Direct observations of the mechanical behaviors of the cytoskeleton in living fibroblasts.
Direct observations of the mechanical behaviors of the cytoskeleton in living fibroblasts.
复制标题
直接观察活细胞骨架的机械行为。
DOI：
10.1083/jcb.145.1.109
复制
发表时间：
1999-04-05
影响因子：
7.8
通讯作者：
Matus, A
中科院分区：
文献类型：
--
作者：
Heidemann, S R;Kaech, S;Buxbaum, R E;Matus, A
用绿色荧光蛋白标记的细胞骨架蛋白直接可视化细胞骨架在决定细胞形状中的机械作用。用玻璃针对大鼠胚胎成纤维细胞（REF 52）进行变形，这些玻璃针要么不涂覆，用于纯粹的物理操作，要么涂覆层粘连蛋白，以诱导与细胞表面的附着。细胞对未包被探针的反应与三层模型一致，在三层模型中，高弹性的细胞核被细胞质微管包围，其表现为果冻状的粘弹性流体。第三，最外层皮层是持续张力下的弹性壳。粘接的，层粘连蛋白涂层的针引起肌动蛋白丝在接触表面区域的局灶性招募，并增加了皮质层的刚度。这种肌动蛋白募集的直接可视化证实了细胞外基质蛋白和肌动蛋白细胞骨架之间机械连接的广泛假设模型。连接在层粘连蛋白处理过的针上的细胞通过主动收缩强烈地抵抗伸长。无论是使用未涂覆的探针施加简单的变形还是层粘连蛋白涂覆的探针来诱导表面与细胞骨架的相互作用，我们观察到实验施加的力只产生肌动蛋白和微管细胞骨架的局部反应。这种局部调节和耗散力与细胞张拉整体决定细胞形状的建议不一致。
Cytoskeletal proteins tagged with green fluorescent protein were used to directly visualize the mechanical role of the cytoskeleton in determining cell shape. Rat embryo (REF 52) fibroblasts were deformed using glass needles either uncoated for purely physical manipulations, or coated with laminin to induce attachment to the cell surface. Cells responded to uncoated probes in accordance with a three-layer model in which a highly elastic nucleus is surrounded by cytoplasmic microtubules that behave as a jelly-like viscoelastic fluid. The third, outermost cortical layer is an elastic shell under sustained tension. Adhesive, laminin-coated needles caused focal recruitment of actin filaments to the contacted surface region and increased the cortical layer stiffness. This direct visualization of actin recruitment confirms a widely postulated model for mechanical connections between extracellular matrix proteins and the actin cytoskeleton. Cells tethered to laminin-treated needles strongly resisted elongation by actively contracting. Whether using uncoated probes to apply simple deformations or laminin-coated probes to induce surface-to-cytoskeleton interaction we observed that experimentally applied forces produced exclusively local responses by both the actin and microtubule cytoskeleton. This local accomodation and dissipation of force is inconsistent with the proposal that cellular tensegrity determines cell shape.