Handling Editor: Maria Carmo-Fonseca
ABSTRACT
Nucleoporin Nup153 is a multifunctional protein and a known binding partner of mitotic checkpoint protein Mad1 (also known as MAD1L1). The functional relevance of their interaction has remained elusive. Here, we have further dissected the interface and functional interplay of Nup153 and Mad1. Using in situ proximity ligation assays, we found that the presence of a nuclear envelope (NE) is a prerequisite for the Nup153–Mad1 association. Time-lapse microscopy revealed that depletion of Mad1 delayed recruitment of Nup153 to anaphase chromatin, which was often accompanied by a prolongation of anaphase. Furthermore, as seen by electron microscopic and three-dimensional structured illumination investigations, Nup153 and Mad1 depletion led to alterations in NE architecture, characterised by a change of membrane curvature at nuclear pore complexes (NPCs) and an expansion of the spacing between inner and outer nuclear membranes. Nup153 depletion, but not Mad1 depletion, caused defects in interphase NPC assembly, with partial displacement of cytoplasmic nucleoporins and a reduction in NPC density. Taken together, our results suggest that Nup153 has separable roles in NE and NPC formation: in post-mitotic NE re-formation in concert with Mad1 and in interphase NPC assembly, independent of Mad1.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: I.M., G.C., V.M., B.F.; Validation: I.M., G.C., B.F.; Formal analysis: I.M., G.C., M.V., B.F.; Investigation: I.M., G.C., V.M., M.V.; Writing - original draft: I.M., B.F.; Writing - review & editing: G.C., B.F.; Supervision: B.F.; Project administration: B.F.; Funding acquisition: B.F.
Funding
This work was supported by a FRIA PhD fellowship to I.M. and research grants to B.F. (grant numbers F.6006.10 and T.0237.13) from the Fonds De La Recherche Scientifique – FNRS.
Supplementary information
Supplementary information available online at https://jcs.biologists.org/lookup/doi/10.1242/jcs.249243.supplemental
- Received May 21, 2020.
- Accepted September 24, 2020.
- © 2020. Published by The Company of Biologists Ltd
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