PND-1186 (VS-4718)

Target: This ligand targets focal adhesion kinase PTK2/FAK in biochemical or cellular target-engagement studies.

Mechanism of Action: Used as the target-protein recognition element, this ligand provides the binding interface for focal adhesion kinase PTK2/FAK. 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 focal adhesion kinase PTK2/FAK 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 BRD Degradation: PND-1186 (VS-4718) can be used as a targeting ligand in PROTAC designs to recruit an E3 ligase and drive ubiquitination-dependent degradation of BRD family targets. This enables functional interrogation of BRD biology by comparing knockdown versus degradation phenotypes, including pathway rewiring, transcriptional changes, and loss-of-function effects.

• E3 Ligase Recruitment Optimization: Incorporate PND-1186 into PROTAC scaffolds with alternative E3 ligase binders to tune ternary complex formation, residence time, and degradation potency. Systematic linker length and attachment-site variation can be used to balance target engagement with productive ubiquitination, improving degradation selectivity while minimizing off-target stabilization.

• Mechanistic Studies of Degradation: Use PND-1186-based PROTACs to dissect degradation mechanisms by monitoring ubiquitin conjugates, proteasome dependence, and lysosomal versus proteasomal routes. Time-course and dose-response experiments can quantify degradation kinetics, establish threshold behaviors, and distinguish catalytic degradation from simple occupancy effects.

• Proteome-Wide Target Validation: Deploy PND-1186 PROTACs in degradomics workflows to validate on-target activity and assess off-target degradation profiles. Combining quantitative proteomics with genetic perturbations (e.g., E3 ligase or target knockouts) helps confirm that observed protein loss is driven by PROTAC-mediated recruitment rather than indirect stress responses.

PND-1186 (VS-4718) is a FAK kinase target ligand intended for use as the target-engaging component or reference ligand in PROTAC discovery workflows. Its known small-molecule recognition profile enables rational linker-vector evaluation and comparative degrader design. This molecule is described in detail below.

Structure: The structure of PND-1186 (VS-4718) is characterized by primary or secondary amine/basic nitrogen centers; amide/urea/sulfonamide hydrogen-bonding motifs; halogenated aryl/heteroaryl ring system; heteroaromatic protein-recognition scaffold. These features provide defined hydrogen-bonding, hydrophobic, and steric elements that can support affinity retention while enabling analogue-based linker-vector selection.

Reactivity: The amine/basic nitrogen-containing motif can be evaluated for acylation, sulfonylation, alkylation, or carbamate/urea linker installation when that vector is solvent exposed. For PROTAC construction, the POI ligand can be paired with CRBN ligands such as thalidomide, pomalidomide, or lenalidomide analogues, VHL ligands such as VH032 derivatives, or less common IAP/MDM2/cIAP-recruiting ligands, with alkyl, PEG, piperazine, triazole, or amide linkers screened for ternary-complex formation. In practice, incorporation into PROTACs should begin from derivatives that preserve the reported binding pharmacophore, followed by systematic variation of linker length, polarity, rigidity, and exit-vector geometry to optimize target engagement, E3 recruitment, and cellular degradation readouts.