Chaudhry Faisal, Jansen Silvia, Little Kristin, Suarez Cristian, Boujemaa-Paterski Rajaa, Blanchoin Laurent, Goode Bruce L
Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA, 02454, U.S.A.
Laboratoire de Physiologie Cellulaire & Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, Centre National de la Recherche Scientifique/Commissariat à l'énergie atomique et aux énergies alternatives/Institut National de la Recherche Agronomique/Université Joseph Fourier, Grenoble 38054, FRANCE.
Cytoskeleton (Hoboken). 2014 Jun;71(6):351-360. doi: 10.1002/cm.21170. Epub 2014 Apr 25.
Recent evidence has suggested that Srv2/CAP (cyclase-associated protein) has two distinct functional roles in regulating actin turnover, with its N-terminus enhancing cofilin-mediated severing of actin filaments and its C-terminus catalyzing actin monomer recycling. However, it has remained unclear to what degree these two activities are coordinated by being linked in one molecule, or whether they can function autonomously. To address this, we physically divided the protein into two separate halves, N-Srv2 and C-Srv2, and asked whether they are able to function in trans both in living cells and in reconstituted assays for F-actin turnover and actin-based motility. Remarkably, in F-actin turnover assays the stimulatory effects of N-Srv2 and C-Srv2 functioning in trans were quantitatively similar to those of intact full-length Srv2. Further, in bead motility assays and in vivo, the fragments again functioned in trans, although not with the full effectiveness of intact Srv2. From these data, we conclude that the functions of the two halves of Srv2/CAP are largely autonomous, although their linkage improves coordination of the two functions in specific settings, possibly explaining why the linkage is conserved across distant plant, animal, and fungal species.
最近的证据表明，Srv2/CAP（环化酶相关蛋白）在调节肌动蛋白周转方面具有两种不同的功能作用，其N端增强了cofilin介导的肌动蛋白丝切断作用，而其C端催化肌动蛋白单体循环利用。然而，目前尚不清楚这两种活性在一个分子中通过连接的方式协调到何种程度，或者它们是否能够自主发挥功能。为了解决这个问题，我们将该蛋白物理分割成两个独立的部分，即N-Srv2和C-Srv2，并研究它们在活细胞以及F-肌动蛋白周转和基于肌动蛋白的运动性的重组实验中是否能够反式发挥功能。值得注意的是，在F-肌动蛋白周转实验中，反式发挥功能的N-Srv2和C-Srv2的刺激作用在数量上与完整全长Srv2的刺激作用相似。此外，在珠粒运动实验和体内实验中，这些片段再次能够反式发挥功能，尽管其效果不如完整的Srv2。根据这些数据，我们得出结论，Srv2/CAP的两个部分的功能在很大程度上是自主的，尽管它们的连接在特定情况下改善了这两种功能的协调性，这可能解释了为什么这种连接在遥远的植物、动物和真菌物种中得以保留。
