Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Carrer del Dr. Aiguader 88, Barcelona, Spain.
Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
Nat Commun. 2024 Oct 29;15(1):9213. doi: 10.1038/s41467-024-53500-1.
During cell division, the microtubule cytoskeleton undergoes dramatic cell cycle-driven reorganizations of its architecture. Coordinated by changes in the phosphorylation patterns of a multitude of microtubule associated proteins, the mitotic spindle first self-assembles to capture the chromosomes and then reorganizes in anaphase as the chromosomes are segregated. A key protein for this reorganization is PRC1 which is differentially phosphorylated by the mitotic kinases CDK1 and PLK1. How the phosphorylation state of PRC1 orchestrates spindle reorganization is not understood mechanistically. Here, we reconstitute in vitro the transition between metaphase and anaphase-like microtubule architectures triggered by the changes in PRC1 phosphorylation. We find that whereas PLK1 regulates its own recruitment by PRC1, CDK1 controls the affinity of PRC1 for antiparallel microtubule binding. Dephosphorylation of CDK1-phosphorylated PRC1 is required and sufficient to trigger the reorganization of a minimal anaphase midzone in the presence of the midzone length controlling kinesin KIF4A. These results demonstrate how phosphorylation-controlled affinity changes regulate the architecture of active microtubule networks, providing new insight into the mechanistic underpinnings of the cell cycle-driven reorganization of the central spindle during mitosis.
在细胞分裂过程中，微管细胞骨架经历了显著的细胞周期驱动的结构重排。通过多种微管相关蛋白的磷酸化模式的变化来协调，有丝分裂纺锤体首先自我组装以捕获染色体，然后在后期重新组织，因为染色体被分离。对于这种重排，PRC1 是一个关键蛋白，它被有丝分裂激酶 CDK1 和 PLK1 差异化磷酸化。PRC1 的磷酸化状态如何协调纺锤体的重排，其机制尚不清楚。在这里，我们在体外重建了由 PRC1 磷酸化变化触发的从中期到类似于后期的微管结构的转变。我们发现，虽然 PLK1 通过 PRC1 调节自身的募集，但 CDK1 控制 PRC1 与平行微管结合的亲和力。去磷酸化 CDK1 磷酸化的 PRC1 是必需的，也是在有丝分裂中期长度控制驱动蛋白 KIF4A 的情况下触发最小后期中体重组的充分条件。这些结果表明，如何通过磷酸化控制亲和力变化来调节活性微管网络的结构，为有丝分裂期间中心纺锤体的细胞周期驱动重排的机制基础提供了新的见解。
