Betz, Timo

[["dc.bibliographiccitation.artnumber","e49910"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","EMBO Reports"],["dc.bibliographiccitation.volume","21"],["dc.contributor.author","Davidson, Patricia M."],["dc.contributor.author","Battistella, Aude"],["dc.contributor.author","Déjardin, Théophile"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Plastino, Julie"],["dc.contributor.author","Borghi, Nicolas"],["dc.contributor.author","Cadot, Bruno"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:51:54Z"],["dc.date.available","2020-11-23T10:51:54Z"],["dc.date.issued","2020-07-03"],["dc.description.abstract","The mechanisms by which cells exert forces on their nuclei to migrate through openings smaller than the nuclear diameter remain unclear. We use CRISPR/Cas9 to fluorescently label nesprin-2 giant, which links the cytoskeleton to the nuclear interior. We demonstrate that nesprin-2 accumulates at the front of the nucleus during nuclear deformation through narrow constrictions, independently of the nuclear lamina. We find that nesprins are mobile at time scales similar to the accumulation. Using artificial constructs, we show that the actin-binding domain of nesprin-2 is necessary and sufficient for this accumulation. Actin filaments are organized in a barrel structure around the nucleus in the direction of movement. Using two-photon ablation and cytoskeleton-inhibiting drugs, we demonstrate an actomyosin-dependent pulling force on the nucleus from the front of the cell. The elastic recoil upon ablation is dampened when nesprins are reduced at the nuclear envelope. We thus show that actin redistributes nesprin-2 giant toward the front of the nucleus and contributes to pulling the nucleus through narrow constrictions, in concert with myosin."],["dc.identifier.doi","10.15252/embr.201949910"],["dc.identifier.pmid","32419336"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68975"],["dc.language.iso","en"],["dc.relation.eissn","1469-3178"],["dc.relation.issn","1469-221X"],["dc.title","Nesprin-2 accumulates at the front of the nucleus during confined cell migration"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","20130005"],["dc.bibliographiccitation.issue","1629"],["dc.bibliographiccitation.journal","Philosophical Transactions of the Royal Society of London. B, Biological Sciences"],["dc.bibliographiccitation.volume","368"],["dc.contributor.author","Carvalho, Kevin"],["dc.contributor.author","Lemière, Joël"],["dc.contributor.author","Faqir, Fahima"],["dc.contributor.author","Manzi, John"],["dc.contributor.author","Blanchoin, Laurent"],["dc.contributor.author","Plastino, Julie"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:41:14Z"],["dc.date.available","2020-11-23T10:41:14Z"],["dc.date.issued","2013"],["dc.description.abstract","Cells use complex biochemical pathways to drive shape changes for polarization and movement. One of these pathways is the self-assembly of actin filaments and myosin motors that together produce the forces and tensions that drive cell shape changes. Whereas the role of actin and myosin motors in cell polarization is clear, the exact mechanism of how the cortex, a thin shell of actin that is underneath the plasma membrane, can drive cell shape changes is still an open question. Here, we address this issue using biomimetic systems: the actin cortex is reconstituted on liposome membranes, in an 'outside geometry'. The actin shell is either grown from an activator of actin polymerization immobilized at the membrane by a biotin-streptavidin link, or built by simple adsorption of biotinylated actin filaments to the membrane, in the presence or absence of myosin motors. We show that tension in the actin network can be induced either by active actin polymerization on the membrane via the Arp2/3 complex or by myosin II filament pulling activity. Symmetry breaking and spontaneous polarization occur above a critical tension that opens up a crack in the actin shell. We show that this critical tension is reached by growing branched networks, nucleated by the Arp2/3 complex, in a concentration window of capping protein that limits actin filament growth and by a sufficient number of motors that pull on actin filaments. Our study provides the groundwork to understanding the physical mechanisms at work during polarization prior to cell shape modifications."],["dc.identifier.doi","10.1098/rstb.2013.0005"],["dc.identifier.pmid","24062578"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68962"],["dc.language.iso","en"],["dc.relation.eissn","1471-2970"],["dc.relation.issn","0962-8436"],["dc.title","Actin polymerization or myosin contraction: two ways to build up cortical tension for symmetry breaking"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2976"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.lastpage","2976"],["dc.bibliographiccitation.volume","12"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:40:17Z"],["dc.date.available","2020-11-23T10:40:17Z"],["dc.date.issued","2016"],["dc.identifier.doi","10.1039/C6SM90032A"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68950"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-531"],["dc.relation.eissn","1744-6848"],["dc.relation.iserratumof","/handle/2/68946"],["dc.relation.issn","1744-683X"],["dc.relation.issn","1744-6848"],["dc.title","Correction: Time resolved membrane fluctuation