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bioRxiv · 10.1101/2023.06.11.544482

PP2A-B55SUR-6 promotes nuclear envelope breakdown in C. elegans embryos

Kapoor, S.·Adhikary, K.·Kotak, S.
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Abstract

Nuclear envelope (NE) disassembly during mitosis is critical to ensure faithful segregation of the genetic material. NE disassembly is a phosphorylation-dependent process wherein mitotic kinases hyper-phosphorylate lamina and nucleoporins to initiate nuclear envelope breakdown (NEBD). In this study, we uncover an unexpected role of the PP2A phosphatase B55SUR-6 in NEBD during the first embryonic division of Caenorhabditis elegans embryo. B55SUR-6 depletion delays NE permeabilization and stabilizes lamina and nucleoporins. As a result, the merging of parental genomes and chromosome segregation is impaired. This NEBD defect upon B55SUR-6 depletion is not due to delayed mitotic onset or mislocalization of mitotic kinases. Importantly, we demonstrate that microtubule-dependent mechanical forces synergize with B55SUR-6 for efficient NE disassembly. Finally, our data suggest that the lamin LMN-1 is likely a bona fide target of PP2A-B55SUR-6. These findings establish a model highlighting biochemical cross-talk between kinases, PP2A-B55SUR-6 phosphatase, and microtubule-generated mechanical forces in timely NE dissolution.

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Kapoor, S., Adhikary, K., Kotak, S.. 2023-06-11. PP2A-B55SUR-6 promotes nuclear envelope breakdown in C. elegans embryos. https://doi.org/10.1101/2023.06.11.544482

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