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  1. Article ; Online: Actin-microtubule dynamic composite forms responsive active matter with memory.

    Kučera, Ondřej / Gaillard, Jérémie / Guérin, Christophe / Théry, Manuel / Blanchoin, Laurent

    Proceedings of the National Academy of Sciences of the United States of America

    2022  Volume 119, Issue 31, Page(s) e2209522119

    Abstract: Active cytoskeletal materials in vitro demonstrate self-organizing properties similar to those observed in their counterparts in cells. However, the search to emulate phenomena observed in living matter has fallen short of producing a cytoskeletal ... ...

    Abstract Active cytoskeletal materials in vitro demonstrate self-organizing properties similar to those observed in their counterparts in cells. However, the search to emulate phenomena observed in living matter has fallen short of producing a cytoskeletal network that would be structurally stable yet possess adaptive plasticity. Here, we address this challenge by combining cytoskeletal polymers in a composite where self-assembling microtubules and actin filaments collectively self-organize due to the activity of microtubule-percolating molecular motors. We demonstrate that microtubules spatially organize actin filaments that in turn guide microtubules. The two networks align in an ordered fashion using this feedback loop. In this composite, actin filaments can act as structural memory and, depending on the concentration of the components, microtubules either write this memory or get guided by it. The system is sensitive to external stimuli, suggesting possible autoregulatory behavior in changing mechanochemical environments. We thus establish an artificial active actin-microtubule composite as a system demonstrating architectural stability and plasticity.
    MeSH term(s) Actin Cytoskeleton/chemistry ; Actin Cytoskeleton/metabolism ; Actins/chemistry ; Actins/metabolism ; Microtubules/metabolism ; Protein Stability
    Chemical Substances Actins
    Language English
    Publishing date 2022-07-25
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2209522119
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  2. Article ; Online: Actin Architecture Steers Microtubules in Active Cytoskeletal Composite.

    Kučera, Ondřej / Gaillard, Jérémie / Guérin, Christophe / Utzschneider, Clothilde / Théry, Manuel / Blanchoin, Laurent

    Nano letters

    2022  Volume 22, Issue 21, Page(s) 8584–8591

    Abstract: Motility assays use surface-immobilized molecular motors to propel cytoskeletal filaments. They have been widely used to characterize motor properties and their impact on cytoskeletal self-organization. Moreover, the motility assays are a promising class ...

    Abstract Motility assays use surface-immobilized molecular motors to propel cytoskeletal filaments. They have been widely used to characterize motor properties and their impact on cytoskeletal self-organization. Moreover, the motility assays are a promising class of bioinspired active tools for nanotechnological applications. While these assays involve controlling the filament direction and speed, either as a sensory readout or a functional feature, designing a subtle control embedded in the assay is an ongoing challenge. Here, we investigate the interaction between gliding microtubules and networks of actin filaments. We demonstrate that the microtubule's behavior depends on the actin architecture. Both unbranched and branched actin decelerate microtubule gliding; however, an unbranched actin network provides additional guidance and effectively steers the microtubules. This effect, which resembles the recognition of cortical actin by microtubules, is a conceptually new means of controlling the filament gliding with potential application in the design of active materials and cytoskeletal nanodevices.
    MeSH term(s) Actins ; Microtubules ; Cytoskeleton ; Actin Cytoskeleton ; Nanotechnology
    Chemical Substances Actins
    Language English
    Publishing date 2022-10-24
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 1530-6992
    ISSN (online) 1530-6992
    DOI 10.1021/acs.nanolett.2c03117
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  3. Article ; Online: Recycling of the actin monomer pool limits the lifetime of network turnover.

    Colin, Alexandra / Kotila, Tommi / Guérin, Christophe / Orhant-Prioux, Magali / Vianay, Benoit / Mogilner, Alex / Lappalainen, Pekka / Théry, Manuel / Blanchoin, Laurent

    The EMBO journal

    2023  Volume 42, Issue 9, Page(s) e112717

    Abstract: Intracellular organization is largely mediated by actin turnover. Cellular actin networks continuously assemble and disassemble, while maintaining their overall appearance. This behavior, called "dynamic steady state," allows cells to sense and adapt to ... ...

