TNO155

Target: TNO155 targets SHP2/PTPN11 as a selective allosteric inhibitor in signaling studies.

Mechanism of Action: TNO155 can provide the SHP2-recognition module for allosteric SHP2 PROTAC development. The TNO155-derived ligand binds SHP2, and the attached linker positions an E3 ligase ligand to recruit a ubiquitin ligase. Because allosteric ligands may impose defined protein conformations, linker design is critical for presenting the SHP2 surface to the E3 complex. A productive ternary complex can enable ubiquitin transfer to SHP2, after which polyubiquitinated SHP2 is directed to proteasomal degradation rather than transient enzymatic inhibition alone. This establishes a testable protein-depletion mechanism for research assays.

• PROTAC-Mediated Degradation: TNO155 can be used as a ligand component in PROTAC constructs to recruit an E3 ubiquitin ligase and drive selective degradation of the intended target protein. This enables mechanistic studies of ubiquitination, proteasome dependence, and degradation kinetics, supporting optimization of linker length, geometry, and cellular potency.

• Target Engagement Mapping: Incorporating TNO155 into PROTACs allows researchers to correlate ligand binding with downstream loss of target protein levels. By comparing degradation versus occupancy across concentrations and time, investigators can define the degradation window, determine whether degradation is driven by high-affinity engagement, and identify conditions that maximize functional knockdown.

• E3 Ligase Recruitment Optimization: TNO155-based PROTACs can be engineered with different E3 ligase recruiters to evaluate how ligase identity influences ubiquitin chain formation and degradation efficiency. Systematic variation of recruiter choice and attachment site can reveal determinants of productive ternary complex formation, improving understanding of why certain PROTAC architectures yield stronger degradation.

• Proteasome-Dependence Studies: TNO155-containing PROTACs are suitable for testing whether observed target loss is mediated through the ubiquitin–proteasome pathway. Using proteasome inhibitors and ubiquitination assays, researchers can confirm mechanism, distinguish degradation from transcriptional or translational effects, and quantify how pathway disruption alters PROTAC-driven turnover.

• Phenotypic and Pathway Dissection: By enabling targeted protein degradation via TNO155-based PROTACs, researchers can connect target removal to changes in signaling outputs and cellular phenotypes. This supports rigorous functional validation, including rescue experiments with degradation-resistant mutants, and helps differentiate on-target effects from compensatory responses triggered by acute protein depletion.

TNO155, also known as batoprotafib, is an SHP2/PTPN11 inhibitor with a heteroaryl thioether and spirocyclic amine architecture. Its polar amino groups and rigid spirocycle can support target-binding studies and exploratory PROTAC design. This molecule is described in detail below.

Structure: The structure contains a chlorinated aminopyridyl thioether linked to an aminopyrazine and a methyl oxa-azaspirodecane amine. This rigid, heteroatom-rich framework provides multiple hydrogen-bonding elements and a three-dimensional basic amine region.

Reactivity: Linker incorporation should be based on structural or SAR evidence for a solvent-exposed amine or peripheral heteroaryl position, because the thioether-linked aminopyridyl/pyrazine system is likely important for SHP2 binding. Alkyl or PEG linkers joined through amide, urea, or secondary-amine chemistry could be screened with CRBN and VHL ligands; E3-ligase and linker length should be varied to identify productive SHP2 ternary-complex geometry.