Tang Haosu, Bidone Tamara C, Vavylonis Dimitrios
Department of Physics, Lehigh University, Bethlehem, Pennsylvania, 18105, USA.
Cytoskeleton (Hoboken). 2015 Oct;72(10):517-33. doi: 10.1002/cm.21258. Epub 2015 Nov 5.
The budding yeast actin cables and contractile ring are important for polarized growth and division, revealing basic aspects of cytoskeletal function. To study these formin-nucleated structures, we built a three-dimensional (3D) computational model with actin filaments represented as beads connected by springs. Polymerization by formins at the bud tip and bud neck, crosslinking, severing, and myosin pulling, are included. Parameter values were estimated from prior experiments. The model generates actin cable structures and dynamics similar to those of wild type and formin deletion mutant cells. Simulations with increased polymerization rate result in long, wavy cables. Simulated pulling by type V myosin stretches actin cables. Increasing the affinity of actin filaments for the bud neck together with reduced myosin V pulling promotes the formation of a bundle of antiparallel filaments at the bud neck, which we suggest as a model for the assembly of actin filaments to the contractile ring.
出芽酵母的肌动蛋白电缆和收缩环对于极化生长和分裂很重要，揭示了细胞骨架功能的基本方面。为了研究这些由formin蛋白成核的结构，我们构建了一个三维（3D）计算模型，其中肌动蛋白丝被表示为由弹簧连接的珠子。该模型包括formin蛋白在芽尖和芽颈处的聚合、交联、切断以及肌球蛋白的拉动。参数值是根据先前的实验估计的。该模型生成的肌动蛋白电缆结构和动力学与野生型和formin缺失突变细胞的相似。聚合速率增加的模拟结果产生长而波浪状的电缆。V型肌球蛋白的模拟拉动会拉伸肌动蛋白电缆。增加肌动蛋白丝对芽颈的亲和力并减少肌球蛋白V的拉动，会促进在芽颈处形成一束反平行丝，我们将其作为肌动蛋白丝组装到收缩环的模型。
