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

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

Blog Article

Summary: 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 Wiring Harness 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.NEBD defect upon B55SUR-6 depletion is not due to delayed mitotic onset or mislocalization of mitotic kinases.Importantly, we demonstrate that Clear Tote Bag microtubule-dependent mechanical forces synergize with B55SUR-6 for efficient NEBD.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 crosstalk between kinases, PP2A-B55SUR-6 phosphatase, and microtubule-generated mechanical forces in timely NE dissolution.