---
_id: '10290'
abstract:
- lang: eng
text: A precise quantitative description of the ultrastructural characteristics
underlying biological mechanisms is often key to their understanding. This is
particularly true for dynamic extra- and intracellular filamentous assemblies,
playing a role in cell motility, cell integrity, cytokinesis, tissue formation
and maintenance. For example, genetic manipulation or modulation of actin regulatory
proteins frequently manifests in changes of the morphology, dynamics, and ultrastructural
architecture of actin filament-rich cell peripheral structures, such as lamellipodia
or filopodia. However, the observed ultrastructural effects often remain subtle
and require sufficiently large datasets for appropriate quantitative analysis.
The acquisition of such large datasets has been enabled by recent advances in
high-throughput cryo-electron tomography (cryo-ET) methods. This also necessitates
the development of complementary approaches to maximize the extraction of relevant
biological information. We have developed a computational toolbox for the semi-automatic
quantification of segmented and vectorized filamentous networks from pre-processed
cryo-electron tomograms, facilitating the analysis and cross-comparison of multiple
experimental conditions. GUI-based components simplify the processing of data
and allow users to obtain a large number of ultrastructural parameters describing
filamentous assemblies. We demonstrate the feasibility of this workflow by analyzing
cryo-ET data of untreated and chemically perturbed branched actin filament networks
and that of parallel actin filament arrays. In principle, the computational toolbox
presented here is applicable for data analysis comprising any type of filaments
in regular (i.e. parallel) or random arrangement. We show that it can ease the
identification of key differences between experimental groups and facilitate the
in-depth analysis of ultrastructural data in a time-efficient manner.
acknowledged_ssus:
- _id: ScienComp
- _id: LifeSc
- _id: Bio
- _id: EM-Fac
acknowledgement: 'This research was supported by the Scientific Service Units (SSUs)
of IST Austria through resources provided by Scientific Computing (SciComp), the
Life Science Facility (LSF), the BioImaging Facility (BIF), and the Electron Microscopy
Facility (EMF). We also thank Victor-Valentin Hodirnau for help with cryo-ET data
acquisition. The authors acknowledge support from IST Austria and from the Austrian
Science Fund (FWF): M02495 to G.D. and Austrian Science Fund (FWF): P33367 to F.K.M.S.'
article_number: '107808'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Georgi A
full_name: Dimchev, Georgi A
id: 38C393BE-F248-11E8-B48F-1D18A9856A87
last_name: Dimchev
orcid: 0000-0001-8370-6161
- first_name: Behnam
full_name: Amiri, Behnam
last_name: Amiri
- first_name: Florian
full_name: Fäßler, Florian
id: 404F5528-F248-11E8-B48F-1D18A9856A87
last_name: Fäßler
orcid: 0000-0001-7149-769X
- first_name: Martin
full_name: Falcke, Martin
last_name: Falcke
- first_name: Florian KM
full_name: Schur, Florian KM
id: 48AD8942-F248-11E8-B48F-1D18A9856A87
last_name: Schur
orcid: 0000-0003-4790-8078
citation:
ama: Dimchev GA, Amiri B, Fäßler F, Falcke M, Schur FK. Computational toolbox for
ultrastructural quantitative analysis of filament networks in cryo-ET data. Journal
of Structural Biology. 2021;213(4). doi:10.1016/j.jsb.2021.107808
apa: Dimchev, G. A., Amiri, B., Fäßler, F., Falcke, M., & Schur, F. K. (2021).
