A mitotic nuclear envelope tether for Gle1 also affects nuclear and nucleolar architecture
| Autor: | Aysha H. Osmani, Mahesh Chemudupati, Stephen A. Osmani |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
biology Nuclear Functions Articles Cell Biology biology.organism_classification Yeast Cell biology 03 medical and health sciences 030104 developmental biology 0302 clinical medicine Meiosis Aspergillus nidulans Inner membrane Molecular Biology Mitosis 030217 neurology & neurosurgery |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| DOI: | 10.1091/mbc.e16-07-0544 |
| Popis: | Study of mitotic redistribution of Gle1 in Aspergillus nidulans identified an orthologue of fission yeast Bqt4, an inner nuclear membrane protein required for meiosis. This protein—MtgA for “mitotic tether for Gle1”—also modulates nucleolar and nuclear architecture, extending the known roles of Bqt4/MtgA-related proteins. During Aspergillus nidulans mitosis, peripheral nuclear pore complex (NPC) proteins (Nups) disperse from the core NPC structure. Unexpectedly, one predicted peripheral Nup, Gle1, remains at the mitotic nuclear envelope (NE) via an unknown mechanism. Gle1 affinity purification identified mitotic tether for Gle1 (MtgA), which tethers Gle1 to the NE during mitosis but not during interphase when Gle1 is at NPCs. MtgA is the orthologue of the Schizosaccharomyces pombe telomere-anchoring inner nuclear membrane protein Bqt4. Like Bqt4, MtgA has meiotic roles, but it is functionally distinct from Bqt4 because MtgA is not required for tethering telomeres to the NE. Domain analyses showed that MtgA targeting to the NE requires its C-terminal transmembrane domain and a nuclear localization signal. Of importance, MtgA functions beyond Gle1 mitotic targeting and meiosis and affects nuclear and nucleolar architecture when deleted or overexpressed. Deleting MtgA generates small, round nuclei, whereas overexpressing MtgA generates larger nuclei with altered nuclear compartmentalization resulting from NE expansion around the nucleolus. The accumulation of MtgA around the nucleolus promotes a similar accumulation of the endoplasmic reticulum (ER) protein Erg24, reducing its levels in the ER. This study extends the functions of Bqt4-like proteins to include mitotic Gle1 targeting and modulation of nuclear and nucleolar architecture. |
| Databáze: | OpenAIRE |
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