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  2. Genetic enhancers of partial PLK1 inhibition reveal hypersensitivity to kinetochore perturbations

Genetic enhancers of partial PLK1 inhibition reveal hypersensitivity to kinetochore perturbations

  • PLoS Genet. 2023 Aug 28;19(8):e1010903. doi: 10.1371/journal.pgen.1010903.
Karine Normandin 1 Jasmin Coulombe-Huntington 1 Corinne St-Denis 1 Alexandre Bernard 1 Mohammed Bourouh 1 Thierry Bertomeu 1 Mike Tyers 1 2 Vincent Archambault 1 3
Affiliations

Affiliations

  • 1 Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada.
  • 2 Département de médecine, Université de Montréal, Montréal, Canada.
  • 3 Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Canada.
Abstract

Polo-like kinase 1 (PLK1) is a serine/threonine kinase required for mitosis and cytokinesis. As Cancer cells are often hypersensitive to partial PLK1 inactivation, chemical inhibitors of PLK1 have been developed and tested in clinical trials. However, these small molecule inhibitors alone are not completely effective. PLK1 promotes numerous molecular and cellular events in the cell division cycle and it is unclear which of these events most crucially depend on PLK1 activity. We used a CRISPR-based genome-wide screening strategy to identify genes whose inactivation enhances cell proliferation defects upon partial chemical inhibition of PLK1. Genes identified encode proteins that are functionally linked to PLK1 in multiple ways, most notably factors that promote centromere and kinetochore function. Loss of the Kinesin KIF18A or the outer kinetochore protein SKA1 in PLK1-compromised cells resulted in mitotic defects, activation of the spindle assembly checkpoint and nuclear reassembly defects. We also show that PLK1-dependent CENP-A loading at centromeres is extremely sensitive to partial PLK1 inhibition. Our results suggest that partial inhibition of PLK1 compromises the integrity and function of the centromere/kinetochore complex, rendering cells hypersensitive to different kinetochore perturbations. We propose that KIF18A is a promising target for combinatorial therapies with PLK1 inhibitors.

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