Versaevel Marie, Braquenier Jean-Baptiste, Riaz Maryam, Grevesse Thomas, Lantoine Joséphine, Gabriele Sylvain
Mechanobiology &Soft Matter Group, Interfaces and Complex Fluids Laboratory, Research Institute for Biosciences, CIRMAP, University of Mons, 20 Place du Parc B-7000 Mons, Belgium.
Nikon Belux Instruments, 50 B Avenue du Bourget, B-1130 Brussels, Belgium.
Sci Rep. 2014 Dec 8;4:7362. doi: 10.1038/srep07362.
Increasing evidences show that the actin cytoskeleton is a key parameter of the nuclear remodeling process in response to the modifications of cellular morphology. However, detailed information on the interaction between the actin cytoskeleton and the nuclear lamina was still lacking. We addressed this question by constraining endothelial cells on rectangular fibronectin-coated micropatterns and then using Structured Illumination Microscopy (SIM) to observe the interactions between actin stress fibers, nuclear lamina and LINC complexes at a super-resolution scale. Our results show that tension in apical actin stress fibers leads to deep nuclear indentations that significantly deform the nuclear lamina. Interestingly, indented nuclear zones are characterized by a local enrichment of LINC complexes, which anchor apical actin fibers to the nuclear lamina. Moreover, our findings indicate that nuclear indentations induce the formation of segregated domains of condensed chromatin. However, nuclear indentations and condensed chromatin domains are not irreversible processes and both can relax in absence of tension in apical actin stress fibers.
越来越多的证据表明，肌动蛋白细胞骨架是细胞形态发生改变时核重塑过程的关键参数。然而，关于肌动蛋白细胞骨架与核纤层之间相互作用的详细信息仍然缺乏。我们通过将内皮细胞限制在矩形纤连蛋白包被的微图案上，然后使用结构照明显微镜（SIM）在超分辨率尺度下观察肌动蛋白应力纤维、核纤层和LINC复合体之间的相互作用，来解决这个问题。我们的结果表明，顶端肌动蛋白应力纤维中的张力会导致核深度凹陷，使核纤层发生显著变形。有趣的是，凹陷的核区域的特征是LINC复合体局部富集，LINC复合体将顶端肌动蛋白纤维锚定到核纤层上。此外，我们的研究结果表明，核凹陷会诱导凝聚染色质分离域的形成。然而，核凹陷和凝聚染色质域不是不可逆的过程，在顶端肌动蛋白应力纤维不存在张力的情况下，两者都可以松弛。
