E3H1 and a PEGylated analogue to show that the handle tolerates a substitution. These findings offers opportunities to synthesize proximity-inducing or degrader modalities2. 
        
       
     
   
  
  
  
  
    
      
        cell based assay data
        
      
      
        A NanoBRET assay was used to show target engagement in cells. 
The interaction was between NanoLuc® tagged degrons and full-length GID4.
        
       
     
   
  
    
      
        references
        
      
      
        - Cheng Dong, Heng Zhang, Li Li, Wolfram Tempel, Peter Loppnau & Jinrong Min. Molecular basis of GID4-mediated recognition of degrons for the Pro/N-end rule pathway. Nature Chemical Biology 14, 466-473 (2018).
 - Aleša Bricelj, Christian Steinebach, Robert Kuchta, Michael Gütschow, and Izidor Sosič. E3 Ligase Ligands in Successful PROTACs: An Overview of Syntheses and Linker Attachment Points, https://doi.org/10.3389/fchem.2021.707317 ; Milka Kostic. Targeted Protein Degradation and Proximity-Based Pharmacology, https://doi.org/10.5281/zenodo.5534371 .
 - Dominic D.G. Owens et al., A chemical probe to modulate human GID4 Pro/N-degron interactions. https://pubmed.ncbi.nlm.nih.gov/38773330/
 - Aliakbar K Yazdi et al., Chemical tools for the Gid4 subunit of the human E3 ligase C-terminal to LisH (CTLH) degradation complex. https://pubmed.ncbi.nlm.nih.gov/38516600/
 
        
       
     
   
  
  
    
      
        co-crystal structures
        
      
      
        Main features
- PFI-7 bound to GID4 substrate-binding pocket
 - Structure overview
 - Overlap with substrate peptide