Related Experiment Video

Updated: Aug 29, 2025

Chemical Inactivation of the E3 Ubiquitin Ligase Cereblon by Pomalidomide-based Homo-PROTACs
10:44

Chemical Inactivation of the E3 Ubiquitin Ligase Cereblon by Pomalidomide-based Homo-PROTACs

Published on: May 15, 2019

13.3K

A small-molecule inhibitor and degrader of the RNF5 ubiquitin ligase

Jingjing Ruan1,2, Dongdong Liang3, Wenjing Yan1

  • 1Center for Biomedical Engineering and Technology, Department of Physiology, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD 21201.

Molecular Biology of the Cell
|September 8, 2022
PubMed

Insights

Researchers developed FX12, a novel small molecule that inhibits and degrades RNF5 E3 ubiquitin ligase. This compound serves as a valuable tool for studying RNF5

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Drug Discovery

Background:

  • RNF5 E3 ubiquitin ligase plays critical roles in various biological processes.
  • Dysregulation of RNF5 is implicated in severe diseases like cystic fibrosis, acute myeloid leukemia, and viral infections.
  • Targeting RNF5 with small molecules is crucial for research and therapeutic development.

Purpose of the Study:

  • To synthesize and characterize a novel small-molecule inhibitor and degrader of RNF5.
  • To investigate the mechanism of action of the new compound, FX12.
  • To provide a chemical biology tool for RNF5 research.

Main Methods:

  • Structure-activity relationship (SAR) study based on the STAT3 inhibitor Stattic.
  • Synthesis of benzo[b]thiophene derivative FX12.
  • In vitro enzymatic assays to assess E3 ligase activity.
  • Cell-based assays to evaluate protein degradation and functional effects.

Main Results:

  • FX12 selectively inhibits RNF5 E3 ubiquitin ligase activity in vitro.
  • FX12 promotes proteasomal degradation of RNF5 in cellular models.
  • FX12 inhibits dislocation of misfolded proteins from the ER lumen, dependent on RNF5.
  • FX12 demonstrates diminished activity against STAT3 activation compared to Stattic.

Conclusions:

  • FX12 is a potent and selective small-molecule inhibitor and degrader of RNF5.
  • FX12 functions as a valuable chemical probe for studying RNF5 biology.
  • The developed compound holds potential for therapeutic development targeting RNF5-related diseases.

More Related Videos

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta10:27

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta

Published on: December 5, 2019

9.0K
High-Throughput Cellular Profiling of Targeted Protein Degradation Compounds Using HiBiT CRISPR Cell Lines05:33

High-Throughput Cellular Profiling of Targeted Protein Degradation Compounds Using HiBiT CRISPR Cell Lines

Published on: November 9, 2020

10.0K

Related Concept Videos

Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
7.5K
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
2.9K
The Proteasome01:13

The Proteasome

Eukaryotic cells can degrade proteins through several pathways. One of the most important among these is the ubiquitin-proteasome pathway. It helps the cell eliminate the misfolded, damaged, or unwarranted cytoplasmic proteins in a highly specific manner.
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
1.1K
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein....
7.0K
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR...
2.1K
Export of Misfolded Proteins out of the ER01:32

Export of Misfolded Proteins out of the ER

After folding, the ER assesses the quality of secretory and membrane proteins. The correctly folded proteins are cleared by the calnexin cycle for transport to their final destination, while misfolded proteins are held back in the ER lumen. The ER chaperones attempt to unfold and refold the misfolded proteins but sometimes fail to achieve the correct native conformation. Such terminally misfolded proteins are then exported to the cytosol by ER-associated degradation or ERAD pathway for...
3.8K