Institut Curie, Centre de Recherche, Paris, France.
Biophys J. 2010 Oct 20;99(8):2423-33. doi: 10.1016/j.bpj.2010.07.065.
Stereocilia are actin-based cellular protrusions essential for hearing. We propose that they are shaped by the detachment dynamics of actin cross-linkers, in particular espin. We account for experimentally observed stereocilium shapes, treadmilling velocity to length relationship, espin 1 localization profile, and microvillus length to espin level relationship. If the cross-linkers are allowed to reattach, our model yields a dynamical phase transition toward unbounded growth. Considering the simplified case of a noninteracting, one-filament system, we calculate the length probability distribution in the growing phase and its stationary form in a continuum approximation of the finite-length phase. Numerical simulations of interacting filaments suggest an anomalous power-law divergence of the protrusion length at the growth transition, which could be a universal feature of cross-linked depolymerizing systems.
纤毛是一种基于肌动蛋白的细胞突起，对于听觉至关重要。我们提出，它们的形状是由肌动蛋白交联剂（特别是 espin）的脱离动力学决定的。我们解释了实验观察到的纤毛形状、 treadmilling 速度与长度的关系、espin 1 定位分布以及微绒毛长度与 espin 水平的关系。如果交联剂允许重新附着，我们的模型将发生向无界生长的动力学相变。在非相互作用的单丝系统的简化情况下，我们计算了生长阶段的长度概率分布及其在有限长度阶段的连续近似中的稳定形式。相互作用的细丝的数值模拟表明，在生长转变处突起长度呈异常幂律发散，这可能是交联解聚系统的普遍特征。