Computational toolbox for ultrastructural quantitative analysis of filament networks
in cryo-ET data. Journal of Structural Biology. Elsevier . https://doi.org/10.1016/j.jsb.2021.107808
chicago: Dimchev, Georgi A, Behnam Amiri, Florian Fäßler, Martin Falcke, and Florian
KM Schur. “Computational Toolbox for Ultrastructural Quantitative Analysis of
Filament Networks in Cryo-ET Data.” Journal of Structural Biology. Elsevier
, 2021. https://doi.org/10.1016/j.jsb.2021.107808.
ieee: G. A. Dimchev, B. Amiri, F. Fäßler, M. Falcke, and F. K. Schur, “Computational
toolbox for ultrastructural quantitative analysis of filament networks in cryo-ET
data,” Journal of Structural Biology, vol. 213, no. 4. Elsevier , 2021.
ista: Dimchev GA, Amiri B, Fäßler F, Falcke M, Schur FK. 2021. Computational toolbox
for ultrastructural quantitative analysis of filament networks in cryo-ET data.
Journal of Structural Biology. 213(4), 107808.
mla: Dimchev, Georgi A., et al. “Computational Toolbox for Ultrastructural Quantitative
Analysis of Filament Networks in Cryo-ET Data.” Journal of Structural Biology,
vol. 213, no. 4, 107808, Elsevier , 2021, doi:10.1016/j.jsb.2021.107808.
short: G.A. Dimchev, B. Amiri, F. Fäßler, M. Falcke, F.K. Schur, Journal of Structural
Biology 213 (2021).
date_created: 2021-11-15T12:21:42Z
date_published: 2021-11-03T00:00:00Z
date_updated: 2023-11-21T08:36:02Z
day: '03'
ddc:
- '572'
department:
- _id: FlSc
doi: 10.1016/j.jsb.2021.107808
external_id:
isi:
- '000720259500002'
file:
- access_level: open_access
checksum: 6b209e4d44775d4e02b50f78982c15fa
content_type: application/pdf
creator: cchlebak
date_created: 2021-11-15T13:11:27Z
date_updated: 2021-11-15T13:11:27Z
file_id: '10291'
file_name: 2021_JournalStructBiol_Dimchev.pdf
file_size: 16818304
relation: main_file
success: 1
file_date_updated: 2021-11-15T13:11:27Z
has_accepted_license: '1'
intvolume: ' 213'
isi: 1
issue: '4'
keyword:
- Structural Biology
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
project:
- _id: 9B954C5C-BA93-11EA-9121-9846C619BF3A
grant_number: P33367
name: Structure and isoform diversity of the Arp2/3 complex
- _id: 2674F658-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: M02495
name: Protein structure and function in filopodia across scales
publication: Journal of Structural Biology
publication_identifier:
issn:
- 1047-8477
publication_status: published
publisher: 'Elsevier '
quality_controlled: '1'
related_material:
record:
- id: '14502'
relation: software
status: public
scopus_import: '1'
status: public
title: Computational toolbox for ultrastructural quantitative analysis of filament
networks in cryo-ET data
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 213
year: '2021'
...
---
_id: '8434'
abstract:
- lang: eng
text: 'Efficient migration on adhesive surfaces involves the protrusion of lamellipodial
actin networks and their subsequent stabilization by nascent adhesions. The actin-binding
protein lamellipodin (Lpd) is thought to play a critical role in lamellipodium
protrusion, by delivering Ena/VASP proteins onto the growing plus ends of actin
filaments and by interacting with the WAVE regulatory complex, an activator of
the Arp2/3 complex, at the leading edge. Using B16-F1 melanoma cell lines, we
demonstrate that genetic ablation of Lpd compromises protrusion efficiency and
coincident cell migration without altering essential parameters of lamellipodia,
including their maximal rate of forward advancement and actin polymerization.
We also confirmed lamellipodia and migration phenotypes with CRISPR/Cas9-mediated
Lpd knockout Rat2 fibroblasts, excluding cell type-specific effects. Moreover,
computer-aided analysis of cell-edge morphodynamics on B16-F1 cell lamellipodia
revealed that loss of Lpd correlates with reduced temporal protrusion maintenance
as a prerequisite of nascent adhesion formation. We conclude that Lpd optimizes
protrusion and nascent adhesion formation by counteracting frequent, chaotic retraction
and membrane ruffling.This article has an associated First Person interview with
the first author of the paper. '
acknowledgement: This work was supported in part by Deutsche Forschungsgemeinschaft
(DFG)[GRK2223/1, RO2414/5-1 (to K.R.), FA350/11-1 (to M.F.) and FA330/11-1 (to J.F.)],as
well as by intramural funding from the Helmholtz Association (to T.E.B.S. andK.R.).
