Department of Biology, Drexel University, Philadelphia, PA 19104, USA.
Traffic. 2012 Feb;13(2):195-203. doi: 10.1111/j.1600-0854.2011.01268.x. Epub 2011 Sep 19.
Eukaryotic cells develop asymmetric shapes suited for specific physiological functions. Morphogenesis of polarized domains and structures requires the amplification of molecular asymmetries by scaffold proteins and regulatory feedback loops. Small monomeric GTPases signal polarity, but how their downstream effectors and targets are spatially co-ordinated to break cell symmetry is poorly understood. Septins comprise a novel family of GTPases that polymerize into non-polar filamentous structures which scaffold and restrict protein localization. Recent studies show that septins demarcate distinct plasma membrane domains and cytoskeletal tracks, enabling the formation of intracellular asymmetries. Here, we review these findings and discuss emerging mechanisms by which septins promote cell asymmetry in fungi and animals.
真核细胞形成不对称的形状以适应特定的生理功能。极性域和结构的形态发生需要支架蛋白和调节反馈环来放大分子不对称性。小分子单体 GTP 酶信号传递极性，但它们的下游效应物和靶标如何在空间上协调以打破细胞对称性，这方面的理解还很有限。GTP 结合蛋白 septin 构成了一个新的 GTP 酶家族，它们聚合成非极性丝状结构，作为支架并限制蛋白质的定位。最近的研究表明，septin 标记出不同的质膜域和细胞骨架轨道，从而形成细胞内的不对称性。在这里，我们回顾这些发现，并讨论 septin 如何在真菌和动物中促进细胞不对称性的新兴机制。
