Contribution of cytoplasm viscoelastic properties to mitotic spindle positioning.
Contribution of cytoplasm viscoelastic properties to mitotic spindle positioning.
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DOI：
10.1073/pnas.2115593119
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发表时间：
2022-02-22
影响因子：
11.1
通讯作者：
Minc N
中科院分区：
文献类型：
--
作者：
Xie J;Najafi J;Le Borgne R;Verbavatz JM;Durieu C;Sallé J;Minc N
有丝分裂纺锤体定位的调节是组织结构、胚胎发育和干细胞的关键过程。迄今为止，大多数模型都假设纺锤体是由极性细胞骨架网络（如微管星形细胞或肌动球蛋白束）施加的力定位的。在这里，使用原位磁镊子施加校准的力和扭矩有丝分裂的纺锤体在活的海胆细胞，我们发现，粘弹性的细胞质介质中，纺锤体嵌入可以保持纺锤体在适当的位置，并将它们移回，如果他们原来的位置被扰动。这些粘弹力很大，可能显著参与了许多细胞类型中有丝分裂纺锤体定位和定向的力平衡。细胞充满了大分子和聚合物网络，这些网络为细胞质设置了尺度依赖的粘性和弹性特性。尽管这些参数在分子扩散、反应动力学和细胞生物化学中的作用正日益被人们所认识，但它们对较大细胞器（如细胞分裂的有丝分裂纺锤体）的运动和定位的贡献仍然未知。在这里，使用磁性镊子来取代和旋转活胚胎中的有丝分裂纺锤体，我们发现细胞质可以赋予粘弹性反应力，将纺锤体或类似大小的被动物体移回其原始位置。这些力量是独立的细胞骨架力发电机，但达到数百微微牛顿和规模与细胞质拥挤。纺锤体运动剪切和流化细胞质，耗散弹性能和限制纺锤体反冲与功能的影响不对称和定向分裂。这些研究结果表明，散装细胞质材料的性能可能构成重要的控制元件，为调节分裂定位和细胞组织。
The regulation of mitotic spindle positioning is a key process for tissue architecture, embryo development, and stem cells. To date, most models have assumed that spindles are positioned by forces exerted by polar cytoskeleton networks, like microtubule asters or actomyosin bundles. Here, using in situ magnetic tweezers to apply calibrated forces and torques to mitotic spindles in live dividing sea urchin cells, we found that the viscoelastic properties of the cytoplasm medium in which spindles are embedded can hold spindles in place and move them back if their original position is perturbed. These viscoelastic forces are large and may significantly participate in the force balance that position and orient mitotic spindles in many cell types. Cells are filled with macromolecules and polymer networks that set scale-dependent viscous and elastic properties to the cytoplasm. Although the role of these parameters in molecular diffusion, reaction kinetics, and cellular biochemistry is being increasingly recognized, their contributions to the motion and positioning of larger organelles, such as mitotic spindles for cell division, remain unknown. Here, using magnetic tweezers to displace and rotate mitotic spindles in living embryos, we uncovered that the cytoplasm can impart viscoelastic reactive forces that move spindles, or passive objects with similar size, back to their original positions. These forces are independent of cytoskeletal force generators yet reach hundreds of piconewtons and scale with cytoplasm crowding. Spindle motion shears and fluidizes the cytoplasm, dissipating elastic energy and limiting spindle recoils with functional implications for asymmetric and oriented divisions. These findings suggest that bulk cytoplasm material properties may constitute important control elements for the regulation of division positioning and cellular organization.
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影响因子：
16.6
作者：
De Simone, A.;Spahr, A.;Gonczy, P.
通讯作者：
Gonczy, P.
影响因子：
2
作者：
Howard, J
通讯作者：
Howard, J
影响因子：
56.9
作者：
Grill, SW;Howard, J;Hyman, A
通讯作者：
Hyman, A
影响因子：
3.7
作者：
ASNES, CF;SCHROEDER, TE
通讯作者：
SCHROEDER, TE
影响因子：
3.7
作者：
CRICK, FHC;HUGHES, AFW
通讯作者：
HUGHES, AFW