Bridging the spatiotemporal scales of macromolecular transport in crowded biomimetic systems

Regan, Kathryn; Wulstein, Devynn; Rasmussen, Hannah; McGorty, Ryan; Robertson‐Anderson, Rae M.

doi:10.1101/431528

Cited by 8 publications

(22 citation statements)

References 56 publications

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“…Further, this increased transport is coupled with larger conformations, at odds with the Newtonian Stokes relationship (D ~ Rcoil-1). We previously showed that linear DNA diffusing in a network of semiflexible actin filaments was more compact and displayed more extreme subdiffusion and lower transport coefficients than when diffusing in a network of more rigid microtubules (19). Further, recent simulations have shown that the slow mobility of large crowders, which results in continuous temporal evolution of the crowding mesh, was required for true anomalous subdiffusion (67).…”

Section: Discussionmentioning

confidence: 99%

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Topology-dependent anomalous dynamics of ring and linear DNA are sensitive to cytoskeleton crosslinking

et al. 2019

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Cytoskeletal crowding plays a key role in the diffusion of DNA molecules through the cell, acting as a barrier to effective intracellular transport and conformational stability required for such processes as transfection, viral infection, and gene therapy. Here we elucidate the transport properties and conformational dynamics of linear and ring DNA molecules diffusing through entangled and crosslinked composite networks of actin and microtubules. We couple single-molecule conformational tracking with differential dynamic microscopy to reveal that ring and linear DNA exhibit surprisingly distinct transport properties that are influenced differently by cytoskeleton crosslinking. Ring DNA coils are swollen and undergo heterogeneous and biphasic subdiffusion that is hindered by crosslinking. Conversely, crosslinking actually facilitates the single-mode subdiffusion that compacted linear chains exhibit. Our collective results demonstrate that transient threading by cytoskeleton filaments plays a key role in the dynamics of ring DNA, whereas the mobility of the cytoskeleton dictates transport of linear DNA.

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Section: Discussionmentioning

confidence: 99%

“…These analysis methods, depicted in Figure 1, have been described and validated previously (19)(20)(21)35). (19,(62)(63)(64). Each ROI is analyzed individually and averaged together post-analysis (Fig.…”

Section: Sample Preparationmentioning

confidence: 99%

Topology-dependent anomalous dynamics of ring and linear DNA are sensitive to cytoskeleton crosslinking

et al. 2019

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“…Few studies have investigated composite networks of actin and microtubules 11,27,57,58 due, in part, to the incompatibility of standard polymerization conditions for each protein 27 . However, methods have recently been introduced to co-polymerize actin and tubulin in situ to create randomly-oriented co-entangled composites of actin and microtubules 27 .…”

Section: Introductionmentioning

confidence: 99%

Varying crosslinking motifs drive the mesoscale mechanics of actin-microtubule composites

Ricketts

Francis

Farhadi

et al. 2019

Preprint

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The cytoskeleton dynamically tunes its mechanical properties by altering the interactions between semiflexible actin filaments, rigid microtubules, and crosslinking proteins. Here, we use optical tweezers microrheology and confocal microscopy to characterize how varying crosslinking motifs impact the microscopic and mesoscale mechanics and mobility of actin-microtubule composites. We show that, upon subtle changes in the crosslinking pattern, composites separate into two distinct classes of force responseprimarily elastic versus more viscous behavior. For example, a composite in which actin and microtubules are crosslinked to each other is markedly more elastic than one in which both filaments are crosslinked but cannot link together. Notably, this distinction only emerges at mesoscopic scales in response to nonlinear forcing, whereas varying crosslinking motifs have little impact on the microscale mechanics and steadystate mobility of composites. Our unexpected scale-dependent results not only inform the physics underlying key cytoskeleton processes and structures, but, more generally, provide valuable perspective to materials engineering endeavors focused on polymer composites.

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“…Differential Dynamic Microscopy. Following our previously described methods, 57,58 where ( ) is the nonergodicity parameter, ( ) is the decay time, and ( ) is the stretching exponent. Using methods similar to those described by Cho et al 38 , we obtain both ( ) and ( ) prior to curve fitting.…”

Section: Discussionmentioning

confidence: 99%

Subtle changes in crosslinking drive diverse anomalous transport characteristics in actin-microtubule networks

Anderson

Garamella

Adalbert

et al. 2020

Preprint

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Anomalous diffusion in crowded and complex environments is widely studied due to its importance in intracellular transport, fluid rheology and materials engineering. Specifically, diffusion through the cytoskeleton, a network comprised of semiflexible actin filaments and rigid microtubules that interact both sterically and via crosslinking, plays a principal role in viral infection, vesicle transport and targeted drug delivery. Here, we elucidate the impact of crosslinking on particle diffusion in composites of actin and microtubules with actin-actin, microtubule-microtubule and actin-microtubule crosslinking. We analyze a suite of complementary transport metrics by coupling single-particle tracking and differential dynamic microscopy. Using these orthogonal techniques, we find that particles display non-Gaussian and non-ergodic subdiffusion that is markedly enhanced by cytoskeletal crosslinking of any type, which we attribute to suppressed microtubule mobility. However, the extent to which transport deviates from normal Brownian diffusion depends strongly on the crosslinking motif - with actin-microtubule crosslinking inducing the most pronounced anomalous characteristics - due to increased actin fluctuation heterogeneity. Our results reveal that subtle changes to actin-microtubule interactions can have dramatic impacts on diffusion in the cytoskeleton, and suggest that less mobile and more locally heterogeneous networks lead to more strongly anomalous transport.

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Bridging the spatiotemporal scales of macromolecular transport in crowded biomimetic systems

Cited by 8 publications

References 56 publications

Topology-dependent anomalous dynamics of ring and linear DNA are sensitive to cytoskeleton crosslinking

Topology-dependent anomalous dynamics of ring and linear DNA are sensitive to cytoskeleton crosslinking

Varying crosslinking motifs drive the mesoscale mechanics of actin-microtubule composites

Subtle changes in crosslinking drive diverse anomalous transport characteristics in actin-microtubule networks

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