TY - GEN A1 - Grafe, Marianne A1 - Batsios, Petros A1 - Meyer, Irene A1 - Lisin, Daria A1 - Baumann, Otto A1 - Goldberg, Martin W. A1 - Gräf, Ralph T1 - Supramolecular Structures of the Dictyostelium Lamin NE81 T2 - Potsprint der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Nuclear lamins are nucleus-specific intermediate filaments (IF) found at the inner nuclear membrane (INM) of the nuclear envelope (NE). Together with nuclear envelope transmembrane proteins, they form the nuclear lamina and are crucial for gene regulation and mechanical robustness of the nucleus and the whole cell. Recently, we characterized Dictyostelium NE81 as an evolutionarily conserved lamin-like protein, both on the sequence and functional level. Here, we show on the structural level that the Dictyostelium NE81 is also capable of assembling into filaments, just as metazoan lamin filament assemblies. Using field-emission scanning electron microscopy, we show that NE81 expressed in Xenopous oocytes forms filamentous structures with an overall appearance highly reminiscent of Xenopus lamin B2. The in vitro assembly properties of recombinant His-tagged NE81 purified from Dictyostelium extracts are very similar to those of metazoan lamins. Super-resolution stimulated emission depletion (STED) and expansion microscopy (ExM), as well as transmission electron microscopy of negatively stained purified NE81, demonstrated its capability of forming filamentous structures under low-ionic-strength conditions. These results recommend Dictyostelium as a non-mammalian model organism with a well-characterized nuclear envelope involving all relevant protein components known in animal cells. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 682 KW - lamin KW - NE81 KW - Dictyostelium KW - nuclear envelope KW - nuclear lamina KW - expansion microscopy Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-425976 SN - 1866-8372 IS - 682 ER - TY - JOUR A1 - Grafe, Marianne A1 - Batsios, Petros A1 - Meyer, Irene A1 - Lisin, Daria A1 - Baumann, Otto A1 - Goldberg, Martin W. A1 - Gräf, Ralph T1 - Supramolecular Structures of the Dictyostelium Lamin NE81 JF - Cells N2 - Nuclear lamins are nucleus-specific intermediate filaments (IF) found at the inner nuclear membrane (INM) of the nuclear envelope (NE). Together with nuclear envelope transmembrane proteins, they form the nuclear lamina and are crucial for gene regulation and mechanical robustness of the nucleus and the whole cell. Recently, we characterized Dictyostelium NE81 as an evolutionarily conserved lamin-like protein, both on the sequence and functional level. Here, we show on the structural level that the Dictyostelium NE81 is also capable of assembling into filaments, just as metazoan lamin filament assemblies. Using field-emission scanning electron microscopy, we show that NE81 expressed in Xenopous oocytes forms filamentous structures with an overall appearance highly reminiscent of Xenopus lamin B2. The in vitro assembly properties of recombinant His-tagged NE81 purified from Dictyostelium extracts are very similar to those of metazoan lamins. Super-resolution stimulated emission depletion (STED) and expansion microscopy (ExM), as well as transmission electron microscopy of negatively stained purified NE81, demonstrated its capability of forming filamentous structures under low-ionic-strength conditions. These results recommend Dictyostelium as a non-mammalian model organism with a well-characterized nuclear envelope involving all relevant protein components known in animal cells. KW - lamin KW - NE81 KW - Dictyostelium KW - nuclear envelope KW - nuclear lamina KW - expansion microscopy Y1 - 2019 U6 - https://doi.org/10.3390/cells8020162 SN - 2073-4409 VL - 8 IS - 2 PB - Molecular Diversity Preservation International CY - Basel ER - TY - JOUR A1 - Batsios, Petros A1 - Gräf, Ralph A1 - Koonce, Michael P. A1 - Larochelle, Denis A. A1 - Meyer, Irene T1 - Nuclear envelope organization in Dictyostelium discoideum JF - The international journal of developmental biology N2 - The nuclear envelope consists of the outer and the inner nuclear membrane, the nuclear lamina and the nuclear pore complexes, which regulate nuclear import and export.The major constituent of the nuclear lamina of Dictyostelium is the lamin NE81. It can form filaments like B-type lamins and it interacts with Sun 1, as well as with the LEM/HeH-family protein Src1. Sun 1 and Src1 are nuclear envelope transmembrane proteins involved in the centrosome-nucleus connection and nuclear envelope stability at the nucleolar regions, respectively. In conjunction with a KASH-domain protein, Sun 1 usually forms a so-called LINC complex.Two proteins with functions reminiscent of KASH-domain proteins at the outer nuclear membrane of Dictyostelium are known; interaptin which serves as an actin connector and the kinesin Kif9 which plays a role in the microtubule-centrosome connector. However, both of these lack the conserved KASH-domain. The link of the centrosome to the nuclear envelope is essential for the insertion of the centrosome into the nuclear envelope and the appropriate spindle formation. Moreover, centrosome insertion is involved in perm eabilization of the mitotic nucleus, which ensures access of tubulin dimers and spindle assembly factors. Our recent progress in identifying key molecular players at the nuclear envelope of Dictyostelium promises further insights into the mechanisms of nuclear envelope dynamics. KW - nuclear envelop KW - Dictyostelium KW - lamin KW - NET KW - centrosome KW - centromere Y1 - 2019 U6 - https://doi.org/10.1387/ijdb.190184rg SN - 0214-6282 SN - 1696-3547 VL - 63 IS - 8-10 SP - 509 EP - 519 PB - UBC Pr CY - Bilbao ER -