NuMA phosphorylation by CDK1 couples mitotic progression with cortical dynein function.
Spindle positioning and spindle elongation are critical for proper cell division. In human cells, an evolutionary conserved ternary complex (NuMA/LGN/Gαi) anchors dynein at the cortex during metaphase, thus ensuring correct spindle positioning. Whether this complex contributes to anaphase spindle elongation is not known. More generally, the mechanisms coupling mitotic progression with spindle behaviour remain elusive. Here, we uncover that levels of cortical dynein markedly increase during anaphase in a NuMA-dependent manner. We demonstrate that during metaphase, CDK1-mediated phosphorylation at T2055 negatively regulates NuMA cortical localization and that this phosphorylation is counteracted by PPP2CA phosphatase activity. We establish that this tug of war is essential for proper levels of cortical dynein and thus spindle positioning during metaphase. Moreover, we find that upon CDK1 inactivation in anaphase, the rise in dephosphorylated NuMA at the cell cortex leads to cortical dynein enrichment, and thus to robust spindle elongation. Our findings uncover a mechanism whereby the status of NuMA phosphorylation coordinates mitotic progression with proper spindle function.
Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
Sachin
S
Kotak
Coralie
C
Busso
Pierre
P
Gönczy
D034961:Antigens, Nuclear / Q000378:metabolism*; D016203:CDC2 Protein Kinase / Q000378:metabolism*; D018797:Cell Cycle Proteins; D004398:Dyneins / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D008938:Mitosis / Q000502:physiology*; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism*; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D008941:Spindle Apparatus / Q000378:metabolism*; D059008:Time-Lapse Imaging
D034961:Antigens, Nuclear; D018797:Cell Cycle Proteins; C050045:NUMA1 protein, human; D034521:Nuclear Matrix-Associated Proteins; D034741:RNA, Small Interfering; D016203:CDC2 Protein Kinase; C517189:PPP2CA protein, human; D054648:Protein Phosphatase 2; D004398:Dyneins