    Abstract Intracellular organization is largely mediated by actin turnover. Cellular actin networks continuously assemble and disassemble, while maintaining their overall appearance. This behavior, called "dynamic steady state," allows cells to sense and adapt to their environment. However, how structural stability can be maintained during the constant turnover of a limited actin monomer pool is poorly understood. To answer this question, we developed an experimental system where polystyrene beads are propelled by an actin comet in a microwell containing a limited amount of components. We used the speed and the size of the actin comet tails to evaluate the system's monomer consumption and its lifetime. We established the relative contribution of actin assembly, disassembly, and recycling for a bead movement over tens of hours. Recycling mediated by cyclase-associated protein (CAP) is the key step in allowing the reuse of monomers for multiple assembly cycles. ATP supply and protein aging are also factors that limit the lifetime of actin turnover. This work reveals the balancing mechanism for long-term network assembly with a limited amount of building blocks.
    MeSH term(s) Actins/metabolism ; Actin Cytoskeleton/metabolism
    Chemical Substances Actins
    Language English
    Publishing date 2023-03-13
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 586044-1
    ISSN 1460-2075 ; 0261-4189
    ISSN (online) 1460-2075
    ISSN 0261-4189
    DOI 10.15252/embj.2022112717
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  4. Article ; Online: Actin network architecture can ensure robust centering or sensitive decentering of the centrosome.

    Yamamoto, Shohei / Gaillard, Jérémie / Vianay, Benoit / Guerin, Christophe / Orhant-Prioux, Magali / Blanchoin, Laurent / Théry, Manuel

    The EMBO journal

    2022  Volume 41, Issue 20, Page(s) e111631

    Abstract: The orientation of cell polarity depends on the position of the centrosome, the main microtubule-organizing center (MTOC). Microtubules (MTs) transmit pushing forces to the MTOC as they grow against the cell periphery. How the actin network regulates ... ...

    Abstract The orientation of cell polarity depends on the position of the centrosome, the main microtubule-organizing center (MTOC). Microtubules (MTs) transmit pushing forces to the MTOC as they grow against the cell periphery. How the actin network regulates these forces remains unclear. Here, in a cell-free assay, we used purified proteins to reconstitute the interaction of a microtubule aster with actin networks of various architectures in cell-sized microwells. In the absence of actin filaments, MTOC positioning was highly sensitive to variations in microtubule length. The presence of a bulk actin network limited microtubule displacement, and MTOCs were held in place. In contrast, the assembly of a branched actin network along the well edges centered the MTOCs by maintaining an isotropic balance of pushing forces. An anisotropic peripheral actin network caused the MTOC to decenter by focusing the pushing forces. Overall, our results show that actin networks can limit the sensitivity of MTOC positioning to microtubule length and enforce robust MTOC centering or decentering depending on the isotropy of its architecture.
    MeSH term(s) Actin Cytoskeleton/metabolism ; Actins/metabolism ; Centrosome/metabolism ; Microtubule-Organizing Center/metabolism ; Microtubules/metabolism
    Chemical Substances Actins
    Language English
    Publishing date 2022-08-02
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 586044-1
    ISSN 1460-2075 ; 0261-4189
    ISSN (online) 1460-2075
    ISSN 0261-4189
    DOI 10.15252/embj.2022111631
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  5. Article ; Online: Microtubules under mechanical pressure can breach dense actin networks.

    Gélin, Matthieu / Schaeffer, Alexandre / Gaillard, Jérémie / Guérin, Christophe / Vianay, Benoit / Orhant-Prioux, Magali / Braun, Marcus / Leterrier, Christophe / Blanchoin, Laurent / Théry, Manuel

    Journal of cell science

    2023  Volume 136, Issue 22

    Abstract: The crosstalk between the actin network and microtubules is essential for cell polarity. It orchestrates microtubule organization within the cell, driven by the asymmetry of actin architecture along the cell periphery. The physical intertwining of these ... ...

