Components of the endosomal sorting complexes required for transport (ESCRT) coordinate membrane remodelling and scission in various cellular processes, including nuclear pore complex (NPC) assembly and resealing of the perturbed nuclear envelope (NE) following cell division. How recruitment of ESCRT to the NE is regulated remains poorly understood. Now, Sigurd Braun and colleagues (Capella et al., 2020) tackle this question using a combination of yeast genetics and biochemistry. They find a genetic interaction between ESCRT-III subunits and Hub1, a ubiquitin-like protein known to promote generation of the short isoform of the inner nuclear membrane protein Heh1 (Heh1-S). The lack of Heh1-S in ESCRT-III-mutant backgrounds resulted in growth defects and accumulation of NPCs. Interestingly, the long isoform of Heh1 (Heh1-L) and its interaction with the ESCRT-III adaptor Chm7 are responsible for the growth phenotypes. Finally, the authors show that Heh1-L and Heh1-S form heterodimers and identify a motif in Heh1-S that controls its interaction with Heh1-L. Collectively, this work proposes a model whereby Hub1-mediated alternative splicing leads to the generation of Heh1-S, which modulates the interaction between Heh1-L and Chm7. This mechanism is crucial for preventing excessive ESCRT-III recruitment during NE repair, thus ensuring nuclear membrane integrity.

• © 2020. Published by The Company of Biologists Ltd