Nuclear envelope budding is a response to cellular stress

Nuclear envelope budding (NEB) is a recently discovered alternative pathway for nucleocytoplasmic communication distinct from the movement of material through the nuclear pore complex. Through quantitative electron microscopy and tomography, we demonstrate how NEB is evolutionarily conserved from early protists to human cells. In the yeast Saccharomyces cerevisiae, NEB events occur with higher frequency during heat shock, upon exposure to arsenite or hydrogen peroxide, and when the proteasome is inhibited. Yeast cells treated with azetidine-2-carboxylic acid, a proline analog that induces protein misfolding, display the most dramatic increase in NEB, suggesting a causal link to protein quality control. This link was further supported by both localization of ubiquitin and Hsp104 to protein aggregates and NEB events, and the evolution of these structures during heat shock. We hypothesize that NEB is part of normal cellular physiology in a vast range of species and that in S. cerevisiae NEB comprises a stress response aiding the transport of protein aggregates across the nuclear envelope.

Automated summary

Nuclear envelope budding (NEB) is an alternative pathway for nucleocytoplasmic communication that is evolutionarily conserved from early protists to human cells. In yeast cells, NEB events occur more frequently under stress conditions such as heat shock, exposure to harmful chemicals, and inhibition of the proteasome. NEB may play a role in aiding the transport of protein aggregates across the nuclear envelope, particularly in response to protein misfolding and heat shock.