    Abstract The crosstalk between the actin network and microtubules is essential for cell polarity. It orchestrates microtubule organization within the cell, driven by the asymmetry of actin architecture along the cell periphery. The physical intertwining of these networks regulates spatial organization and force distribution in the microtubule network. Although their biochemical interactions are becoming clearer, the mechanical aspects remain less understood. To explore this mechanical interplay, we developed an in vitro reconstitution assay to investigate how dynamic microtubules interact with various actin filament structures. Our findings revealed that microtubules can align and move along linear actin filament bundles through polymerization force. However, they are unable to pass through when encountering dense branched actin meshworks, similar to those present in the lamellipodium along the periphery of the cell. Interestingly, immobilizing microtubules through crosslinking with actin or other means allow the buildup of pressure, enabling them to breach these dense actin barriers. This mechanism offers insights into microtubule progression towards the cell periphery, with them overcoming obstacles within the denser parts of the actin network and ultimately contributing to cell polarity establishment.
    MeSH term(s) Actins/physiology ; Microtubules/physiology ; Actin Cytoskeleton/chemistry ; Cell Polarity ; Pseudopodia
    Chemical Substances Actins
    Language English
    Publishing date 2023-11-23
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2993-2
    ISSN 1477-9137 ; 0021-9533
    ISSN (online) 1477-9137
    ISSN 0021-9533
    DOI 10.1242/jcs.261667
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  6. Article ; Online: Friction patterns guide actin network contraction.

    Colin, Alexandra / Orhant-Prioux, Magali / Guérin, Christophe / Savinov, Mariya / Cao, Wenxiang / Vianay, Benoit / Scarfone, Ilaria / Roux, Aurélien / De La Cruz, Enrique M / Mogilner, Alex / Théry, Manuel / Blanchoin, Laurent

    Proceedings of the National Academy of Sciences of the United States of America

    2023  Volume 120, Issue 39, Page(s) e2300416120

    Abstract: The shape of cells is the outcome of the balance of inner forces produced by the actomyosin network and the resistive forces produced by cell adhesion to their environment. The specific contributions of contractile, anchoring and friction forces to ... ...

    Abstract The shape of cells is the outcome of the balance of inner forces produced by the actomyosin network and the resistive forces produced by cell adhesion to their environment. The specific contributions of contractile, anchoring and friction forces to network deformation rate and orientation are difficult to disentangle in living cells where they influence each other. Here, we reconstituted contractile actomyosin networks in vitro to study specifically the role of the friction forces between the network and its anchoring substrate. To modulate the magnitude and spatial distribution of friction forces, we used glass or lipids surface micropatterning to control the initial shape of the network. We adapted the concentration of Nucleating Promoting Factor on each surface to induce the assembly of actin networks of similar densities and compare the deformation of the network toward the centroid of the pattern shape upon myosin-induced contraction. We found that actin network deformation was faster and more coordinated on lipid bilayers than on glass, showing the resistance of friction to network contraction. To further study the role of the spatial distribution of these friction forces, we designed heterogeneous micropatterns made of glass and lipids. The deformation upon contraction was no longer symmetric but biased toward the region of higher friction. Furthermore, we showed that the pattern of friction could robustly drive network contraction and dominate the contribution of asymmetric distributions of myosins. Therefore, we demonstrate that during contraction, both the active and resistive forces are essential to direct the actin network deformation.
    MeSH term(s) Actins ; Friction ; Actomyosin ; Muscle Contraction ; Lipid Bilayers
    Chemical Substances Actins ; Actomyosin (9013-26-7) ; Lipid Bilayers
    Language English
    Publishing date 2023-09-19
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2300416120
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  7. Article ; Online: Architecture dependence of actin filament network disassembly.

    Gressin, Laurène / Guillotin, Audrey / Guérin, Christophe / Blanchoin, Laurent / Michelot, Alphée

    Current biology : CB

    2015  Volume 25, Issue 11, Page(s) 1437–1447

    Abstract: Turnover of actin networks in cells requires the fast disassembly of aging actin structures. While ADF/cofilin and Aip1 have been identified as central players, how their activities are modulated by the architecture of the networks remains unknown. Using ...

