A Genetic Toggle for Chemical Control of Individual Plk1 Substrates

Cell Chem Biol. 2020 Mar 19;27(3):350-362.e8. doi: 10.1016/j.chembiol.2020.01.007. Epub 2020 Feb 3.


Polo-like kinase 1 has hundreds of substrates and multiple functions that operate within the ∼60 min of mitosis. Herein, we describe a chemical-genetic system that allows particular substrates to be "toggled" into or out of chemical control using engineered phosphoacceptor selectivity. Biochemical assays and phosphoproteomic analysis of mitotic cell extracts showed that Plk1S (L197F) and Plk1T (L197S/L211A) selectively phosphorylate Ser and Thr, respectively. Plk1S but not Plk1T sustains mitotic progression to anaphase, affording the opportunity to toggle substrate residues between Ser and Thr to place them under chemical control. Using this system, we evaluated Kif2b, a known substrate of Plk1 that regulates chromosome alignment. Toggling Ser to Thr on Kif2b places these phosphorylation sites under reversible chemical control, as indicated by a sharp increase in the frequency of misaligned chromosomes and prometaphase arrest. Thus, we demonstrate the ability to chemically control a single substrate by a genetic Ser/Thr toggle.

Keywords: Kif2b; chemical biology; chemical-genetics; genetic toggle; kinase; mitosis; phosphoacceptor selectivity; phosphorylation.

Publication types

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

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Humans
  • Mitosis
  • Phosphorylation
  • Protein Engineering
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism*
  • Serine / genetics*
  • Serine / metabolism
  • Substrate Specificity
  • Threonine / genetics*
  • Threonine / metabolism


  • Cell Cycle Proteins
  • Proto-Oncogene Proteins
  • Threonine
  • Serine
  • Protein Serine-Threonine Kinases
  • polo-like kinase 1