We have discovered that basement membrane and its major components can induce rapid, strikingly robust fibronectin organization. In this new matrix assembly mechanism, α5β1 integrin-based focal adhesions slide actively on the underlying matrix toward the ventral cell center through the dynamic shortening of myosin IIA-associated actin stress fibers to drive rapid fibronectin fibrillogenesis distal to the adhesion. This mechanism contrasts with classical fibronectin assembly based on stable or fixed-position focal adhesions containing αVβ3 integrins plus α5β1 integrin translocation into proximal fibrillar adhesions. On basement membrane components, these sliding focal adhesions contain standard focal adhesion constituents but completely lack classical αVβ3 integrins. Instead, peripheral α3β1 or α2β1 adhesions mediate initial cell attachment but over time are switched to α5β1 integrin-based sliding focal adhesions to assemble fibronectin matrix. This basement-membrane-triggered mechanism produces rapid fibronectin fibrillogenesis, providing a mechanistic explanation for the well-known widespread accumulation of fibronectin at many organ basement membranes.

中文翻译：

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基底膜使用由收缩绞盘驱动的滑动粘连来调节纤连蛋白组织。

我们发现基底膜及其主要成分可以诱导快速、惊人的强健纤连蛋白组织。在这种新的基质组装机制中，基于 α5β1 整联蛋白的粘着斑通过肌球蛋白 IIA 相关肌动蛋白应力纤维的动态缩短在底层基质上主动向腹侧细胞中心滑动，以驱动粘连远端的快速纤连蛋白原纤维生成。这种机制与基于稳定或固定位置粘着斑的经典纤连蛋白组装形成对比，该粘着斑含有 αVβ3 整联蛋白加 α5β1 整联蛋白易位到近端纤维粘连。在基底膜组件上，这些滑动粘着斑包含标准粘着斑成分，但完全缺乏经典的 αVβ3 整合素。反而，外周 α3β1 或 α2β1 粘附介导初始细胞粘附，但随着时间的推移被切换到基于 α5β1 整合素的滑动粘着斑以组装纤连蛋白基质。这种基底膜触发机制产生快速的纤连蛋白原纤维生成，为众所周知的纤连蛋白在许多器官基底膜上的广泛积累提供了机制解释。