Travis J L, Kenealy J F, Allen R D
J Cell Biol. 1983 Dec;97(6):1668-76. doi: 10.1083/jcb.97.6.1668.
Lamellipodia have been induced to form within the reticulopodial networks of Allogromia laticollaris by being plated on positively charged substrata. Video-enhanced, polarized light, and differential interference contrast microscopy have demonstrated the presence of positively birefringent fibrils within these lamellipodia. The fibrils correspond to the microtubules and bundles of microtubules observed in whole-mount transmission electron micrographs of lamellipodia. Microtubular fibrils exhibit two types of movements within the lamellipodia: lateral and axial translocations. Lateral movements are often accompanied by reversible lateral associations between adjacent fibrils within a lamellipodium. This lateral association-dissociation of adjacent fibrils has been termed 'zipping' and 'unzipping'. Axial translocations are bidirectional. The axial movements of the microtubular fibrils can result in the extension of filopodia by pushing against the plasma membrane of the lamellipodia. Shortening, or complete withdrawal, of such filopodia is accomplished by the reversal of the direction of the axial movement. The bidirectional streaming characteristic of the reticulopodial networks also occurs within the lamellipodia. In these flattened regions the streaming is clearly seen to occur exclusively in association with the intracellular fibrils. Transport of both organelles and bulk hyaline cytoplasm occurs bidirectionally along the fibrils.
通过将其接种在带正电荷的基质上，在大颈异网菌的网状伪足网络内诱导形成片状伪足。视频增强、偏振光和微分干涉对比显微镜已证明这些片状伪足内存在正双折射纤维。这些纤维与在片状伪足的整装透射电子显微照片中观察到的微管和微管束相对应。微管纤维在片状伪足内表现出两种运动类型：横向和轴向移位。横向运动通常伴随着片状伪足内相邻纤维之间可逆的横向结合。相邻纤维的这种横向结合 - 解离被称为“拉链式”和“解拉链式”。轴向移位是双向的。微管纤维的轴向运动可通过推动片状伪足的质膜导致丝状伪足的延伸。这种丝状伪足的缩短或完全缩回是通过轴向运动方向的反转来完成的。网状伪足网络的双向流动特征也发生在片状伪足内。在这些扁平区域，明显可见流动仅与细胞内纤维相关。细胞器和大量透明细胞质都沿纤维双向运输。
