PF-562271

Target: This ligand targets focal adhesion kinase PTK2/FAK and proline-rich tyrosine kinase PTK2B/PYK2 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 and proline-rich tyrosine kinase PTK2B/PYK2. 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.

• SRC/FAK PROTAC Degradation: PF-562271 can be leveraged as a targeting ligand in PROTAC designs to recruit E3 ligases toward SRC and related kinases. By enabling ternary complex formation, PF-562271-based PROTACs can promote ubiquitination and proteasome-dependent degradation, allowing researchers to dissect kinase network dependencies beyond inhibition alone.

• Kinase Network Perturbation: In targeted protein degradation studies, PF-562271-derived binders can be used to systematically perturb SRC-centered signaling circuits. PROTAC-mediated removal of SRC and proximal regulators supports mechanistic mapping of downstream pathways, including adhesion and survival signaling, and helps distinguish effects driven by catalytic blockade versus protein abundance reduction.

• Resistance Mechanism Studies: PF-562271 PROTACs can be applied to investigate resistance that arises from kinase inhibitor escape. Targeted degradation may overcome reduced drug binding or compensatory signaling by eliminating the kinase protein itself. This approach supports comparative analyses between inhibition and degradation phenotypes in SRC-dependent cellular models.

• Proteomics-Guided Target Validation: PF-562271-based PROTACs can serve as tools for target engagement validation using degradation-focused proteomics. Measuring global and on-target protein loss helps confirm specificity, quantify degradation efficiency, and identify potential off-target degradations, thereby refining PROTAC linker and E3 ligase selection for robust SRC-directed degradation.

PF-562271 is a FAK/Pyk2-oriented kinase ligand scaffold for kinase-directed PROTAC research. The side-chain region is the most appropriate starting point for linker-vector exploration.

Structure: PF-562271 is a kinase ligand containing a fused heteroaryl core, chlorophenyl substituent, methoxy group, and a morpholine/amide-containing polar side chain. The structure includes multiple ring nitrogens and amide functionality consistent with a kinase-binding pharmacophore and solubilizing substituent.

Reactivity: For FAK/Pyk2-directed PROTAC design, linker installation should prioritize solvent-exposed morpholine or amide-associated side-chain vectors while preserving the heteroaryl kinase-binding core. Alkyl, PEG, amide, carbamate, or tertiary-amine-compatible linkers may be paired with CRBN, VHL, or IAP ligands. The selected exit vector should be validated in binding assays because modifications near the heteroaryl core may reduce kinase affinity.