Laboratory of Integrative Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic.
Department of Physiology, Faculty of Science, Charles University, Prague, Czech Republic.
J Cell Biol. 2022 Feb 9;221(3). doi: 10.1083/jcb.202105146.
The coordinated interplay of cytoskeletal networks critically determines tissue biomechanics and structural integrity. Here, we show that plectin, a major intermediate filament-based cytolinker protein, orchestrates cortical cytoskeletal networks in epithelial sheets to support intercellular junctions. By combining CRISPR/Cas9-based gene editing and pharmacological inhibition, we demonstrate that in an F-actin-dependent context, plectin is essential for the formation of the circumferential keratin rim, organization of radial keratin spokes, and desmosomal patterning. In the absence of plectin-mediated cytoskeletal cross-linking, the aberrant keratin-desmosome (DSM)-network feeds back to the actin cytoskeleton, which results in elevated actomyosin contractility. Also, by complementing a predictive mechanical model with Förster resonance energy transfer-based tension sensors, we provide evidence that in the absence of cytoskeletal cross-linking, major intercellular junctions (adherens junctions and DSMs) are under intrinsically generated tensile stress. Defective cytoarchitecture and tensional disequilibrium result in reduced intercellular cohesion, associated with general destabilization of plectin-deficient sheets upon mechanical stress.
细胞骨架网络的协调相互作用对组织生物力学和结构完整性至关重要。在这里，我们表明，网蛋白是一种主要的基于中间丝的细胞连接蛋白，它协调上皮片中的皮质细胞骨架网络，以支持细胞间连接。通过结合 CRISPR/Cas9 基因编辑和药理学抑制，我们证明在 F-肌动蛋白依赖性环境中，网蛋白对于形成环形角蛋白边缘、放射状角蛋白辐条的组织和桥粒图案的形成是必不可少的。在缺乏网蛋白介导的细胞骨架交联的情况下，异常的角蛋白-桥粒（DSM）网络反馈到肌动球蛋白细胞骨架，导致肌球蛋白收缩力升高。此外，通过用Förster 共振能量转移（FRET）张力传感器补充预测性机械模型，我们提供了证据表明，在缺乏细胞骨架交联的情况下，主要的细胞间连接（黏附连接和 DSM）处于内在产生的张应力下。细胞结构缺陷和张力失衡导致细胞间黏附力降低，伴随机械应力下网蛋白缺陷片的普遍不稳定性。
