The Force-Velocity Relationship for the Actin-Based Motility of Listeria monocytogenes

McGrath, James L.; Eungdamrong, Narat J.; Fisher, Charles I.; Peng, Fay; Mahadevan, L.; Mitchison, Timothy J.; Kuo, Scot C.

doi:10.1016/s0960-9822(03)00051-4

Cited by 91 publications

(119 citation statements)

References 24 publications

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“…Increasing the viscosity of the medium by several orders of magnitude only slightly slowed down bead movement (20), suggesting that the propulsive force is much larger than 50 pN. This result is in disagreement with the reported observation of a dramatic decrease in Listeria velocity under a 0-50 pN viscous force (21). Other experiments however (22,23) suggested that the propelling force is much larger, of the order of few nN.…”

contrasting

confidence: 60%

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

Marcy

Prost

Carlier

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

232

208

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Dynamic actin networks generate forces for numerous types of movements such as lamellipodia protrusion or the motion of endocytic vesicles. The actin-based propulsive movement of Listeria monocytogenes or of functionalized microspheres have been extensively used as model systems to identify the biochemical components that are necessary for actin-based motility. However, quantitative force measurements are required to elucidate the mechanism of force generation, which is still under debate. To directly probe the forces generated in the process of actin-based propulsion, we developed a micromanipulation experiment. A comet growing from a coated polystyrene bead is held by a micropipette while the bead is attached to a force probe, by using a specially designed ''flexible handle.'' This system allows us to apply both pulling and pushing external forces up to a few nanonewtons. By pulling the actin tail away from the bead at high speed, we estimate the elastic modulus of the gel and measure the force necessary to detach the tail from the bead. By applying a constant force in the range of ؊1.7 to 4.3 nN, the force-velocity relation is established. We find that the relation is linear for pulling forces and decays more weakly for pushing forces. This behavior is explained by using a dimensional elastic analysis.T he growth of a polymer against a barrier is a general mechanism for production of force in cell biology (1). Spatially controlled polymerization of actin is responsible for a large variety of changes in cell shape leading to cell movement, like the protrusion of the lamellipodium (2), or the intracellular propulsion of vesicles (3, 4) and pathogens (5, 6). Actin assembly in these processes is controlled by various proteins present in the cytoplasm, which have been identified over the last 10 years (see refs. 7 and 8 for review). It is now well established that the Arp2͞3 complex associates with Wiskott-Aldrich Syndrome protein (WASp) family proteins to create new filaments locally by branching them (9), thus generating the dendritic organization of the actin array (10, 11). Because pure actin treadmilling is too slow to account for polymerization speed observed in these systems, this process has to be speeded up by regulatory proteins (8). One experimental model that has been used widely for the identification of these proteins is the bacteria Listeria monocytogenes, which are propelled inside cells by actin polymerization. The minimal subset of proteins necessary and sufficient to reconstitute the Listeria movement has been identified (12). In addition to Arp2͞3 and actin, the regulatory proteins ADF͞ cofilin, profilin, and a capping protein are necessary to enhance the efficiency of treadmilling (13) and control the life time and average length of filaments (14, 15). The essential role of these proteins has been confirmed recently (16) in vivo by using a RNA interference strategy.Biomimetic systems are useful for analyzing the physical aspects of actin-based motility. Listeria movement can be mimicked by fun...

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contrasting

confidence: 60%

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

Marcy

Prost

Carlier

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

232

208

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“…The first assumption, that the energetic state of the bacterium is well approximated by a two-state model, is satisfied if, as suggested by existing experimental data, the bacterium is strongly attached to the surrounding actin gel (18) and does not move except when the attachment is broken, e.g., moves in discrete steps or intervals (19,20). Under these conditions, at any moment in time the bacterium occupies one of two possible states, fixed and moving, with the energy difference between the states determined by the energy required to break the adhesion between the bacterium and surrounding actin gel.…”

Section: Resultsmentioning

confidence: 99%

“…Assuming that the system is near thermal equilibrium and also that the time scale of the measurement is long compared with the transition time between states, the time-average probability of occupying either state then depends exponentially on the time-average free energy difference between the states. According to high-bandwidth laser interferometry measurements of bacterial motion (19,20), the latter condition is true for the relatively long sample intervals that were used here (2 sec).…”

Section: Resultsmentioning

confidence: 99%

“…In the simplest case where an average of N adhesive bonds must be cooperatively broken to free the bacterium, and the free energies of individual bond breakage add linearly, the average free energy difference between the states is N(⌬H 0 Ϫ T⌬S 0 ), where ⌬H 0 is the enthalpy and ⌬S 0 the entropy of breakage of a single adhesive bond, and N is the time-average number of adhesive bonds; in this case, the total enthalpy and entropy both scale linearly with N. A linear dependence of total energy on the number of bonds, N, is not an absolute requirement: any energy summation scheme will work as long as the total enthalpy and entropy scale proportionally. Because the system appears to spend most of its time in the bound state (19,20), the probability p that the bacterium occupies the unbound state is therefore approximately proportional to Exp[ϪN(⌬H 0 Ϫ T⌬S 0 )͞kT], where k is Boltzmann's constant, and T is the absolute temperature. This is an Arrhenius-type temperature dependence of the type we see in the movement of individual bacteria.…”

Section: Resultsmentioning

confidence: 99%

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Adhesion controls bacterial actin polymerization-based movement

Soo

Theriot²

2005

Proc. Natl. Acad. Sci. U.S.A.

