Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, James-Franck-Ring N27, 89081 Ulm, Germany.
J Cell Sci. 2012 Sep 1;125(Pt 17):4103-13. doi: 10.1242/jcs.105320. Epub 2012 May 23.
An understanding of cytokinesis at the molecular level requires a detailed description of the protein complexes that perform central activities during this process. The proteins Hof1p, Cyk3p, Inn1p and Myo1p each represent one of the four genetically defined and partially complementary pathways of cytokinesis in the yeast Saccharomyces cerevisiae. Here we show that the osmosensor Sho1p is required for correct cell-cell separation. Shortly before cytokinesis Sho1p sequentially assembles with Hof1p, Inn1p and Cyk3p, into a complex (the HICS complex) that might help to connect the membrane with the actin-myosin ring. The HICS complex is formed exclusively through interactions between three SH3 domains located in Cyk3p, Hof1p and Sho1p, and five acceptor sites found in Cyk3p, Hof1p and Inn1p. Owing to the overlapping binding specificities of its members the HICS complex is best described as ensembles of isomeric interaction states that precisely coordinate the different functions of the interactors during cytokinesis.
要深入了解细胞分裂的分子机制，需要详细描述在这个过程中发挥核心作用的蛋白复合物。Hof1p、Cyk3p、Inn1p 和 Myo1p 这四种蛋白分别代表酿酒酵母细胞分裂的四个遗传上定义的、部分互补的途径之一。在这里，我们发现渗透压感受器 Sho1p 对于细胞间的正确分离是必需的。在细胞分裂前不久，Sho1p 依次与 Hof1p、Inn1p 和 Cyk3p 形成一个复合物（HICS 复合物），该复合物可能有助于将膜与肌动球蛋白环连接起来。HICS 复合物仅通过位于 Cyk3p、Hof1p 和 Sho1p 中的三个 SH3 结构域与 Cyk3p、Hof1p 和 Inn1p 中发现的五个接受位点之间的相互作用形成。由于其成员的重叠结合特异性，HICS 复合物最好被描述为同型相互作用状态的集合，这些状态在细胞分裂过程中精确协调了相互作用因子的不同功能。