    Abstract Turnover of actin networks in cells requires the fast disassembly of aging actin structures. While ADF/cofilin and Aip1 have been identified as central players, how their activities are modulated by the architecture of the networks remains unknown. Using our ability to reconstitute a diverse array of cellular actin organizations, we found that ADF/cofilin binding and ADF/cofilin-mediated disassembly both depend on actin geometrical organization. ADF/cofilin decorates strongly and stabilizes actin cables, whereas its weaker interaction to Arp2/3 complex networks is correlated with their dismantling and their reorganization into stable architectures. Cooperation of ADF/cofilin with Aip1 is necessary to trigger the full disassembly of all actin filament networks. Additional experiments performed at the single-molecule level indicate that this cooperation is optimal above a threshold of 23 molecules of ADF/cofilin bound as clusters along an actin filament. Our results indicate that although ADF/cofilin is able to dismantle selectively branched networks through severing and debranching, stochastic disassembly of actin filaments by ADF/cofilin and Aip1 represents an efficient alternative pathway for the full disassembly of all actin networks. Our data support a model in which the binding of ADF/cofilin is required to trigger a structural change of the actin filaments, as a prerequisite for their disassembly by Aip1.
    MeSH term(s) Actin Cytoskeleton/metabolism ; Actin Depolymerizing Factors/metabolism ; Actins/metabolism ; Animals ; Microfilament Proteins/metabolism ; Rabbits ; Yeasts
    Chemical Substances Actin Depolymerizing Factors ; Actins ; Microfilament Proteins ; actin interacting protein 1
    Language English
    Publishing date 2015-06-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 1071731-6
    ISSN 1879-0445 ; 0960-9822
    ISSN (online) 1879-0445
    ISSN 0960-9822
    DOI 10.1016/j.cub.2015.04.011
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  8. Article ; Online: Quantitative regulation of the dynamic steady state of actin networks.

    Manhart, Angelika / Icheva, Téa Aleksandra / Guerin, Christophe / Klar, Tobbias / Boujemaa-Paterski, Rajaa / Thery, Manuel / Blanchoin, Laurent / Mogilner, Alex

    eLife

    2019  Volume 8

    Abstract: Principles of regulation of actin network dimensions are fundamentally important for cell functions, yet remain unclear. Using both in vitro and in silico approaches, we studied the effect of key parameters, such as actin density, ADF/Cofilin ... ...

    Abstract Principles of regulation of actin network dimensions are fundamentally important for cell functions, yet remain unclear. Using both in vitro and in silico approaches, we studied the effect of key parameters, such as actin density, ADF/Cofilin concentration and network width on the network length. In the presence of ADF/Cofilin, networks reached equilibrium and became treadmilling. At the trailing edge, the network disintegrated into large fragments. A mathematical model predicts the network length as a function of width, actin and ADF/Cofilin concentrations. Local depletion of ADF/Cofilin by binding to actin is significant, leading to wider networks growing longer. A single rate of breaking network nodes, proportional to ADF/Cofilin density and inversely proportional to the square of the actin density, can account for the disassembly dynamics. Selective disassembly of heterogeneous networks by ADF/Cofilin controls steering during motility. Our results establish general principles on how the dynamic steady state of actin network emerges from biochemical and structural feedbacks.
    MeSH term(s) Actin Depolymerizing Factors/metabolism ; Actins/metabolism ; Animals ; Destrin ; Models, Theoretical ; Protein Interaction Maps ; Protein Multimerization ; Rabbits
    Chemical Substances Actin Depolymerizing Factors ; Actins ; DSTN protein, human ; Destrin
    Language English
    Publishing date 2019-03-14
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2687154-3
    ISSN 2050-084X ; 2050-084X
    ISSN (online) 2050-084X
    ISSN 2050-084X
    DOI 10.7554/eLife.42413
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  9. Article ; Online: Actin filaments regulate microtubule growth at the centrosome.

    Inoue, Daisuke / Obino, Dorian / Pineau, Judith / Farina, Francesca / Gaillard, Jérémie / Guerin, Christophe / Blanchoin, Laurent / Lennon-Duménil, Ana-Maria / Théry, Manuel

    The EMBO journal

    2019  Volume 38, Issue 11

    Abstract: The centrosome is the main microtubule-organizing centre. It also organizes a local network of actin filaments. However, the precise function of the actin network at the centrosome is not well understood. Here, we show that increasing densities of actin ... ...