G.D. was additionally funded by the Austrian Science Fund (FWF) LiseMeitner Program
[M-2495]. A.C.H. and M.W. are supported by the Francis CrickInstitute, which receives
its core funding from Cancer Research UK [FC001209], theMedical Research Council
[FC001209] and the Wellcome Trust [FC001209]. M.K. issupported by the Biotechnology
and Biological Sciences Research Council [BB/F011431/1, BB/J000590/1, BB/N000226/1].
Deposited in PMC for release after 6months.
article_number: jcs239020
article_processing_charge: No
article_type: original
author:
- first_name: Georgi A
full_name: Dimchev, Georgi A
id: 38C393BE-F248-11E8-B48F-1D18A9856A87
last_name: Dimchev
orcid: 0000-0001-8370-6161
- first_name: Behnam
full_name: Amiri, Behnam
last_name: Amiri
- first_name: Ashley C.
full_name: Humphries, Ashley C.
last_name: Humphries
- first_name: Matthias
full_name: Schaks, Matthias
last_name: Schaks
- first_name: Vanessa
full_name: Dimchev, Vanessa
last_name: Dimchev
- first_name: Theresia E. B.
full_name: Stradal, Theresia E. B.
last_name: Stradal
- first_name: Jan
full_name: Faix, Jan
last_name: Faix
- first_name: Matthias
full_name: Krause, Matthias
last_name: Krause
- first_name: Michael
full_name: Way, Michael
last_name: Way
- first_name: Martin
full_name: Falcke, Martin
last_name: Falcke
- first_name: Klemens
full_name: Rottner, Klemens
last_name: Rottner
citation:
ama: Dimchev GA, Amiri B, Humphries AC, et al. Lamellipodin tunes cell migration
by stabilizing protrusions and promoting adhesion formation. Journal of Cell
Science. 2020;133(7). doi:10.1242/jcs.239020
apa: Dimchev, G. A., Amiri, B., Humphries, A. C., Schaks, M., Dimchev, V., Stradal,
T. E. B., … Rottner, K. (2020). Lamellipodin tunes cell migration by stabilizing
protrusions and promoting adhesion formation. Journal of Cell Science.
The Company of Biologists. https://doi.org/10.1242/jcs.239020
chicago: Dimchev, Georgi A, Behnam Amiri, Ashley C. Humphries, Matthias Schaks,
Vanessa Dimchev, Theresia E. B. Stradal, Jan Faix, et al. “Lamellipodin Tunes
Cell Migration by Stabilizing Protrusions and Promoting Adhesion Formation.” Journal
of Cell Science. The Company of Biologists, 2020. https://doi.org/10.1242/jcs.239020.
ieee: G. A. Dimchev et al., “Lamellipodin tunes cell migration by stabilizing
protrusions and promoting adhesion formation,” Journal of Cell Science,
vol. 133, no. 7. The Company of Biologists, 2020.
ista: Dimchev GA, Amiri B, Humphries AC, Schaks M, Dimchev V, Stradal TEB, Faix
J, Krause M, Way M, Falcke M, Rottner K. 2020. Lamellipodin tunes cell migration
by stabilizing protrusions and promoting adhesion formation. Journal of Cell Science.
