SynthSys, Centre for Synthetic and Systems Biology, Institute for Cell Biology, University of Edinburgh, Edinburg EH9 3BD, UK.
Cells. 2020 Sep 1;9(9):2011. doi: 10.3390/cells9092011.
Cellular morphogenesis is governed by the prepattern based on the symmetry-breaking emergence of dense protein clusters. Thus, a cluster of active GTPase Cdc42 marks the site of nascent bud in the baker's yeast. An important biological question is which mechanisms control the number of pattern maxima (spots) and, thus, the number of nascent cellular structures. Distinct flavors of theoretical models seem to suggest different predictions. While the classical Turing scenario leads to an array of stably coexisting multiple structures, mass-conserved models predict formation of a single spot that emerges via the greedy competition between the pattern maxima for the common molecular resources. Both the outcome and the kinetics of this competition are of significant biological importance but remained poorly explored. Recent theoretical analyses largely addressed these questions, but their results have not yet been fully appreciated by the broad biological community. Keeping mathematical apparatus and jargon to the minimum, we review the main conclusions of these analyses with their biological implications in mind. Focusing on the specific example of pattern formation by small GTPases, we speculate on the features of the patterning mechanisms that bypass competition and favor formation of multiple coexisting structures and contrast them with those of the mechanisms that harness competition to form unique cellular structures.
细胞形态发生受基于密集蛋白簇的对称破缺出现的预图案控制。因此，在面包酵母中，活跃的 GTPase Cdc42 簇标记了新出现芽的位置。一个重要的生物学问题是哪些机制控制模式极大值（斑点）的数量，从而控制新出现的细胞结构的数量。不同类型的理论模型似乎给出了不同的预测。虽然经典的 Turing 情景导致一系列稳定共存的多个结构，但质量守恒模型预测形成单个斑点，这是通过模式极大值对共同分子资源的贪婪竞争而出现的。这种竞争的结果和动力学都具有重要的生物学意义，但仍未得到充分探索。最近的理论分析在很大程度上解决了这些问题，但它们的结果尚未被广泛的生物学界完全理解。我们尽可能地减少数学工具和术语，在考虑其生物学意义的基础上，回顾这些分析的主要结论。我们以小 GTPase 模式形成的具体示例为重点，推测了规避竞争并有利于形成多个共存结构的模式形成机制的特征，并将其与利用竞争形成独特细胞结构的机制的特征进行了对比。
