Catalytic inhibition of topoisomerase II during G2 phase delays onset of mitosis due to the activation of the so-called decatenation checkpoint. This checkpoint is less known compared with the extensively studied G2 DNA damage checkpoint and is partially compromised in many tumor cells. We recently identified MCPH1 as a key regulator that confers cells with the capacity to adapt to the decatenation checkpoint. In the present work, we have explored the contributions of checkpoint kinase 1 (Chk1) and polo-like kinase 1 (Plk1), in order to better understand the molecular basis of decatenation checkpoint. Our results demonstrate that Chk1 function is required to sustain the G2 arrest induced by catalytic inhibition of Topo II. Interestingly, Chk1 loss of function restores adaptation in cells lacking MCPH1. Furthermore, we demonstrate that Plk1 function is required to bypass the decatenation checkpoint arrest in cells following Chk1 inhibition. Taken together, our data suggest that MCPH1 is critical to allow checkpoint adaptation by counteracting Chk1-mediated inactivation of Plk1. Importantly, we also provide evidence that MCPH1 function is not required to allow recovery from this checkpoint, which lends support to the notion that checkpoint adaptation and recovery are different mechanisms distinguished in part by specific effectors.
Bibliographical noteFunding Information:
The authors express their gratitude to: H. Neitzel (Institute of Medical and Human Genetics, Charit??Universitaetsmedizin Berlin) for providing the lymphoblast cell lines used in this study; Nieves de la Casa (CICT, Universidad de Ja?n, Spain) for technical assistance; Paul A. Jowsey (University of Newcastle, UK) for providing MCPH1 plasmids; Ciaran Morrison (University of Galway, Ireland), for providing Chk1 plasmid; Gillermo deC?rcer (IIBm-CSIC, Spain), for providing Plk1 plasmid; and Ryoko Kuriyama (University of Minnesota, USA) for helpful discussions. We kindly appreciate the technical support of Cristina Cardoso (University of Darmstadt, Germany) during the revision procedure. Technical and human support provided by CICT of Universidad de Ja?n (UJA, MINECO, Junta de Andaluc?a, FEDER) is gratefully acknowledged. This work was supported by Junta de Andaluc?a (Funding program ?Ayudas a grupos de investigaci?n?, reference RMN-924) and Consejer?a de Salud, Junta de Andaluc?a (Grant number PI-0110-2017). Research in the laboratory of D. Clarke was financially supported by NIH grants R01GM112793 and R01GM130858. M. Arroyo PhD was granted by University of Ja?n (Spain) and was provided with traveling grants to perform short-term stays at the University of Minnesota by EMBO and ?Escuela de Doctorado? (University of Ja?n, Spain), respectively.
© 2020 Federation of European Biochemical Societies
- checkpoint adaptation
- topoisomerase II