AT-7519

Target: This ligand targets multiple cyclin-dependent kinases, including CDK1, CDK2, CDK4, CDK5, CDK6, and CDK9 in biochemical or cellular target-engagement studies.

Mechanism of Action: Used as the target-protein recognition element, this ligand provides the binding interface for multiple cyclin-dependent kinases, including CDK1, CDK2, CDK4, CDK5, CDK6, and CDK9. In PROTAC design, a derivatizable position on the ligand can be connected through an optimized linker to an E3 ligase ligand, such as a CRBN, VHL, or IAP recruiter, while preserving productive target engagement. The resulting bifunctional molecule brings multiple cyclin-dependent kinases into proximity with the recruited E3 ligase, enabling ternary-complex formation. If the complex has favorable geometry and residence time, target lysine ubiquitination is promoted, leading to proteasome-dependent degradation in experimental systems.

• PROTAC-Mediated Degradation Studies: AT-7519 can be used as a ligand component in PROTAC designs to recruit E3 ligases and drive selective degradation of a chosen target protein. In research settings, it supports systematic evaluation of ternary complex formation, ubiquitination efficiency, and degradation kinetics across cell models to identify conditions that maximize target loss.

• Target Engagement and Kinetics: Incorporating AT-7519 into PROTAC constructs enables quantitative assessment of target engagement and time-dependent degradation. Researchers can compare degradation potency versus binding affinity, map dose–response relationships, and determine whether degradation proceeds via rapid ubiquitin–proteasome turnover or slower recycling-dependent pathways.

• Mechanism-of-Action Mapping: AT-7519-based PROTACs can be leveraged to dissect degradation mechanisms by using proteasome and neddylation pathway perturbations. These experiments help confirm ubiquitin–proteasome dependency, evaluate the contribution of E3 ligase recruitment, and distinguish degradation from mere inhibition by monitoring protein levels alongside downstream signaling readouts.

• Structure–Activity Optimization: AT-7519 can serve as a starting ligand for iterative PROTAC optimization, including linker length, attachment position, and stereochemical variants. Systematic structure–activity studies can improve cooperative binding in the ternary complex, enhance ubiquitination efficiency, and tune selectivity profiles to reduce off-target degradation.

• Proteome-Wide Selectivity Profiling: AT-7519-containing PROTACs are suitable for investigating selectivity using proteomics approaches such as quantitative mass spectrometry. By comparing protein degradation signatures across conditions, researchers can identify unintended degraded proteins, refine target specificity, and correlate degradation breadth with ligand properties and E3 ligase usage.

AT-7519 is a CDK-oriented kinase ligand that may support CDK-targeted degrader development. Linker installation should preserve the heteroaryl kinase-binding pharmacophore and use tolerated side-chain vectors.

Structure: AT-7519 is a CDK-oriented ligand containing a chlorobenzamide region, a pyrazole-containing heteroaryl core, and a piperidine or cyclic amine side chain. The structure presents amide hydrogen-bonding functionality, heteroaromatic nitrogens, and a basic solubilizing group.

Reactivity: AT-7519-derived PROTAC design should preserve the heteroaryl kinase-binding pharmacophore and chlorobenzamide recognition elements. Linker attachment is most plausibly explored from the cyclic amine side-chain region or other solvent-exposed vectors in designed analogs. Alkyl, PEG, amide, carbamate, or tertiary-amine-compatible linkers may be paired with CRBN, VHL, or IAP ligands, with experimental validation required to confirm CDK binding and degradation selectivity.