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As part of its infectious life cycle, the bacterial pathogen Listeria monocytogenes propels itself through the host-cell cytoplasm by triggering the polymerization of host-cell actin near the bacterial surface, harnessing the activity of several cytoskeletal proteins used during actin-based cell crawling. To distinguish among several classes of biophysical models of actin-based bacterial movement, we used a high-throughput tracking technique to record the movement of many individual bacteria during temperature shifts. The speed of each bacterium varied strongly with temperature, closely following the Arrhenius rate law. Among bacteria, the prefactor A of the Arrhenius dependence unexpectedly varied exponentially with apparent activation energy, E a, over a wide range (8 -21 kcal͞mol), reminiscent of the ''rate compensation effect'' of classical catalytic reactions. Average E a were increased for mutant bacteria deficient in binding Ena͞VASP proteins and bacteria moving in diluted extract. These two effects were additive. The observed temperature and rate compensation effects are consistent with a class of simple kinetic models in which the bacterium advances through the thermally driven, cooperative breakage of groups of adhesive bonds on its surface. The estimated number of coupled adhesive bonds N on the bacterial surface varies between 10 and 40 bonds. In contrast to other models, this model correctly predicts an experimentally observed negative correlation between bacterial speed and actin gel density. The idea that speed depends on adhesion, rather than polymerization, suggests several alternative mechanisms by which known cytoskeletal regulatory proteins could control cellular movement.ActA ͉ Listeria ͉ motility M any types of eukaryotic cells, including immune system lymphocytes, neurons, and cancer cells, use the forces generated by polymerizing actin filament networks to change shape and to move. In the actin polymerization-based movement of intracellular bacterial pathogens such as Listeria monocytogenes, individual bacteria harness the same cytoskeletal machinery to move within the host-cell cytoplasm (1).Several classes of biophysical models have been proposed to explain the mechanism of actin polymerization-based movement. The models differ in which steps in the motility cycle are proposed to control the rate of bacterial movement.The ''tethered elastic Brownian ratchet'' model (2) proposes that a large force generated by the network of polymerizing actin filaments in the ''comet tail'' behind the bacterium continuously induces the breakage of individual adhesive bonds between the bacterium and the surrounding actin gel, pushing the bacterium forward. In this model, bacteria move at the speed at which propulsive and adhesive forces are balanced; this equilibrium velocity depends strongly on the specific properties of actin polymerization and adhesion. The related ''elastic gel '' model (3) proposes that the elastic expansion of the actin gel behind the bacterium also contributes to propulsion, ''s...

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“…A number of experiments on force generation by an assembly of biofilaments have been reported in the literature [36,39,[41][42][43][44][45][46][47][48][49]. In view of the overall content and objective of our paper we will focus only on the experiments related to single and parallel bundles of growing biofilaments.…”

Section: Introductionmentioning

confidence: 99%

Sufficient conditions for the additivity of stall forces generated by multiple filaments or motors

Bameta

Das

et al. 2017

Phys. Rev. E

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Molecular motors and cytoskeletal filaments work collectively most of the time under opposing forces. This opposing force may be due to cargo carried by motors or resistance coming from the cell membrane pressing against the cytoskeletal filaments. Some recent studies have shown that the collective maximum force (stall force) generated by multiple cytoskeletal filaments or molecular motors may not always be just a simple sum of the stall forces of the individual filaments or motors. To understand this excess or deficit in the collective force, we study a broad class of models of both cytoskeletal filaments and molecular motors. We argue that the stall force generated by a group of filaments or motors is additive, that is, the stall force of N number of filaments (motors) is N times the stall force of one filament (motor), when the system is in equilibrium at stall. Conversely, we show that this additive property typically does not hold true when the system is not at equilibrium at stall. We thus present a novel and unified understanding of the existing models exhibiting such nonaddivity, and generalise our arguments by developing new models that demonstrate this phenomena. We also propose a quantity similar to thermodynamic efficiency to easily predict this deviation from stall-force additivity for filament and motor collectives.

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The Force-Velocity Relationship for the Actin-Based Motility of Listeria monocytogenes

Cited by 91 publications

References 24 publications

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

Forces generated during actin-based propulsion: A direct measurement by micromanipulation

Adhesion controls bacterial actin polymerization-based movement

Sufficient conditions for the additivity of stall forces generated by multiple filaments or motors

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