133(7), jcs239020.
mla: Dimchev, Georgi A., et al. “Lamellipodin Tunes Cell Migration by Stabilizing
Protrusions and Promoting Adhesion Formation.” Journal of Cell Science,
vol. 133, no. 7, jcs239020, The Company of Biologists, 2020, doi:10.1242/jcs.239020.
short: G.A. Dimchev, B. Amiri, A.C. Humphries, M. Schaks, V. Dimchev, T.E.B. Stradal,
J. Faix, M. Krause, M. Way, M. Falcke, K. Rottner, Journal of Cell Science 133
(2020).
date_created: 2020-09-17T14:00:33Z
date_published: 2020-04-09T00:00:00Z
date_updated: 2023-09-05T15:41:48Z
day: '09'
ddc:
- '570'
department:
- _id: FlSc
doi: 10.1242/jcs.239020
external_id:
isi:
- '000534387800005'
pmid:
- ' 32094266'
file:
- access_level: open_access
checksum: ba917e551acc4ece2884b751434df9ae
content_type: application/pdf
creator: dernst
date_created: 2020-09-17T14:07:51Z
date_updated: 2020-10-11T22:30:02Z
embargo: 2020-10-10
file_id: '8435'
file_name: 2020_JournalCellScience_Dimchev.pdf
file_size: 13493302
relation: main_file
file_date_updated: 2020-10-11T22:30:02Z
has_accepted_license: '1'
intvolume: ' 133'
isi: 1
issue: '7'
keyword:
- Cell Biology
language:
- iso: eng
month: '04'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 2674F658-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: M02495
name: Protein structure and function in filopodia across scales
publication: Journal of Cell Science
publication_identifier:
eissn:
- 1477-9137
issn:
- 0021-9533
publication_status: published
publisher: The Company of Biologists
quality_controlled: '1'
status: public
title: Lamellipodin tunes cell migration by stabilizing protrusions and promoting
adhesion formation
type: journal_article
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
volume: 133
year: '2020'
...
---
_id: '8971'
abstract:
- lang: eng
text: The actin-related protein (Arp)2/3 complex nucleates branched actin filament
networks pivotal for cell migration, endocytosis and pathogen infection. Its activation
is tightly regulated and involves complex structural rearrangements and actin
filament binding, which are yet to be understood. Here, we report a 9.0 Å resolution
structure of the actin filament Arp2/3 complex branch junction in cells using
cryo-electron tomography and subtomogram averaging. This allows us to generate
an accurate model of the active Arp2/3 complex in the branch junction and its
interaction with actin filaments. Notably, our model reveals a previously undescribed
set of interactions of the Arp2/3 complex with the mother filament, significantly
different to the previous branch junction model. Our structure also indicates
a central role for the ArpC3 subunit in stabilizing the active conformation.
acknowledged_ssus:
- _id: ScienComp
- _id: LifeSc
- _id: Bio
- _id: EM-Fac
acknowledgement: "This research was supported by the Scientific Service Units (SSUs)
of IST Austria through resources provided by Scientific Computing (SciComp), the
Life Science Facility (LSF), the BioImaging Facility (BIF), and the Electron Microscopy
Facility (EMF). We also thank Dimitry Tegunov (MPI for Biophysical Chemistry) for
helpful discussions\r\nabout the M software, and Michael Sixt (IST Austria) and
Klemens Rottner (Technical University Braunschweig, HZI Braunschweig) for critical
reading of the manuscript. We also thank Gregory Voth (University of Chicago) for
providing us the MD-derived branch junction model for comparison. The authors acknowledge
support from IST Austria and from the Austrian Science Fund (FWF): M02495 to G.D.
and Austrian Science Fund (FWF): P33367 to F.K.M.S. "
article_number: '6437'
article_processing_charge: No
article_type: original
author:
- first_name: Florian
full_name: Fäßler, Florian
id: 404F5528-F248-11E8-B48F-1D18A9856A87
last_name: Fäßler
orcid: 0000-0001-7149-769X
- first_name: Georgi A
full_name: Dimchev, Georgi A
id: 38C393BE-F248-11E8-B48F-1D18A9856A87
last_name: Dimchev
orcid: 0000-0001-8370-6161
- first_name: Victor-Valentin
full_name: Hodirnau, Victor-Valentin
id: 3661B498-F248-11E8-B48F-1D18A9856A87
last_name: Hodirnau
- first_name: William
full_name: Wan, William
last_name: Wan
- first_name: Florian KM
full_name: Schur, Florian KM
id: 48AD8942-F248-11E8-B48F-1D18A9856A87
last_name: Schur
orcid: 0000-0003-4790-8078
citation:
ama: Fäßler F, Dimchev GA, Hodirnau V-V, Wan W, Schur FK. Cryo-electron tomography
structure of Arp2/3 complex in cells reveals new insights into the branch junction.