spectroscopy"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.subtype","erratum_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5317"],["dc.bibliographiccitation.issue","19"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.lastpage","5326"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:39:56Z"],["dc.date.available","2020-11-23T10:39:56Z"],["dc.date.issued","2012"],["dc.identifier.doi","10.1039/C2SM00001F"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68946"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-531"],["dc.relation.eissn","1744-6848"],["dc.relation.haserratum","/handle/2/68950"],["dc.relation.issn","1744-683X"],["dc.relation.issn","1744-6848"],["dc.title","Time resolved membrane fluctuation spectroscopy"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3181"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","Soft Matter"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Lemière, Joël"],["dc.contributor.author","Guevorkian, Karine"],["dc.contributor.author","Campillo, Clément"],["dc.contributor.author","Sykes, Cécile"],["dc.contributor.author","Betz, Timo"],["dc.date.accessioned","2020-11-23T10:40:02Z"],["dc.date.available","2020-11-23T10:40:02Z"],["dc.date.issued","2013"],["dc.identifier.doi","10.1039/c3sm27812c"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68947"],["dc.relation.issn","1744-683X"],["dc.relation.issn","1744-6848"],["dc.title","α-Hemolysin membrane pore density measured on liposomes"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Davidson, Patricia M."],["dc.contributor.author","Battistella, Aude"],["dc.contributor.author","Déjardin, Théophile"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Plastino, Julie"],["dc.contributor.author","Borghi, Nicolas"],["dc.contributor.author","Cadot, Bruno"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:41:34Z"],["dc.date.available","2020-11-23T10:41:34Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1101/713982"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68966"],["dc.title","Nesprin-2 accumulates at the front of the nucleus during confined cell migration"],["dc.type","preprint"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1072"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","1079"],["dc.bibliographiccitation.volume","113"],["dc.contributor.author","Rückerl, Florian"],["dc.contributor.author","Lenz, Martin"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Manzi, John"],["dc.contributor.author","Martiel, Jean-Louis"],["dc.contributor.author","Safouane, Mahassine"],["dc.contributor.author","Paterski-Boujemaa, Rajaa"],["dc.contributor.author","Blanchoin, Laurent"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:38:33Z"],["dc.date.available","2020-11-23T10:38:33Z"],["dc.date.issued","2017-09-05"],["dc.description.abstract","Actin is one of the main components of the architecture of cells. Actin filaments form different polymer networks with versatile mechanical properties that depend on their spatial organization and the presence of cross-linkers. Here, we investigate the mechanical properties of actin bundles in the absence of cross-linkers. Bundles are polymerized from the surface of mDia1-coated latex beads, and deformed by manipulating both ends through attached beads held by optical tweezers, allowing us to record the applied force. Bundle properties are strikingly different from the ones of a homogeneous isotropic beam. Successive compression and extension leads to a decrease in the buckling force that we attribute to the bundle remaining slightly curved after the first deformation. Furthermore, we find that the bundle is solid, and stiff to bending, along the long axis, whereas it has a liquid and viscous behavior in the transverse direction. Interpretation of the force curves using a Maxwell visco-elastic model allows us to extract the bundle mechanical parameters and confirms that the bundle is composed of weakly coupled filaments. At short times, the bundle behaves as an elastic material, whereas at long times, filaments flow in the longitudinal direction, leading to bundle restructuring. Deviations from the model reveal a complex adaptive rheological behavior of bundles. Indeed, when allowed to anneal between phases of compression and extension, the bundle reinforces. Moreover, we find that the characteristic visco-elastic time is inversely proportional to the compression speed. Actin bundles are therefore not simple force transmitters, but instead, complex mechano-transducers that adjust their mechanics to external stimulation. In cells, where actin bundles are mechanical sensors, this property could contribute to their adaptability."],["dc.identifier.doi","10.1016/j.bpj.2017.07.017"],["dc.identifier.pmid","28877490"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68929"],["dc.language.iso","en"],["dc.relation.eissn","1542-0086"],["dc.relation.issn","0006-3495"],["dc.title","Adaptive Response of Actin Bundles under Mechanical Stress"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","15320"],["dc.bibliographiccitation.issue","36"],["dc.bibliographiccitation.journal","Proceedings of the National Academy of Sciences of the United States of America"],["dc.bibliographiccitation.lastpage","15325"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Lenz, Martin"],["dc.contributor.author","Joanny, Jean-François"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:40:31Z"],["dc.date.available","2020-11-23T10:40:31Z"],["dc.date.issued","2009-09-08"],["dc.description.abstract","Red