胞质分裂过程中磷脂分子重分布的机制及影响

Mechanism and effect of membrane phospholipid redistribution in cytokinesis

目的探究真核细胞在有丝分裂过程中,生化刺激与细胞大变形行为之间的关系。方法根据大量来自实验的结论,构建一个基于Zinemanas and Nir模型的生化刺激和力学行为耦合的模型。在这个模型中考虑到,第一,膜上各点接受的生化刺激在膜表面形成了梯度,此梯度驱动磷脂蛋白分子沿表面运动;第二,局部肌动微丝和肌球微丝的聚合取决于膜上同一点的磷脂分子的数目;第三,表面张力包括两个部分:一个是由于膜的被动变形引起的被动张力,另一个是主动微丝收缩引起主动张力,它取决于微丝的重分布和重排列。给出多相共同边界条件,采用边界积分法进行数值计算。结果引入生化刺激后,解释了胞质分裂前期收缩环形成,尝试解释了整个过程中微丝的动态变化,较好的模拟了整个分裂过程。结论磷脂分子的重取向以及微丝的重分布和重取向在细胞分裂过程中具有重要作用。生化刺激的引入使模型描述的细胞分裂过程与实际更为接近。

Objective To explore the relation between the biochemical stimulus and big deformation during cytokinesis in eukaryotes. Methods Basis on many experiment data, A new model is proposed in this study to simulate the entire process by coupling the biochemical stimulus with the mechanical actions based on Zinemanas and Nir ’s hydrodynamic model. There were three assumptions in this model, ie. the movements of phospholipid proteins are driven by gradients of biochemical stimulus on the membrane surface, the local assembly of actin and myosin filament lies on the amount of phospholipid proteins at the same location, and the surface tension includes membrane tensions due to both the passive deformation of membrane and the active contraction of actin filament which is determined by microfilaments redistribution and rearrangement. Results These calculated results from this model showed that the contractile ring formed on early, microfilaments and the cell deformation dynamical varied during cytokinesis. Conclusion The model demonstrated that the reorientation of phospholipid proteins and the redistribution and reorientation of microfilaments may play a crucial role in cell division. This model may better represent the cytokinesis process by the introduction of biochemical stimulus.