Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France.
Université Côte d'Azur, CNRS, Institute Physics of Nice (INPHYNI), Ave. J. Vallot, Nice, France.
Cell Rep. 2019 Aug 20;28(8):2231-2245.e5. doi: 10.1016/j.celrep.2019.07.062.
During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell-a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth.
在对称破缺过程中，高度保守的 Rho GTPase Cdc42 通过放大过程稳定在一个特定的位置。然而，对于已经不对称的细胞中如何建立新的极性位点，人们知之甚少，这是在不断变化的环境中一个关键的过程。人类真菌病原体白念珠菌会根据外部信号从出芽生长切换到丝状生长，这一转变由 Cdc42 控制。在这里，我们使用细胞极性的光遗传学操纵来重置不对称丝状白念珠菌细胞的生长。我们发现，增加质膜上活性 Cdc42 的水平会导致外泌体亚基 Sec3 定位的破坏，并显著出现新的分泌泡簇集。这个新的分泌泡簇是高度动态的，通过跳跃移动，直到建立一个新的生长点。我们的结果表明，在没有定向生长的情况下，分泌泡的聚集也可能发生。
