Cdk1 phosphorylates SPAT-1/Bora to trigger PLK-1 activation and drive mitotic entry in <i>C. elegans</i> embryos

Tavernier, Nicolas; Noatynska, Anna; Panbianco, Costanza Viola Sofia; Martino, Lisa; Hove, Lucie Van; Schwager, Françoise; Léger, Thibaut; Gotta, Monica; Pintard, Lionel

doi:10.1083/jcb.201408064

Cited by 49 publications

(80 citation statements)

References 26 publications

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“…Aurora A phosphorylates Thr-210 in the active loop of Plk1 with the aid of Bora (6). Cdk1 also activates Plk1 via Bora phosphorylation to promote mitotic entry in Caenorhabditis elegans (7). Although mitotic kinases also govern metaphase-anaphase transition and faithful chromosome segregation by ensuring that spindles are properly assembled, their roles in the prometaphase-metaphase transition remain one of the least understood facets of the mitotic process.…”

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confidence: 99%

Phosphorylation of Astrin Regulates Its Kinetochore Function

Chung

Park

Lee

et al. 2016

Journal of Biological Chemistry

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The error-free segregation of chromosomes, which requires the precisely timed search and capture of chromosomes by spindles during early mitotic and meiotic cell division, is responsible for genomic stability and is achieved by the spindle assembly checkpoint in the metaphase-anaphase transition. Mitotic kinases orchestrate M phase events, such as the reorganization of cell architecture and kinetochore (KT) composition with the exquisite phosphorylation of mitotic regulators, to ensure timely and temporal progression. However, the molecular mechanisms underlying the changes of KT composition for stable spindle attachment during mitosis are poorly understood. Here, we show that the sequential action of the kinase Cdk1 and the phosphatase Cdc14A control spindle attachment to KTs. During prophase, the mitotic spindle protein Spag5/Astrin is transported into centrosomes by Kinastrin and phosphorylated at Ser-135 and Ser-249 by Cdk1, which, in prometaphase, is loaded onto the spindle and targeted to KTs. We also demonstrate that Cdc14A dephosphorylates Astrin, and therefore the overexpression of Cdc14A sequesters Astrin in the centrosome and results in aberrant chromosome alignment. Mechanistically, Plk1 acts as an upstream kinase for Astrin phosphorylation by Cdk1 and targeting phospho-Astrin to KTs, leading to the recruitment of outer KT components, such as Cenp-E, and the stable attachment of spindles to KTs. These comprehensive findings reveal a regulatory circuit for protein targeting to KTs that controls the KT composition change of stable spindle attachment and chromosome integrity.The maintenance of genome integrity during mitosis is crucial for cell survival and organismal development. To generate two daughter cells with identical genetic information, each sister chromatid must be captured by spindle microtubules (MTs), 4 aligned at the mitotic equator, and segregated toward the spindle poles. Cells build a proteinaceous structure, known as the KT, at the centromere and form a bipolar spindle with an amphitelic spindle attachment to achieve accurate chromosome segregation (1). The KT is made up of protein complexes that control its localization on the chromosome, assembly, attachment to spindle MTs, and chromosome movements, such as congression and segregation (2). KTs lacking essential proteins for KT-MT attachment, such as Knl1, Mis12, and Ndc80 protein subcomplexes, are unable to attach to spindle MTs (3), which in turn results in chromosome loss and concurrent cell death (4).Entry into mitosis is controlled by the concerted action of several mitotic kinases, such as Cyclin-dependent kinase 1 (Cdk1), Polo-like kinase 1 (Plk1), and Aurora A, whose activities are regulated indirectly in a positive feedback loop (5). Plk1 activates Cdk1 by phosphorylating and activating Cdc25, which then removes inhibitory phosphorylation at the Thr-14 and Tyr-15 sites of Cdk1. Aurora A phosphorylates Thr-210 in the active loop of Plk1 with the aid of Bora (6). Cdk1 also activates Plk1 via Bora phosphorylation to promote mit...

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confidence: 99%

Phosphorylation of Astrin Regulates Its Kinetochore Function

Chung

Park

Lee

et al. 2016

Journal of Biological Chemistry

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“…Embryos expressing a GFP::SPAT-1 7AN mutant transgene, containing 7 Sp/Tp residues in the N-terminal part of the protein mutated into Alanine, phenocopy embryos expressing a non-phosphorylatable GFP::SPAT-1 13A mutant, mutated on the 13 phosphorylation sites. 22 In contrast, embryos expressing a GFP::SPAT-1 6AC transgene containing the 6 remaining Sp/Tp residues in the C-terminal part of the protein mutated to alanine failed to show any significant difference from GFP::SPAT-1 wild-type, suggesting that phospho-sites in the C-terminal part are largely dispensable for SPAT-1 function in vivo. However, these might still play an important role in fine-tuning the activation status of SPAT-1 and therefore PLK-1, for instance by influencing the phosphorylation status of the N-terminal part of the protein.…”

Section: How Is the Interaction Betweenmentioning

confidence: 81%

“…19,20 In agreement with these observations, we found that Bora, produced in E. coli, stimulated Aurora A activity toward Plk1. 22 However, this effect was greatly enhanced when Bora was pre-phosphorylated by Cdk1-CyclinB, strongly suggesting that Cdk1 facilitates Bora binding to Plk1 and in turn Plk1 phosphorylation by Aurora A.…”

Section: How Is the Interaction Betweenmentioning

confidence: 96%

“…22,30 However, mutation of this site did not prevent binding of SPAT-1, phosphorylated by Cdk1, to PLK-1 in vitro and a GFP::SPAT-1 S251A transgenes rescued endogenous SPAT-1 depletion. 22 Consistent with the polo-docking site of SPAT-1 being dispensable for PLK-1 activation in worms, Seki et al showed that the phospho-peptide-binding site in the Plk1 PBD is not required for the activation of Plk1 by Bora and Aurora A 19 . These observations suggest that the interaction of Bora/SPAT-1 with the Plk1/ PLK-1 PBD is dispensable for the ability of these proteins to activate Plk1/PLK-1 phosphorylation by upstream kinases.…”

Section: How Is the Interaction Betweenmentioning

confidence: 99%

“…[18][19][20][21][22] The K D and the PBD regulate each other's activities allosterically. 23,24 Priming phosphorylation of the target allows binding to the PBD, which relieves the auto-inhibition on the K D by the PBD whereas the K D inhibits the binding of the phospho-peptide with the PBD.…”

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confidence: 99%

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