Handling Editor: Jennifer Lippincott-Schwartz
ABSTRACT
Misassembled nuclear pore complexes (NPCs) are removed by sealing off the surrounding nuclear envelope (NE), which is conducted by the endosomal sorting complexes required for transport (ESCRT) machinery. Recruitment of ESCRT proteins to the NE is mediated by the interaction between the ESCRT member Chm7 and the inner nuclear membrane protein Heh1, which belongs to the conserved LEM family. Increased ESCRT recruitment results in excessive membrane scission at damage sites but its regulation remains poorly understood. Here, we show that Hub1-mediated alternative splicing of HEH1 pre-mRNA, resulting in production of its shorter form Heh1-S, is critical for the integrity of the NE in Saccharomyces cerevisiae. ESCRT-III mutants lacking Hub1 or Heh1-S display severe growth defects and accumulate improperly assembled NPCs. This depends on the interaction of Chm7 with the conserved MSC domain, which is only present in the longer variant Heh1-L. Heh1 variants assemble into heterodimers, and we demonstrate that a unique splice segment in Heh1-S suppresses growth defects associated with the uncontrolled interaction between Heh1-L and Chm7. Together, our findings reveal that Hub1-mediated splicing generates Heh1-S to regulate ESCRT recruitment to the NE.
This article has an associated First Person interview with the first author of the paper.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: M.C., S.B., S.J.; Methodology: M.C., L.M.C.; Validation: M.C.; Formal analysis: M.C.; Investigation: M.C., L.M.C.; Data curation: M.C.; Writing - original draft: M.C.; Writing - review & editing: M.C., L.M.C., B.P., S.B.; Visualization: M.C.; Supervision: S.B., S.J.; Project administration: S.B., S.J.; Funding acquisition: S.B., S.J.
Funding
Research in the S.J. laboratory was supported by Max Planck Society, Deutsche Forschungsgemeinschaft, Center for Integrated Protein Science Munich (CIPSM), Louis-Jeantet Foundation and a European Research Council (ERC) Advanced Grant. Research in the S.B. laboratory was supported by grants from the Deutsche Forschungsgemeinschaft (BR 3511/4-1). S.B. is a member of the Collaborative Research Center 1064 funded by the Deutsche Forschungsgemeinschaft and acknowledges infrastructural support.
Supplementary information
Supplementary information available online at https://jcs.biologists.org/lookup/doi/10.1242/jcs.250688.supplemental
- Received June 25, 2020.
- Accepted November 17, 2020.
- © 2020. Published by The Company of Biologists Ltd
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