Asymmetric cell division (ACD) is a cellular process that forms two different cell types through a cell division and is thus critical for the development of all multicellular organisms. Not all but many of the ACD processes are mediated by proper orientation of the mitotic spindle, which segregates the fate determinants asymmetrically into daughter cells. In many cell types, the evolutionarily conserved protein complex of Gαi/AGS-family protein/NuMA-like protein appears to play critical roles in orienting the spindle and/or generating the polarized cortical forces to regulate ACD. Studies in various organisms reveal that this conserved protein complex is slightly modified in each phylum or even within species. In particular, AGS-family proteins appear to be modified with a variable number of motifs in their functional domains across taxa. This apparently creates different molecular interactions and mechanisms of ACD in each developmental program, ultimately contributing to developmental diversity across species. In this review, we discuss how a conserved ACD machinery has been modified in each phylum over the course of evolution with a major focus on the molecular evolution of AGS-family proteins and its impact on ACD regulation.

不对称细胞分裂 (ACD) 是通过细胞分裂形成两种不同细胞类型的细胞过程，因此对所有多细胞生物的发育至关重要。除了许多 ACD 过程外，并非全部由有丝分裂纺锤体的正确方向介导，这将命运决定因素不对称地隔离到子细胞中。在许多细胞类型中，进化上保守的 Gαi/AGS 家族蛋白/NuMA 样蛋白复合物似乎在纺锤体定向和/或产生极化皮质力以调节 ACD 方面发挥着关键作用。对各种生物的研究表明，这种保守的蛋白质复合物在每个门甚至物种内都有轻微的改变。特别是，AGS 家族蛋白似乎在其跨分类群的功能域中用可变数量的基序进行了修饰。这显然在每个发育程序中创造了不同的 ACD 分子相互作用和机制，最终有助于跨物种的发育多样性。在这篇综述中，我们讨论了在进化过程中每个门中保守的 ACD 机制是如何被修改的，主要关注 AGS 家族蛋白的分子进化及其对 ACD 调控的影响。