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The Ska complex promotes Aurora B activity to ensure chromosome biorientation

Redli, Patrick M
Santamaria, Anna
Published in The journal of cell biology. 2016, vol. 215, no. 1, p. 77-93
Abstract Chromosome biorientation and accurate segregation rely on the plasticity of kinetochore-microtubule (KT-MT) attachments. Aurora B facilitates KT-MT dynamics by phosphorylating kinetochore proteins that are critical for KT-MT interactions. Among the substrates whose microtubule and kinetochore binding is curtailed by Aurora B is the spindle and kinetochore-associated (Ska) complex, a key factor for KT-MT stability. Here, we show that Ska is not only a substrate of Aurora B, but is also required for Aurora B activity. Ska-deficient cells fail to biorient and display chromosome segregation errors underlying suppressed KT-MT turnover. These defects coincide with KNL1-Mis12-Ndc80 network hypophosphorylation, reduced mitotic centromere-associated kinesin localization, and Aurora B T-loop phosphorylation at kinetochores. We further show that Ska requires its microtubule-binding capability to promote Aurora B activity in cells and stimulates Aurora B catalytic activity in vitro. Finally, we show that protein phosphatase 1 counteracts Aurora B activity to enable Ska kinetochore accumulation once biorientation is achieved. We propose that Ska promotes Aurora B activity to limit its own microtubule and kinetochore association and to ensure that KT-MT dynamics and stability fall within an optimal balance for biorientation.
Keywords Aurora Kinase B/metabolismBiocatalysisCentromere/metabolismChromosomal ProteinsNon-Histone/metabolismChromosome PositioningChromosome SegregationHeLa CellsHumansKinetochores/metabolismMicrotubules/metabolismMultiprotein Complexes/metabolismPhosphorylationProtein Phosphatase 1/metabolism
PMID: 27697923
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Research group Groupe Meraldi Patrick (physiologie cellulaire et métabolisme) (922)
Swiss National Science Foundation: 31003A 160006
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REDLI, Patrick M et al. The Ska complex promotes Aurora B activity to ensure chromosome biorientation. In: The Journal of Cell Biology, 2016, vol. 215, n° 1, p. 77-93. doi: 10.1083/jcb.201603019 https://archive-ouverte.unige.ch/unige:99477

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Deposited on : 2017-11-22

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