Related Experiment Video

Updated: Jun 23, 2025

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
10:33

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors

Published on: October 26, 2015

11.3K

Optimization of a Novel DEL Hit That Binds in the Cbl-b SH2 Domain and Blocks Substrate Binding

Jun Liang1, Michael J Lambrecht1, Teresita L Arenzana1

  • 1Genentech, Inc., 1 DNA Way, South San Francisco, California 94080, United States.

ACS Medicinal Chemistry Letters
|June 19, 2024
PubMed

Insights

Researchers explored small molecule inhibitors for Casitas B-lineage lymphoma proto-oncogene-b (Cbl-b), a key regulator of T cell activation. They identified a promising compound targeting the SH2 domain, advancing Cbl-b inhibition strategies.

Area of Science:

  • Biochemistry
  • Immunology
  • Medicinal Chemistry

Background:

  • Casitas B-lineage lymphoma proto-oncogene-b (Cbl-b) is a RING E3 ligase crucial for T cell activation regulation.
  • Inhibiting Cbl-b holds therapeutic potential, but targeting protein-protein interactions with small molecules is challenging.

Purpose of the Study:

  • To identify and develop small molecule inhibitors of Cbl-b.
  • To explore the feasibility of targeting Cbl-b's SH2 domain for blocking protein-protein interactions.

Main Methods:

  • Screening of a large DNA-encoded library (DEL) against activated Cbl-b.
  • Biochemical assays and surface plasmon resonance (SPR) for compound validation.
  • Cocrystallography to determine the binding mode of inhibitors.

Main Results:

  • A Cbl-b inhibitor (compound 1) was identified from the DEL screen, with its cis-isomer (compound 2) confirmed.
  • Cocrystal structure revealed compound 2 binds to the Cbl-b SH2 domain via induced fit.
  • Structure-guided optimization yielded compound 27 with measurable, though high-concentration, cell activity.

Conclusions:

  • Small molecules can effectively inhibit Cbl-b by targeting its SH2 domain.
  • This work provides a foundation for developing novel therapeutics targeting T cell signaling pathways.

More Related Videos

Author Spotlight: Evaluating Biophysical Assays for Characterizing PROTACS Ternary Complexes07:22

Author Spotlight: Evaluating Biophysical Assays for Characterizing PROTACS Ternary Complexes

Published on: January 12, 2024

3.4K
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

9.6K

Related Concept Videos

Ligand Binding and Linkage00:49

Ligand Binding and Linkage

Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked.  In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence...
4.8K
Conserved Binding Sites01:49

Conserved Binding Sites

Many proteins’ biological role depends on their interactions with their ligands, small molecules that bind to specific locations on the protein known as ligand-binding sites. Ligand-binding sites are often conserved among homologous proteins as these sites are critical for protein function.
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...
4.2K
The Equilibrium Binding Constant and Binding Strength02:18

The Equilibrium Binding Constant and Binding Strength

The equilibrium binding constant (Kb) quantifies the strength of a protein-ligand interaction. Kb can be calculated as follows when the reaction is at equilibrium:
12.9K
Enzymes02:34

Enzymes

Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
81.4K
Cooperative Allosteric Transitions01:58

Cooperative Allosteric Transitions

Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
7.9K
Allosteric Proteins-ATCase01:19

Allosteric Proteins-ATCase

Binding sites linkages can regulate a protein's function.  For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to  N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis...
5.7K