PROTAC THNAN69 degrades LIMK2, not LIMK1
A cereblon-recruiting degrader based on LIMKi3 and a phenyl dihydrouracil ligand wipes out LIMK2 at nanomolar DC50 while leaving LIMK1 and phospho-cofilin largely intact.
Source
Discovery and Development of a Potent LIMK2 Isoform-Specific Degrader
Study at a glance
- Design
- Animal / in-vitro — CRBN/VHL PROTACs of LIMKi3 ranked by cellular degradation and proteomics
- N
- Cell-based degrader SAR (e.g., HuCCT1 EGFP–LIMK2 / Western blot) — no subject N
- Population
- Cultured cells expressing LIMK2 (including HuCCT1)
- Outcome
- LIMK2-selective degradation potency (THNAN69 DC50 ≈ 1 nM)
Structured fields used in claim comparison tables when every cited study has a complete layer.
What they did
Authors made CRBN and VHL PROTACs of LIMKi3, ranked them by DSF, SPR, NanoBRET, EGFP–LIMK2 live degradation, Western blot, and proteomics, then used MD of ternary complexes to explain isoform bias.
What they found
THNAN69 DC50 = 1 nM (vs 33 nM for thalidomide analogue 21b); 10 nM depletes endogenous LIMK2. Proteome-wide, LIMK2 was the only kinase degraded. VHL PROTACs bound poorly in cells. Cofilin phosphorylation persisted via LIMK1 compensation.
The limits
What it doesn't show
No animal efficacy or clinical data; phospho-cofilin does not fall, so LIMK2-only degradation is not a cofilin-pathway knockout.
Key terms
- PROTAC
- Heterobifunctional molecule that recruits an E3 ligase to ubiquitinate a target protein.
- THNAN69
- Lead LIMK2-selective CRBN degrader (compound 22b) with DC50 ≈ 1 nM.
- CRBN vs VHL
- Two E3 ligases; CRBN PROTACs worked in cells, VHL ones were poorly permeable.
- DC50
- Concentration giving half-maximal target degradation.
- Phenyl dihydrouracil
- CRBN ligand used instead of thalidomide to cut neo-substrate degradation.
Flashcards
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THNAN69’s EGFP–LIMK2 DC50 is about:
Common questions
What is THNAN69’s DC50?
1 nM in the EGFP–LIMK2 assay.
Does it degrade LIMK1?
No—LIMK1 levels stay up; only LIMK2 among kinases fell in proteomics.
Why switch from thalidomide?
Phenyl dihydrouracil CRBN ligand improved potency and reduced neo-substrates.
Does p-cofilin drop?
No—LIMK1 compensates.
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