In vivo assembly of a Dictyostelium lamin mutant induced by light, mechanical stress, and pH
- We expressedDictyosteliumlamin (NE81) lacking both a functional nuclear localization signal and a CAAX-box for C-terminal lipid modification. This lamin mutant assembled into supramolecular, three-dimensional clusters in the cytosol that disassembled at the onset of mitosis and re-assembled in late telophase, thus mimicking the behavior of the endogenous protein. As disassembly is regulated by CDK1-mediated phosphorylation at serine 122, we generated a phosphomimetic S122E mutant called GFP-NE81-S122E-Delta NLS Delta CLIM. Surprisingly, during imaging, the fusion protein assembled into cytosolic clusters, similar to the protein lacking the phosphomimetic mutation. Clusters disassembled again in the darkness. Assembly could be induced with blue but not green or near ultraviolet light, and it was independent of the fusion tag. Assembly similarly occurred upon cell flattening. Earlier reports and own observations suggested that both blue light and cell flattening could result in a decrease of intracellular pH. Indeed, keeping the cellsWe expressedDictyosteliumlamin (NE81) lacking both a functional nuclear localization signal and a CAAX-box for C-terminal lipid modification. This lamin mutant assembled into supramolecular, three-dimensional clusters in the cytosol that disassembled at the onset of mitosis and re-assembled in late telophase, thus mimicking the behavior of the endogenous protein. As disassembly is regulated by CDK1-mediated phosphorylation at serine 122, we generated a phosphomimetic S122E mutant called GFP-NE81-S122E-Delta NLS Delta CLIM. Surprisingly, during imaging, the fusion protein assembled into cytosolic clusters, similar to the protein lacking the phosphomimetic mutation. Clusters disassembled again in the darkness. Assembly could be induced with blue but not green or near ultraviolet light, and it was independent of the fusion tag. Assembly similarly occurred upon cell flattening. Earlier reports and own observations suggested that both blue light and cell flattening could result in a decrease of intracellular pH. Indeed, keeping the cells at low pH also reversibly induced cluster formation. Our results indicate that lamin assembly can be induced by various stress factors and that these are transduced via intracellular acidification. Although these effects have been shown in a phosphomimetic CDK1 mutant of theDictyosteliumlamin, they are likely relevant also for wild-type lamin.…
Author details: | Marianne GrafeORCiDGND, Phillip Hofmann, Petros BatsiosORCiDGND, Irene Meyer, Ralph GräfORCiDGND |
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DOI: | https://doi.org/10.3390/cells9081834 |
ISSN: | 2073-4409 |
Pubmed ID: | https://pubmed.ncbi.nlm.nih.gov/32759812 |
Title of parent work (English): | Cells : open access journal |
Publisher: | MDPI |
Place of publishing: | Basel |
Publication type: | Article |
Language: | English |
Date of first publication: | 2020/08/04 |
Publication year: | 2020 |
Release date: | 2023/01/19 |
Tag: | Dictyostelium; NE81; lamin; nuclear envelope; nuclear lamina |
Volume: | 9 |
Issue: | 8 |
Article number: | 1834 |
Number of pages: | 14 |
Funding institution: | Deutsche Forschungsgemeinschaft (DFG) German Research Foundation (DFG); [GR1642/4-3] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Biochemie und Biologie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie |
Peer review: | Referiert |
Publishing method: | Open Access / Gold Open-Access |
DOAJ gelistet | |
License (German): | CC-BY - Namensnennung 4.0 International |