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Asymmetrical localization of Nup107-160 subcomplex components within the nuclear pore complex in fission yeast.

ABSTRACT: The nuclear pore complex (NPC) forms a gateway for nucleocytoplasmic transport. The outer ring protein complex of the NPC (the Nup107-160 subcomplex in humans) is a key component for building the NPC. Nup107-160 subcomplexes are believed to be symmetrically localized on the nuclear and cytoplasmic sides of the NPC. However, in S. pombe immunoelectron and fluorescence microscopic analyses revealed that the homologous components of the human Nup107-160 subcomplex had an asymmetrical localization: constituent proteins spNup132 and spNup107 were present only on the nuclear side (designated the spNup132 subcomplex), while spNup131, spNup120, spNup85, spNup96, spNup37, spEly5 and spSeh1 were localized only on the cytoplasmic side (designated the spNup120 subcomplex), suggesting the complex was split into two pieces at the interface between spNup96 and spNup107. This contrasts with the symmetrical localization reported in other organisms. Fusion of spNup96 (cytoplasmic localization) with spNup107 (nuclear localization) caused cytoplasmic relocalization of spNup107. In this strain, half of the spNup132 proteins, which interact with spNup107, changed their localization to the cytoplasmic side of the NPC, leading to defects in mitotic and meiotic progression similar to an spNup132 deletion strain. These observations suggest the asymmetrical localization of the outer ring spNup132 and spNup120 subcomplexes of the NPC is necessary for normal cell cycle progression in fission yeast.

SUBMITTER: Asakawa H

PROVIDER: S-EPMC6553703 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Cell-cycle-dependent phosphorylation of the nuclear pore Nup107-160 subcomplex.

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Fission yeast essential nuclear pore protein nup211 regulates the transcriptome

Project description:While nuclear pore proteins mediate nucleo-cytoplasmic transport, they can have important roles in other activities such as transcription, chromatin organization, and cell cycle regulation. The fission yeast nuclear pore protein nup211 localizes to the nuclear basket and is essential for cell viability. Nup211 is important for RNA quality control and the nuclear export of polyadenylated RNAs. Interestingly, several nup211 orthologs have also been shown to regulate transcription at the chromatin level. Although nup211 preferentially associates with heterochromatin, it is unclear whether it modulates transcription. To further investigate the functions of nup211, we constructed a strain in which nup211 expression can be reduced through the addition of thiamine to the growth medium (nup211-so) and examined how cells were affected when nup211 protein was reduced. Down-regulation of nup211 led to severe defects in cell cycle regulation, including septation and cytokinesis. Using RNA-Seq and RT-qPCR, we revealed that loss of nup211 significantly altered global gene expression. Our findings suggest a new role for nup211 in regulating the transcriptome.

2024-10-04 | GSE216106 | GEO

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