Myer Nicole M, Myers Kenneth A
Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia PA 19104, USA.
Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia PA 19104, USA
Biol Open. 2017 Oct 15;6(10):1502-1515. doi: 10.1242/bio.028571.
Endothelial cell (EC) branching is critically dependent upon the dynamic nature of the microtubule (MT) cytoskeleton. Extracellular matrix (ECM) mechanosensing is a prominent mechanism by which cytoskeletal reorganization is achieved; yet how ECM-induced signaling is able to target cytoskeletal reorganization intracellularly to facilitate productive EC branching morphogenesis is not known. Here, we tested the hypothesis that the composition and density of the ECM drive the regulation of MT growth dynamics in ECs by targeting the MT stabilizing protein, cytoplasmic linker associated protein 1 (CLASP1). High-resolution fluorescent microscopy coupled with computational image analysis reveal that CLASP1 promotes slow MT growth on glass ECMs and promotes short-lived MT growth on high-density collagen-I and fibronectin ECMs. Within EC branches, engagement of either high-density collagen-I or high-density fibronectin ECMs results in reduced MT growth speeds, while CLASP1-dependent effects on MT dynamics promotes elevated numbers of short, branched protrusions that guide persistent and directed EC migration.
内皮细胞（EC）分支关键依赖于微管（MT）细胞骨架的动态特性。细胞外基质（ECM）机械传感是实现细胞骨架重组的一个突出机制；然而，ECM诱导的信号如何在细胞内靶向细胞骨架重组以促进有效的EC分支形态发生尚不清楚。在此，我们测试了这样一个假设，即ECM的组成和密度通过靶向MT稳定蛋白细胞质连接相关蛋白1（CLASP1）来驱动EC中MT生长动力学的调节。高分辨率荧光显微镜结合计算图像分析表明，CLASP1促进玻璃ECM上MT的缓慢生长，并促进高密度I型胶原和纤连蛋白ECM上MT的短暂生长。在EC分支内，高密度I型胶原或高密度纤连蛋白ECM的参与导致MT生长速度降低，而CLASP1对MT动力学的依赖性作用促进了大量短而分支的突起，这些突起引导持续且定向的EC迁移。
