RRC ID 80880
Author Thomas L, Taleb Ismail B, Askjaer P, Seydoux G.
Title Nucleoporin foci are stress-sensitive condensates dispensable for C. elegans nuclear pore assembly.
Journal EMBO J
Abstract Nucleoporins (Nups) assemble nuclear pores that form the permeability barrier between nucleoplasm and cytoplasm. Nucleoporins also localize in cytoplasmic foci proposed to function as pore pre-assembly intermediates. Here, we characterize the composition and incidence of cytoplasmic Nup foci in an intact animal, C. elegans. We find that, in young non-stressed animals, Nup foci only appear in developing sperm, oocytes and embryos, tissues that express high levels of nucleoporins. The foci are condensates of highly cohesive FG repeat-containing nucleoporins (FG-Nups), which are maintained near their solubility limit in the cytoplasm by posttranslational modifications and chaperone activity. Only a minor fraction of FG-Nup molecules concentrate in Nup foci, which dissolve during M phase and are dispensable for nuclear pore assembly. Nucleoporin condensation is enhanced by stress and advancing age, and overexpression of a single FG-Nup in post-mitotic neurons is sufficient to induce ectopic condensation and organismal paralysis. We speculate that Nup foci are non-essential and potentially toxic condensates whose assembly is actively suppressed in healthy cells.
Volume 42(13)
Pages e112987
Published 2023-7-3
DOI 10.15252/embj.2022112987
PMID 37254647
PMC PMC10308366
MeSH Active Transport, Cell Nucleus Animals Caenorhabditis elegans / genetics Caenorhabditis elegans / metabolism Cell Nucleus / metabolism Male Nuclear Pore* / genetics Nuclear Pore* / metabolism Nuclear Pore Complex Proteins* / genetics Nuclear Pore Complex Proteins* / metabolism Semen / metabolism
C.elegans tm3039