Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores

Raisch, T.; Ciossani, G.; d'Amico, E.; Cmentowski, V.; Carmignani, S.; Maffini, S.; Merino, F.; Wohlgemuth, S.; Vetter, I. R.; Raunser, S.; Musacchio, A.

doi:10.1101/2021.12.03.471119

bioRxiv · 10.1101/2021.12.03.471119

Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores

Raisch, T.·Ciossani, G.·d'Amico, E.·Cmentowski, V.·Carmignani, S.·Maffini, S.·Merino, F.·Wohlgemuth, S.·Vetter, I. R.·Raunser, S.·Musacchio, A.

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Abstract

In metazoans, a {asymp}1 megadalton (MDa) super-complex comprising the Dynein-Dynactin adaptor Spindly and the ROD-Zwilch-ZW10 (RZZ) complex is the building block of a fibrous biopolymer, the kinetochore fibrous corona. The corona assembles on mitotic kinetochores to promote microtubule capture and spindle assembly checkpoint (SAC) signaling. We report here a high-resolution cryo-EM structure that captures the essential features of the RZZ complex, including a farnesyl binding site required for Spindly binding. Using a highly predictive in vitro assay, we demonstrate that the SAC kinase MPS1 is necessary and sufficient for corona assembly at supercritical concentrations of the RZZ-Spindly (RZZS) complex, and describe the molecular mechanism of phosphorylation-dependent filament nucleation. We identify several structural requirements for RZZS polymerization in rings and sheets. Finally, we identify determinants of kinetochore localization and corona assembly of Spindly. Our results describe a framework for the long-sought-for molecular basis of corona assembly on metazoan kinetochores.

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Raisch, T., Ciossani, G., d'Amico, E., Cmentowski, V., Carmignani, S., Maffini, S., Merino, F., Wohlgemuth, S., Vetter, I. R., Raunser, S., Musacchio, A.. 2021-12-06. Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores. https://doi.org/10.1101/2021.12.03.471119

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