Micron-scale geometrical features of microtubules as regulators of microtubule organization

Mani, Nandini; Wijeratne, Sithara S.; Subramanian, Radhika

doi:10.7554/elife.63880

Cited by 12 publications

(6 citation statements)

References 188 publications

(226 reference statements)

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“…Microtubule polymers, composed of linear protofilaments of α, β‐tubulin heterodimers, form the backbone of diverse cellular structures such as the spindle in dividing cells and axonemes in cilia. In these structures, individual microtubules are arranged in arrays of well‐defined size and geometry (Mani et al., 2021). For instance, anti‐parallel microtubule arrays form the midzone of the mitotic spindle, and parallel arrays of microtubule doublets comprise the axoneme.…”

Section: Introductionmentioning

confidence: 99%

Real‐Time Visualization of Microtubule and Protofilament‐Scale Dynamics in Multi‐Microtubule Arrays by Atomic Force Microscopy

Wijeratne

Subramanian

2023

Current Protocols

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Microtubules, polymers of α, β‐tubulin heterodimers, are organized into multi‐microtubule arrays for diverse cellular functions. The dynamic properties of microtubule arrays govern their structural and functional properties. While numerous insights into the biophysical mechanisms underlying microtubule organization have been gleaned from in vitro reconstitution studies, the assays are largely restricted to visualization of single or pairs of microtubules. Thus, the dynamic processes underlying the remodeling of multi‐microtubule arrays remain poorly understood. Recent work shows that Atomic Force Microscopy (AFM) enables the visualization of nanoscale dynamics within multi‐microtubule 2D arrays. In this assay, electrostatic interactions permit the non‐specific adsorption of microtubule arrays to mica. AFM imaging in tapping mode, a gentle method of imaging, allows the visualization of microtubules and protofilaments without sample damage. The height information captured by AFM imaging enables the tracking of structural changes in microtubules and protofilaments within multi‐microtubule arrays over time. The experimental data from the method described here reveal previously unseen modes of nanoscale dynamics in microtubule bundles formed by the microtubule‐crosslinking protein PRC1 in the presence of the depolymerase MCAK. The observations demonstrate the potential of AFM imaging in transforming our understanding of the fundamental cellular process by which multi‐microtubule arrays are dynamically assembled and disassembled. © 2023 Wiley Periodicals LLC. Basic Protocol: Sample preparation and real‐time visualization of microtubule arrays by atomic force microscopy Alternate Protocol: Protocol for coating surface with poly‐L‐lysine and immobilizing microtubules

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Section: Introductionmentioning

confidence: 99%

Real‐Time Visualization of Microtubule and Protofilament‐Scale Dynamics in Multi‐Microtubule Arrays by Atomic Force Microscopy

Wijeratne

Subramanian

2023

Current Protocols

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“…The constitutive relationship between local stress and microtubules dynamics was devised from recent experiments showing that a tensile force up to ~10 pN increases the polymerization rate and the rescue frequency but decreases the depolymerization rate and the catastrophe frequency (39). The range of stress on the cell wall that we estimated from the previous FE model is [3][4][5][6][7][8][9][10][11][12][13][14][15]. If microtubules feel this large stress directly, the magnitude of forces from the stress is far beyond level that microtubules can sustain without rupturing (46).…”

Section: Constitutive Relationship Between Local Stress and Microtubu...mentioning

confidence: 99%

“…The collision-induced catastrophe and zippering are known to mediate ordered cortical microtubule arrays emerging at cellular scales. It was shown that a balance between steep-angle catastrophe and shallow-angle zippering are necessary and sufficient for promoting self-organization and parallel configuration of microtubules (9, 15). Regardless of collision, microtubules undergoing rapid shrinkage can transition to a growth state, which is called rescue.…”

Section: Introductionmentioning

confidence: 99%

Probing stress-regulated ordering of the plant cortical microtubule array via a computational approach

Szymanski

Kim

2022

Preprint

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Functional properties of cells, tissues, and organs rely on predictable growth outputs. A shape change in plant cells is determined by properties of a tough cell wall that deforms anisotropically in response to high turgor pressure. This morphogenesis requires tight coordination and feedback controls among cytoskeleton-dependent wall patterning, its material properties, and stresses in the wall. Cortical microtubules bias the mechanical anisotropy of cell wall by defining the trajectories of cellulose synthase motility as they polymerize bundled microfibrils in their wake. Cortical microtubules could locally align and orient relative to cell geometry; however, the means by this orientation occurs is not known. Correlations between the microtubule orientation, cell geometry, and predicted tensile forces are strongly established, and here we simulate how different attributes of tensile force can orient and pattern the microtubule array in the cortex. We implemented a discrete model with three-state transient microtubule behaviors influenced by local mechanical stress in order to probe the mechanisms of stress-dependent patterning. We varied the sensitivity of four types of dynamic behaviors observed on the plus ends of microtubules - growth, shrinkage, catastrophe, and rescue - to local stress and then evaluated the extent and rate of microtubule alignments in a square computational domain. We optimized constitutive relationships between local stress and the plus-end dynamics and employed a biomechanically well-characterized cell wall to analyze how stress can influence the density and orientation of microtubule arrays. Our multiscale modeling approaches predict that spatial variability in stress magnitude and anisotropy mediate mechanical feedback between the wall and organization of the cortical microtubule array.

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“…The response of the MT lattice to a crushing force (possibly induced by a severing enzyme) and healing from the breakage have been understood using coarse-grained molecular dynamics simulation [55]. A recent review [56] has proposed two mechanisms to understand severing-induced MT amplification. Firstly, there can be competition between tubulin addition and tubulin dissociation by severing enzymes.…”

Section: Introductionmentioning

confidence: 99%

Computer simulation reveals the effect of severing enzymes on dynamic and stabilized microtubules

Sen

Kunwar

2023

Phys. Biol.

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Microtubule severing enzymes Katanin and Spastin cut the microtubule (MT) into smaller fragments and are being studied extensively using in-vitro experiments due to their crucial role in different cancers andneurodevelopmental disorders. It has been reported that the severing enzymes are either involved in increasing or decreasing the tubulin mass. Currently, there are a few analytical and computational models for MT amplification and severing. However, these models do not capture the action of microtubule severing explicitly, as these are based on partial differential equations in one dimension. On the other hand, a few discrete lattice-based models were used earlier to understand the activity of severing enzymes only on stabilized MTs. Hence, in this study, discrete lattice-based Monte Carlo models that included microtubule dynamics and severing enzyme activity have been developed to understand the effect of severing enzymes on tubulin mass, MT number, and MT length. It was found that the action of severing enzyme reduces average MT length while increasing their number; however, the total tubulin mass can decrease or increase depending on the concentration of GMPCPP (Guanylyl-(α, β)-methylene-diphosphonate) - which is a slowly hydrolyzable analogue of GTP (Guanosine triphosphate). Further, relative tubulin mass also depends on the detachment ratio of GTP/GMPCPP and GDP (Guanosine diphosphate) tubulin dimers and the binding energies oftubulin dimers covered by the severing enzyme.

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Micron-scale geometrical features of microtubules as regulators of microtubule organization

Cited by 12 publications

References 188 publications

Real‐Time Visualization of Microtubule and Protofilament‐Scale Dynamics in Multi‐Microtubule Arrays by Atomic Force Microscopy

Real‐Time Visualization of Microtubule and Protofilament‐Scale Dynamics in Multi‐Microtubule Arrays by Atomic Force Microscopy

Probing stress-regulated ordering of the plant cortical microtubule array via a computational approach

Computer simulation reveals the effect of severing enzymes on dynamic and stabilized microtubules

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