Shekhar Nandini, Neelam Srujana, Wu Jun, Ladd Anthony Jc, Dickinson Richard B, Lele Tanmay P
Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
Cell Mol Bioeng. 2013 Jun 1;6(2):120-129. doi: 10.1007/s12195-013-0281-z.
Despite their rigidity, microtubules in living cells bend significantly during polymerization resulting in greater curvature than can be explained by thermal forces alone. However, the source of the non-thermal forces that bend growing microtubules remains obscure. We analyzed the motion of microtubule tips in NIH-3T3 fibroblasts expressing EGFP-EB1, a fluorescent +TIP protein that specifically binds to the growing ends of microtubules. We found that dynein inhibition significantly reduced the deviation of the growing tip from its initial trajectory. Inhibiting myosin modestly reduced tip fluctuations, while simultaneous myosin and dynein inhibition caused no further decrease in fluctuations compared to dynein inhibition alone. Our results can be interpreted with a model in which dynein linkages play a key role in generating and transmitting fluctuating forces that bend growing microtubules.
尽管微管具有刚性，但活细胞中的微管在聚合过程中会显著弯曲，其曲率大于仅由热力所能解释的程度。然而，使正在生长的微管弯曲的非热力来源仍不清楚。我们分析了在表达EGFP-EB1的NIH-3T3成纤维细胞中微管尖端的运动，EGFP-EB1是一种荧光+TIP蛋白，它特异性地结合到微管的生长末端。我们发现，动力蛋白抑制显著降低了生长尖端与其初始轨迹的偏差。抑制肌球蛋白适度降低了尖端波动，而与单独抑制动力蛋白相比，同时抑制肌球蛋白和动力蛋白并没有使波动进一步降低。我们的结果可以用一个模型来解释，在这个模型中，动力蛋白连接在产生和传递使正在生长的微管弯曲的波动力量中起关键作用。
