Characterization of NE81, the first lamin-like nucleoskeleton protein in a unicellular organism

Krüger, Anne; Batsios, Petros; Baumann, Otto; Luckert, Eva; Schwarz, Heinz; Stick, Reimer; Meyer, Irene; Gräf, Ralph

doi:10.1091/mbc.e11-07-0595

Cited by 73 publications

(113 citation statements)

References 39 publications

(47 reference statements)

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“…In single-celled eukaryotes, coiled-coil proteins that are functionally homologous to lamins have been reported as lamina components. These include NE81 in Dictyostelium (Krüger et al, 2012) and NUP-1 in Trypanosoma (DuBois et al, 2012), neither of which resemble lamins at the amino acid sequence level. These results, together with our findings, indicate that eukaryotic organisms have highly diverse lamina components.…”

Section: (H) To (L) Electron Micrographs Of Nuclei In Root Cells Of Smentioning

confidence: 99%

The Novel Nuclear Envelope Protein KAKU4 Modulates Nuclear Morphology inArabidopsis

et al. 2014

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In animals, the nuclear lamina is a fibrillar meshwork on the inner surface of the nuclear envelope, composed of coiled-coil lamin proteins and lamin binding membrane proteins. Plants also have a meshwork on the inner surface of the nuclear envelope, but little is known about its composition other than the presence of members of the CROWDED NUCLEI (CRWN) protein family, possible plant lamin analogs. Here, we describe a candidate lamina component, based on two Arabidopsis thaliana mutants (kaku2 and kaku4) with aberrant nuclear morphology. The responsible gene in kaku2 encodes CRWN1, and the responsible gene in kaku4 encodes a plant-specific protein of unknown function (KAKU4) that physically interacts with CRWN1 and its homolog CRWN4. Immunogold labeling revealed that KAKU4 localizes at the inner nuclear membrane. KAKU4 deforms the nuclear envelope in a dose-dependent manner, in association with nuclear membrane invagination and stack formation. The KAKU4-dependent nuclear envelope deformation was enhanced by overaccumulation of CRWN1, although KAKU4 can deform the nuclear envelope even in the absence of CRWN1 and/or CRWN4. Together, these results suggest that plants have evolved a unique lamina-like structure to modulate nuclear shape and size.

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Section: (H) To (L) Electron Micrographs Of Nuclei In Root Cells Of Smentioning

confidence: 99%

The Novel Nuclear Envelope Protein KAKU4 Modulates Nuclear Morphology inArabidopsis

et al. 2014

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“…Lamin orthologs are widely distributed across Metazoa and social amoeba, and recently have been described as having broad presence, as well as, being absent from several major lineages (1,15–16). Yeast, which are evolutionarily closely related to animals, lack lamins and no lamina structure has been observed by electron microscopy (EM) (16,17).…”

Section: Introductionmentioning

confidence: 99%

Co-dependence between trypanosome nuclear lamina components in nuclear stability and control of gene expression

et al. 2016

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The nuclear lamina is a filamentous structure subtending the nuclear envelope and required for chromatin organization, transcriptional regulation and maintaining nuclear structure. The trypanosomatid coiled-coil NUP-1 protein is a lamina component functionally analogous to lamins, the major lamina proteins of metazoa. There is little evidence for shared ancestry, suggesting the presence of a distinct lamina system in trypanosomes. To find additional trypanosomatid lamina components we identified NUP-1 interacting proteins by affinity capture and mass-spectrometry. Multiple components of the nuclear pore complex (NPC) and a second coiled-coil protein, which we termed NUP-2, were found. NUP-2 has a punctate distribution at the nuclear periphery throughout the cell cycle and is in close proximity to NUP-1, the NPCs and telomeric chromosomal regions. RNAi-mediated silencing of NUP-2 leads to severe proliferation defects, gross alterations to nuclear structure, chromosomal organization and nuclear envelope architecture. Further, transcription is altered at telomere-proximal variant surface glycoprotein (VSG) expression sites (ESs), suggesting a role in controlling ES expression, although NUP-2 silencing does not increase VSG switching. Transcriptome analysis suggests specific alterations to Pol I-dependent transcription. NUP-1 is mislocalized in NUP-2 knockdown cells and vice versa, implying that NUP-1 and NUP-2 form a co-dependent network and identifying NUP-2 as a second trypanosomatid nuclear lamina component.

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“…The lamin gene is thought to be the ancestral gene of all IF genes, since all metazoa express lamins including those that do not express cytoplasmic IFs. In addition, a lamin-like homologue containing a coiled-coil domain, an Ig domain and a CaaX motif, is expressed at the nuclear envelope in the unicellular organism Dictyostelium discoideum [5]. Furthermore, all lamins contain an extra six heptad repeats in coil 1B that are absent in vertebrate cytoplasmic IFs, and at least one B-type lamin gene is expressed in every metazoan cell, while cytoplasmic IFs show tissue-specific and cellspecific pattern of expression [1].…”

Section: Introductionmentioning

confidence: 99%

Lamins: the structure and protein complexes

Gruenbaum

Medalia

2015

Current Opinion in Cell Biology

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Characterization of NE81, the first lamin-like nucleoskeleton protein in a unicellular organism

Abstract: Dictyostelium NE81 is the first protein found in a lower eukaryote with properties justifying its denomination as a lamin-like protein. Knockout and overexpression mutants revealed an important role for NE81 in nuclear integrity, chromatin organization, and mechanical stability of cells.

Cited by 73 publications

References 39 publications

The Novel Nuclear Envelope Protein KAKU4 Modulates Nuclear Morphology inArabidopsis

The Novel Nuclear Envelope Protein KAKU4 Modulates Nuclear Morphology inArabidopsis

Co-dependence between trypanosome nuclear lamina components in nuclear stability and control of gene expression

Lamins: the structure and protein complexes

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