Related Experiment Video
Updated: Jun 28, 2026
Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Molecular architecture and inhibition mechanism of human ATR-ATRIP
Guangxian Wang1, Po Wang1, Zexuan Zheng1
1Department of Radiation Oncology, the First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230000, China.
Abstract:
The ataxia telangiectasia-mutated and Rad3-related (ATR) kinase is a master regulator of DNA damage response and replication stress in humans. Targeting ATR is the focus of oncology drug pipelines with a number of potent, selective ATR inhibitors currently in clinical development. Here, we determined the cryo-EM structures of the human ATR-ATRIP complex in the presence of VE-822 and RP-3500, two ATR inhibitors currently in Phase II clinical trials, achieving an overall resolution of approximately 3 Å. These structures yield a near-complete atomic model of the ATR-ATRIP complex, revealing subunit stoichiometry, intramolecular and intermolecular interactions, and critical regulatory sites including an insertion in the PIKK regulatory domain (PRD). Structural comparison provides insights into the modes of action and selectivity of ATR inhibitors. The divergent binding modes near the solvent side and in the rear pocket area of VE-822 and RP-3500, particularly their disparate binding orientations, lead to varying conformational changes in the active site. Surprisingly, one ATR-ATRIP complex binds four VE-822 molecules, with two in the ATR active site and two at the ATR-ATR dimer interface. The binding and selectivity of RP-3500 depend on two bound water molecules, which may be further enhanced by the substitution of these bound waters. Our study provides a structural framework for understanding ATR regulation and holds promise for assisting future efforts in rational drug design targeting ATR.
Insights
Cryo-EM structures reveal how ataxia telangiectasia-mutated and Rad3-related (ATR) kinase inhibitors VE-822 and RP-3500 bind to the ATR-ATRIP complex. These findings offer insights into ATR inhibitor selectivity and guide future cancer drug design.
Area of Science:
- Biochemistry and structural biology
- Cancer biology and drug discovery
Background:
- The ataxia telangiectasia-mutated and Rad3-related (ATR) kinase is a key regulator of DNA damage response and replication stress.
- Targeting ATR is a significant strategy in oncology, with several ATR inhibitors in clinical trials.
Purpose of the Study:
- To determine the cryo-electron microscopy (cryo-EM) structures of the human ATR-ATRIP complex bound to two ATR inhibitors, VE-822 and RP-3500.
- To elucidate the molecular mechanisms underlying ATR inhibitor binding, selectivity, and conformational changes.
Main Methods:
- Cryo-electron microscopy (cryo-EM) was used to resolve the structures of the human ATR-ATRIP complex.
- The structures were determined at approximately 3 Å resolution, enabling near-complete atomic modeling.
Main Results:
- Near-complete atomic models of the ATR-ATRIP complex were obtained, detailing subunit stoichiometry and interactions.
- Distinct binding modes of VE-822 and RP-3500 were observed, influencing active site conformation differently.
- One complex bound four VE-822 molecules, two at the active site and two at the dimer interface; RP-3500 binding involved crucial water molecules.
Conclusions:
- The study provides a detailed structural framework for understanding ATR kinase regulation and inhibitor interactions.
- These structural insights are valuable for the rational design of novel ATR-targeting cancer therapeutics.
More Related Videos
10:33Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
Published on: October 26, 2015
10:20Method for Identifying Small Molecule Inhibitors of the Protein-protein Interaction Between HCN1 and TRIP8b
Published on: November 11, 2016
Related Concept Videos
01:19Allosteric Proteins-ATCase
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 pathway,...
01:29Indirect-Acting Cholinergic Agonists: Chemistry and Structure-Activity Relationship
Reversible inhibitors display short to medium durations of action. Short-acting agents include simple alcohols with...
01:18Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
01:29Cholinergic Antagonists: Chemistry and Structure-Activity Relationship
01:31Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
01:28Structure-Activity Relationships and Drug Design
SAR studies the intricate relationship between a drug's chemical structure and biological activity. It focuses on understanding how modifications to a drug's structure can influence its...