dictyNews
Electronic Edition
Volume 48, number 2
January 28, 2022
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Abstracts
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Ena/VASP proteins in cell edge protrusion, migration and adhesion
Jan Faix1,* and Klemens Rottner2,3
1. Institute for Biophysical Chemistry, Hannover Medical School,
Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
2. Division of Molecular Cell Biology, Zoological Institute,
Technical University Braunschweig, Spielmannstrasse 7, 38106
Braunschweig, Germany.
3. Molecular Cell Biology Group, Helmholtz Centre for Infection
Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
Journal of Cell Science
The tightly coordinated, spatio-temporal control of actin filament
remodelling provides the basis of fundamental cellular processes,
such as cell migration and adhesion. Specific protein assemblies,
composed of various actin-binding proteins, are thought to operate
in these processes to nucleate and elongate new filaments, arrange
them into complex 3D arrays and recycle them to replenish the actin
monomer pool. Actin-filament assembly is not only necessary to
generate pushing forces against the leading edge membrane or to
propel pathogens through the cytoplasm, but also coincides with
the generation of stress fibers (SFs) and focal adhesions (FAs)
that generate, transmit and sense mechanical tension. The only
protein families known to date that directly enhance the elongation
of actin filaments are formins and Ena/VASP proteins. Their
mechanisms of action, however, in enhancing processive filament
elongation are distinct. The aim of this Review is to summarize our
current knowledge on the molecular mechanisms of Ena/VASP-
mediated actin filament assembly, and to discuss recent insights
into the cell biological functions of Ena/VASP proteins in cell edge
protrusion, migration and adhesion.
Submitted by Jan Faix [[log in to unmask]]
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Partial Disassembly of the Nuclear Pore Complex Proteins during
Semi-Closed Mitosis in Dictyostelium discoideum
Kristina Mitic, Marianne Grafe, Petros Batsios and Irene Meyer
Department of Cell Biology, University of Potsdam,
Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
Cells 2022, 11(3), 407;
https://doi.org/10.3390/cells11030407 (registering DOI)
Accepted: 21 January 2022 / Published: 25 January 2022
Dictyostelium cells undergo a semi-closed mitosis, during which the
nuclear envelope (NE) persists; however, free diffusion between the
cytoplasm and the nucleus takes place. To permit the formation of
the mitotic spindle, the nuclear envelope must be permeabilized in
order to allow diffusion of tubulin dimers and spindle assembly factors
into the nucleus. In Aspergillus, free diffusion of proteins between the
cytoplasm and the nucleus is achieved by a partial disassembly of the
nuclear pore complexes (NPCs) prior to spindle assembly. In order to
determine whether this is also the case in Dictyostelium, we analysed
components of the NPC by immunofluorescence microscopy and live
cell imaging and studied their behaviour during interphase and mitosis.
We observed that the NPCs are absent from the contact area of the
nucleoli and that some nucleoporins also localize to the centrosome
and the spindle poles. In addition, we could show that, during mitosis,
the central FG protein NUP62, two inner ring components and Gle1
depart from the NPCs, while all other tested NUPs remained at the NE.
This leads to the conclusion that indeed a partial disassembly of the
NPCs takes place, which contributes to permeabilisation of the NE
during semi-closed mitosis.
Submitted by Irene Meyer [[log in to unmask]]
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[End dictyNews, volume 48, number 2]
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