Rapid and reversible knockdown of endogenously tagged endosomal proteins via an optimized HaloPROTAC degrader

Hannah Tovell, Andrea Testa, Chiara Maniaci, Houjiang Zhou, Alan Prescott, Thomas Macartney, Alessio Ciulli (Lead / Corresponding author), Dario Alessi (Lead / Corresponding author)

Research output: Contribution to journalArticlepeer-review

72 Citations (Scopus)
281 Downloads (Pure)


Inducing post-translational protein knockdown is an important approach to probe biology and validate drug targets. An efficient strategy to achieve this involves expression of a protein of interest fused to an exogenous tag, allowing tag-directed chemical degraders to mediate protein ubiquitylation and proteasomal degradation. Here, we combine improved HaloPROTAC degrader probes with CRISPR/Cas9 genome editing technology to trigger rapid degradation of endogenous target proteins. Our optimized probe, HaloPROTAC-E, a chloroalkane conjugate of high-affinity VHL binder VH298, induced reversible degradation of two endosomally localized proteins, SGK3 and VPS34, with a DC 50 of 3-10 nM. HaloPROTAC-E induced rapid (∼50% degradation after 30 min) and complete (D max of ∼95% at 48 h) depletion of Halo-tagged SGK3, blocking downstream phosphorylation of the SGK3 substrate NDRG1. HaloPROTAC-E more potently induced greater steady state degradation of Halo tagged endogenous VPS34 than the previously reported HaloPROTAC3 compound. Quantitative global proteomics revealed that HaloPROTAC-E is remarkably selective inducing only degradation of the Halo tagged endogenous VPS34 complex (VPS34, VPS15, Beclin1, and ATG14) and no other proteins were significantly degraded. This study exemplifies the combination of HaloPROTACs with CRISPR/Cas9 endogenous protein tagging as a useful method to induce rapid and reversible degradation of endogenous proteins to interrogate their function.

Original languageEnglish
Pages (from-to)882-892
Number of pages11
JournalACS Chemical Biology
Issue number5
Early online date12 Apr 2019
Publication statusPublished - 17 May 2019

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine


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