Nature Communications. 2020;11. doi:10.1038/s41467-020-20286-x
apa: Fäßler, F., Dimchev, G. A., Hodirnau, V.-V., Wan, W., & Schur, F. K. (2020).
Cryo-electron tomography structure of Arp2/3 complex in cells reveals new insights
into the branch junction. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-020-20286-x
chicago: Fäßler, Florian, Georgi A Dimchev, Victor-Valentin Hodirnau, William Wan,
and Florian KM Schur. “Cryo-Electron Tomography Structure of Arp2/3 Complex in
Cells Reveals New Insights into the Branch Junction.” Nature Communications.
Springer Nature, 2020. https://doi.org/10.1038/s41467-020-20286-x.
ieee: F. Fäßler, G. A. Dimchev, V.-V. Hodirnau, W. Wan, and F. K. Schur, “Cryo-electron
tomography structure of Arp2/3 complex in cells reveals new insights into the
branch junction,” Nature Communications, vol. 11. Springer Nature, 2020.
ista: Fäßler F, Dimchev GA, Hodirnau V-V, Wan W, Schur FK. 2020. Cryo-electron tomography
structure of Arp2/3 complex in cells reveals new insights into the branch junction.
Nature Communications. 11, 6437.
mla: Fäßler, Florian, et al. “Cryo-Electron Tomography Structure of Arp2/3 Complex
in Cells Reveals New Insights into the Branch Junction.” Nature Communications,
vol. 11, 6437, Springer Nature, 2020, doi:10.1038/s41467-020-20286-x.
short: F. Fäßler, G.A. Dimchev, V.-V. Hodirnau, W. Wan, F.K. Schur, Nature Communications
11 (2020).
date_created: 2020-12-23T08:25:45Z
date_published: 2020-12-22T00:00:00Z
date_updated: 2023-08-24T11:01:50Z
day: '22'
ddc:
- '570'
department:
- _id: FlSc
- _id: EM-Fac
doi: 10.1038/s41467-020-20286-x
external_id:
isi:
- '000603078000003'
file:
- access_level: open_access
checksum: 55d43ea0061cc4027ba45e966e1db8cc
content_type: application/pdf
creator: dernst
date_created: 2020-12-28T08:16:10Z
date_updated: 2020-12-28T08:16:10Z
file_id: '8975'
file_name: 2020_NatureComm_Faessler.pdf
file_size: 3958727
relation: main_file
success: 1
file_date_updated: 2020-12-28T08:16:10Z
has_accepted_license: '1'
intvolume: ' 11'
isi: 1
keyword:
- General Biochemistry
- Genetics and Molecular Biology
- General Physics and Astronomy
- General Chemistry
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
project:
- _id: 9B954C5C-BA93-11EA-9121-9846C619BF3A
grant_number: P33367
name: Structure and isoform diversity of the Arp2/3 complex
- _id: 2674F658-B435-11E9-9278-68D0E5697425
call_identifier: FWF
grant_number: M02495
name: Protein structure and function in filopodia across scales
publication: Nature Communications
publication_identifier:
issn:
- 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
related_material:
link:
- description: News on IST Homepage
relation: press_release
url: https://ist.ac.at/en/news/cutting-edge-technology-reveals-structures-within-cells/
scopus_import: '1'
status: public
title: Cryo-electron tomography structure of Arp2/3 complex in cells reveals new insights
into the branch junction
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 11
year: '2020'
...