blood cells are amazingly deformable structures able to recover their initial shape even after large deformations as when passing through tight blood capillaries. The reason for this exceptional property is found in the composition of the membrane and the membrane-cytoskeleton interaction. We investigate the mechanics and the dynamics of RBCs by a unique noninvasive technique, using weak optical tweezers to measure membrane fluctuation amplitudes with mus temporal and sub nm spatial resolution. This enhanced edge detection method allows to span over >4 orders of magnitude in frequency. Hence, we can simultaneously measure red blood cell membrane mechanical properties such as bending modulus kappa = 2.8 +/- 0.3 x 10(-19)J = 67.6 +/- 7.2 k(B)T, tension sigma = 6.5 +/- 2.1 x 10(-7)N/m, and an effective viscosity eta(eff) = 81 +/- 3.7 x 10(-3) Pa s that suggests unknown dissipative processes. We furthermore show that cell mechanics highly depends on the membrane-spectrin interaction mediated by the phosphorylation of the interconnection protein 4.1R. Inhibition and activation of this phosphorylation significantly affects tension and effective viscosity. Our results show that on short time scales (slower than 100 ms) the membrane fluctuates as in thermodynamic equilibrium. At time scales longer than 100 ms, the equilibrium description breaks down and fluctuation amplitudes are higher by 40% than predicted by the membrane equilibrium theory. Possible explanations for this discrepancy are influences of the spectrin that is not included in the membrane theory or nonequilibrium fluctuations that can be accounted for by defining a nonthermal effective energy of up to E(eff) = 1.4 +/- 0.1 k(B)T, that corresponds to an actively increased effective temperature."],["dc.identifier.doi","10.1073/pnas.0904614106"],["dc.identifier.pmid","19717437"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68953"],["dc.language.iso","en"],["dc.relation.eissn","1091-6490"],["dc.relation.issn","0027-8424"],["dc.title","ATP-dependent mechanics of red blood cells"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","127a"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","128a"],["dc.bibliographiccitation.volume","110"],["dc.contributor.author","Caorsi, Valentina"],["dc.contributor.author","Sangsong, Wu"],["dc.contributor.author","Lemiere, Joël"],["dc.contributor.author","Campillo, Clément"],["dc.contributor.author","Betz, Timo"],["dc.contributor.author","Plastino, Julie"],["dc.contributor.author","Sykes, Cécile"],["dc.date.accessioned","2020-11-23T10:38:28Z"],["dc.date.available","2020-11-23T10:38:28Z"],["dc.date.issued","2016"],["dc.identifier.doi","10.1016/j.bpj.2015.11.732"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68928"],["dc.relation.issn","0006-3495"],["dc.title","How Synergy of Actin Assembly-Disassembly and Myosin Motors Drives Cell Shape Changes"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","854"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Biophysical Journal"],["dc.bibliographiccitation.lastpage","862"],["dc.bibliographiccitation.volume","107"],["dc.contributor.author","Bussonnier, Matthias"],["dc.contributor.author","Carvalho, Kevin"],["dc.contributor.author","Lemière, Joël"],["dc.contributor.author","Joanny, Jean-François"],["dc.contributor.author","Sykes, Cécile"],["dc.contributor.author","Betz, Timo"],["dc.date.accessioned","2020-11-23T10:38:10Z"],["dc.date.available","2020-11-23T10:38:10Z"],["dc.date.issued","2014-08-19"],["dc.description.abstract","Actin is ubiquitous globular protein that polymerizes into filaments and forms networks that participate in the force generation of eukaryotic cells. Such forces are used for cell motility, cytokinesis, and tissue remodeling. Among those actin networks, we focus on the actin cortex, a dense branched network beneath the plasma membrane that is of particular importance for the mechanical properties of the cell. Here we reproduce the cellular cortex by activating actin filament growth on a solid surface. We unveil the existence of a sparse actin network that emanates from the surface and extends over a distance that is at least 10 times larger than the cortex itself. We call this sparse actin network the \"actin cloud\" and characterize its mechanical properties with optical tweezers. We show, both experimentally and theoretically, that the actin cloud is mechanically relevant and that it should be taken into account because it can sustain forces as high as several picoNewtons (pN). In particular, it is known that in plant cells, actin networks similar to the actin cloud have a role in positioning the nucleus; in large oocytes, they play a role in driving chromosome movement. Recent evidence shows that such networks even prevent granule condensation in large cells."],["dc.identifier.doi","10.1016/j.bpj.2014.07.008"],["dc.identifier.pmid","25140420"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/68925"],["dc.language.iso","en"],["dc.relation.eissn","1542-0086"],["dc.relation.issn","0006-3495"],["dc.title","Mechanical detection of a long-range actin network emanating from a biomimetic cortex"],["dc.type","journal_article"],["dc.type.internalPublication","no"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]