BTBBCL6 dimers as building blocks for reversible drug-induced protein oligomerization

Cell Rep Methods. 2022 Apr 13;2(4):100193. doi: 10.1016/j.crmeth.2022.100193. eCollection 2022 Apr 25.

Abstract

Here, we characterize the BTB domain of the transcription factor BCL6 (BTBBCL6) as a small-molecule-controlled, reversible oligomerization switch, which oligomerizes upon BI-3802 treatment and de-oligomerizes upon addition of BI-3812. We show that the magnitude of oligomerization can be controlled in vitro by BI-3802 concentration and exposure time. In cellular models, exposure to BI-3802/BI-3812 can drive multiple cycles of foci formation consisting of BTBBCL6 fused to EGFP, which are not degraded due to the lack of a degron. We generated an epidermal growth factor receptor (EGFR)-BTBBCL6 fusion. Treatment with BI-3802, as an ON switch, induced EGFR-BTBBCL6 phosphorylation and activation of downstream effectors, which could in part be reversed by the addition of BI-3812, as an OFF switch. Finally, BI-3802-induced oligomerization of the EGFR-BTBBCL6 fusion enhanced proliferation of an EGF-dependent cell line in absence of EGF. These results demonstrate the successful application of small-molecule-induced, reversible oligomerization as a switch for synthetic biology.

Keywords: BI-3802; BI-3812; BTB domain; BTB switch; polymerization switch; protein polymerization; reversibility.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Epidermal Growth Factor / metabolism
  • ErbB Receptors / genetics
  • Gene Expression Regulation
  • Humans
  • Phosphorylation
  • Protein Multimerization
  • Proto-Oncogene Proteins c-bcl-6* / chemistry
  • Proto-Oncogene Proteins c-bcl-6* / genetics
  • Signal Transduction

Substances

  • Epidermal Growth Factor
  • ErbB Receptors
  • BCL6 protein, human
  • Proto-Oncogene Proteins c-bcl-6