Elastic Coupling Effects in Cooperative Transport by a Pair of Molecular Motors

Berger, Florian; Keller, Corina; Lipowsky, Reinhard; Klumpp, Stefan

doi:10.1007/s12195-012-0258-3

Cited by 22 publications

(39 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(i) The average velocity and the effective diffusion coefficient of the motor cargo assembly reduces with increase of the elastic coupling constant κ. Our results are consistent with some of the observations made in earlier studies [25,26] where it was reported that, the average cargo velocity reduces as a function of stiffness of the motor-cargo linker. (ii) Asymptotically, the average velocity becomes independent of motor number N while the effective diffusion constant decreases as 1/N .…”

Section: Discussionsupporting

confidence: 93%

“…Several studies have appeared in the last few years, based (mostly) on Hookean spring-like interaction between motor and the cargo [19,20,21,22,23,24,25,26,27,28,29]. In Kunwar et al [20], along with elastic interaction among the motors, non-linear force-velocity relations are assigned to different motors.…”

Section: Introductionmentioning

confidence: 99%

“…Some of the formalisms developed in the above mentioned analytical studies were applied to simple cases with at most two motor proteins driving a cargo [24,25,26,28], while many other studies are by and large computational in nature [19,20,22,23,29]. A general theoretical framework to study the motion of a cargo driven by arbitrary number of elastically bound motors has not been developed.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transport of organelles by elastically coupled motor proteins

Bhat

Gopalakrishnan

2016

Eur. Phys. J. E

View full text Add to dashboard Cite

Abstract. Motor-driven intracellular transport is a complex phenomenon where multiple motor proteins simultaneously attached on to a cargo engage in pulling activity, often leading to tug-of-war, displaying bidirectional motion. However, most mathematical and computational models ignore the details of the motor-cargo interaction. A few studies have focused on more realistic models of cargo transport by including elastic motor-cargo coupling, but either restrict the number of motors and/or use purely phenomenological forms for force-dependent hopping rates. Here, we study a generic model in which N motors are elastically coupled to a cargo, which itself is subjected to thermal noise in the cytoplasm and to an additional external applied force. The motor-hopping rates are chosen to satisfy detailed balance with respect to the energy of elastic stretching. With these assumptions, an (N + 1)− variable master equation is constructed for dynamics of the motor-cargo complex. By expanding the hopping rates to linear order in fluctuations in motor positions, we obtain a linear Fokker-Planck equation. The deterministic equations governing the average quantities are separated out and explicit analytical expressions are obtained for the mean velocity and diffusion coefficient of the cargo. We also study the statistical features of the force experienced by an individual motor and quantitatively characterize the load-sharing among the cargo-bound motors. The mean cargo velocity and the effective diffusion coefficient are found to be decreasing functions of the stiffness. While increase in the number of motors N does not increase the velocity substantially, it decreases the effective diffusion coefficient which falls as 1/N asymptotically. We further show that the cargo-bound motors share the force exerted on the cargo equally only in the limit of vanishing elastic stiffness; as stiffness is increased, deviations from equal load sharing are observed. Numerical simulations agree with our analytical results where expected. Interestingly, we find in simulations that the stall force of a cargo elastically coupled to motors is independent of the stiffness of the linkers. PACS

show abstract

Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Transport of organelles by elastically coupled motor proteins

Bhat

Gopalakrishnan

2016

Eur. Phys. J. E

View full text Add to dashboard Cite

show abstract

“…However, these studies could not explain the experimental observations that two coupled kinesins pull each other from the filament, but move with a velocity that is close to the velocity of a single motor [22]. This interference effect has been studied theoretically by explicitly considering the coupling between the motors not only for kinesin, but also for dynein and myosin motors [11,17,34,35], In general, depending on the single motor dynamics and the elastic coupling, motor pairs can exhibit four different transport regimes [11], The emergence of these distinct regimes can be understood from intuitive time scale arguments that were derived for transport in the absence of an external load force [11,36],…”

Section: Introductionmentioning

confidence: 99%

External forces influence the elastic coupling effects during cargo transport by molecular motors

et al. 2015

Self Cite

View full text Add to dashboard Cite

Cellular transport is achieved by the cooperative action of molecular motors which are elastically linked to a common cargo. When the motors pull on the cargo at the same time, they experience fluctuating elastic strain forces induced by the stepping of the other motors. These elastic coupling forces can influence the motors' stepping and unbinding behavior and thereby the ability to transport cargos. Based on a generic single motor description, we introduce a framework that explains the response of two identical molecular motors to a constant external force. In particular, we relate the single motor parameters, the coupling strength and the external load force to the dynamics of the motor pair. We derive four distinct transport regimes and determine how the crossover lines between the regimes depend on the load force. Our description of the overall cargo dynamics takes into account relaxational displacements of the cargo caused by the unbinding of one motor. For large forces and weak elastic coupling these back-shifts dominate the displacements. To develop an intuitive understanding about motor cooperativity during cargo transport, we introduce a time scale for load sharing. This time scale allows us to predict how the regulation of single motor parameters influences the cooperativity. As an example, we show that up-regulating the single motor processivity enhances load sharing of the motor pair.

show abstract

“…However, most of these studies focused on only a single molecule. Recently, there have been many studies of the cooperative function of multiple motor proteins, as the importance of cooperativity is a hot topic in biophysics [11][12][13][14]. To further understand the physicochemical mechanism of protein functioning, attention is now shifting upward through the hierarchy, from individual elements to the cooperative behavior of the supramolecular system, suggesting the need of an additional technique that transcends conventional single-molecule measurement.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous nano-tracking of multiple motor proteins via spectral discrimination of quantum dots

Kakizuka

Ikezaki

Kaneshiro³

et al. 2016

Biomed. Opt. Express

View full text Add to dashboard Cite

Simultaneous nanometric tracking of multiple motor proteins was achieved by combining multicolor fluorescent labeling of target proteins and imaging spectroscopy, revealing dynamic behaviors of multiple motor proteins at the sub-diffraction-limit scale. Using quantum dot probes of distinct colors, we experimentally verified the localization precision to be a few nanometers at temporal resolution of 30 ms or faster. One-dimensional processive movement of two heads of a single myosin molecule and multiple myosin molecules was successfully traced. Furthermore, the system was modified for two-dimensional measurement and applied to tracking of multiple myosin molecules. Our approach is useful for investigating cooperative movement of proteins in supramolecular nanomachinery.

show abstract

Elastic Coupling Effects in Cooperative Transport by a Pair of Molecular Motors

Cited by 22 publications

References 64 publications

Transport of organelles by elastically coupled motor proteins

Transport of organelles by elastically coupled motor proteins

External forces influence the elastic coupling effects during cargo transport by molecular motors

Simultaneous nano-tracking of multiple motor proteins via spectral discrimination of quantum dots

Contact Info

Product

Resources

About