CDK5-cyclin B1 regulates mitotic fidelity

Affiliations

• Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA.
• Department of Chemistry and Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, USA.
• Translational Science and Therapeutics Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
• Department of Biostatistics and Translational Medicine, Medical University of Łódź, Łódź, Poland.
• Department of Oncology and Radiotherapy, Medical University of Gdańsk, Faculty of Medicine, Gdańsk, Poland.
• Broad Institute of Harvard and MIT, Cambridge, MA, USA.
• Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA. Alexander_Spektor@dfci.harvard.edu.
• Broad Institute of Harvard and MIT, Cambridge, MA, USA. Alexander_Spektor@dfci.harvard.edu.
• Division of Radiation and Genome Stability, Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA. Dipanjan_Chowdhury@dfci.harvard.edu.
• Broad Institute of Harvard and MIT, Cambridge, MA, USA. Dipanjan_Chowdhury@dfci.harvard.edu.
• Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA. Dipanjan_Chowdhury@dfci.harvard.edu.

PMID:  39232161  DOI: 10.1038/s41586-024-07888-x

Abstract

CDK1 has been known to be the sole cyclin-dependent kinase (CDK) partner of cyclin B1 to drive mitotic progression1. Here we demonstrate that CDK5 is active during mitosis and is necessary for maintaining mitotic fidelity. CDK5 is an atypical CDK owing to its high expression in post-mitotic neurons and activation by non-cyclin proteins p35 and p392. Here, using independent chemical genetic approaches, we specifically abrogated CDK5 activity during mitosis, and observed mitotic defects, nuclear atypia and substantial alterations in the mitotic phosphoproteome. Notably, cyclin B1 is a mitotic co-factor of CDK5. Computational modelling, comparison with experimentally derived structures of CDK-cyclin complexes and validation with mutational analysis indicate that CDK5-cyclin B1 can form a functional complex. Disruption of the CDK5-cyclin B1 complex phenocopies CDK5 abrogation in mitosis. Together, our results demonstrate that cyclin B1 partners with both CDK5 and CDK1, and CDK5-cyclin B1 functions as a canonical CDK-cyclin complex to ensure mitotic fidelity.

CDK1 一直被认为是cyclin B1 的唯一细胞周期依赖性激酶（CDK）伴侣，负责推动有丝分裂进程。在此，我们展示了 CDK5 在有丝分裂期间的活性，并且它对维持有丝分裂的准确性是必要的。由于其在有丝分裂后神经元中的高表达和通过非细胞周期蛋白 p35 和 p39 激活，CDK5 是一种非典型 CDK。我们使用独立的化学遗传学方法，特异性地抑制了有丝分裂期间 CDK5 的活性，观察到了有丝分裂缺陷、核异常和有丝分裂磷酸蛋白组的显著变化。值得注意的是，细胞周期蛋白 B1 是 CDK5 的一个有丝分裂共因子。计算建模、与实验得出的 CDK-细胞周期蛋白复合物结构的比较以及通过突变分析的验证表明，CDK5-细胞周期蛋白 B1 可以形成一个功能性复合物。破坏 CDK5-细胞周期蛋白 B1 复合物在有丝分裂中表现出与 CDK5 活性丧失相似的表型。综上所述，我们的结果表明，细胞周期蛋白 B1 与 CDK5 和 CDK1 都有合作关系，CDK5-细胞周期蛋白 B1 作为经典的 CDK-细胞周期蛋白复合物，确保了有丝分裂的准确性。