Department of Mathematics, Department of Mathematical and Life Sciences, Graduate School of Integrated Science for Life, Hiroshima University, Kagamiyama 1-3-1, Hiroshima, 700-0046, Japan.
Bull Math Biol. 2021 Feb 17;83(4):29. doi: 10.1007/s11538-021-00860-0.
In the process of asymmetric cell division, the mother cell induces polarity in both the membrane and the cytosol by distributing substrates and components asymmetrically. Such polarity formation results from the harmonization of the upstream and downstream polarities between the cell membrane and the cytosol. MEX-5/6 is a well-investigated downstream cytoplasmic protein, which is deeply involved in the membrane polarity of the upstream transmembrane protein PAR in the Caenorhabditis elegans embryo. In contrast to the extensive exploration of membrane PAR polarity, cytoplasmic polarity is poorly understood, and the precise contribution of cytoplasmic polarity to the membrane PAR polarity remains largely unknown. In this study, we explored the interplay between the cytoplasmic MEX-5/6 polarity and the membrane PAR polarity by developing a mathematical model that integrates the dynamics of PAR and MEX-5/6 and reflects the cell geometry. Our investigations show that the downstream cytoplasmic protein MEX-5/6 plays an indispensable role in causing a robust upstream PAR polarity, and the integrated understanding of their interplay, including the effect of the cell geometry, is essential for the study of polarity formation in asymmetric cell division.
在不对称细胞分裂过程中，母细胞通过不对称地分配基质和成分在细胞膜和细胞质中诱导极性。这种极性的形成是由于细胞膜和细胞质之间的上游和下游极性的协调。MEX-5/6 是一种研究得很好的下游细胞质蛋白，它深入参与了秀丽隐杆线虫胚胎中跨膜蛋白 PAR 的膜极性。与对膜 PAR 极性的广泛探索相比，细胞质极性的理解很差，细胞质极性对膜 PAR 极性的精确贡献在很大程度上仍然未知。在这项研究中，我们通过开发一个整合了 PAR 和 MEX-5/6 的动力学并反映细胞几何形状的数学模型，探索了细胞质 MEX-5/6 极性和膜 PAR 极性之间的相互作用。我们的研究表明，下游细胞质蛋白 MEX-5/6 在引起强大的上游 PAR 极性方面起着不可或缺的作用，对它们相互作用的综合理解，包括细胞几何形状的影响，对于不对称细胞分裂中极性形成的研究至关重要。
