Ozawa Kentaro, Taomori Hirotaka, Hoshida Masayuki, Kunita Ituki, Sakurazawa Sigeru, Honda Hajime
Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan.
Department of Information Engineering, University of the Ryukyus, Nakagami-gun, Okinawa 903-0213, Japan.
Biophys Physicobiol. 2019 Jan 9;16:1-8. doi: 10.2142/biophysico.16.0_1. eCollection 2019.
The movements of single actin filaments along a myosin-fixed glass surface were observed under a conventional fluorescence microscope. Although random at a low concentration, moving directions of filaments were aligned by the presence of over 1.0 mg/mL of unlabeled filaments. We found that actin filaments when at the intermediate concentrations ranging from 0.1 to 1.0 mg/mL, formed winding belt-like patterns and moved in a two-directional manner along the belts. These patterns were spread over a millimeter range and found to have bulged on the glass in a three-dimensional manner. Filaments did not get closer than about 37.5 nm to each other within each belt-pattern. The average width and the curvature radius of the pattern did not apparently change even when the range of actin concentrations was between 0.05 and 1.0 mg/mL or the sliding velocity between 1.2 and 3.2 μm/sec. However, when the length of filaments was shortened by ultrasonic treatments or the addition of gelsolin molecules, the curvature radius became small from 100 to 60 μm. These results indicate that this belt-forming nature of actin filaments may be due to some inter-filament interactions.
在传统荧光显微镜下观察了单根肌动蛋白丝在固定有肌球蛋白的玻璃表面上的运动。尽管在低浓度时是随机的，但当未标记的肌动蛋白丝浓度超过1.0 mg/mL时，肌动蛋白丝的运动方向会排列整齐。我们发现，当肌动蛋白丝浓度处于0.1至1.0 mg/mL的中间浓度范围时，会形成蜿蜒的带状图案，并沿这些带双向移动。这些图案在毫米范围内展开，并在玻璃上以三维方式凸起。在每个带状图案内，肌动蛋白丝彼此之间的距离不会小于约37.5 nm。即使肌动蛋白浓度范围在0.05至1.0 mg/mL之间或滑动速度在1.2至3.2μm/秒之间，图案的平均宽度和曲率半径也没有明显变化。然而，当通过超声处理或添加凝溶胶蛋白分子使肌动蛋白丝长度缩短时，曲率半径会从100μm减小到60μm。这些结果表明，肌动蛋白丝的这种带状形成特性可能归因于一些丝间相互作用。