    Abstract The centrosome is the main microtubule-organizing centre. It also organizes a local network of actin filaments. However, the precise function of the actin network at the centrosome is not well understood. Here, we show that increasing densities of actin filaments at the centrosome of lymphocytes are correlated with reduced amounts of microtubules. Furthermore, lymphocyte activation resulted in disassembly of centrosomal actin and an increase in microtubule number. To further investigate the direct crosstalk between actin and microtubules at the centrosome, we performed
    MeSH term(s) Actin Cytoskeleton/physiology ; Actins/metabolism ; Animals ; Cattle ; Cells, Cultured ; Centrosome/metabolism ; Humans ; Jurkat Cells ; Mice ; Microtubule-Associated Proteins/metabolism ; Microtubules/metabolism
    Chemical Substances Actins ; Microtubule-Associated Proteins
    Language English
    Publishing date 2019-03-22
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 586044-1
    ISSN 1460-2075 ; 0261-4189
    ISSN (online) 1460-2075
    ISSN 0261-4189
    DOI 10.15252/embj.201899630
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  10. Article ; Online: MICAL2 enhances branched actin network disassembly by oxidizing Arp3B-containing Arp2/3 complexes.

    Galloni, Chiara / Carra, Davide / Abella, Jasmine V G / Kjær, Svend / Singaravelu, Pavithra / Barry, David J / Kogata, Naoko / Guérin, Christophe / Blanchoin, Laurent / Way, Michael

    The Journal of cell biology

    2021  Volume 220, Issue 8

    Abstract: The mechanisms regulating the disassembly of branched actin networks formed by the Arp2/3 complex still remain to be fully elucidated. In addition, the impact of Arp3 isoforms on the properties of Arp2/3 are also unexplored. We now demonstrate that Arp3 ... ...

    Abstract The mechanisms regulating the disassembly of branched actin networks formed by the Arp2/3 complex still remain to be fully elucidated. In addition, the impact of Arp3 isoforms on the properties of Arp2/3 are also unexplored. We now demonstrate that Arp3 and Arp3B isocomplexes promote actin assembly equally efficiently but generate branched actin networks with different disassembly rates. Arp3B dissociates significantly faster than Arp3 from the network, and its depletion increases actin stability. This difference is due to the oxidation of Arp3B, but not Arp3, by the methionine monooxygenase MICAL2, which is recruited to the actin network by coronin 1C. Substitution of Arp3B Met293 by threonine, the corresponding residue in Arp3, increases actin network stability. Conversely, replacing Arp3 Thr293 with glutamine to mimic Met oxidation promotes disassembly. The ability of MICAL2 to enhance network disassembly also depends on cortactin. Our observations demonstrate that coronin 1C, cortactin, and MICAL2 act together to promote disassembly of branched actin networks by oxidizing Arp3B-containing Arp2/3 complexes.
    MeSH term(s) Actin Cytoskeleton/genetics ; Actin Cytoskeleton/metabolism ; Actin-Related Protein 2-3 Complex/genetics ; Actin-Related Protein 2-3 Complex/metabolism ; Actin-Related Protein 3/genetics ; Actin-Related Protein 3/metabolism ; Cortactin/genetics ; Cortactin/metabolism ; HeLa Cells ; Humans ; Microfilament Proteins/genetics ; Microfilament Proteins/metabolism ; Microscopy, Fluorescence ; Oxidation-Reduction ; Oxidoreductases/genetics ; Oxidoreductases/metabolism ; Vaccinia virus/genetics ; Vaccinia virus/metabolism
    Chemical Substances ACTR3 protein, human ; ACTR3B protein, human ; Actin-Related Protein 2-3 Complex ; Actin-Related Protein 3 ; CTTN protein, human ; Cortactin ; Microfilament Proteins ; MICAL2 protein, human ; Oxidoreductases (EC 1.-)
    Language English
    Publishing date 2021-06-09
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Video-Audio Media
    ZDB-ID 218154-x
    ISSN 1540-8140 ; 0021-9525
    ISSN (online) 1540-8140
    ISSN 0021-9525
    DOI 10.1083/jcb.202102043
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