Grega-Larson Nathan E, Crawley Scott W, Tyska Matthew J
Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee.
Cytoskeleton (Hoboken). 2016 Nov;73(11):670-679. doi: 10.1002/cm.21317. Epub 2016 Aug 22.
Cordon-bleu (COBL) is a multifunctional WASP-Homology 2 (WH2) domain-containing protein implicated in a wide variety of cellular functions ranging from dendritic arborization in neurons to the assembly of microvilli on the surface of transporting epithelial cells. In vitro biochemical studies suggest that COBL is capable of nucleating and severing actin filaments, among other activities. How the multiple activities of COBL observed in vitro contribute to its function in cells remains unclear. Here, we used live imaging to evaluate the impact of COBL expression on the actin cytoskeleton in cultured cells. We found that COBL induces the formation of dynamic linear actin structures throughout the cytosol. We also found that stabilizing these dynamic structures with the parallel actin-bundling protein espin slows down their turnover and enables the robust formation of self-supported protrusions on the dorsal cell surface. Super-resolution imaging revealed a global remodeling of the actin cytoskeleton in cells expressing these two factors. Taken together, these results provide insight as to how COBL contributes to the assembly of actin-based structures such as epithelial microvilli. © 2016 Wiley Periodicals, Inc.
蓝带蛋白（COBL）是一种多功能蛋白，含有WASP同源2（WH2）结构域，参与多种细胞功能，从神经元的树突分支到运输上皮细胞表面微绒毛的组装。体外生化研究表明，COBL除其他活性外，还能够使肌动蛋白丝成核并切断肌动蛋白丝。在体外观察到的COBL的多种活性如何在细胞中发挥作用仍不清楚。在这里，我们使用实时成像来评估COBL表达对培养细胞中肌动蛋白细胞骨架的影响。我们发现COBL在整个细胞质中诱导动态线性肌动蛋白结构的形成。我们还发现，用平行肌动蛋白束蛋白espin稳定这些动态结构会减慢它们的周转，并能在细胞背表面强力形成自支撑突起。超分辨率成像揭示了表达这两种因子的细胞中肌动蛋白细胞骨架的整体重塑。综上所述，这些结果为COBL如何促进基于肌动蛋白的结构（如上皮微绒毛）的组装提供了见解。©2016威利期刊公司。
