AZ 628

Target: This ligand targets RAF-family kinases, including BRAF and CRAF/RAF1 in biochemical or cellular target-engagement studies.

Mechanism of Action: Used as the target-protein recognition element, this ligand provides the binding interface for RAF-family kinases, including BRAF and CRAF/RAF1. 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 RAF-family 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: AZ 628 can be used as a ligand component to build PROTACs that recruit an E3 ligase and drive selective ubiquitination of a chosen target protein. In targeted degradation workflows, this enables testing whether ligand engagement translates into efficient protein loss rather than only inhibition, supporting mechanism-of-action studies and pathway dissection.

• E3 Ligase Recruitment Optimization: Incorporate AZ 628 into PROTAC architectures with different E3 ligase recruiters to map how ligase selection affects ubiquitin transfer, degradation kinetics, and cellular potency. Systematic linker and recruiter variation can identify configurations that maximize ternary complex stabilization and promote sustained target depletion across relevant cellular contexts.

• Ternary Complex Mechanism Studies: Use AZ 628-based PROTAC designs to evaluate ternary complex formation between the target, the PROTAC, and the recruited E3 ligase. Biophysical and cellular assays can quantify binding cooperativity and correlate it with degradation efficiency, helping determine whether degradation is driven by stable ternary engagement or alternative ubiquitination dynamics.

• Resistance and Selectivity Profiling: Deploy AZ 628-containing PROTACs to probe target degradation robustness under perturbations such as pathway rewiring, target mutations, or altered ubiquitin-proteasome activity. Comparing degradation profiles across related proteins supports selectivity assessment and helps identify degradation mechanisms that may overcome resistance to conventional occupancy-based inhibitors.

AZ 628 is a RAF-family kinase ligand scaffold that may support RAF-directed degrader development. PROTAC design should preserve the fused heteroaryl recognition region and evaluate peripheral linker vectors.

Structure: AZ 628 is a RAF-family kinase ligand scaffold containing a fused heteroaryl lactam-like core, an anilide/benzamide region, a tert-alkyl nitrile substituent, and methylated heteroaryl features. The structure is aromatic, rigid, and includes several hydrogen-bond acceptors and donors.

Reactivity: For RAF-directed PROTAC design, the fused heteroaryl kinase-binding core and anilide recognition region should be retained. Linker installation is more plausibly explored from solvent-exposed aryl or amide-associated periphery in a designed analog rather than through direct modification of the parent compound. Alkyl, PEG, amide, carbamate, or aryl-linker systems may be paired with CRBN, VHL, or IAP ligands after confirming target engagement and avoiding disruption of the nitrile-bearing recognition region.