ESCRT recruitment by the S. cerevisiae inner nuclear membrane protein Heh1 is regulated by Hub1-mediated alternative splicing

J Cell Sci. 2020 Dec 21;133(24):jcs250688. doi: 10.1242/jcs.250688.


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.

Keywords: ESCRT; LEM domain; Nuclear envelope surveillance; Nuclear pore complex; Splicing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Alternative Splicing / genetics
  • Endosomal Sorting Complexes Required for Transport / genetics
  • Endosomal Sorting Complexes Required for Transport / metabolism
  • Humans
  • Ligases / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Nuclear Envelope / metabolism
  • Saccharomyces cerevisiae Proteins* / genetics
  • Saccharomyces cerevisiae Proteins* / metabolism
  • Saccharomyces cerevisiae* / genetics
  • Saccharomyces cerevisiae* / metabolism


  • Adaptor Proteins, Signal Transducing
  • Chm7 protein, S cerevisiae
  • Endosomal Sorting Complexes Required for Transport
  • Membrane Proteins
  • Saccharomyces cerevisiae Proteins
  • Ligases
  • HUB1 protein, S cerevisiae